Coagulation factor inhibitors

(anti-factor antibodies; anti-factor VIII most common)

• Etiologies: hemophilia; postpartum; lymphoproliferative & autoimmune disorders; cancers

• Diagnosis: ↑ PTT (does not normalize w/ mixing study); Bethesda assay quantitates titer

• Rx: if high titer → recomb. factor VIIa, porcine factor concentrates, activated prothrombin complex; for others → high-purity human factor, plasmapheresis, immunosuppression