Cooperative Study of Spontaneously-Occurring Factor VIII Inhibitors in Patients with Hemophilia A

摘要

Among 1,522 hemophilic patients studied, 216 had inhibitors at entry and an additional 31 developed inhibitors during the study. 95% of inhibitors occurred in patients with VIIIC levels <.03 U/ml. Prevalence of inhibitors was 50% higher in blacks than in whites. A non-random distribution of inhibitors was found in 167 sibships with two or more hemophiliacs, and a significantly different distribution of HLA subtype Al was found among inhibitor and non-inhibitor patients, both results suggesting a genetic factor in inhibitor formation. A controlled, double-blind trial of PCC in inhibitor patients demonstrated a highly significant beneficial effect of PCC as opposed to placebo, 50% versus 20-25% effectiveness, respectively. Liver enzyme tests were elevated in 20% of patients, although the elevation was marked in less than 3%. 6% of patients were persistently positive for HBsAg and 66% were persistently positive for anti-HBsAg, although 90% of patients showed some evidence of prior infection with HBV on at least one sampling. The average per patient utilization of FVIII was approximately 40,000 units per year, with patients on home therapy using significantly more than those not receiving home care.