Clmieal and Experimental Allergy.. 1992, Volume 22. pages 673-680
SPEGIAL ARTIGLE
The Jack Pepys Lecture The hypersensitivity reactions—some personal reflections R. R. A. GOOMBS Presented at the annual meeting of the British Society for Allergy and Clinical Immunology. September 1991
This lectureship honours Jack Pepys. who is distinguished by his researches on the hypersensitivity reactions from both the scientific and clinical aspects, and also by his promotion of clinical immunology in general. Our paths lirst crossed in the early 1950s when, in our own ways, we collaborated with C. J. C. Britton, an early member of this Society, and with Bencard. We both also played our parts in the foundation of the British Society for Immunology. Jack Pepys being treasurer 1957 64. Philip Gell and I were very pleased thai he agreed to contribute several chapters to the 1st. 2nd and 3rd editions of Clinical Aspects of Immunology, together with his colleagues. Parish. Longbottom and TurnerWarwick. He built up. by tireless efforts, an MRC-supported Research Group in Clinical Immunology at the Brompton and by 1968, became Professor of Clinical Immunology witb a Department. From his early detailed researches on aspergillosis and farmer's lung disease he became one of the leading authorities in the world on several diseases grouped together as extrinsic allergic alveolitis. Another considerable, but domestic achievement of Jack Pepys. Professor of Clinical Immunology, was to father, nurture and raise another Professor—^a Professor of Immunological Medicine (please note the subtle distinction between the fields of reference of these two Chairs—a distinction of which I absolutely approve!). We, in Cambridge, were very pleased when Mark, the son in question, came to our Department to undertake bis researches for the PhD degree. Another very well deserved accolade is having a lectureship endowed and named after him. I am greatly honoured to be invited to give this—the first Jack Pepys lecture. I greatly appreciate having the Jack Pepys lecture to voice and record some very personal reflections on both allergy and the hypersensitivity reactions—these reflections being made after 3 years of retirement. Definition of allergy and classification of the hypersensitivity reactions A considerable regret of mine is the total failure of our efforts to restore the meaning of the word "allergy' to that
intended by von Pirquct when he introduced it in 1906. Everyone should read this paper [1] which we reproduced in an English translation by Carl Prausnit/ Giles (a one time clinical assistant to von PIrquet from 1910 to 1912) in the first three editions of Clinical Aspects of Immunology. At this time (1906) the so-called "paradoxical reactions' (von Behring), e.g. anaphylaxis, serum sickness and cellular "supersensitivity" were being recognized and reported. It was a real contradiction in terms and Iruly paradoxical in that so-called 'immune responses' should produce such effects. There was a definite need fora 'new general term which prejudices tmthing'. The term von Pirquet suggested was "allergy', meaning altered reactivity (in relation to antigens, antibodies and cellular reactivity). Very few persons, it appears, have fully understood ihc real point von Pirquet was getting at or its full significance. Over the years most medical people, including very distinguished immunologists and so-called "allergists' including Coca, Zinsser and Ratner have misinterpreted, either unconsciously or wilfully von Pirquet's concept. They wished to retain the word, but in a totally incorrect way as a synonym for the so-called paradoxical reactions themselves or the hypersensitivity reactions, leaving, as before, the absurd paradox of the immune responses causing harmful reactions and even death. Philip Gell and I, witb the enthusiastic blessing of Prausnitz, tried very hard to re-introduce and restore von Pirquet's teaching in the early editions of Clinical Aspects of Immunology (sec Fig. I)— I regret to say, witb little lasting impact. The stand we took was not for pedanticism. for von Pirquet's concept of allergy {as expressed in his 1906 paf>er) avoids all contradictions and absurdities. We are now, as I have said, back again to the 'dark ages' where the harmful paradoxical or hypersensitivity reactions are manifestations of the immune responses—a return to the status quo ante. A very distinguished physician, medical teacher and writer (Dr A. E. Clarke Kennedy) came up to me one day and said "You immunologists are quite absurd—how can you have auto-immune diseases? How can you be immune to yourself'?' To one who always talks of auto-allergicdiscases,thiswashard indeed. After 3 yearsof retirement. I still regret this lost opportunity very much. 673
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Biological Response
Clinical Outcome IMMUNITY
ALLERGIC resp.
(profecMve)
(prejudices nothing)
HYPERSENSITIVITY (harmful)
IMMUNITY IMMUNE resp
(protective)
(prejudiced M
ALLERGY (harmful I t t Parodowcal-the very reason von Prrquet introduced the word 'allergy.'
Classification of the hypersensitivitv reactions
It was in the 1963 edition of Clinical Aspects of ImtmtnoItf^y that we first presented a simple classification (Types I IV) of the various hypersensitivity reactions. In inviting me to give this lecture, your President asked specifically, if I may quote from his letter: (i) how the ideas for such a classification emerged? and secondly (ii) how I now consider this classification in the light of new knowledge? To answer the first question. Gell and I were both in the teaching business and even in 1960 there was still considerable confusion in the literature on the hypersensitivity reactions. Many ofthe classical and significant papers went back over a 50 year period and. for instance, three quite distinct reactions were called 'anaphylaxis'. Having to teach is a great elarifier ofthe mind! I think the best way to answer your President's second enquiry— *how do 1 consider the classification in the light of new knowledge?' is to re-emphasize what we clearly stated at the time—lhat. as with all man-made classifications, il should remain for only so long as it is proving helpful. If it is considered to be no longer serving a purpose or is misleading it should be discarded! But this is for others lo decide.
Food allergic diseases In planning this talk. 1 was surprised how frequently our researches, in the past, had been related to food allergy. Food allergy, of course, means no more and no less than allergy to foods which may be either protective and beneficial or harmful, causing disease—food allergic disease (Fig. 2). The main protective roles of allergy to foods and other contents of Ihe gut (mostly bacteria) are
X
Kig. 1. The intended meaning of the word allergy—response (resp.), state and reaction, v ' ' indicates correct usage. X indicates the common bul wrong usage. Il is clearly paradoxical that the imtmtne (protective) response should produce the harmful allergic reactions.
probably: (i) preventing excessive absorption, from the gut. of antigenic food molecules (before they have undergone complete digestion); and (ii) using that imaginative euphemistn of Bienenslock. "protecting ihe internal milicit of the body from the sewer running right through it'. Without this normal allergic response and reactivity in the gut to foods, all of us would probably become clinically hyperscnsilivc lo many, if not all. the foods we eat (let alone succumb to microbial infections from the gut). So food allergy, as such, is not a bad thing! On the other hand, under certain cotiditioti.K and vircunisiance.s ihese same allergic responses may become exaggerated and involved in disease—food allergic disease. I wish to stress that it is \hcse partiiuiar conditions attd circwiisiancc.s, aboul which we are totally ignorant, and not ihe allergic reactions themselves. Why should this be? I will venture certain suggestions: firstly until fairly recently, there has been a complete lack of objective methods for testing the target organ (i.e. the gut) of patients for allergic reactivity: secondly, the lack of knowledge on the normal and abnormal permeability of the gul ti) protein molecules and the ability to measure it. Changing permeubility lo radio-labelled sugars is no measure of permeability lo proteins. Thirdly, there are virtually no appropriate and realistic animal models. Human patients with food allergic diseases (a small percentage of the whole population) present themselves to the clinic. There is no opportunity for this selection wilh laboratory animais. Also each species of laboratory animals behaves differently, which also makes for a diflicull choice. Lastly, I ihink the medical profession itself must bear some of the responsibility by not encouraging proper collahoralion between the experimentalist in his laboratory and the clinician in his clinic.
The Jack Pepys Lecture
Biological Response
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Clinical Outcome IMMUNITY + protection (1) Preventing excessive absorption ot tood antigens
(FOOD) ALLEROY Fig. 2. (Food) allergy is a biological response and is not necessarily harmful. When it is harmful and produces disease we have the (food) allergic diseases.
Many clinical practitioners do not even believe in food allergic diseases! Looking back now, 1 feel ashamed that so much of our own researches on tbod allergic disease has been dilettante, to say the least. For instance: With regard to coetiac disease We. at one time, asked the question whether the allergic reaction to gliadin in patienls with coeliac disease was a primary or secondary phenomenon as regards the aetiology. We first developed a very satisfactory and simple anlibody-Iabelled red cell assay for measuring gliudin antibodies in human sera [2]. We then examined sera of rabbits, rats and guinea pigs (all on very similar high gluten diets) with a view to selecting the animal species to use in our experiments. Rats had gliadin antibody levels comparable with those in normal humans. Rabbits had very high gliadin antibody levels as in human coeliacs while guinea pigs had no trace of serum antibodies! These were all healthy animals. The guinea pigs responded wilh high antibody levels if they were injected with gliadin [3]. But even if the gliadin was injected together wilh Freund's complete adjuvant (to encourage ihe development of delayed-type hypersensitivity as well as serum antibodies) the animals failed to develop any gut lesions even when fed high levels of gluten or even gliadin in alcohol. No socalled enteropathic changes were observed*. These rather trivia! experiments seemed, however, to indicate the requirement of some accompanying abnormality of the gut. *The collaboralion of Dr D. Wight gralcfully acknowledged.
^ - "
(II) From 'internal sewer': Bienenstock
^ (FOOD) ALLERGIC DISEASES (tiarmful)
Mccliatti.stns of diarrhoea in food aUergiv disease Another excursion we undertook concerns the mechanism of the diarrhoea so commonly seen as a manifeslation of food allergic disease. The question asked by our colleagues Cuthbcrt and Baird (pharmacologists) and ourselves was could electrogcnic chloride secretion, associated with the secretory diarrhoeas, be also generated by allergens reacting wilh gut mucosa of a sensiti/ed animal in essentially what would be a Type 1 hypersensilivlly reaction? The gut mucous membrane (comprising epithelium. basement membrane, and lamnia propria containing the mucosal mast cells) of guinea pigs sensitized to /{lactoglobulin. by previous injection or by simply drinking cows' milk, was mounted, as a tissue diaphragm, across an Ussing chamber with monitoring electrodes in place on both sides. Any generated electric current, produced by addition of allergen (/Macloglobulin), can be measured, under so-called voltage-clamped conditions, as shorl circuit current. Both colon and ileum were tested [4.5]. On the samples from the colon, addition of/Mactoglobulin. but on the basolaterai side only, produced a large inward flowing current due to inappropriate chloride ion secretion. This was inhibited by indomeihacin suggesting prostanoids as mediators. With samples from the ileutn, challenging with /Macloglobulin from either side produced an inward fiowing current associated with a fiux of bicarbonaie ions and 5 hydroxy tryplamine seemed to be ihe mediator. Secretion of fluid could also be measured. Unfortunately, for quite non-scientific reasons these researches had to be terminated here but these findings
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indicated lhal diarrhoea in food allergy could be explained by a Type I reaction triggered by allergen reacting on mucosal mast cells. Further, as the guinea pigs, on which the test were done, themselves exhibited no diarrhoea, attention is again directed to: (i) the question of gut permeability; and (ii) the concept of latent sensitivity.
significant to remember that both man and the guinea pig behave very similarly with regard to anaphylaxis and, in both species, the lung is the major shock organ. It is also quite accepted that, in infants, aspiration or inhalation of milk is common. Such an intra-tracheal challenge with cows' milk is the crux of the modified anaphylaxis model for cot-death. The sequence of events according to this hypothesis is:
Cot-death
Sensitization to cows' milk (latent or otherwise begins when cows' milk is introduced into the infant's diet (no dissent here!) The anaphylactic reaction which kills the infant occurs during sleep (deep sleep, as light anaesthesia, is presumed to modify the reaction) following regurgitation (gastrooesophageai reflux) of gastric contents (containing milk)—and inhalation of some of this material, including the milk allergens, into the lungs.
This question oflatent anaphylactic sensitivity is also very relevant to our researches on cot-death, which go back over a 30 year period beginning when Dr Parish was working with me in Cambridge. I want simply to consider three issues; (i) this matter of latent sensitivity; (ii) hazardous routes for anaphylactic challenge; and (iii) oral tolerance. Guinea pigs (and please keep young infants in mind also) drinking cows" milk appear to be wonderfully healthy (with lovely glossy coats!); but despite this excellent health they develop a latent anaphytactic sensitivity to ihe proteins in cows' milk. This latent sensitivity can be revealed: either (i) by intravenous injection of milk proteins—^in which case the guinea-pigs die: or (ii) by in vitro tests on isolated organs. These hazards are of little concern for the guinea pig—that is unless, of course, some *hcll-bent' immunologist comes along and injects them intravenously. In much later experiments in 1980 McLaughian and myself [6] showed that a latent anaphylactic sensitivity to milk proteins exists also in some infants (as. of course, would be expected!), it is obviously not possible with infants, however, to use the intravenous challenge to reveal this, but it is possible to perform in vitro tests on freshly taken random blood samples. The test was measuring the histaminc-relcase from the blood basophils on addition of milk allergens. Our findings showed that 37"/n of infants, under 26 weeks of age, showed no release of histamine at all, white 24% released over 10'^ of their blood histamine—and one-half of these, i.e. 12% of the lotal sample released 20 65% of their blood histamine^—a figure indicating considerable sensitization to cows' milk. However, no-one in his right mind (not even that hellbent immunologist!) is going to inject infants intravenously with cows' milk proteins and so supposedly such a latent anaphylactic sensitivity does not put the infants at any risk at all. This is ///.sv not so for, on the basis of our experimental evidence, such infants would be at considerable risk from aspiration or inhalation of milk. Parish. Barrett and myself [7] back in 1960 showed that, in anaphylactically-sensitized guinea pigs intra-tracheal administration (equivalent to inhalation) was just as lethal a route for challenge as was intravenous injection. It is also
This is really no "pie in the sky" armchair hypothesis. There is a large body of supporting data from both studies in infants and experiments in guinea pigs 18,9], but as yet there is still no hard proof either for oragain.st it and proof might elude us for some time. Professor Holgate has a group in his department developing assays for stable mediators of the anaphylactic reaction in man, which if measurable post-mortem, up to many hours after death, might possibly open up new opportunities in establishing whether any sudden death had been brought about by modified anaphylaxis. The events we envisage really should occur. We should possibly ask why such reactions do not occur more frequently! So we come to the last of the three considerations r wished to put before you—namely oral tolerance. Oral tolerance Could oral tolerance be the reason why such anaphylactic reactions to cows" milk in infants do not occur more frequently? In 1987, together with Weaver and Koritz, we [10, see also 11] showed that the development of latent anaphylactic sensitivity to cows" milk in milk-drinking guinea pigs was prevented if the baby guinea pigs began drinking cows" milk (instead of their mothers" milk) before the second day of life (Fig. 3). A clinical situation possibly indicating this phenomenon in infants comes to mind from observations of Professor D. P. Davies in Cardiff (personal communication). He has stated that the incidence of cot-death is very uncommon indeed in Hong Kong, where (also according to his findings) al! infants are totally bottle-fed from birth. This extremely low incidence of cot-death could be explained by oral tolerance to the development of anaphylactic antibody as shown in guinea pigs.
The Jack Pepys Lecture
Fig. 3. Oral tolerance to cows' milk proteins: anaphylactic sensitivity (shaded areas) developing in 36 baby guinea pigs drinking eows' milk (pasteurized) from the second day of life. During life the anaphylactie sensitivity was shown by testing the sera (obtained by eardiae puncture) every 2 weeks for milk antibodies giving passive eutaneous anaphylaxis. On the I IDth day, four guinea pigs, ehosen al random, from group A all failed, on direct challenge, to suffer anaphylaxis while another four guinea pigs from group B all died on challenge from anaphylaxis. Taken with permission from Weaver, Koritz and Coombs (1987) [10].
Comment on cot-death research I have been away from the research bench for the last 3 years and as I have said I have had ample time for refiection. And concerning cot-death: (i) I am still totally astonished that the 'anaphyiactic hypothesis' (as well as the experimental work upon which it is based) is not taken much more seriously, especially by those whose responsibility it has been to promote and direct research into these deaths. I can only think they don't really understand! (ii) Suffocation by external application (i.e. smothering) has always been accepted as a possibility—and in each case of cot-death needs to be excluded. But sulTocation brought about internally by anaphylactic bronchial constriction is not accepted as a real possibility! Why? (iii) In retrospect, 1 think T have been wrong in the past in not being more aggressive, vocally, in forcing the hypothesis onto the agenda for debate—but without proof in the cadaver for anaphylactic death it is not easy to do this (but others could do it!), (iv) Were the hypothesis, in the future, substantiated it would surely represent the most exotic example of food allergic disease.
Rheumatoid arthritis The Types I-IV classification of the hypersensitivity reactions, which your President suggested I discuss, is not only a clinical aid: but should also be helpful in interpreting pathological lesions with regard to aetiology. Yet rheumatoid arthritis, with abounding hallmarks suggesting major allergic involvement, still has an unknown aetiology! The 'scratchings'—I use this word advisedly— of literally hundreds and hundreds of immunologists over
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>A
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50
60
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the last 40 years have not solved the enigmas of this disease. My colleagues and I have also been \cratchers' for a period of 20 years. But our scratchings have, on the whole, ut least been aimed at elucidating the essential initiating events—mostly with the help of animal models. A successful model for this disease must, in my opinion, accommodate: (i) the characteristic pathological features: (ii) the various modulating clinical patterns of the disease—with eventual chronicity; (iii) that tell-tale characteristic of thediseasc—almost pathognomonic, i.e. rheumatoid factor (RF) and immune complexes in the serum; (iv) the experimental procedures used must not involve direct injection of antigens into the joints (this does not occur in real life!): (v) the choice of the experimental animal, which is a very difficult decision. My introduction to research on rheumatoid disease was with Dame Honor Fell, at that time (1965) Director of the Strangeways Laboratory in Cambridge. She and her biochemist colleague, Dr Dingle were then primarily interested in the breakdown of cartilage and bone in chick embryo explants growing, in vitro, in organ culture. The question we asked was could degradative processes be initiated by adding antibody raised against cell membrane antigens and complement to the explants growing in culture. Complete breakdown of cartilage matrix and some resorption of bone could, in fact, be brought about under these conditions and the changes were reversible by transferring the explants back into normal medium [12]. Biochemical analysis of the culture fluids indicated that the loss of cartilage structure followed the release of lysomal proteases from the chondrocytes, and the cartilage proteoglycans being degraded by these proteases. The assumption was that antibody and complement
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acting at the cell surface triggered the release into the extracellular lluid oflhese lysosomal enzymes [13]. I specially mcniion these experiments as they presented the first prototype example for a Type II cytostimulatory (as opposed lo cytotoxic) hypersensitivity reaction in our Types I-IV classification. We suggested thai another example could be that of LATS (long acting thyroid stimulator) in thyrotoxic patients. A further example could be in relapsing polychondritis where an IgG autoantibody reaetion with chondrocytes could stimulate these cells to secrete iheir lysosomal hydrolases. But 1 must return to our intention of focusing on the primary cause(s) or initiating events of rheumatoid joint disease. Models for investigating the primary events 'Immune complex' disease Having familiarized ourselves with selected literature and using our best judgement we decided to examine, morbid-histologically. the joints of rabbits with experimental serum sickness or immune complex disease. We were encouraged in this course by the views of the distinguished rhcumatologist. Charles L. Christian of New York. To quote his opinion—"if the immune response (he meant allergic reactions!) to an environmental antigen were responsible for the pathogenesis of rheumatoid arthritis, the closest experimental model would be chronic serum sickness.' So we proceeded and in a series of papers in the middle 1970s. Poole. Oldham and myself reported [14-17] on the development of rhcumatoid-like lesions in the synovial capsules and joints of rabbits following repeated intravenous injections of bland foreign scriun with its very many and varied antigens (or even cows' milk!). No injections were made into the joints. Ten to 20% of these experimental rabbits developed the following pathological synovial changes in their knee joints 20 80 days after commencing the schedules of injections: (i) enlargements and hyperplasia of lining cells of the synovial membranes; (ii) accumulation of small lymphocytes and plasma cells, often around small blood vessels; (iii) focal lymphocytes accuinulaiion and evidence of germinal centre-formation; (iv) villus formation; and even (v) pannus formation with loss of proteoglycan from the adjoining cartilage. It was interesting that no polymorphonuclear leucocytes were seen in the synovia, but polymorphs were plentiful in the joint cavities. Antigen antibody complexes could be shown in the joint tissues by immuno-fluorescence—as in the human rheumatoid joint disease. Attempts to exacerbate the lesions by switching some of the antibodies to the IgE isotype [16] or incorporating a delayed hypersensitivity response were without effect [17].
Complexes induced by milk drinking Together with Jane Welsh and Angela Hanglow, we also tried to produce such joint lesions under more natural conditions with rabbits simply drinking cows' milk over long periods—a regimen in rabbits which we had previously found produced high levels of serum antibodies to milk proteins. Within 12 weeks up to W/,, of the rabbits had similar lesions in the synovial capsules of their knee joints although the lesions tended to be milder than in the injected rabbits [18-20]. Also, after 12 weeks, the lesions were regressing and at this time it was possible to show the secretion into the gut of secretory IgA antibodies to milk proteins. These IgA antibodies could be extracted from the faecal pellets. This was a possible example of a protective role of food allergy—that of blocking further absorption of native milk proteins. To have any relevance to rheumatoid arthritis (i) the joint lesions had, on the whole, lo be progressive and (ii) above all. the animals had also to produce RF—an autoanlibody to autologous IgG—which none of the milkdrinking animals did. In the light of these two points the milk-drinking experiments were discontinued and also the serum-injection experiments were interrupted for the time being as injecting serum made testing for RF difficult—certainly difficult to interpret for the simple reason we were injecting IgG—in either scrum or milk. However, it was appreciated that the relatively mild and transient lesions following milk-drinking probably reflected the underlying pathogenic mechanism for what Panush [21] in his allergy clinic and others call allergic synovitis or food-induced allergic arthritis or arthralgia (possibly more correct). Joint lesions produced following intravenous injeclion of killed bacteria Another series of experiments was then initialed, focusing especially on the experimental production in rabbits of RF a .v//u' qua mm for a rheumatoid model In man. besides rheumatoid disease. RF is also found to very high titres in bacterial endocarditis. And again in 1961, Christian together with Abruzzo [22] had shown that RF could be stimulated in rabbits by intravenous injection of killed bacteria using very similar schedules to those used in 1953 by my wife and myself [23] to stimulate immunoconglutinin auto-antibody, not to IgG. but to autologous fixed complement. Immunoconglutinins are also produced in rheumatoid disease! In our further experiments [24] we injected rabbits intravenously with E. eoli or B. .suhtilis and. as previously reported by Abruzzo and Christian [22] the rabbits produced truly autologous R.F. However, we did something that Abruzzo and Christian did nol do. We examined the knee joints of the rabbits, morbid histoiogi-
The Jack Pepys Lecture
cally. and to our surprise and gratification a large number had (i) significant rheumatoid-iike lesions in the synovia atid (ii) large numbers of T lymphocyles in the synovial fiuids. These findings, together with those of Aoki and his colleagues [25] in Japan on rabbits developing even more severe joint lesions by intramuscular injection of killed E. coli emulsified in Frcund's incomplete adjuvant, indicated a very promising line to be explored further, especially in conjunction with procedures generating immune-complexes. However, there results were obtained and published only 2 years before I was due to retire and Granting Bodies, devoted to rheumatoid research, in their wisdom were not sympathetic to extending the financial support. In these circumstances we were emasculated, a hazard of research workers these days, and, as a consequence, these lines of investigation were brought to an abrupt end! Concluding remarks It is now 3 years since my retirement and, looking back on my researches on the hypersensitivity reactions, certainly the biggest regret, and that which I still nurse, was being compelled to terminate these investigations on rheumatoid disease at that very incomplete, yet promising stage. It would be a great satisfaction to me to see these lines of investigation continued. On coi-dcaili. my regret is of a quite different kind. Our investigations were completed. Further research on the anaphylaxis model must come from others with a diflerent expertise. My regret is that the hypothesis has seldom been placed on the agenda for proper scientific discussion. As regards the word 'allergy' I can only repeat what Richard Wagner [26], the medical biographer of von Pirquet, wrote in 1968 thai Immunology had a need for such a word uncommitted with regard to either immunity or hypersensitivity, but embracing both. How right he was, I am really most grateful for the opportunity the Jack Pepys Lecture has given me to put before you these very personal refiections on the hypersensitivity reaction and to pay my respects to Professor Pepys. References 1 von Pirqucl C. Allergic. Miinch mcd Wochcnschr 1906; 30:1457-8. 2 Kicffcr M. Frazier PJ, Daniels NWR. Ciclitira PJ. Coombs RRA, Scrum antibodies (measured hy MRSPAH to alcoholsoluhlc gliadin.s in adult coeiiac patients. J Immunol Methods 1981; 42:129-36. 3 Coombs RRA. KiefferM, Fraser DR, Frazier PJ. Naturally developing antibodies to wheat gliadin fractions and to alher cereal antigens in rabbiis, rats and guinea pigs on
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normal laboratory diets. Int Archs Allergy appl Imniiin 1983; 70:200-4. 4 Cuthberl AW, McLaughlan P, Coombs RRA. Immediate hypersensitivity reaction to/Mactoglobulm ini he cpilhclium lining of the colon of guinea pigs fed cows' milk. Int Archs Allergy Appl Immun 1983; 72:34 40. 5 Baiid AW, Coombs RRA, McLaughlan P. Cuthberl AW. Immediate hypersensitivity reactions to cows" milk proteins in the isolated epithelium from ileumofmilk drinking guinea pigs: comparison with eolonic epithelia. Int Archs Allergy app! Immun 1984; 75:255 65. 6 McLaughian P. Coombs RRA, Latent anaphylactie sensitivity of infants to cows'milk proteins: histamine release from blood basophiis, Clin Allergy 1983; 13:1 9, 7 Parish WE, Barrett AM, Coombs RRA. Inhalation of cow's milk by sensitized guinea pigs in the eonscious and anaesthetized state. Immunology 1960; 3:307 24. 8 Coombs RRA McLaughlan P. The enigma of cot death: is the modified-anaphyla.\is hypothesis an explanlation Tor some cases? Lancet 1982; i:I388 9, 9 Coombs RRA, Holgate ST. Allergy and cot death: with special focus on allergic sensitivity to cows' milk and anaphylaxis. Clin Exp Allergy 1990; 20:359 66. 10 Weaver LT, Korit/ TN. Coombs RRA. Tolerance to orally induced anaphylaetie sensitization to cow's milk proteins and patency ofthe intestinal mucosa in the neonatal guinea pig. Int Arch Allergy appl Immun 19S7; 83:220-2. 11 Coombs RRA Devey ME Anderson KJ. Relractariness to Linaphylaetic shock after continuous feeding of cows'milk to guinea pigs, Clin exp Immunol 1978; 32:263-71. 12 Fell HB, Coombs RRA, Dingle JT. The breakdown of embryonic (chick) cartilage and bone cultivated in the presence of complement-suHicient antiscrum. 1, Morphological changes, iheir rcversibiliiy and inhibition. Int Arch Allergy 1966; 30:146-76, 13 Dingle JT, Fell HB. Coombs RRA. The breakdown of embryonic cariilage and bone cultivated in the presence of complement-sufficient antiserum. 2. Biochemical changes and the role ofthe lysosomai system, Int Arch Allergy 1967; 31:283 303. 14 Poole AR. Coombs RRA. Rheumutoid-like joint lesions in rahbits injected intravenously with bovine serum. Int Arch Allergy appl Immun 1977; 54:97 M 3. 15 Poole AR, Oldham G. Coombs RRA. Early rheumatoidlike lesions in rabbits injected with foreign serum: relationship to localization of immune complexes in Ihe lining tissues of joints and cellular content of synovial fluid. Int Arch Allergy appl Immun I97S: 57:135^5, 16 Oldham G. Coombs RRA. Early rheumatoid-like joint lesions in rabbits injected with foreign serimi or milk proteins. HI. Influence of concomitant !gH-like antibodies and ofthe breed of rabbit, Int Arch Allergy appl Immun 1980:61:81 90, 17 Oldham G, Bowyer DR, Coombs RRA, Early rheumatoidlike joint lesions in rabbits injected with foreign serum, IV. Influence of delayed type hypersensitivity, Int Arch Allergy appl Immun 1981; 65:114-20.
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18 Welsh CJR, Hunglow AC. Conn P, Barker THW. Coombs RRA. Early rhcumaioid-likc synovial lesiotis in rabbits drinking cow's milk. I. Joint pathology. Int Archs Allergy appl Imtnun 1985; 78:145-51. ly Hanglow AC, Welsh CJR, Conn P, Coombs RRA. Early rhcumatoid-like synovia! lesions in rabbits drinking cow's milk, II. Antibody responses lo bovitic serum proteins. Int Arch Allergy appl Immun 1985: 78:152-60. 20 Welsh CJR, Hanglow AC, Conn P. Coombs RRA. Comparison of the arthritogenic properties of dietary cow's milk, egg albumin and soya milk in experimental animals. Int Arch Allergy appl immun 1986: 80:192 9. 21 Paniish RS, Stroud RM, Webster EM. Food-induced (allergic) arthritis: inflammatory arthritis exacerbated by milk. Arih Rheum 1986: 29:220-6. 22 Abrtizzo JL. Christian CL. The induction of a rheumatoid faclor-hke substance in rabbits. J Exp Med 1961; 114:791806.
23 Coombs AM, Coombs RRA. The conglutination phenomenon. IX. The production of immuno-conglutinin in rabbils. JHyg{Camb.) 195.^: 51:509-31. 24 Hanglow AC. Welsh CJR. Conn P. Pitts JM, Rampling A, Coombs RRA. Experimental induction of rheumatoid factor and joint lesions in rabbits after intravenous injection of killed bacteria. Annal Rheum Dis 1986; 45:50-9. 25 Aoki S. Ikuta K, Nonogaki T. Ito Y. Induction of chronic polyarthritis in rabbits by hypcritnmunization with Escherichia coli. I. Pathological and serological features in two breeds of rabbits. Arthr Rheum 1985; 28:522 8. 26 Wagner R. Clemens Von Pirquet—His life and work. Baltimore: Johns Hopkins Press, 1968.
SPEGIAL ARTIGLE
The Jack Pepys Lecture The hypersensitivity reactions—some personal reflections R. R. A. GOOMBS Presented at the annual meeting of the British Society for Allergy and Clinical Immunology. September 1991
This lectureship honours Jack Pepys. who is distinguished by his researches on the hypersensitivity reactions from both the scientific and clinical aspects, and also by his promotion of clinical immunology in general. Our paths lirst crossed in the early 1950s when, in our own ways, we collaborated with C. J. C. Britton, an early member of this Society, and with Bencard. We both also played our parts in the foundation of the British Society for Immunology. Jack Pepys being treasurer 1957 64. Philip Gell and I were very pleased thai he agreed to contribute several chapters to the 1st. 2nd and 3rd editions of Clinical Aspects of Immunology, together with his colleagues. Parish. Longbottom and TurnerWarwick. He built up. by tireless efforts, an MRC-supported Research Group in Clinical Immunology at the Brompton and by 1968, became Professor of Clinical Immunology witb a Department. From his early detailed researches on aspergillosis and farmer's lung disease he became one of the leading authorities in the world on several diseases grouped together as extrinsic allergic alveolitis. Another considerable, but domestic achievement of Jack Pepys. Professor of Clinical Immunology, was to father, nurture and raise another Professor—^a Professor of Immunological Medicine (please note the subtle distinction between the fields of reference of these two Chairs—a distinction of which I absolutely approve!). We, in Cambridge, were very pleased when Mark, the son in question, came to our Department to undertake bis researches for the PhD degree. Another very well deserved accolade is having a lectureship endowed and named after him. I am greatly honoured to be invited to give this—the first Jack Pepys lecture. I greatly appreciate having the Jack Pepys lecture to voice and record some very personal reflections on both allergy and the hypersensitivity reactions—these reflections being made after 3 years of retirement. Definition of allergy and classification of the hypersensitivity reactions A considerable regret of mine is the total failure of our efforts to restore the meaning of the word "allergy' to that
intended by von Pirquct when he introduced it in 1906. Everyone should read this paper [1] which we reproduced in an English translation by Carl Prausnit/ Giles (a one time clinical assistant to von PIrquet from 1910 to 1912) in the first three editions of Clinical Aspects of Immunology. At this time (1906) the so-called "paradoxical reactions' (von Behring), e.g. anaphylaxis, serum sickness and cellular "supersensitivity" were being recognized and reported. It was a real contradiction in terms and Iruly paradoxical in that so-called 'immune responses' should produce such effects. There was a definite need fora 'new general term which prejudices tmthing'. The term von Pirquet suggested was "allergy', meaning altered reactivity (in relation to antigens, antibodies and cellular reactivity). Very few persons, it appears, have fully understood ihc real point von Pirquet was getting at or its full significance. Over the years most medical people, including very distinguished immunologists and so-called "allergists' including Coca, Zinsser and Ratner have misinterpreted, either unconsciously or wilfully von Pirquet's concept. They wished to retain the word, but in a totally incorrect way as a synonym for the so-called paradoxical reactions themselves or the hypersensitivity reactions, leaving, as before, the absurd paradox of the immune responses causing harmful reactions and even death. Philip Gell and I, witb the enthusiastic blessing of Prausnitz, tried very hard to re-introduce and restore von Pirquet's teaching in the early editions of Clinical Aspects of Immunology (sec Fig. I)— I regret to say, witb little lasting impact. The stand we took was not for pedanticism. for von Pirquet's concept of allergy {as expressed in his 1906 paf>er) avoids all contradictions and absurdities. We are now, as I have said, back again to the 'dark ages' where the harmful paradoxical or hypersensitivity reactions are manifestations of the immune responses—a return to the status quo ante. A very distinguished physician, medical teacher and writer (Dr A. E. Clarke Kennedy) came up to me one day and said "You immunologists are quite absurd—how can you have auto-immune diseases? How can you be immune to yourself'?' To one who always talks of auto-allergicdiscases,thiswashard indeed. After 3 yearsof retirement. I still regret this lost opportunity very much. 673
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Biological Response
Clinical Outcome IMMUNITY
ALLERGIC resp.
(profecMve)
(prejudices nothing)
HYPERSENSITIVITY (harmful)
IMMUNITY IMMUNE resp
(protective)
(prejudiced M
ALLERGY (harmful I t t Parodowcal-the very reason von Prrquet introduced the word 'allergy.'
Classification of the hypersensitivitv reactions
It was in the 1963 edition of Clinical Aspects of ImtmtnoItf^y that we first presented a simple classification (Types I IV) of the various hypersensitivity reactions. In inviting me to give this lecture, your President asked specifically, if I may quote from his letter: (i) how the ideas for such a classification emerged? and secondly (ii) how I now consider this classification in the light of new knowledge? To answer the first question. Gell and I were both in the teaching business and even in 1960 there was still considerable confusion in the literature on the hypersensitivity reactions. Many ofthe classical and significant papers went back over a 50 year period and. for instance, three quite distinct reactions were called 'anaphylaxis'. Having to teach is a great elarifier ofthe mind! I think the best way to answer your President's second enquiry— *how do 1 consider the classification in the light of new knowledge?' is to re-emphasize what we clearly stated at the time—lhat. as with all man-made classifications, il should remain for only so long as it is proving helpful. If it is considered to be no longer serving a purpose or is misleading it should be discarded! But this is for others lo decide.
Food allergic diseases In planning this talk. 1 was surprised how frequently our researches, in the past, had been related to food allergy. Food allergy, of course, means no more and no less than allergy to foods which may be either protective and beneficial or harmful, causing disease—food allergic disease (Fig. 2). The main protective roles of allergy to foods and other contents of Ihe gut (mostly bacteria) are
X
Kig. 1. The intended meaning of the word allergy—response (resp.), state and reaction, v ' ' indicates correct usage. X indicates the common bul wrong usage. Il is clearly paradoxical that the imtmtne (protective) response should produce the harmful allergic reactions.
probably: (i) preventing excessive absorption, from the gut. of antigenic food molecules (before they have undergone complete digestion); and (ii) using that imaginative euphemistn of Bienenslock. "protecting ihe internal milicit of the body from the sewer running right through it'. Without this normal allergic response and reactivity in the gut to foods, all of us would probably become clinically hyperscnsilivc lo many, if not all. the foods we eat (let alone succumb to microbial infections from the gut). So food allergy, as such, is not a bad thing! On the other hand, under certain cotiditioti.K and vircunisiance.s ihese same allergic responses may become exaggerated and involved in disease—food allergic disease. I wish to stress that it is \hcse partiiuiar conditions attd circwiisiancc.s, aboul which we are totally ignorant, and not ihe allergic reactions themselves. Why should this be? I will venture certain suggestions: firstly until fairly recently, there has been a complete lack of objective methods for testing the target organ (i.e. the gut) of patients for allergic reactivity: secondly, the lack of knowledge on the normal and abnormal permeability of the gul ti) protein molecules and the ability to measure it. Changing permeubility lo radio-labelled sugars is no measure of permeability lo proteins. Thirdly, there are virtually no appropriate and realistic animal models. Human patients with food allergic diseases (a small percentage of the whole population) present themselves to the clinic. There is no opportunity for this selection wilh laboratory animais. Also each species of laboratory animals behaves differently, which also makes for a diflicull choice. Lastly, I ihink the medical profession itself must bear some of the responsibility by not encouraging proper collahoralion between the experimentalist in his laboratory and the clinician in his clinic.
The Jack Pepys Lecture
Biological Response
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Clinical Outcome IMMUNITY + protection (1) Preventing excessive absorption ot tood antigens
(FOOD) ALLEROY Fig. 2. (Food) allergy is a biological response and is not necessarily harmful. When it is harmful and produces disease we have the (food) allergic diseases.
Many clinical practitioners do not even believe in food allergic diseases! Looking back now, 1 feel ashamed that so much of our own researches on tbod allergic disease has been dilettante, to say the least. For instance: With regard to coetiac disease We. at one time, asked the question whether the allergic reaction to gliadin in patienls with coeliac disease was a primary or secondary phenomenon as regards the aetiology. We first developed a very satisfactory and simple anlibody-Iabelled red cell assay for measuring gliudin antibodies in human sera [2]. We then examined sera of rabbits, rats and guinea pigs (all on very similar high gluten diets) with a view to selecting the animal species to use in our experiments. Rats had gliadin antibody levels comparable with those in normal humans. Rabbits had very high gliadin antibody levels as in human coeliacs while guinea pigs had no trace of serum antibodies! These were all healthy animals. The guinea pigs responded wilh high antibody levels if they were injected with gliadin [3]. But even if the gliadin was injected together wilh Freund's complete adjuvant (to encourage ihe development of delayed-type hypersensitivity as well as serum antibodies) the animals failed to develop any gut lesions even when fed high levels of gluten or even gliadin in alcohol. No socalled enteropathic changes were observed*. These rather trivia! experiments seemed, however, to indicate the requirement of some accompanying abnormality of the gut. *The collaboralion of Dr D. Wight gralcfully acknowledged.
^ - "
(II) From 'internal sewer': Bienenstock
^ (FOOD) ALLERGIC DISEASES (tiarmful)
Mccliatti.stns of diarrhoea in food aUergiv disease Another excursion we undertook concerns the mechanism of the diarrhoea so commonly seen as a manifeslation of food allergic disease. The question asked by our colleagues Cuthbcrt and Baird (pharmacologists) and ourselves was could electrogcnic chloride secretion, associated with the secretory diarrhoeas, be also generated by allergens reacting wilh gut mucosa of a sensiti/ed animal in essentially what would be a Type 1 hypersensilivlly reaction? The gut mucous membrane (comprising epithelium. basement membrane, and lamnia propria containing the mucosal mast cells) of guinea pigs sensitized to /{lactoglobulin. by previous injection or by simply drinking cows' milk, was mounted, as a tissue diaphragm, across an Ussing chamber with monitoring electrodes in place on both sides. Any generated electric current, produced by addition of allergen (/Macloglobulin), can be measured, under so-called voltage-clamped conditions, as shorl circuit current. Both colon and ileum were tested [4.5]. On the samples from the colon, addition of/Mactoglobulin. but on the basolaterai side only, produced a large inward flowing current due to inappropriate chloride ion secretion. This was inhibited by indomeihacin suggesting prostanoids as mediators. With samples from the ileutn, challenging with /Macloglobulin from either side produced an inward fiowing current associated with a fiux of bicarbonaie ions and 5 hydroxy tryplamine seemed to be ihe mediator. Secretion of fluid could also be measured. Unfortunately, for quite non-scientific reasons these researches had to be terminated here but these findings
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indicated lhal diarrhoea in food allergy could be explained by a Type I reaction triggered by allergen reacting on mucosal mast cells. Further, as the guinea pigs, on which the test were done, themselves exhibited no diarrhoea, attention is again directed to: (i) the question of gut permeability; and (ii) the concept of latent sensitivity.
significant to remember that both man and the guinea pig behave very similarly with regard to anaphylaxis and, in both species, the lung is the major shock organ. It is also quite accepted that, in infants, aspiration or inhalation of milk is common. Such an intra-tracheal challenge with cows' milk is the crux of the modified anaphylaxis model for cot-death. The sequence of events according to this hypothesis is:
Cot-death
Sensitization to cows' milk (latent or otherwise begins when cows' milk is introduced into the infant's diet (no dissent here!) The anaphylactic reaction which kills the infant occurs during sleep (deep sleep, as light anaesthesia, is presumed to modify the reaction) following regurgitation (gastrooesophageai reflux) of gastric contents (containing milk)—and inhalation of some of this material, including the milk allergens, into the lungs.
This question oflatent anaphylactic sensitivity is also very relevant to our researches on cot-death, which go back over a 30 year period beginning when Dr Parish was working with me in Cambridge. I want simply to consider three issues; (i) this matter of latent sensitivity; (ii) hazardous routes for anaphylactic challenge; and (iii) oral tolerance. Guinea pigs (and please keep young infants in mind also) drinking cows" milk appear to be wonderfully healthy (with lovely glossy coats!); but despite this excellent health they develop a latent anaphytactic sensitivity to ihe proteins in cows' milk. This latent sensitivity can be revealed: either (i) by intravenous injection of milk proteins—^in which case the guinea-pigs die: or (ii) by in vitro tests on isolated organs. These hazards are of little concern for the guinea pig—that is unless, of course, some *hcll-bent' immunologist comes along and injects them intravenously. In much later experiments in 1980 McLaughian and myself [6] showed that a latent anaphylactic sensitivity to milk proteins exists also in some infants (as. of course, would be expected!), it is obviously not possible with infants, however, to use the intravenous challenge to reveal this, but it is possible to perform in vitro tests on freshly taken random blood samples. The test was measuring the histaminc-relcase from the blood basophils on addition of milk allergens. Our findings showed that 37"/n of infants, under 26 weeks of age, showed no release of histamine at all, white 24% released over 10'^ of their blood histamine—and one-half of these, i.e. 12% of the lotal sample released 20 65% of their blood histamine^—a figure indicating considerable sensitization to cows' milk. However, no-one in his right mind (not even that hellbent immunologist!) is going to inject infants intravenously with cows' milk proteins and so supposedly such a latent anaphylactic sensitivity does not put the infants at any risk at all. This is ///.sv not so for, on the basis of our experimental evidence, such infants would be at considerable risk from aspiration or inhalation of milk. Parish. Barrett and myself [7] back in 1960 showed that, in anaphylactically-sensitized guinea pigs intra-tracheal administration (equivalent to inhalation) was just as lethal a route for challenge as was intravenous injection. It is also
This is really no "pie in the sky" armchair hypothesis. There is a large body of supporting data from both studies in infants and experiments in guinea pigs 18,9], but as yet there is still no hard proof either for oragain.st it and proof might elude us for some time. Professor Holgate has a group in his department developing assays for stable mediators of the anaphylactic reaction in man, which if measurable post-mortem, up to many hours after death, might possibly open up new opportunities in establishing whether any sudden death had been brought about by modified anaphylaxis. The events we envisage really should occur. We should possibly ask why such reactions do not occur more frequently! So we come to the last of the three considerations r wished to put before you—namely oral tolerance. Oral tolerance Could oral tolerance be the reason why such anaphylactic reactions to cows" milk in infants do not occur more frequently? In 1987, together with Weaver and Koritz, we [10, see also 11] showed that the development of latent anaphylactic sensitivity to cows" milk in milk-drinking guinea pigs was prevented if the baby guinea pigs began drinking cows" milk (instead of their mothers" milk) before the second day of life (Fig. 3). A clinical situation possibly indicating this phenomenon in infants comes to mind from observations of Professor D. P. Davies in Cardiff (personal communication). He has stated that the incidence of cot-death is very uncommon indeed in Hong Kong, where (also according to his findings) al! infants are totally bottle-fed from birth. This extremely low incidence of cot-death could be explained by oral tolerance to the development of anaphylactic antibody as shown in guinea pigs.
The Jack Pepys Lecture
Fig. 3. Oral tolerance to cows' milk proteins: anaphylactic sensitivity (shaded areas) developing in 36 baby guinea pigs drinking eows' milk (pasteurized) from the second day of life. During life the anaphylactie sensitivity was shown by testing the sera (obtained by eardiae puncture) every 2 weeks for milk antibodies giving passive eutaneous anaphylaxis. On the I IDth day, four guinea pigs, ehosen al random, from group A all failed, on direct challenge, to suffer anaphylaxis while another four guinea pigs from group B all died on challenge from anaphylaxis. Taken with permission from Weaver, Koritz and Coombs (1987) [10].
Comment on cot-death research I have been away from the research bench for the last 3 years and as I have said I have had ample time for refiection. And concerning cot-death: (i) I am still totally astonished that the 'anaphyiactic hypothesis' (as well as the experimental work upon which it is based) is not taken much more seriously, especially by those whose responsibility it has been to promote and direct research into these deaths. I can only think they don't really understand! (ii) Suffocation by external application (i.e. smothering) has always been accepted as a possibility—and in each case of cot-death needs to be excluded. But sulTocation brought about internally by anaphylactic bronchial constriction is not accepted as a real possibility! Why? (iii) In retrospect, 1 think T have been wrong in the past in not being more aggressive, vocally, in forcing the hypothesis onto the agenda for debate—but without proof in the cadaver for anaphylactic death it is not easy to do this (but others could do it!), (iv) Were the hypothesis, in the future, substantiated it would surely represent the most exotic example of food allergic disease.
Rheumatoid arthritis The Types I-IV classification of the hypersensitivity reactions, which your President suggested I discuss, is not only a clinical aid: but should also be helpful in interpreting pathological lesions with regard to aetiology. Yet rheumatoid arthritis, with abounding hallmarks suggesting major allergic involvement, still has an unknown aetiology! The 'scratchings'—I use this word advisedly— of literally hundreds and hundreds of immunologists over
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>A
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30
UO
50
60
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m m
Days after birth
the last 40 years have not solved the enigmas of this disease. My colleagues and I have also been \cratchers' for a period of 20 years. But our scratchings have, on the whole, ut least been aimed at elucidating the essential initiating events—mostly with the help of animal models. A successful model for this disease must, in my opinion, accommodate: (i) the characteristic pathological features: (ii) the various modulating clinical patterns of the disease—with eventual chronicity; (iii) that tell-tale characteristic of thediseasc—almost pathognomonic, i.e. rheumatoid factor (RF) and immune complexes in the serum; (iv) the experimental procedures used must not involve direct injection of antigens into the joints (this does not occur in real life!): (v) the choice of the experimental animal, which is a very difficult decision. My introduction to research on rheumatoid disease was with Dame Honor Fell, at that time (1965) Director of the Strangeways Laboratory in Cambridge. She and her biochemist colleague, Dr Dingle were then primarily interested in the breakdown of cartilage and bone in chick embryo explants growing, in vitro, in organ culture. The question we asked was could degradative processes be initiated by adding antibody raised against cell membrane antigens and complement to the explants growing in culture. Complete breakdown of cartilage matrix and some resorption of bone could, in fact, be brought about under these conditions and the changes were reversible by transferring the explants back into normal medium [12]. Biochemical analysis of the culture fluids indicated that the loss of cartilage structure followed the release of lysomal proteases from the chondrocytes, and the cartilage proteoglycans being degraded by these proteases. The assumption was that antibody and complement
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acting at the cell surface triggered the release into the extracellular lluid oflhese lysosomal enzymes [13]. I specially mcniion these experiments as they presented the first prototype example for a Type II cytostimulatory (as opposed lo cytotoxic) hypersensitivity reaction in our Types I-IV classification. We suggested thai another example could be that of LATS (long acting thyroid stimulator) in thyrotoxic patients. A further example could be in relapsing polychondritis where an IgG autoantibody reaetion with chondrocytes could stimulate these cells to secrete iheir lysosomal hydrolases. But 1 must return to our intention of focusing on the primary cause(s) or initiating events of rheumatoid joint disease. Models for investigating the primary events 'Immune complex' disease Having familiarized ourselves with selected literature and using our best judgement we decided to examine, morbid-histologically. the joints of rabbits with experimental serum sickness or immune complex disease. We were encouraged in this course by the views of the distinguished rhcumatologist. Charles L. Christian of New York. To quote his opinion—"if the immune response (he meant allergic reactions!) to an environmental antigen were responsible for the pathogenesis of rheumatoid arthritis, the closest experimental model would be chronic serum sickness.' So we proceeded and in a series of papers in the middle 1970s. Poole. Oldham and myself reported [14-17] on the development of rhcumatoid-like lesions in the synovial capsules and joints of rabbits following repeated intravenous injections of bland foreign scriun with its very many and varied antigens (or even cows' milk!). No injections were made into the joints. Ten to 20% of these experimental rabbits developed the following pathological synovial changes in their knee joints 20 80 days after commencing the schedules of injections: (i) enlargements and hyperplasia of lining cells of the synovial membranes; (ii) accumulation of small lymphocytes and plasma cells, often around small blood vessels; (iii) focal lymphocytes accuinulaiion and evidence of germinal centre-formation; (iv) villus formation; and even (v) pannus formation with loss of proteoglycan from the adjoining cartilage. It was interesting that no polymorphonuclear leucocytes were seen in the synovia, but polymorphs were plentiful in the joint cavities. Antigen antibody complexes could be shown in the joint tissues by immuno-fluorescence—as in the human rheumatoid joint disease. Attempts to exacerbate the lesions by switching some of the antibodies to the IgE isotype [16] or incorporating a delayed hypersensitivity response were without effect [17].
Complexes induced by milk drinking Together with Jane Welsh and Angela Hanglow, we also tried to produce such joint lesions under more natural conditions with rabbits simply drinking cows' milk over long periods—a regimen in rabbits which we had previously found produced high levels of serum antibodies to milk proteins. Within 12 weeks up to W/,, of the rabbits had similar lesions in the synovial capsules of their knee joints although the lesions tended to be milder than in the injected rabbits [18-20]. Also, after 12 weeks, the lesions were regressing and at this time it was possible to show the secretion into the gut of secretory IgA antibodies to milk proteins. These IgA antibodies could be extracted from the faecal pellets. This was a possible example of a protective role of food allergy—that of blocking further absorption of native milk proteins. To have any relevance to rheumatoid arthritis (i) the joint lesions had, on the whole, lo be progressive and (ii) above all. the animals had also to produce RF—an autoanlibody to autologous IgG—which none of the milkdrinking animals did. In the light of these two points the milk-drinking experiments were discontinued and also the serum-injection experiments were interrupted for the time being as injecting serum made testing for RF difficult—certainly difficult to interpret for the simple reason we were injecting IgG—in either scrum or milk. However, it was appreciated that the relatively mild and transient lesions following milk-drinking probably reflected the underlying pathogenic mechanism for what Panush [21] in his allergy clinic and others call allergic synovitis or food-induced allergic arthritis or arthralgia (possibly more correct). Joint lesions produced following intravenous injeclion of killed bacteria Another series of experiments was then initialed, focusing especially on the experimental production in rabbits of RF a .v//u' qua mm for a rheumatoid model In man. besides rheumatoid disease. RF is also found to very high titres in bacterial endocarditis. And again in 1961, Christian together with Abruzzo [22] had shown that RF could be stimulated in rabbits by intravenous injection of killed bacteria using very similar schedules to those used in 1953 by my wife and myself [23] to stimulate immunoconglutinin auto-antibody, not to IgG. but to autologous fixed complement. Immunoconglutinins are also produced in rheumatoid disease! In our further experiments [24] we injected rabbits intravenously with E. eoli or B. .suhtilis and. as previously reported by Abruzzo and Christian [22] the rabbits produced truly autologous R.F. However, we did something that Abruzzo and Christian did nol do. We examined the knee joints of the rabbits, morbid histoiogi-
The Jack Pepys Lecture
cally. and to our surprise and gratification a large number had (i) significant rheumatoid-iike lesions in the synovia atid (ii) large numbers of T lymphocyles in the synovial fiuids. These findings, together with those of Aoki and his colleagues [25] in Japan on rabbits developing even more severe joint lesions by intramuscular injection of killed E. coli emulsified in Frcund's incomplete adjuvant, indicated a very promising line to be explored further, especially in conjunction with procedures generating immune-complexes. However, there results were obtained and published only 2 years before I was due to retire and Granting Bodies, devoted to rheumatoid research, in their wisdom were not sympathetic to extending the financial support. In these circumstances we were emasculated, a hazard of research workers these days, and, as a consequence, these lines of investigation were brought to an abrupt end! Concluding remarks It is now 3 years since my retirement and, looking back on my researches on the hypersensitivity reactions, certainly the biggest regret, and that which I still nurse, was being compelled to terminate these investigations on rheumatoid disease at that very incomplete, yet promising stage. It would be a great satisfaction to me to see these lines of investigation continued. On coi-dcaili. my regret is of a quite different kind. Our investigations were completed. Further research on the anaphylaxis model must come from others with a diflerent expertise. My regret is that the hypothesis has seldom been placed on the agenda for proper scientific discussion. As regards the word 'allergy' I can only repeat what Richard Wagner [26], the medical biographer of von Pirquet, wrote in 1968 thai Immunology had a need for such a word uncommitted with regard to either immunity or hypersensitivity, but embracing both. How right he was, I am really most grateful for the opportunity the Jack Pepys Lecture has given me to put before you these very personal refiections on the hypersensitivity reaction and to pay my respects to Professor Pepys. References 1 von Pirqucl C. Allergic. Miinch mcd Wochcnschr 1906; 30:1457-8. 2 Kicffcr M. Frazier PJ, Daniels NWR. Ciclitira PJ. Coombs RRA, Scrum antibodies (measured hy MRSPAH to alcoholsoluhlc gliadin.s in adult coeiiac patients. J Immunol Methods 1981; 42:129-36. 3 Coombs RRA. KiefferM, Fraser DR, Frazier PJ. Naturally developing antibodies to wheat gliadin fractions and to alher cereal antigens in rabbiis, rats and guinea pigs on
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normal laboratory diets. Int Archs Allergy appl Imniiin 1983; 70:200-4. 4 Cuthberl AW, McLaughlan P, Coombs RRA. Immediate hypersensitivity reaction to/Mactoglobulm ini he cpilhclium lining of the colon of guinea pigs fed cows' milk. Int Archs Allergy Appl Immun 1983; 72:34 40. 5 Baiid AW, Coombs RRA, McLaughlan P. Cuthberl AW. Immediate hypersensitivity reactions to cows" milk proteins in the isolated epithelium from ileumofmilk drinking guinea pigs: comparison with eolonic epithelia. Int Archs Allergy app! Immun 1984; 75:255 65. 6 McLaughian P. Coombs RRA, Latent anaphylactie sensitivity of infants to cows'milk proteins: histamine release from blood basophiis, Clin Allergy 1983; 13:1 9, 7 Parish WE, Barrett AM, Coombs RRA. Inhalation of cow's milk by sensitized guinea pigs in the eonscious and anaesthetized state. Immunology 1960; 3:307 24. 8 Coombs RRA McLaughlan P. The enigma of cot death: is the modified-anaphyla.\is hypothesis an explanlation Tor some cases? Lancet 1982; i:I388 9, 9 Coombs RRA, Holgate ST. Allergy and cot death: with special focus on allergic sensitivity to cows' milk and anaphylaxis. Clin Exp Allergy 1990; 20:359 66. 10 Weaver LT, Korit/ TN. Coombs RRA. Tolerance to orally induced anaphylaetie sensitization to cow's milk proteins and patency ofthe intestinal mucosa in the neonatal guinea pig. Int Arch Allergy appl Immun 19S7; 83:220-2. 11 Coombs RRA Devey ME Anderson KJ. Relractariness to Linaphylaetic shock after continuous feeding of cows'milk to guinea pigs, Clin exp Immunol 1978; 32:263-71. 12 Fell HB, Coombs RRA, Dingle JT. The breakdown of embryonic (chick) cartilage and bone cultivated in the presence of complement-suHicient antiscrum. 1, Morphological changes, iheir rcversibiliiy and inhibition. Int Arch Allergy 1966; 30:146-76, 13 Dingle JT, Fell HB. Coombs RRA. The breakdown of embryonic cariilage and bone cultivated in the presence of complement-sufficient antiserum. 2. Biochemical changes and the role ofthe lysosomai system, Int Arch Allergy 1967; 31:283 303. 14 Poole AR. Coombs RRA. Rheumutoid-like joint lesions in rahbits injected intravenously with bovine serum. Int Arch Allergy appl Immun 1977; 54:97 M 3. 15 Poole AR, Oldham G. Coombs RRA. Early rheumatoidlike lesions in rabbits injected with foreign serum: relationship to localization of immune complexes in Ihe lining tissues of joints and cellular content of synovial fluid. Int Arch Allergy appl Immun I97S: 57:135^5, 16 Oldham G. Coombs RRA. Early rheumatoid-like joint lesions in rabbits injected with foreign serimi or milk proteins. HI. Influence of concomitant !gH-like antibodies and ofthe breed of rabbit, Int Arch Allergy appl Immun 1980:61:81 90, 17 Oldham G, Bowyer DR, Coombs RRA, Early rheumatoidlike joint lesions in rabbits injected with foreign serum, IV. Influence of delayed type hypersensitivity, Int Arch Allergy appl Immun 1981; 65:114-20.
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18 Welsh CJR, Hunglow AC. Conn P, Barker THW. Coombs RRA. Early rhcumaioid-likc synovial lesiotis in rabbits drinking cow's milk. I. Joint pathology. Int Archs Allergy appl Imtnun 1985; 78:145-51. ly Hanglow AC, Welsh CJR, Conn P, Coombs RRA. Early rhcumatoid-like synovia! lesions in rabbits drinking cow's milk, II. Antibody responses lo bovitic serum proteins. Int Arch Allergy appl Immun 1985: 78:152-60. 20 Welsh CJR, Hanglow AC, Conn P. Coombs RRA. Comparison of the arthritogenic properties of dietary cow's milk, egg albumin and soya milk in experimental animals. Int Arch Allergy appl immun 1986: 80:192 9. 21 Paniish RS, Stroud RM, Webster EM. Food-induced (allergic) arthritis: inflammatory arthritis exacerbated by milk. Arih Rheum 1986: 29:220-6. 22 Abrtizzo JL. Christian CL. The induction of a rheumatoid faclor-hke substance in rabbits. J Exp Med 1961; 114:791806.
23 Coombs AM, Coombs RRA. The conglutination phenomenon. IX. The production of immuno-conglutinin in rabbils. JHyg{Camb.) 195.^: 51:509-31. 24 Hanglow AC. Welsh CJR. Conn P. Pitts JM, Rampling A, Coombs RRA. Experimental induction of rheumatoid factor and joint lesions in rabbits after intravenous injection of killed bacteria. Annal Rheum Dis 1986; 45:50-9. 25 Aoki S. Ikuta K, Nonogaki T. Ito Y. Induction of chronic polyarthritis in rabbits by hypcritnmunization with Escherichia coli. I. Pathological and serological features in two breeds of rabbits. Arthr Rheum 1985; 28:522 8. 26 Wagner R. Clemens Von Pirquet—His life and work. Baltimore: Johns Hopkins Press, 1968.
