Summary of Discussion

Abstract

DR. THOMAS: We have been interested in the possible implication of Mycoplasma in human diseases other than primary atypical pneumonia, partly because it seems unreasonable for this ubiquitous class of microbes, known to be related causally to such a wide variety of diseases elsewhere in the animal and the plant kingdoms, to be responsible for only one or perhaps two varieties of human disease. Because of this special interest, the model originally uncovered by Henry Adler and associates seems particularly useful even though it involves turkeys and chickens, at first blush a long distance from human pathology. There are two reasons for interest in Adler's model. One is that it is possible with the S6 strain of Mycoplasma gallisepticum to produce lesions that resemble quite closely those that characterize human disease ascribed either to systemic hypersensitivity reactions or lesions of autoimmunity: to wit, polyarteritis nodosa, which the S6 strain produces with extraordinary reproducibility in virtually all of the arteries of the central nervous system, and a variety of arthritis that Adler and associates have recently described in detail, which is, like rheumatoid arthritis, regularly associated with the occurrence of polyarteritis with fibrinoid necrosis in the walls of arteries in the periarticular tissue and, by and large, only in those environments. It is true that chickens given a large enough dose of the S6 strain will also undergo arteritis in the central nervous system, but by far the most frequently involved arteries are those in the periarticular tissues. The arthritis itself is a spectacular lesion that is characteristically progressive and can become a chronic destructive disease. There is another reason for interest in the lesions produced by M. gallisepticum in the consideration of their possible relationship to human disease. This is that all of the lesions, the polyarteritis and the arthritis, are prevented or can be cured by treatment of the animals with gold salts. It has long been a source of puzzlement to students of human arthritis that while other proposed remedies for arthritis have come and gone down the decades, only two pharmaceutical agents seem generally accepted as being significantly effective against this disease in man. One of these is aspirin (and drugs related to aspirin), which at best has some kind of palliative effect and some effect generally described by the term antiinflammatory, that has little meaning but makes patients with arthritis feel better. The other drug is gold. You may be interested in knowing, as I certainly was, something of the story of how gold came into the armamentarium of rheumatology. It is a rather typical story about medicine. Sometime in the 1920's efforts were being made by Forrester and others to discover better pharmacologic agents for the management of pulmonary tuberculosis. At that time the realization had just dawned that metals were good for certain diseases, particularly syphilis, and, therefore, a study was begun involving treatment in large numbers of cases of pulmonary tuberculosis with every available metal that could be dissolved and injected, and among these was gold. Gold, and, indeed, all of the other metals tested, had no beneficial effect on pulmonary tuberculosis, but the clinicians involved in this study noticed that several patients with rheumatoid arthritis who had been included along with the tuberculous patients seemed to recover from their arthritis, and this was reported. Subsequently others confirmed the observation and since that time, to my knowledge, no one has failed (and many studies have been undertaken) to confirm the original observation that treatment with gold salts will, in a significant number of the patients with active intractable rheumatoid arthritis, bring about subsidence of all manifestations of the disease and in some cases, what appears to be a cure.