Autoimmune Acquired Factor XIII Deficiency: A Case Report.

Autoimmune acquired factor XIII (FXIII) deficiency is a rare disorder characterized by severe spontaneous hematomas and autoantibodies against FXIII. High mortality rates have been reported (18% within a year of diagnosis). We present a 70-year-old patient with recurrent muscular hematomas. The basic hemostasis study and the coagulation factors were within normal ranges. The aggregation platelet study was also normal and von Willebrand disease was excluded. Bearing in mind the recurrent bleeding history and the described laboratory results, we considered a FXIII deficiency, that was confirmed (FXIII<10%). In addition, we suspected an acquired FXIII deficiency since the patient did not report a personal or family history of bleeding and FXIII gene sequencing study was normal. Non-immune causes were ruled out, and plasma autoantibodies against FXIII were detected. Immunosuppression was rapidly initiated to eradicate inhibitor as was hemostatic treatment to obtain bleeding control. Currently, the patient is asymptomatic, but a low level of FXIII inhibitor remains.