Relapse pattern and long-term outcomes in subjects with acquired haemophilia A

Acquired haemophilia A (AHA) is a rare autoimmune bleeding disorder caused by neutralizing antibodies against factor VIII (FVIII). Despite significant initial morbidity and mortality, most patients achieve remission with immunosuppressive therapy.

Long-term follow-up data from the Quebec Reference Centre for Inhibitors (QRCI) were analysed to identify factors predictive of AHA relapse and the influence of relapse on survival.

Criteria used to define AHA were levels of FVIII <0.3 IU/mL and FVIII inhibitor titres ≥0.6 Bethesda Units (BU). Complete remission was defined as FVIII >0.5 IU/mL and/or FVIII inhibitor titres <0.6 BU while not on immunosuppression.

Between 2000 and 2012, 111 subjects met the inclusion criteria and were followed for a median of 25.6 months. Ninety per cent of them reached remission on immunosuppression in a median time of 45 days. Fourteen patients presented one or more relapses in a median time of 13.4 months. Most relapse episodes were successfully treated. Associated lymphoproliferative syndromes (LPS) were predictive of relapse, whereas FVIII activity and inhibitor titres at initial diagnosis or immunosuppressive regimens were not. The overall survival (OS) was the same, with or without relapse.

Among the recognized potential risk factors for relapse, only LPS was statistically significant. The long-term follow-up of our patients also showed that late or multiple relapses may occur, but that relapse is not associated with a worse OS. Thus, long-term follow-up is important for optimal management of AHA.