MODULATION OF AUTOIMMUNE RESPONSES BY INTRAVENOUS IMMUNOGLOBULIN (IVIG)

Significant progresss has been made in understanding the mechanisms by which intravenous immunoglobulins (IVIg) exert immunomodulatory effec ts in the treatment of autoimmune diseases. A unique property of immun oglobulins is the diversity of variable (V) regions. The evidence disc ussed in this communication supports our notion that the diversity of V regions in IVIg preparations is a determining factor for the anti-in flammatory substitutive and immunomodulatory functions of IVIg therapy We have demonstrated the presence in IVIg, of anti-idiotypic antibodi es directed against various autoantibodies. The ability of IVIg to int eract through V regions with complementary V regions of antibodies and antigen receptors as well as with relevant soluble and surface molecu les provides the basis for inducing the selection of immune repertoire s. The study of the mechanisms by which IVIg mediates selection of aut oreactive repertoires is essential for our understanding of the mechan isms underlying the emergence of pathological autoimmunity and of the physiological role of natural antibodies in the establishment and main tenance of tolerance to self and homeostasis of autoreactivity in heal thy individuals.