Treatment of autoimmune disease: synergy between plasma exchange and intravenous immunoglobulins.

Therapeutic plasma exchange (PE) has been used for three decades in the treatment of autoimmune disease. Its mechanism of action hinges on a profound modulation of the immune system which is only partially understood. Removal of circulating immune complexes, immunoglobulins, and complement components play a role. Moreover, the substitution of plasma components like anti-idiotypic antibodies and immunoglobulins targeted against a host of antigens may add to its beneficial effects. Recently, intravenous administration of immunoglobulins was found to mimic the effects of PE in certain diseases. In fact, downregulation of Fc receptors, modulation of the complement activation, and anti-idiotypic downregulation of primary autoantibodies are mechanisms held to be responsible for its immunosuppressive effects. This article summarizes the effects of both treatment modalities, discusses their pros and cons, and makes differential therapeutic suggestions for the clinician of which to use in various autoimmune diseases.