[Cytotoxic complement-dependent anti-thrombocyte antibodies in rheumatoid arthritis patients].

Sera of 38 patients and 10 blood donors were examined for cytotoxicity against human thymocytes. As method for testing the complement-dependent cytotoxicity the lymphocytotoxicity test was adapted for thymocytes. The sera of blood donors and of patients with non-rheumatic diseases showed no or only a very small rate of cytolysis (3.6%). The rate of cytolysis of sera of patients with arthroses (8.5%) and of collagenoses (14.5%) were below 20%, i.e. still within the limits of normal. The sera of seronegative arthritides (30%) and of patients with rheumatoid arthritis (40%) showed an unequivocally pathological cytotoxicity. The complement-dependent thymocytotoxicity might be coordinated to the clinical arthritis.