Defective ADAMTS13 synthesis as a possible consequence of NASH in an obese patient with recurrent thrombotic thrombocytopenic purpura

Abstract

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 ADAMTS13, a disintegrin and metalloprotease with thrombospondin (TSP)-1 repeats, cleaving high molecular weight von Willebrand Factor (ULVWF) multimers. Decreased plasma ADAMTS13 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. We describe an unusual case of fatal recurrent TTP in a morbid obese female with non-alcoholic steatohepatitis (NASH) and severe ADAMTS13 activity deficiency due neither to an inhibitory autoantibody nor to a gene mutation. Visceral obesity is associated with non-alcoholic fatty liver disease (NAFLD) and NASH: we hypothesized that these conditions can influence ADAMTS13 antigen and activity. In fact, hepatic stellate cells (HSC) are the main producers of ADAMTS13, and a decrease in ADAMTS13 activity has been reported in liver disease.