Immune modulating effects of intravenous immunoglobulin (IVIg) in autoimmune diseases.

Administration of intravenous immunoglobulins (IVIg) have now been reported to be beneficial in a large number of autoimmune diseases, whether mediated by autoantibodies or by T cells. We have proposed that the immunoregulatory effect of IVIg in autoimmune diseases is dependent on the selection of recipient's immune repertoires by variable (V) regions of infused immunoglobulins. Thus: (a) IVIg contains antibodies reactive with idiotypes of natural and disease-related autoantibodies and surface immunoglobulins of B cells; IVIg also contains antibodies reactive with idiotype, framework and constant regions of the beta chain of the alpha beta T cell receptor; (b) infusion of IVIg results in transient or long-lasting suppression of specific autoantibody clones in vivo and in stimulation of a distinct subset of B cells reactive with F(ab')2 fragments of IVIg; (c) infusion of IVIg alters the general "architecture" of the network as assessed by studying the kinetic patterns of spontaneous fluctuations of natural autoantibodies in serum; (d) infusion of normal mouse Ig in healthy adult mice selects expressed immune repertoire by removing late pre-B and B cells in the bone marrow, mostly those expressing D proximal VH genes, and by activating distinct subsets of B cells and CD4+ T cells in the spleen; and (e) infusion of IVIg results in a modulation of synthesis and release of cytokines. Although dependent on the V-region reactivities (composition) or injected preparations, these effects probably also require that the infused immunoglobulin contains an intact Fc moiety. This review focuses on autoimmune and inflammatory diseases in which IVIg therapy has been beneficial. Recent recommendations from a committee of experts for IVIg therapy have been pointed out.