Thrombocytosis associated with enzyme replacement therapy in Gaucher disease

We describe a patient with an intact spleen and moderately severe symptoms of Gaucher disease in whom, after initiation of (low-dose) enzyme replacement therapy (ERT), thrombocytosis (720 x 10(9)/l) was documented. Checking the International Gaucher Registry database revealed that this patient is the only nonsplenectomized patient of more than 1,000 treated patients to experience ERT-induced thrombocytosis. Platelet counts dropped immediately after the discontinuation of ERT.