Factor VIII inhibitors in patients with hemophilia A

In 58 hemophilia A patients aged 1-18 years (mean 9.5 +/- 4.7 years), the p revalence-of inhibitors was found to be 27% by the Bethesda method in Novem ber 1995. Inhibitor activity was not detected in any of 14 patients with mi ld hemophilia while it was present in 9 of 27 (33%) patients with moderate, and 7 of 17 (41%) with severe disease, During follow-up, the inhibitors we re transient in 10 of 16 patients (17%) and the prevalence of inhibitors wa s 10% at the end of the study. Our study has demonstrated that the patients ' age, factor VIII (F VIII) coagulant activity levels, type of F VIII repla cement therapy, and frequency of F VIII administration affect inhibitor dev elopment, and these factors should be considered in the follow-up of hemoph iliacs.