Role of red blood cells “annexin V” and platelets “P-selectin” in patients with thalassemia

Abstract

Objective/BackgroundCertain hemostatic anomalies found in patients with thalassemia suggest the existence of a chronic hypercoagulable state. Several etiologic factors may play a role in the pathogenesis of the hypercoagulable state in those patients. One of these factors is abnormal thalassemic red blood cells (RBCs), which may provide a procoagulant. To substantiate these findings, we measured the ability of RBCs from thalassemia patients to bind annexin V with increased fraction of platelets carrying the activation marker CD62P (P-selectin). To study the expression of RBC annexin V and platelets P-selectin in study patients (those with thalassemia major, thalassemia intermedia, thalassemia minor) and control group, four-color flow cytometry was performed and the correlation between these two markers was evaluated. MethodsA case–control study was conducted on 50 β-thalassemia patients (10 patients with thalassemia minor, 30 patients with thalassemia major, and 10 patients with thalassemia intermedia, with 10 normal adult volunteers as a control) from June 2016 to March 2017. Flow cytometry was used to study the expression of anionic phospholipids (Annexin V) on the RBCs and CD62P (P-selectin) on the activated platelet. ResultsThe mean expression of annexin V in patients with thalassemia major and intermedia was significantly higher than that in the control group and patients with thalassemia minor. Although the mean expression was higher in patients with thalassemia intermedia than in those with thalassemia major, it was not statistically significant. ConclusionThe mean expression of platelets P-selectin in patients with thalassemia major and thalassemia intermedia was significantly higher than that in controls and patients with thalassemia minor. However, its expression was significantly higher in patients with thalassemia intermedia than in those with thalassemia major. Annexin V also showed a positive correlation with P-selectin, and both markers positively correlated with regularity of blood transfusion.