With the introduction of plasma therapy 30 years ago, the survival to adulthood of patients with severe hemophilia became commonplace. The incidence and severity of crippling deformities decreased when hemorrhages were treated promptly with infusions of plasma or, more recently, clottingfactor concentrates. Despite therapy, most persons with severe hemophilia still gradually accumulate some impairments of musculoskeletal function. Prevention of hemorrhage in such patients by regular infusions of plasma or concentrate would be desirable if it were feasible, and if the risks and cost were tolerable.
The serious risks of plasma infusion are the chance of transmitting hepatitis virus and the possibility of inducing the formation of antibodies to the deficient clotting factor. Prophylaxis is not likely to increase these risks substantially in patients with severe hemophilia who already have received, or expect to receive, innumerable therapeutic infusions. Those few patients with classic hemophilia who develop severe factor VIII inhibitors do