[Polyclonal activated circulating B-lymphocytes in patients with rheumatoid arthritis]

Peripheral B lymphocytes were studied to investigate the role of polyclonal B-cell activation in the pathogenesis of rheumatoid arthritis (RA). Proliferative responses to anti-mu antibodies coupled to sepharose used as a B-cell-specific mitogen were reduced as compared to healthy controls. When cell surface antigens were studied by flow cytometry employing monoclonal antibodies, B cells from patients with RA showed enhanced expression of Interleukin-2 (IL-2) receptor. In-vivo-activated, in-vitro spontaneously proliferating Epstein-Barr virus transformed B cells positive for immunoglobulin M, G, and A were obtained from patients with RA. In summary, our findings suggest the presence of polyclonal activated B cells in the peripheral blood of patients with RA, and a close relationship of polyclonal activated B cells and the activity of the disease process.