Platelet and Fibrinogen Kinetics with [⁷⁵Se]‐Selenomethionine in Patients with Myeloproliferative Disorders

Summary: Simultaneous platelet and fibrinogen kinetics were determined with a cohort label, [ 75 Se]selenomethionine, in three patients with chronic myelocytic leukaemia (CML), three with subacute myelogenous leukaemia (SML) and three with myelofibrosis with myeloid metaplasia (MF). In the CML group platelet survival was normal to increased (10.5–14.0 days), platelet turnover was essentially within the control range (22 000–51 000 platelets/μ/day), fibrinogen survival was prolonged (11.0–19.0 days) and fibrinogen turnover decreased (0.12–0.32 mg/ml/day). In two patients with MF platelet survival was decreased (5.0–7.5 days) and platelet turnover sharply increased (215 000–385 000 platelet/μl/day): one of these patients had multiple thrombotic episodes with an associated decrease in fibrinogen survival (4.0 days) and increased fibrinogen turnover (0.85 mg/ml/day): the other patient had no haemorrhagic or thrombotic episodes and his fibrinogen survival and turnover were within normal limits. Four patients, three with SML and one with MF, presented with thrombocytopenia. Kinetic studies were performed to aid in selecting those patients that might benefit from splenectomy. Splenectomy was performed in two with excellent results. Platelet and fibrinogen kinetics are important adjuncts to the study of the pathogenesis, differential diagnosis, and therapy of the myeloproliferative disorders.