The effect of serum and allogeneic antiglobulin preparations on the mitogenic reactivity of peripheral blood lymphocytes from patients with rheumatoid arthritis.

: In vitro transofrmation of peripheral blood lymphocytes (PBL) by phytohaemagglutinin (PHA) and concanavalin A (Con A) was found to be decreased in 17 RA patients. The addition of 50 microliter RA serum or serum from normal controls exhibited an inhibitory effect on the mitogenic reactivity to Con A but not to PHA of both normal and RA patient's PBL. Allogeneic antiglobulin preparations (a-Ig) stimulated the spontaneous in vitro DNA synthesis of PBL from normal control and, to a smaller degree, also from RA patients. The simultaneous addition of a-Ig's and mitogens to PBL of normal controls and RA patients did not exhibit a significant effect on the mitogenic reactivity.