Immunoregulation in rheumatoid arthritis: evaluation of T lymphocyte function in the control of polyclonal immunoglobulin synthesis in vitro.

Immunoglobulin production by peripheral blood B lymphocytes in cultures containing various combinations of B and T cells was studied by a reverse hemolytic plaque forming cell assay in 21 patients with definite rheumatoid arthritis (RA) and 26 normal controls. Responses were markedly enhanced in controls when T cells were irradiated at 3200 rads or T cells bearing Fc receptors for IgG were removed by rosetting prior to coculture with B cells, while no such responses were observed in rheumatoids. In allogeneic cultures and T depleted cultures supplemented by normal T replacing factors, RA B lymphocytes functioned normally. These data suggest that there is an abnormality in immunoregulation that exists at the level of the T cell and that the defect involves T helper cells and/or their interaction with B lymphocytes. An increase in the ratio of T helper:suppressor (OKT4:OKT5) cells due to a reduction in suppressor cells among active RA patients was observed but did not correlate with this defect that was independent of disease activity. These data imply that functional alterations exist in vitro in circulating helper T cells from RA peripheral blood.