Intravenous immune globulin in autoimmune and allergic diseases: Mechanisms of action

Almost twenty years ago, intravenous immune globulin (IVIG) was introduced as a treatment modality for patients with humoral immune deficiencies. Through a number of clinical observations, it became apparent that IVIG has a number of immune modulatory and anti-inflammatory effects. Experimental evidence has shown that IVIG can modify T- and B-cell function, block Fc receptor function, inhibit the uptake of activated C3 and C4 on target cells, regulate the idiotypic network, and modify cytokine and chemokine production. These observations on the immune regulatory effects of IVIG suggests that IVIG might be a useful treatment modality for a wide spectrum of immune-based diseases. This review will summarize our understanding of the mechanism(s) by which the immune modulating and anti- inflammatory effects of IVIG may benefit autoimmune and inflammatory diseases. Although IVIG is effective in a number of autoimmune and inflammatory disorders, its clinical use requires careful, cost-benefit considerations, and should be reserved in some diseases as an alternative treatment modality.