MODULATION OF COMPLEMENT-MEDIATED IMMUNE DAMAGE BY INTRAVENOUS IMMUNEGLOBULIN

High-dose intravenous immune globulin (IVIG) exerts a beneficial effec t in a variety of immune disorders. One possible underlying mechanism of this effect could be interference with the complement system. This conclusion was based on the results obtained in animal models of compl ement-mediated pathology, in vitro complement assays and studies on re lated human diseases. Clearance of IgM-sensitized erythrocytes was spe cifically suppressed by IVIG treatment. The same therapy prevented pul monary endothelial cell lesions, the hallmark of Forssman shock, in 75 % of animals. All control animals, either untreated or injected with c ontrol reagents, died within minutes following induction of Forssman s hock. In vitro uptake of C3b and C4b complement fragments on to corpus culate immune complexes was significantly inhibited by IVIG. Studies t hat involved patients suffering from disorders with pathogenesis simil ar to animal models of complement-mediated immune injury fully support ed the hypothesis that IVIG interacts with activated complement compon ents and prevents their deposition on target cells. The author's resul ts suggest that IVIG can be an effective modulator of inappropriate co mplement attack.