Factor VIII related antigen-concanavalin A binding in plasma and serum

The Factor VIII Related Antigen (FVIIIRAG) was determined by electroimmunodiffusion and the per cent concanavalin A (% con A) binding of FVIIIRAG was determined by crossed affinity electrophoresis (CAIEP) in the plasma and serum of 8 hospitalized patients. The FVIIIRAG in plasma and serum was 669 and 501% of lyophilized plasma, respectively (correlation coefficient, r = 0.92). The FVIIIRAG con A-binding of plasma and serum were 44 and 16%, respectively (p less than 0.01), while the FVIIIRAG-con A binding of lyophilized plasma is 78%. We conclude that plasma has a higher content of electrophoretically slower, high con A affinity FVIIIRAG multimers than serum. The high FVIIIRAG levels of both serum and plasma and the comparatively low plasma FVIIIRAG-con A binding here may reflect the acute phase reaction.