1431
EDITORIALS
Hepatitis C virus upstanding Hepatitis C
virus (HCV) is believed to be the main bloodborne non-A, non-B (NANB) hepatitis virus.1 In 1982 work began at the Chiron Corporation in California to identify this agent.2 Pooled chimpanzee plasma known to contain a high concentration of infectious material was ultracentrifuged so that even the smallest infectious particle would be contained in the pellet. Total nucleic acid was extracted from the pellet and denatured, and complementary DNA (cDNA) was prepared by use of random primers of
transcriptase. The resulting cDNA library screened with serum known to be positive for NANB hepatitis antibody, and one clone (5-1-1) was selected. This clone was subsequently shown to be derived from a single-stranded RNA molecule of 10 000 nucleosides that was specific for HCV.33 Comparative sequence analyses suggest that HCV may be a distant relative of the flaviviridae.1 The 5-1-1 clone was subsequently shown to encode for an epitope (or epitopes) which bound to antibodies in a high proportion of serum samples from patients with NANB hepatitis. This clone was ligated, together with overlapping clones 32, 36, and 81, to produce clone C100, which is located in the nonstructural region of the HCV polyprotein. The C100 clone was then fused with the human gene encoding superoxide dismutase and expressed in recombinant yeast. The resultant fusion polypeptide, C100-3, was used to coat wells of microtitre trays, and forms the basis of the Ortho Diagnostic Systems enzyme-linked immunosorbent assay (ELISA), the first available assay for HCV antibody. In commercially this test, patients’ serum is bound to the antigencoated microtitre well and is detected with horseradish peroxidase conjugated to a mouse monoclonal antibody to human gamma chain immunoglobulin. About 80% of patients worldwide with bloodborne NANB hepatitis tested in this way have antibodies to HCV.‘’-6 However, the frequency of HCV antibodies in blood donors is very low—1-2—14% in the USA and Japan, 0-9% in Italy, 0.7% in France, and 0.4% in Gennany.1 Initial studies in UK blood donors have shown a frequency of 0.3-0.7%.7 The highest HCV antibody prevalence is found in patients (eg, haemophiliacs) who have received untreated blood or blood products from many donors--64% of such patients in Spain8 and 85% in reverse was
the UK9 have these antibodies. Haemophiliacs treated only with dry-heated factor VIII do not acquire HCV infection by this route. 10 Many intravenous drug users worldwide also have antibodies: in separate studies, 48% of Germany 70% of Spanish and81% ofUK11 intravenous drug users were HCV antibody positive. Since HCV antibody is not detected until an average of 15 weeks (range 4-32 weeks) after the onset of hepatitis ’12 the results of this assay must be interpreted cautiously and with reference to the patient’s clinical and social history. In particular, HCV infection cannot be exluded in those whose serum is antibody-negative up to 6 months after the onset of symptoms. Preliminary data suggest that in some patients seroconversion may be barely detectable or inapparent until at least a year after the onset of symptoms.4 Thus, HCV antibody assays will identify some but not all blood donors who have been infected with the virus. Removal of HCV antibody-positive donors from plasma pools for the preparation of albumin, coagulation factors, and immunoglobulins is a controversial issue. French workers13 feel that HCV antibody-positive donors should be excluded from these pools, but the US Food and Drug Administration has decidedl4 that source plasma should not be screened for HCV antibody until it is known whether testing will adversely affect the safety of blood-derived products-ie, as the FDA researchers point out, "Screening for anti-HCV may produce little or no decrease in the amount of virus but it could substantially lower the amount of antibody". There have also been concerns about the specificity of the HCV antibody assay /5,16 especially in patients with liver disease. Gray et ahsimproved the specificity by modifying the Ortho ELI SA to include a wash step incorporating urea, which dissociates low-avidity non-specific antibody from the antigen. Ikeda et al 17 suggested that these non-specific reactions might be related to the superoxide dismutase component in the Ortho ELISA antigen. Skidmore,18 in a limited evaluation of the recombinant immunoblot assay (RIBA) developed by Chiron and Ortho, has suggested that RIBA may be more specific than the Ortho ELISA and suitable as a confirmatory test for blood donor screening. Although it would be prudent to regard all HCV antibody-positive blood as infectious, this may not always be the case, because HCV antibody assays
1432
cannot distinguish reliably between infectious and non-infectious blood. Sensitive assays for detection of HCV RNA have been described.1920 HCV RNA was detected in serum samples from experimentally infected chimpanzees in the absence of HCV antibody. This type of assay, when further refined, may prove invaluable for the identification of infectious patients. In this issue (p 1419), Dr Garson and his colleagues describe a sensitive "nested" polymerase chain reaction assay that detects HCV RNA sequences in serum samples. They show a good correlation between the detection of HCV RNA sequences and proven infectivity of the samples and report that some patients remain positive for HCV RNA for at least 9 years. This kind of assay may well be more suitable for screening of blood donations than are HCV antibody tests. The most important decisions to be faced now are when to begin testing blood donors for evidence of HCV infection and what tests should be used. Many countries are already committed to testing and excluding positive donors.
1. Choo Q-L, Weiner AJ, Overby LR, Kuo G, Houghton M. Hepatitis C virus: the major causative agent of viral non-A, non-B hepatitis. Br Med Bull 1990; 46: 423-41. 2. Editorial. Will the real hepatitis C stand up? Lancet 1989; ii: 307-08. 3. Choo Q-L, Kuo G, Weiner AJ, et al. Isolation of a cDNA clone derived from a blood-borne non-A, non-B viral hepatitis genome. Science 1989; 244: 359-62. 4. Kuo G, Choo Q-L, Alter HJ, et al. An assay for circulating antibodies to a major etiologic virus of human non-A, non-B hepatitis. Science 1989; 244: 362-64. 5. Roggendorf M, Deinhardt F, Rasshofer R, et al. Antibodies to hepatitis C virus. Lancet 1989; ii: 324-25. 6. Van der Poel C, Reesink HW, Lelie PN, et al. Anti-hepatitis C antibodies and non-A, non-B post-transfusion hepatitis in the Netherlands. Lancet 1989; ii: 297-98. 7. Contreras M, Barbara JAJ. Screening for hepatitis C virus antibody. Lancet 1989; ii: 505. 8. Esteban JI, Esteban R, Viladomiu L, et al. Hepatitis C virus antibodies among risk groups in Spain. Lancet 1989; ii: 294-97. 9. Ludlam CA, Chapman D, Cohen B, Litton PA. Antibodies to hepatitis C virus in haemophilia. Lancet 1989; ii: 560-61. 10. Skidmore SJ, Pasi KJ, Mawson SJ, Williams MD, Hill FGH. Serological evidence that dry heating of clotting factor concentrates prevents transmission of non-A, non-B hepatitis. J Med Virol 1990; 30: 50-52. 11. Mortimer PP, Cohen BJ, Litton PA, et al. Hepatitis C virus antibody. Lancet 1989; ii: 798. 12. Alter HJ, Purcell RH, Shih JW, et al. Detection of antibody to hepatitis C virus in prospectively followed transfusion recipients with acute and chronic non-A, non-B hepatitis. N Engl J Med 1989; 321: 1494-500. 13. Habibi B, Garretta M. Screening for hepatitis C virus antibody in plasma for fractionation. Lancet 1990; 335: 855-56. 14. Finlayson JS, Tankersley DL. Anti-HCV screening and plasma fractionation: the case against. Lancet 1990; 335: 1274-75. 15. Gray JJ, Wreghitt TG, Fnend PJ, Wight DGD, Sundaresan V, Calne RY. Differentiation between specific and non-specific hepatitis C antibodies in chronic liver disease. Lancet 1990; 335: 609-10. 16. McFarlane IG, Smith HM, Johnson PJ, Bray GP, Vergan D, Williams R. False positivity for antibodies to hepatitis C virus in chronic active hepatitis. Lancet 1990; 335: 754-57. 17. Ikeda Y, Toda G, Hashimoto N, Kurokawa K. Antibody to superoxide dismutase, autoimmune hepatitis, and antibody tests for hepatitis C virus. Lancet 1990; 335: 1345-46. 18. Skidmore S. Recombinant immunoblot assay for hepatitis C antibody. Lancet 1990; 335: 1346. 19. Weiner AJ, Kuo G, Bradley DW, et al. Detection of hepatitis C viral sequences in non-A, non-B hepatitis. Lancet 1990; 335: 1-3. 20. Kaneko S, Unoura M, Kobayashi K, Kuno K, Murakami S, Hattori N. Detection of serum hepatitis C virus RNA. Lancet 1990; 335: 976.
Diagnosis of schizophrenia diagnosis of schizophrenia was introduced by Kraepelin1 and by Bleuler.Both workers described a The
form of the illness in which there was an insidious deterioration in personality and coping abilities. Such self-absorbed, idle, and aimless patients were eventually recognised by clinicians as having simple schizophrenia (schizophrenia simplex), a disease that was easily misunderstood by family and friends. These features are now described as the negative symptoms of schizophrenia (after Hughlings Jackson’s model of brain function). There is a reduction in the amount and information content of spontaneous speech; drive, initiative, interest, and attention are poor; mood is shallow; and the expression of emotions and the capacity to experience emotions are restricted. Bleuler believed that such symptoms were "primary", and they have been associated with neurological findings,3atrophic or
dysplastic changes on computed tomography,4 cognitive impairments,s and a poor outcome.6,7 Destitution and imprisonment can easily result ;8 Kraepelin noted "probably already a long time previously changes of the personality in the sense of dementia praecox had taken place, which then made the patient a habitual criminal and vagrant". Despite impeccable historical probity, the American diagnostic system contained in the third, revised edition of the American Diagnostic and Statistical Manual (DSM IIIR)9 excludes simple schizophrenia as a subgroup of schizophrenia and places such patients in the category of schizotypal personality disorder or borderline personality disorder. The boundaries of personality disorder have thereby been extended at the expense of the original concept of schizophrenia. Many find personality disorder a pejorative term, which encompasses psychopathy, a difficult and unreliable diagnosis10 that merges with administrative considerations without secure scientific justification.ll Moreover, Bleuler described the development of simple schizophrenia in maturity, whereas "personality disorders are development conditions" which "always appear during childhood or adolescence" (ICD-10, 1989, in draft of chapter V, World Health Organisation, Division of Mental Health, Geneva). The American diagnostic criteria for schizophrenia had earlier been much looser than the British criteria. Consequently the prevalence of schizophrenia in the USA at one time was apparently double that in the UK 12 and dubious aetiological models of malign family relationships held sway.13 A reliable diagnostic process to determine the "true" prevalence was needed, an endeavour that was encouraged by the successful treatment of manic depressive illness with lithium salts and the need to differentiate the two disorders. The "first rank" symptoms of Schneiderl’ formed an unambiguous basis for this purpose. is (Schneider’s list encompassed audible thoughts;
EDITORIALS
Hepatitis C virus upstanding Hepatitis C
virus (HCV) is believed to be the main bloodborne non-A, non-B (NANB) hepatitis virus.1 In 1982 work began at the Chiron Corporation in California to identify this agent.2 Pooled chimpanzee plasma known to contain a high concentration of infectious material was ultracentrifuged so that even the smallest infectious particle would be contained in the pellet. Total nucleic acid was extracted from the pellet and denatured, and complementary DNA (cDNA) was prepared by use of random primers of
transcriptase. The resulting cDNA library screened with serum known to be positive for NANB hepatitis antibody, and one clone (5-1-1) was selected. This clone was subsequently shown to be derived from a single-stranded RNA molecule of 10 000 nucleosides that was specific for HCV.33 Comparative sequence analyses suggest that HCV may be a distant relative of the flaviviridae.1 The 5-1-1 clone was subsequently shown to encode for an epitope (or epitopes) which bound to antibodies in a high proportion of serum samples from patients with NANB hepatitis. This clone was ligated, together with overlapping clones 32, 36, and 81, to produce clone C100, which is located in the nonstructural region of the HCV polyprotein. The C100 clone was then fused with the human gene encoding superoxide dismutase and expressed in recombinant yeast. The resultant fusion polypeptide, C100-3, was used to coat wells of microtitre trays, and forms the basis of the Ortho Diagnostic Systems enzyme-linked immunosorbent assay (ELISA), the first available assay for HCV antibody. In commercially this test, patients’ serum is bound to the antigencoated microtitre well and is detected with horseradish peroxidase conjugated to a mouse monoclonal antibody to human gamma chain immunoglobulin. About 80% of patients worldwide with bloodborne NANB hepatitis tested in this way have antibodies to HCV.‘’-6 However, the frequency of HCV antibodies in blood donors is very low—1-2—14% in the USA and Japan, 0-9% in Italy, 0.7% in France, and 0.4% in Gennany.1 Initial studies in UK blood donors have shown a frequency of 0.3-0.7%.7 The highest HCV antibody prevalence is found in patients (eg, haemophiliacs) who have received untreated blood or blood products from many donors--64% of such patients in Spain8 and 85% in reverse was
the UK9 have these antibodies. Haemophiliacs treated only with dry-heated factor VIII do not acquire HCV infection by this route. 10 Many intravenous drug users worldwide also have antibodies: in separate studies, 48% of Germany 70% of Spanish and81% ofUK11 intravenous drug users were HCV antibody positive. Since HCV antibody is not detected until an average of 15 weeks (range 4-32 weeks) after the onset of hepatitis ’12 the results of this assay must be interpreted cautiously and with reference to the patient’s clinical and social history. In particular, HCV infection cannot be exluded in those whose serum is antibody-negative up to 6 months after the onset of symptoms. Preliminary data suggest that in some patients seroconversion may be barely detectable or inapparent until at least a year after the onset of symptoms.4 Thus, HCV antibody assays will identify some but not all blood donors who have been infected with the virus. Removal of HCV antibody-positive donors from plasma pools for the preparation of albumin, coagulation factors, and immunoglobulins is a controversial issue. French workers13 feel that HCV antibody-positive donors should be excluded from these pools, but the US Food and Drug Administration has decidedl4 that source plasma should not be screened for HCV antibody until it is known whether testing will adversely affect the safety of blood-derived products-ie, as the FDA researchers point out, "Screening for anti-HCV may produce little or no decrease in the amount of virus but it could substantially lower the amount of antibody". There have also been concerns about the specificity of the HCV antibody assay /5,16 especially in patients with liver disease. Gray et ahsimproved the specificity by modifying the Ortho ELI SA to include a wash step incorporating urea, which dissociates low-avidity non-specific antibody from the antigen. Ikeda et al 17 suggested that these non-specific reactions might be related to the superoxide dismutase component in the Ortho ELISA antigen. Skidmore,18 in a limited evaluation of the recombinant immunoblot assay (RIBA) developed by Chiron and Ortho, has suggested that RIBA may be more specific than the Ortho ELISA and suitable as a confirmatory test for blood donor screening. Although it would be prudent to regard all HCV antibody-positive blood as infectious, this may not always be the case, because HCV antibody assays
1432
cannot distinguish reliably between infectious and non-infectious blood. Sensitive assays for detection of HCV RNA have been described.1920 HCV RNA was detected in serum samples from experimentally infected chimpanzees in the absence of HCV antibody. This type of assay, when further refined, may prove invaluable for the identification of infectious patients. In this issue (p 1419), Dr Garson and his colleagues describe a sensitive "nested" polymerase chain reaction assay that detects HCV RNA sequences in serum samples. They show a good correlation between the detection of HCV RNA sequences and proven infectivity of the samples and report that some patients remain positive for HCV RNA for at least 9 years. This kind of assay may well be more suitable for screening of blood donations than are HCV antibody tests. The most important decisions to be faced now are when to begin testing blood donors for evidence of HCV infection and what tests should be used. Many countries are already committed to testing and excluding positive donors.
1. Choo Q-L, Weiner AJ, Overby LR, Kuo G, Houghton M. Hepatitis C virus: the major causative agent of viral non-A, non-B hepatitis. Br Med Bull 1990; 46: 423-41. 2. Editorial. Will the real hepatitis C stand up? Lancet 1989; ii: 307-08. 3. Choo Q-L, Kuo G, Weiner AJ, et al. Isolation of a cDNA clone derived from a blood-borne non-A, non-B viral hepatitis genome. Science 1989; 244: 359-62. 4. Kuo G, Choo Q-L, Alter HJ, et al. An assay for circulating antibodies to a major etiologic virus of human non-A, non-B hepatitis. Science 1989; 244: 362-64. 5. Roggendorf M, Deinhardt F, Rasshofer R, et al. Antibodies to hepatitis C virus. Lancet 1989; ii: 324-25. 6. Van der Poel C, Reesink HW, Lelie PN, et al. Anti-hepatitis C antibodies and non-A, non-B post-transfusion hepatitis in the Netherlands. Lancet 1989; ii: 297-98. 7. Contreras M, Barbara JAJ. Screening for hepatitis C virus antibody. Lancet 1989; ii: 505. 8. Esteban JI, Esteban R, Viladomiu L, et al. Hepatitis C virus antibodies among risk groups in Spain. Lancet 1989; ii: 294-97. 9. Ludlam CA, Chapman D, Cohen B, Litton PA. Antibodies to hepatitis C virus in haemophilia. Lancet 1989; ii: 560-61. 10. Skidmore SJ, Pasi KJ, Mawson SJ, Williams MD, Hill FGH. Serological evidence that dry heating of clotting factor concentrates prevents transmission of non-A, non-B hepatitis. J Med Virol 1990; 30: 50-52. 11. Mortimer PP, Cohen BJ, Litton PA, et al. Hepatitis C virus antibody. Lancet 1989; ii: 798. 12. Alter HJ, Purcell RH, Shih JW, et al. Detection of antibody to hepatitis C virus in prospectively followed transfusion recipients with acute and chronic non-A, non-B hepatitis. N Engl J Med 1989; 321: 1494-500. 13. Habibi B, Garretta M. Screening for hepatitis C virus antibody in plasma for fractionation. Lancet 1990; 335: 855-56. 14. Finlayson JS, Tankersley DL. Anti-HCV screening and plasma fractionation: the case against. Lancet 1990; 335: 1274-75. 15. Gray JJ, Wreghitt TG, Fnend PJ, Wight DGD, Sundaresan V, Calne RY. Differentiation between specific and non-specific hepatitis C antibodies in chronic liver disease. Lancet 1990; 335: 609-10. 16. McFarlane IG, Smith HM, Johnson PJ, Bray GP, Vergan D, Williams R. False positivity for antibodies to hepatitis C virus in chronic active hepatitis. Lancet 1990; 335: 754-57. 17. Ikeda Y, Toda G, Hashimoto N, Kurokawa K. Antibody to superoxide dismutase, autoimmune hepatitis, and antibody tests for hepatitis C virus. Lancet 1990; 335: 1345-46. 18. Skidmore S. Recombinant immunoblot assay for hepatitis C antibody. Lancet 1990; 335: 1346. 19. Weiner AJ, Kuo G, Bradley DW, et al. Detection of hepatitis C viral sequences in non-A, non-B hepatitis. Lancet 1990; 335: 1-3. 20. Kaneko S, Unoura M, Kobayashi K, Kuno K, Murakami S, Hattori N. Detection of serum hepatitis C virus RNA. Lancet 1990; 335: 976.
Diagnosis of schizophrenia diagnosis of schizophrenia was introduced by Kraepelin1 and by Bleuler.Both workers described a The
form of the illness in which there was an insidious deterioration in personality and coping abilities. Such self-absorbed, idle, and aimless patients were eventually recognised by clinicians as having simple schizophrenia (schizophrenia simplex), a disease that was easily misunderstood by family and friends. These features are now described as the negative symptoms of schizophrenia (after Hughlings Jackson’s model of brain function). There is a reduction in the amount and information content of spontaneous speech; drive, initiative, interest, and attention are poor; mood is shallow; and the expression of emotions and the capacity to experience emotions are restricted. Bleuler believed that such symptoms were "primary", and they have been associated with neurological findings,3atrophic or
dysplastic changes on computed tomography,4 cognitive impairments,s and a poor outcome.6,7 Destitution and imprisonment can easily result ;8 Kraepelin noted "probably already a long time previously changes of the personality in the sense of dementia praecox had taken place, which then made the patient a habitual criminal and vagrant". Despite impeccable historical probity, the American diagnostic system contained in the third, revised edition of the American Diagnostic and Statistical Manual (DSM IIIR)9 excludes simple schizophrenia as a subgroup of schizophrenia and places such patients in the category of schizotypal personality disorder or borderline personality disorder. The boundaries of personality disorder have thereby been extended at the expense of the original concept of schizophrenia. Many find personality disorder a pejorative term, which encompasses psychopathy, a difficult and unreliable diagnosis10 that merges with administrative considerations without secure scientific justification.ll Moreover, Bleuler described the development of simple schizophrenia in maturity, whereas "personality disorders are development conditions" which "always appear during childhood or adolescence" (ICD-10, 1989, in draft of chapter V, World Health Organisation, Division of Mental Health, Geneva). The American diagnostic criteria for schizophrenia had earlier been much looser than the British criteria. Consequently the prevalence of schizophrenia in the USA at one time was apparently double that in the UK 12 and dubious aetiological models of malign family relationships held sway.13 A reliable diagnostic process to determine the "true" prevalence was needed, an endeavour that was encouraged by the successful treatment of manic depressive illness with lithium salts and the need to differentiate the two disorders. The "first rank" symptoms of Schneiderl’ formed an unambiguous basis for this purpose. is (Schneider’s list encompassed audible thoughts;
