Decreased precipitation of factor VIII related antigen with concanavalin A in patients with a variant of von Willebrand's disease and disseminated intravascular coagulation.

Precipitation pattern of factor VIII related antigen (VIIIR:AG) with concanavalin A (Con A), a glycoprotein binding lectin, was investigated in normal subjects and patients with a variant of von Willebrand's disease (VWD) and disseminated intravascular coagulation (DIC). Decreased precipitation with Con A was demonstrated in patients with a variant of VWD in which VIIIR:AG showed an increase in electrophoretic mobility on crossed immunoelectrophoresis (CIE). Similar findings were obtained in patients with DIC which revealed normal electrophoretic mobility of VIIIR:AG. This procedure was assumed to be useful for the detection of a qualitative abnormality of the factor VIII protein.