Defective ADAMTS 13 synthesis as a possible consequence of NASH in an obese patient with recurrent thrombotic thrombocytopenic purpura

Objectives Thrombotic thrombocytopenic purpura ( TTP ) is a rare and devastating hematologic disorder frequently associated with multiple organ failure and sometimes death. This syndrome is mainly associated with severe deficiency of ADAMTS 13, a disintegrin and metalloprotease with thrombospondin ( TSP )‐1 repeats, cleaving high molecular weight von Willebrand Factor ( ULVWF ) multimers. Decreased plasma ADAMTS 13 activity results in the accumulation of ULVWF multimers with consequent platelet activation. Recently, obesity has been considered as a potential independent risk factor for TTP , but the reason of this association is still unknown. Methods and results We describe an unusual case of fatal recurrent TTP in a morbid obese female with non‐alcoholic steatohepatitis ( NASH ) and severe ADAMTS 13 activity deficiency due neither to an inhibitory autoantibody nor to a gene mutation. Conclusions Visceral obesity is associated with non‐alcoholic fatty liver disease ( NAFLD ) and NASH : we hypothesized that these conditions can influence ADAMTS 13 antigen and activity. In fact, hepatic stellate cells ( HSC ) are the main producers of ADAMTS 13, and a decrease in ADAMTS 13 activity has been reported in liver disease.