Usefulness of anti-factor VIII IgG ELISA in acquired hemophilia A follow-up.

Acquired hemophilia A (AHA) is a rare autoimmune bleeding disorder due to the presence of neutralizing autoantibodies directed against the coagulation factor VIII (FVIII). The reference method to detect and quantify anti-FVIII antibodies is the Bethesda assay (BA), but it presents some limitations such as a lack of sensitivity for low titers of inhibitor and the need for experienced laboratory. A commercially available ELISA detecting anti-FVIII antibodies has demonstrated excellent sensitivity and specificity. The aim of our study was to assess the performance of this ELISA for the detection of anti-FVIII IgG in AHA patients during the follow-up. In total, 11 acquired hemophilia A patients were recruited, and anti-FVIII antibody levels were monitored by BA and ELISA. Anti-FVIII IgG ELISA showed 100% sensitivity and 100% specificity, and it correlated with the BA. Discrepancies observed in 13.3% of cases were consistent with patients' biological evolution. All these data suggest the possible use of anti-FVIII IgG ELISA for both diagnosis and follow-up of AHA patients.