Acquired hemophilia in patients with hematologic malignancies

Objectives.-To evaluate the occurrence of acquired hemophilia in patients w ith hematologic malignancies and to assess their response to treatment. Design.-Data on 8 patients with hematologic neoplastic disorders and inhibi tor against factor VIII were analyzed retrospectively. Setting.-Three large tertiary-care centers. Results.-All 8 patients presented with spontaneous or posttraumatic hemorrh ages. The mean inhibitor titer at the time of diagnosis was 79 Bethesda uni ts (BU), and residual factor VIII activity was detectable in 3 patients. Th e inhibitor disappeared in 5 patients after a mean of 92 days, but persiste d in the 3 other patients. The patients who achieved complete resolution of their circulating anticoagulant had lower mean inhibitor titers at the tim e of diagnosis than those who had persistent inhibitor (27 BU vs 167 BU, re spectively). Two patients died as a result of major hemorrhages that did no t respond to treatment. Conclusions.-Antibodies against factor VIII may be responsible for some ble eding episodes in patients with lymphoid or myeloid malignancies. Acquired hemophilia in this setting should be differentiated from other causes of bl eeding because the approach to treatment is different. No conclusion can be drawn regarding the association between the activity of the underlying ill ness and the inhibitor titer, although it appears that at least in some pat ients such a relationship may exist. The underlying pathogenetic mechanisms responsible for the production of autoantibodies against factor VIII remai n unclear, but we provide a few explanations in this article.