Intravenous immunoglobulin was originally developed for the treatment of primary immunodeficiencies and subsequently it has been used increasingly in the treatment of patients with autoimmune and inflammatory diseases with beneficial effects. The mode of action of intravenous immunoglobulin is probably multiple distinct mechanisms involving Fc receptor blockade, inhibition of complement binding, modulation of cytokine production, restoration of the idiotypic network and neutralization of pathogenic autoantibodies, modulation of T and B cell activation and differentiation. This article discusses the proposed mechanisms of action of intravenous immunoglobulin in various disorders
