Antibodies to factor VIII: specificity and kinetics of iso and hetero antibodies in hemophilia A

Abstract

Time course inactivation of isologous and heterologous AHF preparations induced by anti factor VIII antibodies from hemophiliacs followed two major patterns: one was consistent with a second order reaction, the other more complex. The second order type, characterized by a plateau of residual factor VIII activity occurring after 2-4 hr of incubation, was observed in the interaction of factor VIII with its corresponding and specific antibody. The complex type, showing a gradual decline of factor VIII activity following a rapid initial fall, was detected in antigen antibody reactions relying predominantly on crossreactions. It is proposed that reactions of the second order type reflect the formation of stable antigen antibody complexes, while reactions of the complex order type express a tendency to spontaneous dissociation of antigen antibody complexes.