Acquired Hemophilia A. Experience Of a Single Center

Acquired hemophilia A is a rare and serious autoimmune disease. Morbidity and mortality are associated with advanced age, comorbidities, toxicity of treatment and bleeding severity. Treatment goals are control of the bleeding and eradication of the inhibitor, while treating the underlying condition if it is present.

To describe the baseline characteristics of acquired hemophilia A patients and to assess the response to treatment.

Between November 1991 and April 2013, 27 patients were diagnosed with acquired hemophilia A (mean age 59, range 21-86; 18 women - 66%) in the Departamento de Hemostasia y Trombosis. Five patients were lost from follow-up. APTT mixing studies with normal plasma (1:1) and time-temperature dependent effect on the APTT were performed for a-FVIII diagnosis. Whenever possible, inhibitor activity was titrated by Bethesda method at diagnosis (BU/mL). Medical records were reviewed to evaluate the initial symptoms, underlying diseases, treatments and outcome.

The mean follow-up was 86 weeks (range 1-640). Underlying etiologies included: idiopathic 70.4%, postpartum 14.8%, malignancy 11.1%, autoimmune disease 3.7%. All patients had bleeding at diagnosis. The most frequent sites of bleeding were: muscular 32%, soft tissue 18%, urinary tract 9%, gastrointestinal tract 6%; being from multiple sites in 9%. At diagnosis, the mean value for FVIII was 6% (range 1-40), and inhibitor titer 220 BU/mL (range 2.2-1173). Initial therapeutic scheme included glucocorticoids in 97% of the patients, 13 in monotherapy (mean age 53 years ± 19), 13 with cyclophosphamide (63 years ± 18) (p= ns), and human immunoglobulin in 1 patient. This last patient died after 1 week of diagnosis due to uncontrolled gastrointestinal bleeding (previous to the era of rVIIa). As a second-line therapy, rituximab was used in 3 patients.

Sixty-three (63%) patients achieved complete response (CR) (inhibitor titer < 0.6 BU/mL without bleeding episodes), and 23% achieved partial response (PR) (reduction in inhibitor titer > 50% without bleeding episodes), without differences between monotherapy or combined. Overall, women responded more frequently than men (93.3% vs. 71.4%, p= ns). All patients that received rituximab achieved CR.

In this study, the overall response rate was higher than 80%. In most cases, the disease has a prolonged course like other autoimmune diseases, with remissions and relapses.

No relevant conflicts of interest to declare.