Physiopathological aspect of Glynn's type of experimental arthritis

Knee joint arthritis is induced among rabbits previously immunized by intradermal injection with egg albumin (EA) emulsified in adjuvant containing either M. tuberculosis or M. butyricum, then by intra-articular injection with EA. Arthritis evolution involves two phases, an early one during the first 2 months and a late one from 3 months to 1 year. During the early phase, arthritis intensities are similar no matter which Mycobacterium is used. However, during the late phase, only rabbits immunized with M. tuberculosis develop self-perpetuating arthritis. Among more than 50% of arthritic rabbits, immunological lesions of aortic artery and cardiac valvules are found. Among the rabbits immunized with M. tuberculosis, the humoral anti-EA antibody level remains constant during the whole arthritis evolution; but, among the rabbits immunized with M. butyricum, the arthritis intensity decreases from 3 months of evolution. The correlation between arthritis index (AI) and humoral antibody level is only significant among the rabbits with early arthritis. The intradermally immunized rabbits show a positive skin test with EA and tuberculin. The more intense the cutaneous reactions, the greater the chances of developing self-perpetuating arthritis after the EA intra-articular injection. The fluorescent anit-EA antibodies in the synovia and spleen are found only among the early arthritis. After 2 months of evolution, fluorescent antibodies disappear whatever the immunization may be. Among the immunized rabbits, it is probable that antigenic EA does not persist in the synovia. Indeed, the autologous inflamed synovia transplantation, from the donor-challenged knee joint, does not develop an inflammatory reaction in the non-challenged knee joint. The fluorescent immunoglobulins IgG and IgM in the synovium of arthritic rabbits are found with the same percentages as fluorescent anti-EA antibodies. The lymphocyte response to EA, PHA and PWM are positive whatever the immunization and arthritis evolution may be. There is no correlation between AIs and lymphocyte responses to specific and nonspecific mitogens. It is probable that self-perpetuation depends closely on M. tuberculosis whose adjuvant power is much superior than M. butyricum and not on antigenic EA whose essential role would be to trigger the inflammatory process.