[The aetiology of rheumatoid arthritis (author's transl)].

An ineffective aetiology for rheumatoid arthritis and other connective tissue diseases has been frequently postulated but never proven. Despite the failure to obtain firm evidence of viral infection in most patients with these disorders for several reasons this theory should not be discarded. Firstly several mechanisms have been discovered by which virus infections can persist in lymphocytes and other tissue thereby provoking inflammation without the production of complete readily detectable virus particles. Secondly there are numerous ways in which host resistance to virus can be subverted with the perpetuation of an ineffective or inappropriate immune response. Thirdly the immunopathological features of these diseases are entirely compatible with an infective aetiology. The main problem is likely to prove the difficulty in attributing a primary pathogenetic role to any isolated virus rather than regarding it as a passenger virus which has been non-specifically activated by the disease process. However preoccupation with a viral aetiology should not blind one to other possibilities since many environmental allergens can produce immunopathological disease of highly protean nature.