RESUMO
INTRODUCTION: The coagulation activation in ß-thalassaemia is multifactorial and most likely a consequence of the exposure of phosphatidylserine (PS) on RBCs surface. The degree of PS exposure and procoagulant activity of RBCs in ß-thalassaemia trait (BTT) subjects carrying common Mediterranean mutations were assessed. METHODS: Eighty BTT subjects carrying common Mediterranean mutations (ß+, n = 53 and ß0 , n = 27) and sixty healthy subjects served as controls were studied. Plasma prothrombin fragment 1+2 (F1+2), percentage of PS expression on RBCs membrane, clotting times of modified thromboplastin generation test (MTGT) and modified partial thromboplastin with kaolin (MPTTK) were estimated. RESULTS: The percentage of annexin V positive RBCs and plasma F1+2 had a significant increase and MTGT had a significant decrease in BTT subjects versus controls and in ß0 group versus ß+ group. MPTTK was significantly shorter in BTT subjects than controls, but no significant deference between BTT subjects. The percentage of annexin V positive RBCs showed a significant negative correlation with haemoglobin level, MTGT and MPTTK, and a significant positive correlation with plasma F1+2. CONCLUSION: BTT subjects may have a risk of hypercoagulable state particularly in ß0 genotype. Measurement of PS exposure on RBCs and the plasma F1+2 is useful to evaluate hypercoagulability state.
