Antibody-mediated lymphocytotoxicity in rheumatoid arthritis and systemic lupus erythematosus.

Lymphocyte-dependent antibody cytotoxicity (LDAC) was studied using peripheral blood and in some instances synovial fluid cells from patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). No difference from normal controls was observed with peripheral blood lymphocytes from either RA or SLE. Marked decrement in LDAC effector cell activity was present particularly with RA synovial fluid cells. Sera from patients with RA or SLE as well as RA synovial fluids markedly inhibited LDAC.