A chronic hypercoagulable state in patients with beta-thalassaemia major is already present in childhood

A higher than normal incidence of thromboembolic events has been observed i n adult patients with beta-thalassaemia major (TM) and certain haemostatic anomalies found in these patients suggest the existence of a chronic hyperc oagulable state. Thalassaemic red blood cells (RBC) were demonstrated to fa cilitate thrombin formation due to altered asymmetry of the membrane phosph olipids with enhanced exposure of phosphatidylserine. Since RBC anomalies e xist in thalassaemia from the first months of life, we studied markers of h ypercoagulability and thrombophilia in 36 adult patients (range 19-38 years ) and 26 children (range 2-18 years) with beta-TM. All the patients were in steady state and none had experienced clinical signs or symptoms of thromb osis. Highly elevated urinary levels of 11-dehydro-thromboxane B-2 and sign ificantly elevated plasma levels of thrombin-antithrombin III (TAT) complex es were observed to the same extent in TM children and adults. The levels o f factor II were decreased while factors V, VII + X and plasminogen were wi thin the normal range. The natural coagulation inhibitors, protein C (PC) a nd protein S (PS) were significantly decreased in all TM patients investiga ted, regardless of age, but the PS binding protein (C4bBP) and antithrombin III levels were normal. The frequency of other thrombophilic mutations was not increased. Thus, a chronic hypercoagulable state already exists in tha lassaemia in childhood and may contribute to the cardiac and pulmonary anom alies and the thrombotic events which occur later.