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Lymphokines
1490
Lymphokines INCREASING attention is being paid to the question
resources; but this must
depend on local enterprise, local gain efficiency and local pride a prudent distribution of money, staff, and equipment, and this is hardly feasible while in each area the general medical services are financially divorced from the rest. Where the centre can help the periphery is in providing guidelines on the money and effort to be devoted to the extremely expensive but often only marginally helpful forms of treatment which have been developed in the past The clinical, ethical, and human two decades. problems these present are complex: partial solutions (there will never be perfect answers) may best be sought by political decisions informed by public opinion on the one hand and expert advice on the other.
with from
a
clear
to
With friends of the Health Service busily tidying up loose ends, its opponents are no less intent on undermining its structure or at least on setting up The people-a majority-who have a rival one. the N.H.S. include a full share embraced cheerfully of the articulate well-to-do; and it is no doubt partly owing to their participation in the N.H.S. that relations between N.H.S. staff on the one hand and patients on the other are so relatively good. Any Government setting out to destroy or seriously weaken the Health Service would do so at its peril. The minority who want no truck with the collectivism of the N.H.S. must look for salvation to an alternative system sustained by personal payment or private insurance. Only a very few could manage personal payment. As to private insurance, in the United Kingdom existing insurance schemes, because they lean for capital and other expenses on the State Service, provide no reliable index. A truly independent service would be vastly more costly and could fall within the reach of only a handful of people; and any second system would tend both to weaken and to raise the cost of the existing one. No country-literally no country-can now afford more than one health-service system. Skills, techniques, buildings, and equipment are becoming so expensive and so scarce that pluralism, where it still survives, must give way to singularity-but to a singularity in which experiment and innovation (for instance, in systems of hospital care) are actively and constantly encouraged. This truth will be concealed for as long as possible by insurance companies and other entrepreneurs; but it cannot be hidden for ever. In countries where medical expenses are still met from personal purses with or without an element of
private insurance, any long or complicated illness may spell financial ruin for families which, until the illness, were not poor. This reality, if nothing else, will sooner or later drive other countries to follow the example of the National Health Service Act of 1946-Britain’s most important single item of social legislation in a century.
of how cellular immune responses are mediated in man and laboratory animals. There is now abundant evidence that lymphocytes, activated under certain conditions by various antigens, release substances known as lymphokines, lymphocyte effector mole-
cules,
or
lymphocyte-associated products.I-4 Lym-
phokines have been characterised by DUMONDE and his colleagues 1-3 as" cell free soluble factors which are generated during interaction of sensitised lymphocytes with specific antigen but which are expressed without reference to immune specificity ".1 GRANGER4 has described two categories of lymphokines-materials secreted by activated lymphoid cells and associated with cell-free culture fluids, and materials which can be extracted from intact lymphoid cells. The first and larger group includes the familiar lymphocyte-transforming factors (L.T.F.), chemotactic factors, macrophage inhibiting and activating factors (M.I.F. and M.A.F.), cytostatic and cytotoxic factors affecting macrophages or lymphocytes, skin reactive factor (S.R.F.), and interferon-like factors. The second and much smaller group includes LAWRENCE’S problematical transfer factor (T.F.)5 which, since it confers specific immune responsiveness, should probably be regarded as different from
lymphokine.I-3 Thymus-derived (T) lymphocytes are generally regarded as the major source of lymphokines,6 but a
true
the evidence for this view is still indirect.7-9 Work on the thymus-dependence and bursa-dependence of M.I.F. in the chicken suggests that T cells are initially involved alone ; later, B cells may also be implicated.lo It is not known whether a single activated lymphocyte generates one or several lymphokines. Possibly lymphokines may be formed by other cell types such as macrophages and granulocytes 4; but the difficulties of excluding contamination with lymphoid cells and the formation of lymphokine-like artefacts as a byproduct of cell breakdown make such claims hard to evaluate. Lymphokines appear to be released in response to various stimuli. The first and most obvious is 4 exposure to antigen-a process of specific induction. The antigens concerned may be soluble or particulate, and fragments as well as complete molecules may be effective." Lymphokines may also be induced non1. 2. 3. 4. 5. 6. 7. 8.
Dumonde, D. C., Wolstencroft, R. A., Panay, G. S., Matthew, M., Morley, J., Howson, W. T. Nature, 1969, 224, 338. Dumonde, D. C. Proc. R. Soc. Med. 1970, 63, 899. Dumonde, D. C., Maini, R. N. Clin. Allergy, 1971, 1, 123. Granger, G. A. Ser. Hœmat. 1972, 5, no. 4, p. 8. Good, R. A. Cell. Immun. 1972, 3, i. Raff, M. C. Nature, 1973, 242, 19. Pick, E., Krejci, J., Turk, J. L. ibid. 1970, 225, 236. Pick, E., Brostoff, J., Krejči, J., Turk, J. L. Cell. Immun. 1970,1, 92.
9. 10. 11.
Kelly, R. H., Wolstencroft, R. A., Dumonde, D. C., Balfour, B. M. Clin. exp. Immun. 1972, 10, 49. Oates, C. M., Bissenden, J. F., Maini, R. N., Payne, L. N., Dumonde, D. C. Nature New Biol. 1972, 239, 137. Bergstrand, H., Kallén, B. Cell. Immun. 1972, 3, 660.
1491
specifically in mitogens such
unsensitised cells as
incubated with
phytohsemagglutinin (P.H.A.).8,9
There is also a third miscellaneous group of conditions where lymphokines are generated, such as in continuous cell-lines.12 Irrespective of the stimulus, the release of lymphokines seems to be rapid, appearing (in the case of M.I.F.) within hours and continuing for several days.13 Secretion of lymphokines thus begins well before morphological transformation is completed, and the process seems to be initially independent Of D.N.A. synthesis and cell division. On the other hand, release of lymphokines is blocked by inhibitors of protein synthesis such as actinomycin D and puromycin.8,9,14 The time-scale of events suggests that lymphokines may already be partly or completely formed in their cell of origin and that stimulation provokes their transport and extracellular release.4 The amount and type of lymphokines produced depend on the nature and intensity of the stimulus ;-, but it appears that usually a mixture of lymphokines is elaborated.l-4 This diversity of the lymphokine response is particularly difficult to analyse, since factors with mutually antagonistic effects may be demonstrable within the same supernatant. A second, more general problem is that most lymphokines, whether present in whole supernatants or in fractions, have to be assayed in various in-vitro systems. Invivo procedures are feasible for investigating inflammatory factors and the lymph-node activating factor (L.N.A.F.) but the results with several other lymphokines tested in animals continue to provoke controversy, mainly directed to the specificity and reproducibility of the changes observed. Reactions of lymphokines with target cells are specific for a given cell type such as the macrophage but not for a given species: cross-reactions with the same type of target cell from different species are characteristic of lymphokines, though there may be variations in the sensitivity of such target cells according to their origin.4 Details of the interaction between liberated lymphokines and target cells are almost entirely lacking: receptors sensitive to proteolytic enzymes may be involved4 and it is possible that at least some selectivity for the action of lymphokines is determined by the nature and distribution of these receptor sites on the-target-cell membranes. Electron microscopy has been done on the contact zone of membranes of activated lymphocytes attached to target cells,15 and
cytological techniques such as freeze-etching electron microscopy 16 may provide more insight
newer
and into subcellular events at the cell membrane and also in the depths of the cell. But it seems likely that problems of specificity will complicate the interpretation of any such ultrastructural changes. Much discussion has centred round the chemical 12. Glade, P. R., Hirschhorn, K. Am. J. Path. 1970, 60, 483. 13. Bennett, B., Bloom, B. Transplantation, 1967, 5, 996. 14. Lolekha, S., Gotoff, S. Cell. Immun. 1971, 2, 386. 15. Able, M. E., Lee, J. C., Rosenau, W. Am. J. Path. 1970, 60, 421. 16. Scott, R. E., Marchesi, V. T. Cell. Immun. 1972, 3, 301.
heterogeneity of lymphokines. They are macromolecules, usually protein or glycoprotein, though none has yet been completely purified. The chemical structure of M.I.F. has been partly characterised in guineapig 17 and man,ls and, again in the guineapig, chemotactic factors have been convincingly separated.l9 Some controversy surrounds the molecular weight of M.I.F., and the daunting possibility that there are different molecular species of lymphokines cannot be excluded.17 It will be obvious that technical aspects are still of overriding importance in work on lymphokines, and that every aspect of handling lymphokine-rich supernatants-their production, storage, assay and chemical analysis-needs to be rigidly controlled. Nevertheless, assays for at least one lymphokine (M.I.F.) are now well established and are used in clinical immunology as an index of cell-mediated immunity 3-for instance, in pollen hypersensitivity,2o autoallergic diseases,3 granulomatous hypersensitivity,21 and in monitoring impending graft rejection 22-24though the consistency of results from different laboratories still needs to be improved and there is scope for further modifications in the basic techniques.25 M.I.F. and, in the future, other lymphokine assays are likely to be increasingly used in the diagnosis and management of immunological conditions, and, possibly, as an eventual means of treatment 3; but much still remains to be clarified about their wider implications. The basic immunobiology and chemistry of lymphokines are beset with formidable problems, but their putative role as a means of coordinating and amplifying some components of the immune and inflammatory responses is a measure of their great potential importance. M.I.F.
and
two
PULMONARY COMPLICATIONS OF BURNS THE high mortality (80-90%) associated with pulmonary complications of burn injury has lately been highlighted by Achauer and his colleagues, 26 who report such changes in 22 out of 100 patients admitted to their clinic during one year. The incidence
of such
complications was correlated mainly with the severity and extent of the burn and with a history of being burned in an enclosed space (21 out of the 22). Achauer et al. describe three main categories of 17.
Remold, H. G., Katz, A. B., Haber, E., David, J. R. ibid. 1970, 1,
18. 19. 20. 21.
Rocklin, R. E., Remold, H. G., David, J. R. ibid. 1972, 5, 436. Ward, P. A., Remold, H. G., David, J. R. ibid. 1970, 1, 162. Brostoff, J. Proc. R. Soc. Med. 1970, 63, 905. Jones Williams, W., Pioli, E., Jones, D. J., Dighero, M. J. clin. Path. 1972, 25, 951. Weeke, E., Weeke, B., Bendixen, G. Acta med. scand. 1970, 188,
133.
22.
307.
Eddleston, A. L. W. F., Smith, M. G. M., Mitchell, C. G., Williams, R. Transplantation, 1971, 12, 11. 24. House, A. K., Boak, J. L., Carolin, D. ibid. 1973, 15, 359. 25. Federlin, K., Maini, R. N., Russell, A. S., Dumonde, D. C. J. clin. Path. 1971, 24, 533. 26. Achauer, B. M., Allyn, P. A., Furnas, D. W., Bartlett, R. H. Ann. Surg. 1973, 177, 311. 23.
Lymphokines INCREASING attention is being paid to the question
resources; but this must
depend on local enterprise, local gain efficiency and local pride a prudent distribution of money, staff, and equipment, and this is hardly feasible while in each area the general medical services are financially divorced from the rest. Where the centre can help the periphery is in providing guidelines on the money and effort to be devoted to the extremely expensive but often only marginally helpful forms of treatment which have been developed in the past The clinical, ethical, and human two decades. problems these present are complex: partial solutions (there will never be perfect answers) may best be sought by political decisions informed by public opinion on the one hand and expert advice on the other.
with from
a
clear
to
With friends of the Health Service busily tidying up loose ends, its opponents are no less intent on undermining its structure or at least on setting up The people-a majority-who have a rival one. the N.H.S. include a full share embraced cheerfully of the articulate well-to-do; and it is no doubt partly owing to their participation in the N.H.S. that relations between N.H.S. staff on the one hand and patients on the other are so relatively good. Any Government setting out to destroy or seriously weaken the Health Service would do so at its peril. The minority who want no truck with the collectivism of the N.H.S. must look for salvation to an alternative system sustained by personal payment or private insurance. Only a very few could manage personal payment. As to private insurance, in the United Kingdom existing insurance schemes, because they lean for capital and other expenses on the State Service, provide no reliable index. A truly independent service would be vastly more costly and could fall within the reach of only a handful of people; and any second system would tend both to weaken and to raise the cost of the existing one. No country-literally no country-can now afford more than one health-service system. Skills, techniques, buildings, and equipment are becoming so expensive and so scarce that pluralism, where it still survives, must give way to singularity-but to a singularity in which experiment and innovation (for instance, in systems of hospital care) are actively and constantly encouraged. This truth will be concealed for as long as possible by insurance companies and other entrepreneurs; but it cannot be hidden for ever. In countries where medical expenses are still met from personal purses with or without an element of
private insurance, any long or complicated illness may spell financial ruin for families which, until the illness, were not poor. This reality, if nothing else, will sooner or later drive other countries to follow the example of the National Health Service Act of 1946-Britain’s most important single item of social legislation in a century.
of how cellular immune responses are mediated in man and laboratory animals. There is now abundant evidence that lymphocytes, activated under certain conditions by various antigens, release substances known as lymphokines, lymphocyte effector mole-
cules,
or
lymphocyte-associated products.I-4 Lym-
phokines have been characterised by DUMONDE and his colleagues 1-3 as" cell free soluble factors which are generated during interaction of sensitised lymphocytes with specific antigen but which are expressed without reference to immune specificity ".1 GRANGER4 has described two categories of lymphokines-materials secreted by activated lymphoid cells and associated with cell-free culture fluids, and materials which can be extracted from intact lymphoid cells. The first and larger group includes the familiar lymphocyte-transforming factors (L.T.F.), chemotactic factors, macrophage inhibiting and activating factors (M.I.F. and M.A.F.), cytostatic and cytotoxic factors affecting macrophages or lymphocytes, skin reactive factor (S.R.F.), and interferon-like factors. The second and much smaller group includes LAWRENCE’S problematical transfer factor (T.F.)5 which, since it confers specific immune responsiveness, should probably be regarded as different from
lymphokine.I-3 Thymus-derived (T) lymphocytes are generally regarded as the major source of lymphokines,6 but a
true
the evidence for this view is still indirect.7-9 Work on the thymus-dependence and bursa-dependence of M.I.F. in the chicken suggests that T cells are initially involved alone ; later, B cells may also be implicated.lo It is not known whether a single activated lymphocyte generates one or several lymphokines. Possibly lymphokines may be formed by other cell types such as macrophages and granulocytes 4; but the difficulties of excluding contamination with lymphoid cells and the formation of lymphokine-like artefacts as a byproduct of cell breakdown make such claims hard to evaluate. Lymphokines appear to be released in response to various stimuli. The first and most obvious is 4 exposure to antigen-a process of specific induction. The antigens concerned may be soluble or particulate, and fragments as well as complete molecules may be effective." Lymphokines may also be induced non1. 2. 3. 4. 5. 6. 7. 8.
Dumonde, D. C., Wolstencroft, R. A., Panay, G. S., Matthew, M., Morley, J., Howson, W. T. Nature, 1969, 224, 338. Dumonde, D. C. Proc. R. Soc. Med. 1970, 63, 899. Dumonde, D. C., Maini, R. N. Clin. Allergy, 1971, 1, 123. Granger, G. A. Ser. Hœmat. 1972, 5, no. 4, p. 8. Good, R. A. Cell. Immun. 1972, 3, i. Raff, M. C. Nature, 1973, 242, 19. Pick, E., Krejci, J., Turk, J. L. ibid. 1970, 225, 236. Pick, E., Brostoff, J., Krejči, J., Turk, J. L. Cell. Immun. 1970,1, 92.
9. 10. 11.
Kelly, R. H., Wolstencroft, R. A., Dumonde, D. C., Balfour, B. M. Clin. exp. Immun. 1972, 10, 49. Oates, C. M., Bissenden, J. F., Maini, R. N., Payne, L. N., Dumonde, D. C. Nature New Biol. 1972, 239, 137. Bergstrand, H., Kallén, B. Cell. Immun. 1972, 3, 660.
1491
specifically in mitogens such
unsensitised cells as
incubated with
phytohsemagglutinin (P.H.A.).8,9
There is also a third miscellaneous group of conditions where lymphokines are generated, such as in continuous cell-lines.12 Irrespective of the stimulus, the release of lymphokines seems to be rapid, appearing (in the case of M.I.F.) within hours and continuing for several days.13 Secretion of lymphokines thus begins well before morphological transformation is completed, and the process seems to be initially independent Of D.N.A. synthesis and cell division. On the other hand, release of lymphokines is blocked by inhibitors of protein synthesis such as actinomycin D and puromycin.8,9,14 The time-scale of events suggests that lymphokines may already be partly or completely formed in their cell of origin and that stimulation provokes their transport and extracellular release.4 The amount and type of lymphokines produced depend on the nature and intensity of the stimulus ;-, but it appears that usually a mixture of lymphokines is elaborated.l-4 This diversity of the lymphokine response is particularly difficult to analyse, since factors with mutually antagonistic effects may be demonstrable within the same supernatant. A second, more general problem is that most lymphokines, whether present in whole supernatants or in fractions, have to be assayed in various in-vitro systems. Invivo procedures are feasible for investigating inflammatory factors and the lymph-node activating factor (L.N.A.F.) but the results with several other lymphokines tested in animals continue to provoke controversy, mainly directed to the specificity and reproducibility of the changes observed. Reactions of lymphokines with target cells are specific for a given cell type such as the macrophage but not for a given species: cross-reactions with the same type of target cell from different species are characteristic of lymphokines, though there may be variations in the sensitivity of such target cells according to their origin.4 Details of the interaction between liberated lymphokines and target cells are almost entirely lacking: receptors sensitive to proteolytic enzymes may be involved4 and it is possible that at least some selectivity for the action of lymphokines is determined by the nature and distribution of these receptor sites on the-target-cell membranes. Electron microscopy has been done on the contact zone of membranes of activated lymphocytes attached to target cells,15 and
cytological techniques such as freeze-etching electron microscopy 16 may provide more insight
newer
and into subcellular events at the cell membrane and also in the depths of the cell. But it seems likely that problems of specificity will complicate the interpretation of any such ultrastructural changes. Much discussion has centred round the chemical 12. Glade, P. R., Hirschhorn, K. Am. J. Path. 1970, 60, 483. 13. Bennett, B., Bloom, B. Transplantation, 1967, 5, 996. 14. Lolekha, S., Gotoff, S. Cell. Immun. 1971, 2, 386. 15. Able, M. E., Lee, J. C., Rosenau, W. Am. J. Path. 1970, 60, 421. 16. Scott, R. E., Marchesi, V. T. Cell. Immun. 1972, 3, 301.
heterogeneity of lymphokines. They are macromolecules, usually protein or glycoprotein, though none has yet been completely purified. The chemical structure of M.I.F. has been partly characterised in guineapig 17 and man,ls and, again in the guineapig, chemotactic factors have been convincingly separated.l9 Some controversy surrounds the molecular weight of M.I.F., and the daunting possibility that there are different molecular species of lymphokines cannot be excluded.17 It will be obvious that technical aspects are still of overriding importance in work on lymphokines, and that every aspect of handling lymphokine-rich supernatants-their production, storage, assay and chemical analysis-needs to be rigidly controlled. Nevertheless, assays for at least one lymphokine (M.I.F.) are now well established and are used in clinical immunology as an index of cell-mediated immunity 3-for instance, in pollen hypersensitivity,2o autoallergic diseases,3 granulomatous hypersensitivity,21 and in monitoring impending graft rejection 22-24though the consistency of results from different laboratories still needs to be improved and there is scope for further modifications in the basic techniques.25 M.I.F. and, in the future, other lymphokine assays are likely to be increasingly used in the diagnosis and management of immunological conditions, and, possibly, as an eventual means of treatment 3; but much still remains to be clarified about their wider implications. The basic immunobiology and chemistry of lymphokines are beset with formidable problems, but their putative role as a means of coordinating and amplifying some components of the immune and inflammatory responses is a measure of their great potential importance. M.I.F.
and
two
PULMONARY COMPLICATIONS OF BURNS THE high mortality (80-90%) associated with pulmonary complications of burn injury has lately been highlighted by Achauer and his colleagues, 26 who report such changes in 22 out of 100 patients admitted to their clinic during one year. The incidence
of such
complications was correlated mainly with the severity and extent of the burn and with a history of being burned in an enclosed space (21 out of the 22). Achauer et al. describe three main categories of 17.
Remold, H. G., Katz, A. B., Haber, E., David, J. R. ibid. 1970, 1,
18. 19. 20. 21.
Rocklin, R. E., Remold, H. G., David, J. R. ibid. 1972, 5, 436. Ward, P. A., Remold, H. G., David, J. R. ibid. 1970, 1, 162. Brostoff, J. Proc. R. Soc. Med. 1970, 63, 905. Jones Williams, W., Pioli, E., Jones, D. J., Dighero, M. J. clin. Path. 1972, 25, 951. Weeke, E., Weeke, B., Bendixen, G. Acta med. scand. 1970, 188,
133.
22.
307.
Eddleston, A. L. W. F., Smith, M. G. M., Mitchell, C. G., Williams, R. Transplantation, 1971, 12, 11. 24. House, A. K., Boak, J. L., Carolin, D. ibid. 1973, 15, 359. 25. Federlin, K., Maini, R. N., Russell, A. S., Dumonde, D. C. J. clin. Path. 1971, 24, 533. 26. Achauer, B. M., Allyn, P. A., Furnas, D. W., Bartlett, R. H. Ann. Surg. 1973, 177, 311. 23.