Study of platelet activation markers and plasma cytokines in sickle cell disease patients during vaso-occlusive pain crises

The present study was designed to examine platelet function during the sickle cell disease (SCD) vaso-occlusive pain crisis (VOC) in comparison with steady-state SCD patients and healthy controls. Platelets were immunophenotyped using different activation CD markers in a group of 34 patients with SCD. Among those SCD patients, 19 patients were admitted to our hospital for symptoms of VOC pain crises. Fifteen patients of SCD were studied in parallel during asymptomatic steady state (SS) of their disease. Fifteen healthy control volunteers were immunophenotyped in parallel. In addition, all patients and healthy control plasma were assayed for levels of the inflammatory cytokines which are IL-8, TGF-β1, and TNF-α. Our results confirmed the strong expression of activation markers CD40, CD41a, CD42a, CD61, CD62p, CD36, CD49f, and CD59 on platelets from patients studied during VOC pain episodes (P ˂ 0.005). However, both the steady-state SCD patients and normal healthy controls did not show increased expression of any of these markers on their platelets. In addition, the mean levels of IL-8 in the plasma of VOC-SCD patients were statistically significant superior to IL-8 mean values of normal control plasma (P = 0.008). These results suggest over activation of platelets in SCD patients during VOC pain episodes compared to SCD steady state or normal controls. Alongside, we found significant increase of plasma IL-8 levels during VOC pain crises. These findings indicate over activation of platelets, together with over production of IL-8 during VOC pain crises in SCD patients.