Autoantibodies against Tmu and B lymphocytes in patients with rheumatoid arthritis.

Patients with rheumatoid arthritis have decreased numbers of T mu lymphocytes in their peripheral blood. To find out whether these low number of T mu lymphocytes were associated with the presence of anti-lymphocyte antibodies, the sera of 27 patients with definite or classical rheumatoid arthritis (RA) were investigated for the presence of autoantibodies against subsets of lymphocytes. In addition the numbers of T, T mu, T gamma and B lymphocytes in the peripheral blood of these patients were investigated. Patients with active RA showed lower numbers of T mu lymphocytes in their peripheral blood than patients with inactive RA. However, both groups of RA patients had significantly decreased numbers of T mu lymphocytes in their peripheral blood as compared with 22 age matched healthy donors. Moreover, mainly in patients with active RA cold reactive antibodies were found directed against T mu and B lymphocytes, but never against T gamma lymphocytes of healthy donors. Similar results were found in the indirect immunofluorescence procedure when tested for reactivity against T-cell subsets. This serum reactivity was not caused by rheumatoid factors or antinuclear antibodies. Since RA sera after precipitation with 2.5% polyethyleneglycol, still showed cytotoxicity against T and B lymphocytes, it is suggested that this serum reactivity is not caused by immune complexes but by antibodies.