Oncology/Hematology
Systemic Amyloidosis Robert A. Kyle and Morie A. Gertz I.
INTRODUCTION*
The autopsy of a young man with ascites, jaundice, and epistaxis revealed an abscess in the liver and a large spleen that was filled with white stones. This case, described in 1639 by Nicolaus Fontanus (Fonteyn) in Responsionum et Curationum Medicinalium Liber Unus, may have been the first description of the sago spleen of amyloidosis. In 1657, Thomas Bartholin, discoverer of the lymphatic system, described in his Historiarum Anatomicarum Rariorum Centuria the autopsy of a woman whose spleen resembled indurated flesh. These two autopsy reports were included among the nearly 3000 collected in Theophile Bonet’s Sepulchretum sive Anatomia Practica, published in 1679. In his monumental 1700-page work, Bonet attempted to summarize the significant medical literature of the previous 2 centuries. The two cases are believed to be the first described examples of amyloidosis,’ but it is impossible to be certain because the descriptions are brief and microscopic studies or special stains were not available at that time. The term “amyloid” was coined by Matthias Schleiden, a German botanist, in 1838 to describe a normal amylaceous constituent of plants. Rudolf Vimhow,* in 1854, used the term “amyloid” because the iodine-sulfuric acid test indicated that the substance producing “lardaceous” change was similar to cellulose. The term “lardaceous disease” had been used more than 60 years before by Antoine Portal, a French physician, but was popularized by Karl Rokitansky in 1842. “Waxy” was used interchangeably with “lardaceous” in describing the distinctive substance, which was recognized as albuminous rather than fatty by William Budd, an English physician, in the 1840s. He stated that the fat content of an enlarged liver was approximately 0.5%, whereas in a normal liver it would be 3to 4% .3 Nikolaus Friedreich, a German physician, and Fredrick KekulC, a German chemist who described the chemical structure of benzene, also believed that amyloid was proteinaceous, but they advised that the term “amyloid” be retained. Johann Meckel reported that the lardaceous changes were present not only in the liver and kidneys, but also in the aorta, arteries, and intestinal wall - the distribution of amyloid that is now recognized. Primary amyloidosis was probably first reported in 1856, when Wilks4 described a 51-year-old man with “lardaceous viscera” in whom the changes were unrelated to syphilis, osteomyelitis, other osseous disease, or tuberculosis. The first case of amyloidosis associated with multiple myeloma was reported by WeberS in 1867; autopsy revealed myeloma and amyloid in the kidneys and spleen. In 1872, Adams6 reported *
The article was originally
submitted
for publication
in November
a 61-year-old woman with “lardaceous” changes in the liver and spleen and multiple pathologic fractures. The bone marrow was infiltrated with plasma cells and a pinkish gelatinous material. Even so, the first report of primary amyloidosis is usually accredited to Wild. ’ The metachromatic stains for amyloidosis were introduced in 1875. * These aniline dyes - methyl violet and crystal violet - produced color changes in amyloid tissues. Congo red@, introduced by Bennholdg in 1922, is considered to be the most specific stain. Divry and Florkin” first described the green birefringence when tissue stained with Congo red@ was observed under polarized light. The fibrillar structure seen in primary and secondary amyloidoses, as well as that of amyloid induced in rabbits, was first reported in 1959 by Cohen and Calkins
’’
II. MICROSCOPIC APPEARANCE ULTRASTRUCTURE
AND
Amyloid is a substance that appears to be homogeneous and amorphous under the light microscope and stains pink with hematoxylin and eosin and metachromatically with methyl violet or crystal violet. Under polarized light, amyloid stained with Congo red@ produces an apple-green birefringence. Care must be taken to avoid underdecolorization, which may produce a false-positive result. ‘* The amorphous, hyaline-like appearance of amyloid is misleading because it is a fibrous protein. Electron microscopy reveals that amyloid consists of rigid, linear, nonbranching, aggregated fibrils that are 7.5 to 10 nm wide and of indefinite length. I3 Each amyloid fibril consists of two to five filaments and is arranged in an antiparaliel or cross B-pleated sheet configuration. Amyloid fibrils are insoluble and generally resist proteolytic digestion. They constitute the extracellular amyloid deposits that infiltrate and replace normal tissues.
Ill. CLASSIFICATION OF AMYLOIDOSIS A completely satisfactory classification of amyloidosis does
R. A. Kyle received a B S degree from the University of North Dakota in Grand Forks, a M.D. degree from Northwestern University in Chicago, Illinois, and a M.S. degree from the University of Minnesota in Minneapolis, Minnesota. Dr. Kyle is currently a Professor of Medicine and of Laboratoy Medicine in the Mayo Medical School in Rochester, Minnesota. M. A. Gertz received a B.A. degree from Northwestern University in Evanston, Illinois, and a M.D. degree from Loyola Medical School in Maywood, Illinois. Dr. Gertz is currently an Associate Professor of Medicine in the Mayo Medical School in Rochester, Minnesota.
1988.
1990
49
Critical Reviews in not exist. The classification in Table 1 is based on what is currently known about the biochemistry of the amyloid fibril. Consistent differences between primary amyloidosis (AL) and secondary amyloidosis (AA) have not been demonstrated by organ distribution or by electron microscopy.” AA amyloid usually involves the liver, spleen, and kidneys, while the heart and gastrointestinal tract are spared. AL amyloid mainly involves the kidney, heart, tongue, gastrointestinal tract, peripheral and autonomic nerves, and blood vessels, but virtually all organs are involved microscopically, except the central nervous system. Small amounts of AA amyloid have been found in kidneys with AL amyloid.16 The significance of this is unknown. Generally, AA amyloid and P,-microglobulin amyloid lose their affinity for Congo red@ and polarization characteristics after exposure to potassium permanganate, whereas AL amyloid, senile cardiac amyloidosis, familial amyloidosis, and nodular pulmonary amyloidosis are resistant to potassium permanganate.” However, this reaction is not specific, and the affinity of AL amyloid for Congo red@ may be reduced after treatment with potassium permanganate. ‘* The unlabeled immunoperoxidase method utilizing antisera to the amyloid fibrils is being used to identify the amyloid type and will become more routine in the future. l9
Table 1 Classification of Amyloidosis Amyloid
type
classllication Primary No evidence of preceding or coexisting disease except multiple myeloma Secondary Coexistence with other conditions such as rheumatoid arthritis or chronic infection Localized Involvement of a single organ without evidence of generalized involvement Familial Neurologic (type I) Portuguese
AL
Ig-V, (K or A)
AA
Protein A
AL
Ig-v,
The relationship of Bence Jones protein to amyloid was first postulated by Magnus-Levy20,2’ more than 50 years ago. Osserman and associates** proposed that Bence Jones proteins are directly involved in the production of amyloid and that these light chains have a greater affinity for certain tissues. Glenner et al ,23demonstrated that amyloid fibrils from a patient with primary amyloidosis are virtually identical to the variable portion of a monoclonal light chain (Bence Jones protein). Thus, the variable portion of a monoclonal light chain, or in some instances the intact light chain, constitutes the fibril subunit of primary amyloid. Subsequently, typical amyloid fibrils were produced in vitro by the digestion of monoclonal human Bence-Jones proteins by pepsin.23 The light-chain class is more frequently A than K (2:l) in AL amyloid. This ratio is the reverse of that seen in most cases of multiple myeloma and other monoclonal gammopathies. Solomon et aLz4 found that 11 (55%) of 20 cases of amyloidosis with A chains were of the A,, subgroup. Of 97 A-type Bence Jones proteins, only 11% were A,,. All recognized A,, proteins have been associated with amyloidosis. Solomon et al.% noted that the A,, proteins had a two-residue insertion at positions 68 and 69. Dwulet et aLz5 confirmed the finding of a tworesidue insertion at positions 68 and 69 in another A,, amyloid protein. This supports the hypothesis that some light chains possess distinct structural features that render them “amyloidogenic” , but it does not exclude the possibility that light50
Volume
(K
or A)
AF
Japanese
AF
Swedish
AF,
Transthyretin (prealbumin) Transthyretin (prealbumin) Transthyretin (prealbumin) Transthyretin (prealbumin) Transthyretin (prealbumin)
AA
Protein A
AF,
Jewish Indiana (type II)
IV. BIOCHEMISTRY AND PATHOGENESIS
Major protein component
Nephropathic Familial Mediterranean ostertag Muckle-Wells Cardiopathic Danish
fever
Transthyretin (prealbumin) Transthyretin (prealbumin)
Appalachian Cutaneous Senile Senile cardiac
amyloid
ASc,
Isolated atria1 amyloid
IAA
Endocrine Medullary carcinoma Islets of Langerhans
of thyroid
Dialysis arthropathy
Modifiedfrom
Kyle, R. A. and Greipp, 1983. With permission.
Transthyretin (prealbumin) ANP (atrial natriuretic peptide) Calcitonin Insulin-associated polypeptide (IAPP) RrMicroglobulin
P. R., Mayo Clin. Proc., 58, 665.
chain degradation is abnormal in the pathogenesis of AL amyloid. Smaller A fragments (molecular weight of 10,000 to 12,000) have been found in a patient’s serum and in amyloid deposits.26 This work has been supported by the report that 5 of 14 patients with AL synthesized immunologically identifiable light chains that were of lower molecular weight than that of intact light chains. This difference suggests that patients
Oncology/Hematology with amyloidosis may have aberrant de nova synthesis of light chains and/or abnormal proteolytic processing.27 Unfortunately, an animal model for AL has not been found. In AA, the major component of the amyloid fibril is protein A. It has a molecular weight of 8500, consists of 76 amino acids, and is not related to any known immunoglobulin.28 Using an antiserum to AA (amyloid A), an antigenically related larger molecule (molecular weight of 12,500) known as serum AArelated protein (SAA) has been found in the sera of normal patients as well as in patients with amyloidosis. SAA has 104 amino acid residues, and the amino acid sequence of protein A corresponds to the NH, = terminal residues of SAA. This is strong evidence that protein A is derived by the proteolytic cleavage of SAA. In human and rabbit sera, SAA binds strongly to high-density lipoproteins. 29SAA levels are increased markedly in AA amyloidosis and modestly in AL, but are within normal limits in heredofamilial amyloidosis.30 Some workers have found increased levels of SAA in elderly patients,30 but others have detected no age-related increase.31 SAA levels are greatly elevated in rheumatoid arthritis and Crohn’s disease, but only modestly increased in lupus erythematosus and chronic ulcerative colitis. The SAA level corresponds to the incidence of secondary arnyloidosis in these entities.32 Maury,33 in a series of 3000 parallel measurements of SAA and C-reactive protein (CRP) in various inflammatory processes, showed that the two were closely related, but that SAA was more sensitive than CRP in reflecting inflammatory activity. SAA is synthesized by the liveIJ4 and is found in the rough endoplasmic reticulum and Golgi apparatus of the hepatocytes. In addition, it is also localized on the free surface of the hepatocyte membrane, indicating that it is retained for several hours before being released into the plasma.35 Six polymorphic forms of SAA have been identified;36 some of these may be preferentially amyloidogenic. In the mouse, SAA is encoded by a family of three genes. SAA,, which seems to be the sole precursor of murine amyloid fibril protein AA, is selectively removed from the circulating pool of SAA, and SAA2.37This selectively indicates that protein A does not simply deposit because of the excessive production of SAA,. Yamamoto et a13* showed that the SAA, expression was greatly reduced in SJL mice, a strain resistant to amyloid. This resistance to casein-induced amyloidosis is probably due to the defective expression of the SAA, gene. In 1922, Kuczynski39 reported that injections of casein produced amyloidosis (AA) in animals. This model has been utilized to study the effect of accelerating factors or blocking agents as well as the effect of T and B lymphocytes on amyloid formation. Mori et al.@ reported that syngeneic extracts from liver or kidney produced large deposits of amyloid in the liver, kidney, and spleen in three species of mice. If mice injected with casein are given purified human SAA parenterally, the deposits contain both human and murine AA amyloid. This provides direct evidence that human AA amyloid is derived from the proteolysis of human SAA.
Amyloid P-component (AP) is a glycoprotein that migrates as an o,-globulin. It is composed of ten identical glycosylated polypeptide subunits, each with a molecular weight of 23,500 and arranged as two pentamers. Human serum amyloid Pcomponent (SAP) is produced in the liver, is present in normal persons, and shows 50 to 60% homology with CRP.4’ SAP is bound to the amyloid fibrils in a calcium-dependent fashion, but is not an integral part of the tibrillar structure. It is found in all types of amyloid, including vessel walls of Alzheimer’s disease.42 SAP levels are higher in Waldenstrom’s macroglobulinemia, multiple myeloma, and systemic lupus erythematosus than in healthy adult controls, but unlike that in the mouse, SAP is not an acute-phase protein in the human. Patients with seropositive rheumatoid arthritis and ankylosing spondylitis have modestly elevated SAP levels.43 However, in another report, the levels of SAP were no higher in patients with AL, AA, or AF arnyloidosis than in control patients.” SAP levels are reduced in cirrhosis and chronic active hepatitis.45 Levo et al.& found that SAP levels were decreased in 80% of patients with hepatic dysfunction caused by measles and suggested that the SAP level might be a useful and sensitive indicator of liver disease. SAP selectively enhances interleukin- 1 (IL- 1) production by mononuclear phagocytes.47 Shirahama et a1.48demonstrated that antisera to AP often showed a stronger reaction to the basement membrane than to adjacent amyloid deposits and suggested that the binding between AP and the amyloid fibril may not be a specific marker for amyloid deposits. AP inhibits the activity of porcine pancreatic elastase and thereby may protect amyloid fibrils from proteolysis and resorption.49 Neither the physiologic function of AP nor its pathologic role in amyloidosis is known. The catabolism or breakdown of amyloid fibrils is an important factor in pathogenesis. Lavie and associatesso reported that monocytes in patients with amyloidosis fail to degrade AA amyloid, whereas the monocytes from normal patients do, suggesting that monocyte dysfunction may contribute to the development of amyloidosis. Elastase-type proteases in the monocyte have been implicated in the degradation of SAA.51.52 Degradation of SAA to protein AA with incubation and cultures of peripheral blood mononuclear leukocytes has been confirmed.53 Degradation of protein A or AA amyloid fibrils by polymorphonuclear lysosomal enzymes (elastase),54 plasmin, and kallikrein has also been reported.53 Skinner et al .55 demonstrated elastolytic enzyme activity from human neutrophil elastase on amyloid fibrils of AL, AA, and familial amyloid (AF) origin. This activity may represent a physiologic mechanism for amyloid degradation. Inhibition of amyloid-degrading activity may cause accumulation of amyloid fibrils.56 The amyloid-degrading activity correlates closely with the albumin level, although albumin has no demonstrable effect on AA fibrils.57 However, the amyloid-degrading activity is probably of doubtful pathophysiologic significance.‘* The mechanism for the deposition of monoclonal light chains as amyloid is not clear. More than 40 years ago, Herbut 1990
51
Critical Reviews In and Ef19 showed that plasma cells contained amyloid. Nomura et a160 described a patient with myeloma in whom the plasma cells contained K light chains, crystals, lysosomes, and amyloid fibrils and suggested that amyloid was formed intracellularly . In another report, bone marrow cells that were cultured from a patient with multiple myeloma and AL revealed Congo red@ positive material in macrophages, but not in plasma cells. The authors postulated that Bence Jones proteins were synthesized by plasma cells and then processed in the lysosomes of macrophages to produce amyloid fibrils.6’ Amyloidosis results from the interplay of many factors, including the degradation or slow removal of amyloid fibrils and the excessive deposition of amyloid. Much more work is needed to elucidate these mechanisms. The pathogenesis of systemic amyloidosis has been reviewed.62 Localized amyloidosis and amyloid associated with medullary carcinoma of the thyroid gland are not included in this review of systemic amyloidosis .
V. PRIMARY AMYLOIDOSIS (AL) From 1961 to 1970, 11,586 autopsies were performed at the Royal Victoria Hospital in Belfast - AL was found in 43 cases (0.4%) and secondary amyloidosis (AA) was found in 39 (0.4%).63 From 1937 to 1946, among 3414 autopsies done at the same institution, there were 6 cases of AL amyloidosis and 10 of AA (total, 0.5%). van Rijswijk and co-workers64 have estimated the incidence of amyloidosis at 1 per 60,000 population (0.002%). An environmental factor or a genetic predisposition may have a role in some cases of AL. In 1986, Hertz et a1.65reported three separate families who had two first-degree relatives with AL. No significant increase in frequency of any HLA antigens was observed in 5.5 cases of AL.66 Immunoglobulin allotypes are not involved in the development of either AL or AA.67 During the IO-year period from 1977 to 1986, 724 patients with amyloidosis were seen at the Mayo Clinic. Almost three fourths had AL (Table 2). Table 2 Distribution of 724 Patients According to Type of Amyloidosis (Mayo Clinic, 1977 to 1988) Type
No.
%
primary (AL) Secondary (AA) Localized Familial
538 30 143 13
74 4 20 2
Total
724
100
AL amyloidosis can be divided into two categories (AL and AL with multiple myeloma) on the basis of the appearance and number of plasma cells in the bone marrow, the amount 52
Volume
of M-protein in the serum and urine, and the presence or absence of skeletal lesions. However, differentiation on the basis of these features is often difficult because there is some overlapping of these findings between patients with and those without myeloma. Furthermore, the amyloid fibrils consist of the NH,-terminal amino acid residues of the variable or constant (or both) portions of a monoclonal immunoglobulin light chain in both AL and AL with myeloma. In both instances, the Mprotein is a product of the plasma cell, and, consequently, each condition represents a plasma cell proliferative process. In addition, the presence or absence of multiple myeloma does not influence survival during the first year after the diagnosis of amyloidosis. Consequently, it is preferable to consider both categories together as AL. A. Clinical Findings The clinical and laboratory findings were obtained from a review of 298 patients with histologically proven AL seen at the Mayo Clinic from 1982 to 1986. From 1972 to 1976, 75% of patients had the diagnosis of amyloidosis made at the Mayo Clinic. In contrast, 1 decade later (1982 to 1986), only 41% of the patients had the diagnosis made at the Mayo Clinic. This decrease reflects not only that the awareness of the disease by physicians has increased, but also that many patients were sent for a second opinion or for consideration for participation in a prospective randomized therapy program. 1. Age and Sex AL is a disease associated with older patients (Figure 1). The median age at diagnosis is similar to that of multiple myeloma. Although 97% of patients are 40 years old or older, AL has been seen in children.68.69 2. HistoJy Weakness or fatigue and loss of weight are the most frequent symptoms and are seen in more than half the patients. Loss of weight may be striking and amounted to more than 45 kg in three of our patients. The median loss of weight was 11 kg. Pain - if multiple myeloma is not present - is uncommon and is due to peripheral neuropathy or generalized abdominal pain without obvious cause. Dyspnea and pedal edema are frequently noted by patients with congestive heart failure. Paresthesias, lightheadedness, and syncope are seen in patients with peripheral or autonomic neuropathy. Hoarseness or change of voice to a weak, high-pitched or a deep, husky tone should alert the physician to the possibility of amyloidosis. 3. Physical Findings The principal initial physical findings include hepatomegaly, ankle edema, purpura, and macroglossia. The liver is palpable in about one fifth of patients, but extension more than 5 cm below the right costal margin has been noted in only 9%. Splenomegaly was an initial finding in only 6%, and in only one patient did the spleen extend more than 5 cm below the
Oncology/Hematology 40
30
-
0 Male, 66% (n = 219) Female, 34% (n = 114) Median, 61 yr ‘ Range, 32-90 28
36
8 ti E Q) ‘-F
20
2 10
0
< 40
40-49
FIGURE 1. Age and sex distributions 1982 to 1986.
50-59
of patients with primary
left costal margin. Thus, hepatosplenomegaly is usually of modest degree in AL. Macroglossia can be impressive (Figure 2)) but it is observed in only one tenth of patients. Occasionally, excessive vascularity of an enlarged tongue causes troublesome bleeding. It is sometimes difficult to decide whether the tongue is enlarged or not. Increased firmness noted by increased resistance to a tongue blade, enlargement of the submandibular structures (often confused with adenopathy), and presence of dental indentations are helpful in the recognition of macroglossia. Computed tomography of the base of the tongue may be useful in determining the presence of macroglossia when results of the physical examination are equivocal.” Purpura is common and often involves the neck and face, particularly the upper eyelids. Orbital purpura may be striking after proctoscopy (postproctoscopic palpebral purpura) (Figure 3), but it can also be seen after vomiting or coughing. Purpura of the skin may be elicited by pinching or gentle scratching. Gross bleeding may be seen. The skin is fragile and occasionally will be easily traumatized during physical examination. Ankle edema is common and is usually the result of congestive heart failure or the nephrotic syndrome. Orthostatic hypotension may be extremely troublesome, with some patients unable to stand without experiencing syncope, particularly in the morning. Generalized lymphadenopathy is infrequent, but it may be the initial manifestation of systemic amyloidosis. Specific signs of congestive heart failure, nephrotic syndrome, malabsorption, peripheral neuropathy, and the carpal tunnel syndrome must be sought during the history taking and physical examination. 4. Syndromes Almost one third of patients have the nephrotic syndrome
60-69 amyloidosis
70-79
~80
(AL) who were seen at the Mayo Clinic from
at the time of diagnosis of amyloidosis. Other conditions also may be present, such as the carpal tunnel syndrome, congestive heart failure, peripheral neuropathy, and orthostatic hypotension (Figure 4). Symptoms of congestive heart failure, orthostatic hypotension, and nephrotic syndrome typically begin approximately 3 months before the amyloidosis is diagnosed, but symptoms of peripheral neuropathy or carpal tunnel syndrome usually are present for at least 1 year before the diagnosis is made. This difference probably represents the patient’s delay in seeking medical attention. Congestive heart failure and or-
FIGURE 2. Macroglossia and dental indentations in a patient with primary amyloidosis (AL). (From Kyle, R. A. and Bayrd, E. D., Medicine (Ealrimore), 54, 271, 1975. With permission of the Williams & Wilkins Company.)
1990
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Critical Reviews In thostatic hypotension develop often during the course of the disease. The presence of one of these syndromes and an Mprotein in the serum or urine is a strong indication of amyloidosis, for which appropriate diagnostic (biopsy) studies must be made. In recent years, more patients are being seen who have fatigue due to amyloid cardiomyopathy and who do not have overt congestive heart failure. In these patients, the only clue that leads to a diagnostic echocardiographic study is a Mprotein. Occasionally, a patient will have >l g of urinary protein per 24 h, a level that is not in the nephrotic range. The detection of a M-protein should warrant further evaluation in patients who have urinary protein >l g/24 h. B. Laboratory Findings 1. Hematologic Anemia is not a prominent feature in AL. When present, anemia is usually due to renal insufficiency, multiple myeloma, or gastrointestinal bleeding. Leukocyte and differential counts are usually normal. Thrombocytosis (thrombocyte count >500,000/mm3) occurs in 5 to 10% of patients and may be an important clue to the diagnosis. Thrombocytopenia is not a feature of AL. The erythrocyte sedimentation rate is usually 70% of patients.2so*251 Overstaining and underdecolorization are potential problems with this technique. Collagen takes up Congo red@, but generally is white instead of apple-green under polarized light. Experience in the staining technique must be obtained before using it routinely. If the abdominal fat is negative, a bone marrow aspirate and biopsy specimen may be helpful. These are easy to obtain and also provide an estimate of the degree of plasmacytosis. Unfortunately, the bone marrow reveals amyloid in less than half of patients (Figure 7). If the bone marrow 97
Bone marrow n=162
Rectum Kidney n=106
n=30
Carpal tunnel n=ll
Liver n=lO
Sural nerve n=12
Fat n=62
FIGURE 7. Biopsy sensitivity and sites of involvement in patients with primary amyloidosis (AL) who were seen at the Mayo Clinic from 1982 to 1986.
62
and abdominal fat are negative, a rectal biopsy specimen should be taken. This procedure is reasonably free of complications and produces positive findings in 80% of cases. We have seen a rare patient with postbiopsy rectal bleeding, but it has almost always responded to fulguration. To be adequate, the biopsy specimen must contain submucosa, because submucosa is involved more frequently than mucosa. If these sites are normal, tissue should be obtained from a suspected involved organ. Renal biopsy results in a high incidence of positive findings, but the procedure is more difficult than the obtaining of abdominal fat, bone marrow, or rectal tissue. The incidence of hematuria is not higher than that after renal biopsy in nonamyloid patients. Subepithelial spicular structures in the glomerular capillary loops are a helpful diagnostic finding. 252Electron microscopy may be necessary for recognition of small amounts of amyloid. Liver biopsy frequently discloses amyloid. Only two of our patients who underwent needle biopsy of the liver had bleeding - one required two units of packed erythrocytes, whereas transfusion was unnecessary in the other. However, rupture of the liver has been reported in rare instances. Tissue obtained at carpal tunnel decompression should always be examined for amyloid because it is positive in a high percentage of patients with AL. In peripheral neuropathy, the sural nerve is an excellent source for biopsy material. This nerve should be biopsied only if the peripheral neuropathy is severe, because biopsy results in loss of local sensation. Endomyocardial biopsy may be very useful. We found amyloid in the endomyocardial biopsy specimens of 30 patients with AL. Findings on 2-dimensional echocardiography were consistent with the diagnosis of amyloidosis in two thirds of the patients and were abnormal but nonspecific in the remainder. The procedure was uncomplicated, except for transient hypotension in one patient.253 Biopsy of the small intestine is frequently positive. Biopsy of the skin may be positive even when there are no discernible skin lesions. 2s4Biopsy or examination of the prostate at autopsy often reveals amyloid; the use of prostatic tissue for diagnosis may be helpful. 2ss Biopsy of gingiva or alveolar mucosa may be useful, but the marginal gingiva should be avoided because it is often inflamed and may give spurious results.2s6 An autopsy study demonstrated more deposition of amyloid in the stomach than in the rectum. The authors suggested that gastric biopsy is superior to rectal biopsy for the diagnosis of AL.2s7 Increased uptake of technetium-99 pyrophosphate (99mT~PYP) has been reported as useful in the diagnosis of amyloid heart disease.258We have shown that 99”Tc-PYP scans detected amyloid in only 3 of 20 patients with biopsy-proven cardiac amyloidosis. Of the 17 patients, 14 had 1 + or 2+ uptake, a finding that was also present in 15 of the 20 control patients without cardiac disease.259Gallium imaging is positive in more than 90% of patients with biopsy-proven renal amyloid.“’ However, specificity of gallium scanning has not been proven. Examination of the urinary sediment has been reported as help-
Volume 10, Issue 1
Oncology/Hematology ful in the diagnosis of amyloidosis, but this is an unreliable technique. The Paunz test (Congo red@) is no longer used because it is imprecise and anaphylactic reactions may occur.
Probability
E. Prognosis The mean survival after diagnosis in an earlier Mayo Clinic series of 81 patients who had AL, with or without myeloma, seen between 1935 and 1959, was 4.9 months.260 In a Mayo Clinic series of 193 patients seen between 1960 and 1972, the median survival after histologic diagnosis of amyloid was 14.7 months for patients with AL and 4 months for those with AL and myeloma.” The median survival of 229 patients with AL seen at the Mayo Clinic from 1970 to 1980 was 12 months less than one fourth were alive at 3 years.14 Median survival was 5 months for those with myeloma and 13 months for those without myeloma. The median survival of the 401 patients seen during the past 6 years (1982 to 1987) was 2 years. In a series of patients with AL, Pick et alz6’ reported that none survived more than 12 months after diagnosis. In a series of 48 patients with AL, the l-year survival was 23%.262 All were dead at 3 years. The major cause of death was cardiac disease (13 patients), renal disease (10 patients), and gastrointestinal involvement (7 patients). In another series, the median survival of 32 patients with AL was 14 months after histologic diagnosis. 263 Prognosis varies greatly among the various syndromes. Median survival from onset of congestive heart failure until death was 0.6 years (Table 4; Figure 8). The groups were arranged in a hierarchical fashion - that is, patients were placed only in the first group in which they occurred. Thus, none of the 93 patients listed as presenting with a nephrotic syndrome had either congestive heart failure or orthostatic hypotension, but some may have had carpal tunnel syndrome or peripheral neuropathy. Death of patients presenting with only the carpal tunnel syndrome or peripheral neuropathy (or both) was usually due to eventual involvement of other organs.
0
Congestive heart failure Orthostatic hypotension Nephrotic syndrome Carpal tunnel syndrome Peripheral neuropathy
65 30 93 42 22
1
2 q
3
4
time in years
5
253.>1)
FIGURE8. Survival from onset of syndrome in patients with primary amyloidosis (AL). (From Kyle, R. A. and Greipp, P. R., Mayo C/in. hoc.. 58, 665, 1983. With permission.)
Table 5 Causes of Death of 122 Patients with Primary Amyloidosis (AL) CatLSe Cardiac Renal Infection “Amyloidosis” Unknown Other Miscellaneous Total
No.
%
54 16 10 26 7 7 2
44 13 8 21 6 6 2
122
100
of malignancy. Multivariate analysis was applied to data from 168 patients with AL seen at the Mayo Clinic between 1970 and 1980 in whom all laboratory and clinical studies were performed within 1 month of diagnosis. The proportional-hazards method of Cox identified four variables - congestive heart faihue, urinary light chain, hepatomegaly, and the amount of weight loss - that had a highly significant influence on survival during the first year. The proportional-hazards model was also used to identify variables whose value at diagnosis influenced the rate of subsequent mortality among the 84 patients who survived 1 year after diagnosis. Serum cmatinine level, diagnosis of multiple myeloma, and presence of orthostatic hypotension and monoclonal serum protein had a highly significant adverse influence on survival after one year.26)
Median survival No.
t
t
Table 4 Prognosis in Primary Amyloidosis (AL) According to Associated Syndrome condition
of survival to
Orears) 0.6 1.5 2.0 2.3 >5
F. Therapy 1. Measurwnent of Response to Treatment Therapeutic responses in amyloidosis are difficult to evaluate. Although uptake of Congo red@(Paunz test), Evans blue, or 99”Tc-PYP has been used, there is no accurate method for measuring the amount of amyloid in the body. Furthermore,
Death was attributed to cardiac involvement in 44% of the 122 patients (Table 5). The actual number is probably higher because some patients whose death was ascribed to “amyloidosis” probably had terminal cardiac arrhythmia. Renal failure was the cause of death in 13%. Only one of the patients died 1990
Critical Reviews In in animals, the redistribution of amyloid deposits from the spleen and liver to the kidneys increases the problem of evaluation.265 In addition, resolution of the nephrotic syndrome does not necessarily reflect a reduction of amyloid deposits in the kidney.266 Presently, evaluation of response to therapy is limited to measurement of physical findings, evaluation of organ function, and improvement in laboratory test abnormalities. The most important measurement of response is prolongation of survival. A prospective randomized trial is essential because earlier diagnosis and improvement in supportive care make the use of historical controls unreliable. Evidence of improvement of the nephrotic syndrome is an increase of the serum albumin level and a 50% decrease in the 24-h urine protein excretion in the absence of progressive renal insufficiency. Serum creatinine levels reflect renal function. Improvement in gastrointestinal function may be manifested by normalization of prothrombin time and serum carotene levels. Hepatic function can be monitored by measuring the levels of alkaline phosphatase, aspartate aminotransferase, and bilirubin and the prothrombin time. Levels of serum and urine Mprotein, bone marrow plasma cells, and hemoglobin are helpful monitors of plasma cell proliferation. Serial echocardiograms are useful in measuring myocardial infiltration and function. Despite all these measurements, a reliable method for determining the amount of amyloid in a patient is not available and is a critical problem. 2. Specific Therapeutic Measures Treatment for AL is not satisfactory. The amyloid fibrils consist of the variable portion of monoclonal immunoglobulin light chains and are synthesized by plasma cells. Increased numbers of plasma cells are commonly found in the bone marrow of patients with AL. It is therefore reasonable to attempt treatment with alkylating agents, which are known to be effective against plasma cell proliferative processes such as multiple myeloma. In a placebo-controlled double-blind study of 55 patients with AL, patients randomized to melphalanprednisone therapy continued treatment longer and received larger doses than did patients in the placebo group before the code was broken because of progressive disease. Among the 24 patients treated with melphalan-prednisone who had the nephrotic syndrome, proteinuria almost disappeared in 2 and was reduced by more than 50% in 8 others. Renal insufficiency did not become worse in these 10 patients. Among 13 patients who received melphalan-prednisone for more than 12 months, the disease decreased in 6, was stable in 3, and worsened in 4.267 We have reported a patient with biopsy-proven hepatic AL in whom histologic regression was demonstrated after therapy with melphalan and prednisone.268 We reviewed data on six other patients reported in the literature with regression of hepatic involvement documented by biopsy. However, the development of a myelodysplastic syndrome or acute nonlym-
Volume
phocytic leukemia (presumably from the alkylating agent) has been recognized and occurs in at least 5% of patients with AL who received melphalan. Chromosome studies of the bone marrow are useful in assessing the development of a myelodysplastic syndrome. Colchicine is being used in the treatment of patients with AL. It inhibits casein induction of amyloidosis in mice and has been effective in the control of abdominal pain and the prevention of amyloidosis in patients with familial Mediterranean fever. Colchicine may inhibit amyloidosis by blocking the formation of amyloid-enhancing factor.269 Colchicine ako inhibits the secretion of serum amyloid A protein from hepatocytes . 270Cohen et al.*” reported a median survival of 6 months for 29 patients seen between 1961 and 1973 who were not treated with colchicine, and a median survival of 17 months for 53 patients seen between 1976 and 1983 who were treated with colchicine. They noted that females survived longer than males. Scheinberg et al. *‘* found no change in renal function in five patients given colchicine for 6 months. In the murine model, a colchicine analog, 3-demethylthiocolchicine, was as effective as colchicine in blocking amyloid deposition, but threefold higher doses were well tolerated. This analog may replace co1chicine.273 In a prospective randomized study of melphalan (0.15 mg/ kg/d for 7 d) plus prednisone (0.8 mg/kg/d for the same 7 d) every 6 weeks vs. daily colchicine therapy, 101 patients were stratified according to their dominant clinical manifestation. If the disease progressed, the other regimen was added. There was no difference in survival when the two groups were compared in total (melphalan and prednisone, 25.2 months vs. colchicine, 18 months; p = 0.23). When the survival of patients who received only one regimen was analyzed or when survival was analyzed from the time of entry into the study to the time of death or progression of disease, significant differences (p
Systemic Amyloidosis Robert A. Kyle and Morie A. Gertz I.
INTRODUCTION*
The autopsy of a young man with ascites, jaundice, and epistaxis revealed an abscess in the liver and a large spleen that was filled with white stones. This case, described in 1639 by Nicolaus Fontanus (Fonteyn) in Responsionum et Curationum Medicinalium Liber Unus, may have been the first description of the sago spleen of amyloidosis. In 1657, Thomas Bartholin, discoverer of the lymphatic system, described in his Historiarum Anatomicarum Rariorum Centuria the autopsy of a woman whose spleen resembled indurated flesh. These two autopsy reports were included among the nearly 3000 collected in Theophile Bonet’s Sepulchretum sive Anatomia Practica, published in 1679. In his monumental 1700-page work, Bonet attempted to summarize the significant medical literature of the previous 2 centuries. The two cases are believed to be the first described examples of amyloidosis,’ but it is impossible to be certain because the descriptions are brief and microscopic studies or special stains were not available at that time. The term “amyloid” was coined by Matthias Schleiden, a German botanist, in 1838 to describe a normal amylaceous constituent of plants. Rudolf Vimhow,* in 1854, used the term “amyloid” because the iodine-sulfuric acid test indicated that the substance producing “lardaceous” change was similar to cellulose. The term “lardaceous disease” had been used more than 60 years before by Antoine Portal, a French physician, but was popularized by Karl Rokitansky in 1842. “Waxy” was used interchangeably with “lardaceous” in describing the distinctive substance, which was recognized as albuminous rather than fatty by William Budd, an English physician, in the 1840s. He stated that the fat content of an enlarged liver was approximately 0.5%, whereas in a normal liver it would be 3to 4% .3 Nikolaus Friedreich, a German physician, and Fredrick KekulC, a German chemist who described the chemical structure of benzene, also believed that amyloid was proteinaceous, but they advised that the term “amyloid” be retained. Johann Meckel reported that the lardaceous changes were present not only in the liver and kidneys, but also in the aorta, arteries, and intestinal wall - the distribution of amyloid that is now recognized. Primary amyloidosis was probably first reported in 1856, when Wilks4 described a 51-year-old man with “lardaceous viscera” in whom the changes were unrelated to syphilis, osteomyelitis, other osseous disease, or tuberculosis. The first case of amyloidosis associated with multiple myeloma was reported by WeberS in 1867; autopsy revealed myeloma and amyloid in the kidneys and spleen. In 1872, Adams6 reported *
The article was originally
submitted
for publication
in November
a 61-year-old woman with “lardaceous” changes in the liver and spleen and multiple pathologic fractures. The bone marrow was infiltrated with plasma cells and a pinkish gelatinous material. Even so, the first report of primary amyloidosis is usually accredited to Wild. ’ The metachromatic stains for amyloidosis were introduced in 1875. * These aniline dyes - methyl violet and crystal violet - produced color changes in amyloid tissues. Congo red@, introduced by Bennholdg in 1922, is considered to be the most specific stain. Divry and Florkin” first described the green birefringence when tissue stained with Congo red@ was observed under polarized light. The fibrillar structure seen in primary and secondary amyloidoses, as well as that of amyloid induced in rabbits, was first reported in 1959 by Cohen and Calkins
’’
II. MICROSCOPIC APPEARANCE ULTRASTRUCTURE
AND
Amyloid is a substance that appears to be homogeneous and amorphous under the light microscope and stains pink with hematoxylin and eosin and metachromatically with methyl violet or crystal violet. Under polarized light, amyloid stained with Congo red@ produces an apple-green birefringence. Care must be taken to avoid underdecolorization, which may produce a false-positive result. ‘* The amorphous, hyaline-like appearance of amyloid is misleading because it is a fibrous protein. Electron microscopy reveals that amyloid consists of rigid, linear, nonbranching, aggregated fibrils that are 7.5 to 10 nm wide and of indefinite length. I3 Each amyloid fibril consists of two to five filaments and is arranged in an antiparaliel or cross B-pleated sheet configuration. Amyloid fibrils are insoluble and generally resist proteolytic digestion. They constitute the extracellular amyloid deposits that infiltrate and replace normal tissues.
Ill. CLASSIFICATION OF AMYLOIDOSIS A completely satisfactory classification of amyloidosis does
R. A. Kyle received a B S degree from the University of North Dakota in Grand Forks, a M.D. degree from Northwestern University in Chicago, Illinois, and a M.S. degree from the University of Minnesota in Minneapolis, Minnesota. Dr. Kyle is currently a Professor of Medicine and of Laboratoy Medicine in the Mayo Medical School in Rochester, Minnesota. M. A. Gertz received a B.A. degree from Northwestern University in Evanston, Illinois, and a M.D. degree from Loyola Medical School in Maywood, Illinois. Dr. Gertz is currently an Associate Professor of Medicine in the Mayo Medical School in Rochester, Minnesota.
1988.
1990
49
Critical Reviews in not exist. The classification in Table 1 is based on what is currently known about the biochemistry of the amyloid fibril. Consistent differences between primary amyloidosis (AL) and secondary amyloidosis (AA) have not been demonstrated by organ distribution or by electron microscopy.” AA amyloid usually involves the liver, spleen, and kidneys, while the heart and gastrointestinal tract are spared. AL amyloid mainly involves the kidney, heart, tongue, gastrointestinal tract, peripheral and autonomic nerves, and blood vessels, but virtually all organs are involved microscopically, except the central nervous system. Small amounts of AA amyloid have been found in kidneys with AL amyloid.16 The significance of this is unknown. Generally, AA amyloid and P,-microglobulin amyloid lose their affinity for Congo red@ and polarization characteristics after exposure to potassium permanganate, whereas AL amyloid, senile cardiac amyloidosis, familial amyloidosis, and nodular pulmonary amyloidosis are resistant to potassium permanganate.” However, this reaction is not specific, and the affinity of AL amyloid for Congo red@ may be reduced after treatment with potassium permanganate. ‘* The unlabeled immunoperoxidase method utilizing antisera to the amyloid fibrils is being used to identify the amyloid type and will become more routine in the future. l9
Table 1 Classification of Amyloidosis Amyloid
type
classllication Primary No evidence of preceding or coexisting disease except multiple myeloma Secondary Coexistence with other conditions such as rheumatoid arthritis or chronic infection Localized Involvement of a single organ without evidence of generalized involvement Familial Neurologic (type I) Portuguese
AL
Ig-V, (K or A)
AA
Protein A
AL
Ig-v,
The relationship of Bence Jones protein to amyloid was first postulated by Magnus-Levy20,2’ more than 50 years ago. Osserman and associates** proposed that Bence Jones proteins are directly involved in the production of amyloid and that these light chains have a greater affinity for certain tissues. Glenner et al ,23demonstrated that amyloid fibrils from a patient with primary amyloidosis are virtually identical to the variable portion of a monoclonal light chain (Bence Jones protein). Thus, the variable portion of a monoclonal light chain, or in some instances the intact light chain, constitutes the fibril subunit of primary amyloid. Subsequently, typical amyloid fibrils were produced in vitro by the digestion of monoclonal human Bence-Jones proteins by pepsin.23 The light-chain class is more frequently A than K (2:l) in AL amyloid. This ratio is the reverse of that seen in most cases of multiple myeloma and other monoclonal gammopathies. Solomon et aLz4 found that 11 (55%) of 20 cases of amyloidosis with A chains were of the A,, subgroup. Of 97 A-type Bence Jones proteins, only 11% were A,,. All recognized A,, proteins have been associated with amyloidosis. Solomon et al.% noted that the A,, proteins had a two-residue insertion at positions 68 and 69. Dwulet et aLz5 confirmed the finding of a tworesidue insertion at positions 68 and 69 in another A,, amyloid protein. This supports the hypothesis that some light chains possess distinct structural features that render them “amyloidogenic” , but it does not exclude the possibility that light50
Volume
(K
or A)
AF
Japanese
AF
Swedish
AF,
Transthyretin (prealbumin) Transthyretin (prealbumin) Transthyretin (prealbumin) Transthyretin (prealbumin) Transthyretin (prealbumin)
AA
Protein A
AF,
Jewish Indiana (type II)
IV. BIOCHEMISTRY AND PATHOGENESIS
Major protein component
Nephropathic Familial Mediterranean ostertag Muckle-Wells Cardiopathic Danish
fever
Transthyretin (prealbumin) Transthyretin (prealbumin)
Appalachian Cutaneous Senile Senile cardiac
amyloid
ASc,
Isolated atria1 amyloid
IAA
Endocrine Medullary carcinoma Islets of Langerhans
of thyroid
Dialysis arthropathy
Modifiedfrom
Kyle, R. A. and Greipp, 1983. With permission.
Transthyretin (prealbumin) ANP (atrial natriuretic peptide) Calcitonin Insulin-associated polypeptide (IAPP) RrMicroglobulin
P. R., Mayo Clin. Proc., 58, 665.
chain degradation is abnormal in the pathogenesis of AL amyloid. Smaller A fragments (molecular weight of 10,000 to 12,000) have been found in a patient’s serum and in amyloid deposits.26 This work has been supported by the report that 5 of 14 patients with AL synthesized immunologically identifiable light chains that were of lower molecular weight than that of intact light chains. This difference suggests that patients
Oncology/Hematology with amyloidosis may have aberrant de nova synthesis of light chains and/or abnormal proteolytic processing.27 Unfortunately, an animal model for AL has not been found. In AA, the major component of the amyloid fibril is protein A. It has a molecular weight of 8500, consists of 76 amino acids, and is not related to any known immunoglobulin.28 Using an antiserum to AA (amyloid A), an antigenically related larger molecule (molecular weight of 12,500) known as serum AArelated protein (SAA) has been found in the sera of normal patients as well as in patients with amyloidosis. SAA has 104 amino acid residues, and the amino acid sequence of protein A corresponds to the NH, = terminal residues of SAA. This is strong evidence that protein A is derived by the proteolytic cleavage of SAA. In human and rabbit sera, SAA binds strongly to high-density lipoproteins. 29SAA levels are increased markedly in AA amyloidosis and modestly in AL, but are within normal limits in heredofamilial amyloidosis.30 Some workers have found increased levels of SAA in elderly patients,30 but others have detected no age-related increase.31 SAA levels are greatly elevated in rheumatoid arthritis and Crohn’s disease, but only modestly increased in lupus erythematosus and chronic ulcerative colitis. The SAA level corresponds to the incidence of secondary arnyloidosis in these entities.32 Maury,33 in a series of 3000 parallel measurements of SAA and C-reactive protein (CRP) in various inflammatory processes, showed that the two were closely related, but that SAA was more sensitive than CRP in reflecting inflammatory activity. SAA is synthesized by the liveIJ4 and is found in the rough endoplasmic reticulum and Golgi apparatus of the hepatocytes. In addition, it is also localized on the free surface of the hepatocyte membrane, indicating that it is retained for several hours before being released into the plasma.35 Six polymorphic forms of SAA have been identified;36 some of these may be preferentially amyloidogenic. In the mouse, SAA is encoded by a family of three genes. SAA,, which seems to be the sole precursor of murine amyloid fibril protein AA, is selectively removed from the circulating pool of SAA, and SAA2.37This selectively indicates that protein A does not simply deposit because of the excessive production of SAA,. Yamamoto et a13* showed that the SAA, expression was greatly reduced in SJL mice, a strain resistant to amyloid. This resistance to casein-induced amyloidosis is probably due to the defective expression of the SAA, gene. In 1922, Kuczynski39 reported that injections of casein produced amyloidosis (AA) in animals. This model has been utilized to study the effect of accelerating factors or blocking agents as well as the effect of T and B lymphocytes on amyloid formation. Mori et al.@ reported that syngeneic extracts from liver or kidney produced large deposits of amyloid in the liver, kidney, and spleen in three species of mice. If mice injected with casein are given purified human SAA parenterally, the deposits contain both human and murine AA amyloid. This provides direct evidence that human AA amyloid is derived from the proteolysis of human SAA.
Amyloid P-component (AP) is a glycoprotein that migrates as an o,-globulin. It is composed of ten identical glycosylated polypeptide subunits, each with a molecular weight of 23,500 and arranged as two pentamers. Human serum amyloid Pcomponent (SAP) is produced in the liver, is present in normal persons, and shows 50 to 60% homology with CRP.4’ SAP is bound to the amyloid fibrils in a calcium-dependent fashion, but is not an integral part of the tibrillar structure. It is found in all types of amyloid, including vessel walls of Alzheimer’s disease.42 SAP levels are higher in Waldenstrom’s macroglobulinemia, multiple myeloma, and systemic lupus erythematosus than in healthy adult controls, but unlike that in the mouse, SAP is not an acute-phase protein in the human. Patients with seropositive rheumatoid arthritis and ankylosing spondylitis have modestly elevated SAP levels.43 However, in another report, the levels of SAP were no higher in patients with AL, AA, or AF arnyloidosis than in control patients.” SAP levels are reduced in cirrhosis and chronic active hepatitis.45 Levo et al.& found that SAP levels were decreased in 80% of patients with hepatic dysfunction caused by measles and suggested that the SAP level might be a useful and sensitive indicator of liver disease. SAP selectively enhances interleukin- 1 (IL- 1) production by mononuclear phagocytes.47 Shirahama et a1.48demonstrated that antisera to AP often showed a stronger reaction to the basement membrane than to adjacent amyloid deposits and suggested that the binding between AP and the amyloid fibril may not be a specific marker for amyloid deposits. AP inhibits the activity of porcine pancreatic elastase and thereby may protect amyloid fibrils from proteolysis and resorption.49 Neither the physiologic function of AP nor its pathologic role in amyloidosis is known. The catabolism or breakdown of amyloid fibrils is an important factor in pathogenesis. Lavie and associatesso reported that monocytes in patients with amyloidosis fail to degrade AA amyloid, whereas the monocytes from normal patients do, suggesting that monocyte dysfunction may contribute to the development of amyloidosis. Elastase-type proteases in the monocyte have been implicated in the degradation of SAA.51.52 Degradation of SAA to protein AA with incubation and cultures of peripheral blood mononuclear leukocytes has been confirmed.53 Degradation of protein A or AA amyloid fibrils by polymorphonuclear lysosomal enzymes (elastase),54 plasmin, and kallikrein has also been reported.53 Skinner et al .55 demonstrated elastolytic enzyme activity from human neutrophil elastase on amyloid fibrils of AL, AA, and familial amyloid (AF) origin. This activity may represent a physiologic mechanism for amyloid degradation. Inhibition of amyloid-degrading activity may cause accumulation of amyloid fibrils.56 The amyloid-degrading activity correlates closely with the albumin level, although albumin has no demonstrable effect on AA fibrils.57 However, the amyloid-degrading activity is probably of doubtful pathophysiologic significance.‘* The mechanism for the deposition of monoclonal light chains as amyloid is not clear. More than 40 years ago, Herbut 1990
51
Critical Reviews In and Ef19 showed that plasma cells contained amyloid. Nomura et a160 described a patient with myeloma in whom the plasma cells contained K light chains, crystals, lysosomes, and amyloid fibrils and suggested that amyloid was formed intracellularly . In another report, bone marrow cells that were cultured from a patient with multiple myeloma and AL revealed Congo red@ positive material in macrophages, but not in plasma cells. The authors postulated that Bence Jones proteins were synthesized by plasma cells and then processed in the lysosomes of macrophages to produce amyloid fibrils.6’ Amyloidosis results from the interplay of many factors, including the degradation or slow removal of amyloid fibrils and the excessive deposition of amyloid. Much more work is needed to elucidate these mechanisms. The pathogenesis of systemic amyloidosis has been reviewed.62 Localized amyloidosis and amyloid associated with medullary carcinoma of the thyroid gland are not included in this review of systemic amyloidosis .
V. PRIMARY AMYLOIDOSIS (AL) From 1961 to 1970, 11,586 autopsies were performed at the Royal Victoria Hospital in Belfast - AL was found in 43 cases (0.4%) and secondary amyloidosis (AA) was found in 39 (0.4%).63 From 1937 to 1946, among 3414 autopsies done at the same institution, there were 6 cases of AL amyloidosis and 10 of AA (total, 0.5%). van Rijswijk and co-workers64 have estimated the incidence of amyloidosis at 1 per 60,000 population (0.002%). An environmental factor or a genetic predisposition may have a role in some cases of AL. In 1986, Hertz et a1.65reported three separate families who had two first-degree relatives with AL. No significant increase in frequency of any HLA antigens was observed in 5.5 cases of AL.66 Immunoglobulin allotypes are not involved in the development of either AL or AA.67 During the IO-year period from 1977 to 1986, 724 patients with amyloidosis were seen at the Mayo Clinic. Almost three fourths had AL (Table 2). Table 2 Distribution of 724 Patients According to Type of Amyloidosis (Mayo Clinic, 1977 to 1988) Type
No.
%
primary (AL) Secondary (AA) Localized Familial
538 30 143 13
74 4 20 2
Total
724
100
AL amyloidosis can be divided into two categories (AL and AL with multiple myeloma) on the basis of the appearance and number of plasma cells in the bone marrow, the amount 52
Volume
of M-protein in the serum and urine, and the presence or absence of skeletal lesions. However, differentiation on the basis of these features is often difficult because there is some overlapping of these findings between patients with and those without myeloma. Furthermore, the amyloid fibrils consist of the NH,-terminal amino acid residues of the variable or constant (or both) portions of a monoclonal immunoglobulin light chain in both AL and AL with myeloma. In both instances, the Mprotein is a product of the plasma cell, and, consequently, each condition represents a plasma cell proliferative process. In addition, the presence or absence of multiple myeloma does not influence survival during the first year after the diagnosis of amyloidosis. Consequently, it is preferable to consider both categories together as AL. A. Clinical Findings The clinical and laboratory findings were obtained from a review of 298 patients with histologically proven AL seen at the Mayo Clinic from 1982 to 1986. From 1972 to 1976, 75% of patients had the diagnosis of amyloidosis made at the Mayo Clinic. In contrast, 1 decade later (1982 to 1986), only 41% of the patients had the diagnosis made at the Mayo Clinic. This decrease reflects not only that the awareness of the disease by physicians has increased, but also that many patients were sent for a second opinion or for consideration for participation in a prospective randomized therapy program. 1. Age and Sex AL is a disease associated with older patients (Figure 1). The median age at diagnosis is similar to that of multiple myeloma. Although 97% of patients are 40 years old or older, AL has been seen in children.68.69 2. HistoJy Weakness or fatigue and loss of weight are the most frequent symptoms and are seen in more than half the patients. Loss of weight may be striking and amounted to more than 45 kg in three of our patients. The median loss of weight was 11 kg. Pain - if multiple myeloma is not present - is uncommon and is due to peripheral neuropathy or generalized abdominal pain without obvious cause. Dyspnea and pedal edema are frequently noted by patients with congestive heart failure. Paresthesias, lightheadedness, and syncope are seen in patients with peripheral or autonomic neuropathy. Hoarseness or change of voice to a weak, high-pitched or a deep, husky tone should alert the physician to the possibility of amyloidosis. 3. Physical Findings The principal initial physical findings include hepatomegaly, ankle edema, purpura, and macroglossia. The liver is palpable in about one fifth of patients, but extension more than 5 cm below the right costal margin has been noted in only 9%. Splenomegaly was an initial finding in only 6%, and in only one patient did the spleen extend more than 5 cm below the
Oncology/Hematology 40
30
-
0 Male, 66% (n = 219) Female, 34% (n = 114) Median, 61 yr ‘ Range, 32-90 28
36
8 ti E Q) ‘-F
20
2 10
0
< 40
40-49
FIGURE 1. Age and sex distributions 1982 to 1986.
50-59
of patients with primary
left costal margin. Thus, hepatosplenomegaly is usually of modest degree in AL. Macroglossia can be impressive (Figure 2)) but it is observed in only one tenth of patients. Occasionally, excessive vascularity of an enlarged tongue causes troublesome bleeding. It is sometimes difficult to decide whether the tongue is enlarged or not. Increased firmness noted by increased resistance to a tongue blade, enlargement of the submandibular structures (often confused with adenopathy), and presence of dental indentations are helpful in the recognition of macroglossia. Computed tomography of the base of the tongue may be useful in determining the presence of macroglossia when results of the physical examination are equivocal.” Purpura is common and often involves the neck and face, particularly the upper eyelids. Orbital purpura may be striking after proctoscopy (postproctoscopic palpebral purpura) (Figure 3), but it can also be seen after vomiting or coughing. Purpura of the skin may be elicited by pinching or gentle scratching. Gross bleeding may be seen. The skin is fragile and occasionally will be easily traumatized during physical examination. Ankle edema is common and is usually the result of congestive heart failure or the nephrotic syndrome. Orthostatic hypotension may be extremely troublesome, with some patients unable to stand without experiencing syncope, particularly in the morning. Generalized lymphadenopathy is infrequent, but it may be the initial manifestation of systemic amyloidosis. Specific signs of congestive heart failure, nephrotic syndrome, malabsorption, peripheral neuropathy, and the carpal tunnel syndrome must be sought during the history taking and physical examination. 4. Syndromes Almost one third of patients have the nephrotic syndrome
60-69 amyloidosis
70-79
~80
(AL) who were seen at the Mayo Clinic from
at the time of diagnosis of amyloidosis. Other conditions also may be present, such as the carpal tunnel syndrome, congestive heart failure, peripheral neuropathy, and orthostatic hypotension (Figure 4). Symptoms of congestive heart failure, orthostatic hypotension, and nephrotic syndrome typically begin approximately 3 months before the amyloidosis is diagnosed, but symptoms of peripheral neuropathy or carpal tunnel syndrome usually are present for at least 1 year before the diagnosis is made. This difference probably represents the patient’s delay in seeking medical attention. Congestive heart failure and or-
FIGURE 2. Macroglossia and dental indentations in a patient with primary amyloidosis (AL). (From Kyle, R. A. and Bayrd, E. D., Medicine (Ealrimore), 54, 271, 1975. With permission of the Williams & Wilkins Company.)
1990
53
Critical Reviews In thostatic hypotension develop often during the course of the disease. The presence of one of these syndromes and an Mprotein in the serum or urine is a strong indication of amyloidosis, for which appropriate diagnostic (biopsy) studies must be made. In recent years, more patients are being seen who have fatigue due to amyloid cardiomyopathy and who do not have overt congestive heart failure. In these patients, the only clue that leads to a diagnostic echocardiographic study is a Mprotein. Occasionally, a patient will have >l g of urinary protein per 24 h, a level that is not in the nephrotic range. The detection of a M-protein should warrant further evaluation in patients who have urinary protein >l g/24 h. B. Laboratory Findings 1. Hematologic Anemia is not a prominent feature in AL. When present, anemia is usually due to renal insufficiency, multiple myeloma, or gastrointestinal bleeding. Leukocyte and differential counts are usually normal. Thrombocytosis (thrombocyte count >500,000/mm3) occurs in 5 to 10% of patients and may be an important clue to the diagnosis. Thrombocytopenia is not a feature of AL. The erythrocyte sedimentation rate is usually 70% of patients.2so*251 Overstaining and underdecolorization are potential problems with this technique. Collagen takes up Congo red@, but generally is white instead of apple-green under polarized light. Experience in the staining technique must be obtained before using it routinely. If the abdominal fat is negative, a bone marrow aspirate and biopsy specimen may be helpful. These are easy to obtain and also provide an estimate of the degree of plasmacytosis. Unfortunately, the bone marrow reveals amyloid in less than half of patients (Figure 7). If the bone marrow 97
Bone marrow n=162
Rectum Kidney n=106
n=30
Carpal tunnel n=ll
Liver n=lO
Sural nerve n=12
Fat n=62
FIGURE 7. Biopsy sensitivity and sites of involvement in patients with primary amyloidosis (AL) who were seen at the Mayo Clinic from 1982 to 1986.
62
and abdominal fat are negative, a rectal biopsy specimen should be taken. This procedure is reasonably free of complications and produces positive findings in 80% of cases. We have seen a rare patient with postbiopsy rectal bleeding, but it has almost always responded to fulguration. To be adequate, the biopsy specimen must contain submucosa, because submucosa is involved more frequently than mucosa. If these sites are normal, tissue should be obtained from a suspected involved organ. Renal biopsy results in a high incidence of positive findings, but the procedure is more difficult than the obtaining of abdominal fat, bone marrow, or rectal tissue. The incidence of hematuria is not higher than that after renal biopsy in nonamyloid patients. Subepithelial spicular structures in the glomerular capillary loops are a helpful diagnostic finding. 252Electron microscopy may be necessary for recognition of small amounts of amyloid. Liver biopsy frequently discloses amyloid. Only two of our patients who underwent needle biopsy of the liver had bleeding - one required two units of packed erythrocytes, whereas transfusion was unnecessary in the other. However, rupture of the liver has been reported in rare instances. Tissue obtained at carpal tunnel decompression should always be examined for amyloid because it is positive in a high percentage of patients with AL. In peripheral neuropathy, the sural nerve is an excellent source for biopsy material. This nerve should be biopsied only if the peripheral neuropathy is severe, because biopsy results in loss of local sensation. Endomyocardial biopsy may be very useful. We found amyloid in the endomyocardial biopsy specimens of 30 patients with AL. Findings on 2-dimensional echocardiography were consistent with the diagnosis of amyloidosis in two thirds of the patients and were abnormal but nonspecific in the remainder. The procedure was uncomplicated, except for transient hypotension in one patient.253 Biopsy of the small intestine is frequently positive. Biopsy of the skin may be positive even when there are no discernible skin lesions. 2s4Biopsy or examination of the prostate at autopsy often reveals amyloid; the use of prostatic tissue for diagnosis may be helpful. 2ss Biopsy of gingiva or alveolar mucosa may be useful, but the marginal gingiva should be avoided because it is often inflamed and may give spurious results.2s6 An autopsy study demonstrated more deposition of amyloid in the stomach than in the rectum. The authors suggested that gastric biopsy is superior to rectal biopsy for the diagnosis of AL.2s7 Increased uptake of technetium-99 pyrophosphate (99mT~PYP) has been reported as useful in the diagnosis of amyloid heart disease.258We have shown that 99”Tc-PYP scans detected amyloid in only 3 of 20 patients with biopsy-proven cardiac amyloidosis. Of the 17 patients, 14 had 1 + or 2+ uptake, a finding that was also present in 15 of the 20 control patients without cardiac disease.259Gallium imaging is positive in more than 90% of patients with biopsy-proven renal amyloid.“’ However, specificity of gallium scanning has not been proven. Examination of the urinary sediment has been reported as help-
Volume 10, Issue 1
Oncology/Hematology ful in the diagnosis of amyloidosis, but this is an unreliable technique. The Paunz test (Congo red@) is no longer used because it is imprecise and anaphylactic reactions may occur.
Probability
E. Prognosis The mean survival after diagnosis in an earlier Mayo Clinic series of 81 patients who had AL, with or without myeloma, seen between 1935 and 1959, was 4.9 months.260 In a Mayo Clinic series of 193 patients seen between 1960 and 1972, the median survival after histologic diagnosis of amyloid was 14.7 months for patients with AL and 4 months for those with AL and myeloma.” The median survival of 229 patients with AL seen at the Mayo Clinic from 1970 to 1980 was 12 months less than one fourth were alive at 3 years.14 Median survival was 5 months for those with myeloma and 13 months for those without myeloma. The median survival of the 401 patients seen during the past 6 years (1982 to 1987) was 2 years. In a series of patients with AL, Pick et alz6’ reported that none survived more than 12 months after diagnosis. In a series of 48 patients with AL, the l-year survival was 23%.262 All were dead at 3 years. The major cause of death was cardiac disease (13 patients), renal disease (10 patients), and gastrointestinal involvement (7 patients). In another series, the median survival of 32 patients with AL was 14 months after histologic diagnosis. 263 Prognosis varies greatly among the various syndromes. Median survival from onset of congestive heart failure until death was 0.6 years (Table 4; Figure 8). The groups were arranged in a hierarchical fashion - that is, patients were placed only in the first group in which they occurred. Thus, none of the 93 patients listed as presenting with a nephrotic syndrome had either congestive heart failure or orthostatic hypotension, but some may have had carpal tunnel syndrome or peripheral neuropathy. Death of patients presenting with only the carpal tunnel syndrome or peripheral neuropathy (or both) was usually due to eventual involvement of other organs.
0
Congestive heart failure Orthostatic hypotension Nephrotic syndrome Carpal tunnel syndrome Peripheral neuropathy
65 30 93 42 22
1
2 q
3
4
time in years
5
253.>1)
FIGURE8. Survival from onset of syndrome in patients with primary amyloidosis (AL). (From Kyle, R. A. and Greipp, P. R., Mayo C/in. hoc.. 58, 665, 1983. With permission.)
Table 5 Causes of Death of 122 Patients with Primary Amyloidosis (AL) CatLSe Cardiac Renal Infection “Amyloidosis” Unknown Other Miscellaneous Total
No.
%
54 16 10 26 7 7 2
44 13 8 21 6 6 2
122
100
of malignancy. Multivariate analysis was applied to data from 168 patients with AL seen at the Mayo Clinic between 1970 and 1980 in whom all laboratory and clinical studies were performed within 1 month of diagnosis. The proportional-hazards method of Cox identified four variables - congestive heart faihue, urinary light chain, hepatomegaly, and the amount of weight loss - that had a highly significant influence on survival during the first year. The proportional-hazards model was also used to identify variables whose value at diagnosis influenced the rate of subsequent mortality among the 84 patients who survived 1 year after diagnosis. Serum cmatinine level, diagnosis of multiple myeloma, and presence of orthostatic hypotension and monoclonal serum protein had a highly significant adverse influence on survival after one year.26)
Median survival No.
t
t
Table 4 Prognosis in Primary Amyloidosis (AL) According to Associated Syndrome condition
of survival to
Orears) 0.6 1.5 2.0 2.3 >5
F. Therapy 1. Measurwnent of Response to Treatment Therapeutic responses in amyloidosis are difficult to evaluate. Although uptake of Congo red@(Paunz test), Evans blue, or 99”Tc-PYP has been used, there is no accurate method for measuring the amount of amyloid in the body. Furthermore,
Death was attributed to cardiac involvement in 44% of the 122 patients (Table 5). The actual number is probably higher because some patients whose death was ascribed to “amyloidosis” probably had terminal cardiac arrhythmia. Renal failure was the cause of death in 13%. Only one of the patients died 1990
Critical Reviews In in animals, the redistribution of amyloid deposits from the spleen and liver to the kidneys increases the problem of evaluation.265 In addition, resolution of the nephrotic syndrome does not necessarily reflect a reduction of amyloid deposits in the kidney.266 Presently, evaluation of response to therapy is limited to measurement of physical findings, evaluation of organ function, and improvement in laboratory test abnormalities. The most important measurement of response is prolongation of survival. A prospective randomized trial is essential because earlier diagnosis and improvement in supportive care make the use of historical controls unreliable. Evidence of improvement of the nephrotic syndrome is an increase of the serum albumin level and a 50% decrease in the 24-h urine protein excretion in the absence of progressive renal insufficiency. Serum creatinine levels reflect renal function. Improvement in gastrointestinal function may be manifested by normalization of prothrombin time and serum carotene levels. Hepatic function can be monitored by measuring the levels of alkaline phosphatase, aspartate aminotransferase, and bilirubin and the prothrombin time. Levels of serum and urine Mprotein, bone marrow plasma cells, and hemoglobin are helpful monitors of plasma cell proliferation. Serial echocardiograms are useful in measuring myocardial infiltration and function. Despite all these measurements, a reliable method for determining the amount of amyloid in a patient is not available and is a critical problem. 2. Specific Therapeutic Measures Treatment for AL is not satisfactory. The amyloid fibrils consist of the variable portion of monoclonal immunoglobulin light chains and are synthesized by plasma cells. Increased numbers of plasma cells are commonly found in the bone marrow of patients with AL. It is therefore reasonable to attempt treatment with alkylating agents, which are known to be effective against plasma cell proliferative processes such as multiple myeloma. In a placebo-controlled double-blind study of 55 patients with AL, patients randomized to melphalanprednisone therapy continued treatment longer and received larger doses than did patients in the placebo group before the code was broken because of progressive disease. Among the 24 patients treated with melphalan-prednisone who had the nephrotic syndrome, proteinuria almost disappeared in 2 and was reduced by more than 50% in 8 others. Renal insufficiency did not become worse in these 10 patients. Among 13 patients who received melphalan-prednisone for more than 12 months, the disease decreased in 6, was stable in 3, and worsened in 4.267 We have reported a patient with biopsy-proven hepatic AL in whom histologic regression was demonstrated after therapy with melphalan and prednisone.268 We reviewed data on six other patients reported in the literature with regression of hepatic involvement documented by biopsy. However, the development of a myelodysplastic syndrome or acute nonlym-
Volume
phocytic leukemia (presumably from the alkylating agent) has been recognized and occurs in at least 5% of patients with AL who received melphalan. Chromosome studies of the bone marrow are useful in assessing the development of a myelodysplastic syndrome. Colchicine is being used in the treatment of patients with AL. It inhibits casein induction of amyloidosis in mice and has been effective in the control of abdominal pain and the prevention of amyloidosis in patients with familial Mediterranean fever. Colchicine may inhibit amyloidosis by blocking the formation of amyloid-enhancing factor.269 Colchicine ako inhibits the secretion of serum amyloid A protein from hepatocytes . 270Cohen et al.*” reported a median survival of 6 months for 29 patients seen between 1961 and 1973 who were not treated with colchicine, and a median survival of 17 months for 53 patients seen between 1976 and 1983 who were treated with colchicine. They noted that females survived longer than males. Scheinberg et al. *‘* found no change in renal function in five patients given colchicine for 6 months. In the murine model, a colchicine analog, 3-demethylthiocolchicine, was as effective as colchicine in blocking amyloid deposition, but threefold higher doses were well tolerated. This analog may replace co1chicine.273 In a prospective randomized study of melphalan (0.15 mg/ kg/d for 7 d) plus prednisone (0.8 mg/kg/d for the same 7 d) every 6 weeks vs. daily colchicine therapy, 101 patients were stratified according to their dominant clinical manifestation. If the disease progressed, the other regimen was added. There was no difference in survival when the two groups were compared in total (melphalan and prednisone, 25.2 months vs. colchicine, 18 months; p = 0.23). When the survival of patients who received only one regimen was analyzed or when survival was analyzed from the time of entry into the study to the time of death or progression of disease, significant differences (p
