Immobilized IgG-aggregate-induced cytolytic activity of lymphocytes from patients with rheumatoid arthritis

T-depleted lymphocytes can lyse nonsensitized target cells subsequent to interacting with immobilized IgG-aggregate, while T cells from healthy individuals can suppress this cytolytic response. In the present study we have compared the activity of non-T effector cells and T suppressor cells from the peripheral blood of healthy individuals with that of cells from the peripheral blood and synovial fluids of patients with rheumatoid arthritis (RA). Unlike peripheral blood lymphocytes (PBL) from healthy donors, which were never lytic without removing T suppressor cells, PBL from RA patients were occasionally active without removing T cells; lymphocytes from joint fluids were almost always active. The lytic response of RA joint fluid lymphocytes could be suppressed by T cells from autologous or healthy donor peripheral blood, thus suggesting that the suppressor cell which regulates this lytic mechanism might be defective or absent in joint fluids of RA patients.