Prolonged inhibition of von Willebrand factor-cleaving protease after splenectomy in a 22-year-old patient with acute and plasma refractory thrombotic thrombocytopenic purpura


Dr Florian Langer, Department of Oncology and Haematology, Clinic of Internal Medicine, University Hospital Eppendorf, Martinistraße 52, D-20246 Hamburg, Germany. E-mail:


Summary. We report a 22-year-old woman with acute, plasma refractory thrombotic thrombocytopenic purpura (TTP) in whom splenectomy led to consistent stabilization of platelet counts, but who showed complete inhibition of vonWillebrand factor-cleaving protease (VWF-cp) after 6 months of follow up. Persistent protease deficiency and resolved clinical and haematological TTP symptoms resulted in the transient appearance of unusually large VWF multimers in the patient plasma. As low but significant protease activity (10%) was first detectable as late as 9 months after splenectomy, we conclude tentatively that, at least in a subgroup of patients with acquired TTP, the beneficial effect of splenectomy is not exclusively due to the removal of splenic B lymphocytes producing an inhibitor of VWF-cp.