[Mycoplasma and rheumatoid arthritis].

The view that rheumatoid arthritis may have an infective aetiology dates from the 1930s at least, and enjoys a fluctuating popularity. It is based on some similarities between rheumatoid arthritis and diseases known to be caused by infective agents (Hill, 1968; Ford, 1963, 1968; Lancet, 1970; Buchanan and Dick, 1972) or on the similarity of the pathological changes in human rheumatoid arthritis compared with those in arthritis of animals known to be caused by mycoplasmas (Sabin, 1939a,b; Sharp, 1964; Sharp and Riggs, 1967; Ross and Switzer, 1968). The response of mycoplasmal arthritis in mice (Sabin and Warren, 1940; British Medical Journal, 1965) and of rheumatoid arthritis in man (Ford, 1968) to treatment with gold salts has been taken as suggesting a mycoplasmal cause of the latter disease. Recent work (Smiley, Sachs, and Ziff, 1968) has shown a substantial local, committed, synthesis of immunoglobulins in the synovium, but the nature of the stimulating antigen is unknown. Many attempts have been made to isolate mycoplasmas from specimens of synovial fluid or synovial membrane from patients with rheumatoid arthritis. A summary of some attempts over the last 12 years is shown in Table I. It will be seen that results were variable, sometimes with higher isolation rates from non-RA cases or controls. Those series with high rates of isolation in cell-free media are Fahlberg, and others (1966), Williams (1968), Marcolongo and others, (1969), and Jansson and others (1971a,b). Other workers used cell culture inoculation as a preliminary step to cultivation on cell-free media. Williams (1968) identified his isolates as strains of Mycoplasma fermentans, and Jansson and her co-workers (1971a) showed their small-colony mycoplasmas to be related serologically to Mycoplasma arthritidis. The existence of the more striking positive reports made it imperative to try and repeat the results. The present report describes a series of attempts to isolate mycoplasma from specimens of rheumatoid synovial membrane and synovial fluid over a period of 8 years from 1964 to 1972. A wide variety of techniques and media was used. Materials