Increased antibody production in peripheral blood mononuclear cells after plasma exchange therapy in multiple sclerosis.

It has been difficult to study antibody synthesis in vivo following plasma exchange (PE) because of the intra- and extravascular compartmentation of immunoglobulins, and their altered lymphatic flow and catabolism after the procedure. There is fragmentary experimental and clinical evidence that antibody synthesis may increase due to removal of autoregulatory factors by PE. The present study showed increased in vitro spontaneous immunoglobulin (Ig) G and IgM production, as well as increased spontaneous lymphocytic proliferation, after intensive PE in 10 multiple sclerosis (MS) patients. Cytofluorometric control of cultured mononuclear cell populations revealed no change with treatment except for a small increase in B lymphocytes inadequate to account for the increased immunoglobulin production. These findings indicate an activation of the immune system through PE, and suggest the possible need for adjunctive immunosuppression to control antibody production in autoimmune diseases with subacute, relapsing, or chronic courses when PE is employed as a therapeutic modality.