Autoimmune factor XIII deficiency with unusual laboratory and clinical phenotype.

Hemorrhagic diathesis due to anti-factor XIII (FXIII) autoantibody is a rare but severe disorder. Challenges of the diagnosis and treatment is demonstrated by the case of a 67-year-old female without previous bleeding history, who suffered a huge muscular hematoma. Without blank subtraction 18% plasma FXIII activity was measured; however, after correction for blank the activity was below the limit of detection and the lack of fibrin cross-linking in the patient's plasma confirmed the latter result. FXIII-A2 antigen was not detectable by enzyme-linked immunosorbent assay (ELISA); however, it was well detected by western blotting. The autoantibody showed high affinity toward FXIII-A2 . Its considerable inhibitory activity was demonstrated by high titer in Bethesda units and the low immunoglobulin G concentration required for inhibition. The main biochemical effect was the inhibition of Ca2+ -induced activation. Eradication therapy was only partially successful. Four months after the last hemorrhagic event the patient suffered deep vein thrombosis complicated by pulmonary embolism.

[ADAMTS13 and thrombotic thrombocytopenic purpura retrospective study at the hospital of Le Mans]. / ADAMTS13 et purpura thrombotique thrombocytopénique Étude rétrospective au Centre hospitalier du Mans.

Thrombotic thrombocytopenic purpura (TTP) is a rare disease with poor prognosis in the absence of treatment. The aim of the study was to compare with the literature, the clinical, biological and therapeutic management of PTT at the hospital of Le Mans (CHM) and to identify sub groups. The criteria for inclusion were all patients hospitalized between 2006 and 2012 at CHM with a number of platelets, level of hemoglobin and ADAMTS13 activity respectively less than 150 G/L, 110 g/L and 10 %. Eleven patients were included, confirming the epidemiological level rarity of this disease and the prevalence in young women, with immune dysfunction, and Afro-Caribbean origin. Consistent with literature, patients had heterogeneous symptoms but mainly neurological symptoms. Biological results were heteregenous and also different from the diagnostic described by Amorosi. Concerning therapy, all patients underwent plasma exchange with fresh frozen plasma substitution, confirming this as a reference treatment of first intention. Sub-group analysis have highlighted three predictive factors of mortality which were: an age over 70 years of age, a renal failure and a haptoglobin level superior to 0.10 g/dL. This study reminded the clinical, biological and therapeutic recommendations about TTP and described predictive factors of mortality.