RESUMEN
In recent years, it is suspected that vascular endothelial cells may have some role in vascular complications noted in thalassemic patients. Activated or injured endothelial cells release their protein constituents mainly thrombomodulin into the circulation. Thrombomodulin is considered the most important indicator of vascular endothelial injury. To study serum thrombomodulin level in children with B-thalassaemia major and its relation to the duration of disease and extent of iron overload. The present study was carried out on 35 patients with fl-thalassaemia major. They were divided according to the age into two groups. Group I: included 15 young children aged less than 10 years. Their mean disease duration was 5.5 years. Group II: included 20 older children and adolescents aged from 10 to 20 years. Their mean disease duration was 15.6 years. Ten apparently healthy children of matching age and sex served as control group. Estimation of serum levels of Thrombomodulin [TM] by ELISA. Echocardiography, two-dimensional, M-mode, and Doppler studies. Cardiomegaly was found in 7 [35%] patients of group II. Pulmonary hypertension was encountered only in 4 [20%] patients of group II. Thromboembolic manifestations [femoral deep vein thrombosis] were found in only 1 [5%] thalassaemic patient in group II. The serum TM level was significantly higher in both groups, in comparison with controls [F=10.36, p<0.001]. No significant difference was found between both thalassaemic groups [t=0.421, p=0.673]. Moreover, no significant difference was found between TM levels in splenectomized and non-splenectomized cases [t=0.62, p=0.541]. TM levels of both thalassemic groups showed no significant correlation with serum ferritin level [r=-0.02, p=0.914]. A significantly higher mean value of right ventricular wall thickness was encountered in group II thalassaemic patient as compared to group I [t=2, 57, P=0.019]. In conclusion, increased serum TM level in our polytransfused thalassaemic patients reflects a state of endothelial cell activation and/or injury in these patients. The statistically significant negative correlation between serum TM level and pulmonary acceleration time [r=-0.45, p=0.047], may point to the possible role of pulmonary vascular endothelium injury as a contributory factor in the pathogenesis of pulmonary hypertension in our thalassaemic patients