Immunologic Characterization of 12 Factor VIII Inhibitors

Twelve Factor VIII inhibitors were characterized as immunoglobulins by highly specific antisera. All 12 inhibitors were characterized as belonging to the γG class of immunoglobulins. Ten inhibitors contained only K type light chain determinants and two contained only γ chain determinants. Therefore, these inhibitors were homogeneous by these criteria. Homogeneity cannot be established, however, until H-chain subtyping can be carried out.