Densitometric profiles of the reactivity of anti-FVIII IgG.

Anti-FVIII IgG was affinity-purified from the plasma of 4 hemophilia patients with inhibitor (A), 2 patients with autoantibodies to FVIII (B), 3 healthy blood donors and pooled normal human IgG (IVIg) (C), and 5 nonresponder hemophilia patients (D). IgG was tested at a concentration of 50 μg/mL. The densitometric pattern of reactivities of IgG of each individual is depicted as a full-line curve; that of anti-FVIII IgG from IVIg is depicted as a broken-line curve in panel C. Gray areas depict the densitometric pattern observed in the presence of secondary antibody alone. Migration distances and optical densities are expressed as arbitrary units (AU). Arrows in panel A indicate the FVIII digestion fragments of 44 and 72 kd. For each group of individuals, a representative immunoblot is shown below the X axis.