D-penicillamine induced suppression of B cell function: in vivo effect of D-penicillamine.

We assessed the immunoglobulin secretory capacity of circulating B lymphocytes in 9 patients with classical rheumatoid arthritis (RA) before and after treatment with D-penicillamine. Peripheral blood lymphocytes (PBL) from patients with RA spontaneously synthesized more IgG and IgA than normals. The secretory rate of rheumatoid PBL could not be induced by the polyclonal activator, pokeweed mitogen (PWM). The presence of D-penicillamine in cultures significantly suppressed PWM stimulated immunoglobulin synthesis of control PBL but did not inhibit synthesis of mitogen stimulated RA PBL. After D-penicillamine therapy for 3 months immunoglobulin synthesis by PBL from patients with RA was reduced with or without PWM. The T mu:T gamma ratio was also decreased after therapy. These results support the hypothesis that D-penicillamine selectively impairs helper T cells in vivo, preventing the T dependent expansion and activation of B cells characteristic of RA.