Reactivity of T-cells from patients with rheumatoid arthritis to anti-CD3 antibody

The ability of an anti-CD3 monoclonal antibody (OKT3) to induce proliferation was examined in peripheral blood mononuclear cells (PBM) from 30 patients with rheumatoid arthritis (RA). Controls consisted of 10 patients with osteoarthritis, 12 patients with psoriatic arthritis, and 12 healthy subjects. The results revealed enhanced PBM reactivity in patients with active RA relative to inactive RA patients and all control groups. PBM of patients with mild/moderate clinical disease activity exhibited augmented anti-CD3 reactivity while those with severe disease demonstrated impaired reactivity. Enhanced reactivity was also observed in the active RA group using another anti-CD3 monoclonal antibody (Leu-4). Differences in anti-CD3 dose-response or time kinetics could not account for the results. Studies of enriched T-cell preparations revealed a markedly enhanced anti-CD3 reactivity of RA T-cells relative to normal control T-cells. Monocyte/T-cell mixing experiments revealed no enhanced reactivity of RA monocytes in the anti-CD3 response. RA T-cell preparations depleted of monocytes by limiting dilution reacted significantly more to anti-CD3 in the presence of IL-2 relative to controls. The enhanced reactivity could be accounted for in part by hyperreactivity of the OKT8-bearing subpopulation of T-cells.