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To the Editor,
Acquired inhibitors of blood coagulation are endogenously produced pathologic substances that either react directly with clotting factors or inhibit their reactions. Acquired hemophilia A (AHA) is caused by polyclonal inhibitory immunoglobulins G (predominantly IgG1 and IgG4) against factor VIII (FVIII). They react with A2, A3, or C2 domains of the FVIII molecule, blocking its interactions with active factor IX, phospholipids, and von Willebrand factor. A disturbed proportion of CD4+ Th1 to Th2 cells plays a role in autoantibody production and reactivity [1,2]. FVIII inhibitors have most often been associated with autoimmune diseases, drugs, immunosuppressive therapies, malignant neoplasms, or obstetric accidents in the postpartum period [3].
Here we report a rare case of a patient with AHA and multiple myeloma, where the disappearance of the hematologic malignancy induced by chemotherapy resulted in a regression of the coagulation disorder.
A 67-year-old man came under our observation for plasmacytoma. Significantly, his past medical history included both high blood pressure and hip replacement. His concomitant medication was only lacidipine. In 2009 the patient underwent cholecystectomy without bleeding. In 2014, he underwent a surgical excision of basal cell carcinoma in the pectoral region without bleeding.
In 2014 the patient was diagnosed, at a different hematological center, with congenital mild hemophilia A and monoclonal gammopathy of undetermined significance IgG kappa. At that time, FVIII was 29.1%. He also underwent a desmopressin test, which displayed an increase of FVIII activity (15% at basal level) up to 90% after 60 min. Elevation of IgG (2319 mg/dL) was present, while the rest of the immunoglobulins were within normal values. IgG k-type monoclonal protein was detected in...