Factor VIII inhibitors in haemophiliacs: a single-centre experience over 34 years, 1964-97

A retrospective study of the natural history of factor VIII inhibitors in h aemophilia A patients experienced in a single comprehensive haemophilia cen tre over three decades is reported. 431 haemophilia A patients of all sever ities have been followed-up for a total of 5626 patient-years. The frequenc y of inhibitors was 10% in the severe haemophilia A patients and 37% occurr ed in children <10 pars. The majority of the patients received several prod ucts before developing the inhibitors, 59% of patients had <50 exposure day s and 48% were high responders (>5 BU). An 8-year (1987-95) inhibitor-free period was seen during which all previously untreated patients were treated with an intermediate-purity factor VIII concentrate. A moderate haemophili ac with a misense mutation that has not been described in association with inhibitor is reported. Six HIV-positive patients preserved their antibody r esponse to factor VIII even at the advanced stage of their disease.