Clinical Significance of Assessment of Thrombospondin and Placenta Growth Factor Levels in Patients with Sickle Cell Anemia: Two Centers Egyptian Studies

BACKGROUND: Sickle cell disease has a worldwide distribution. Vaso-occlusive crisis (VOC) is one of the most important clinical features of the disease. Thrombospondin (TSP1) and Placenta growth factor (PlGF) have been reported to be involved in sickle cell diseases (SCD). OBJECTIVE: The aim of this study was to assess the clinical significance of Thrombospondin and Placenta growth factor profiles in patients with sickle cell disease. PATIENTS AND METHODS: This study was carried out in sixty patients with sickle cell anemia who were attendants to Hematology units, Pediatric Departments, Tanta and Elmenofia University Hospitals in the period between December 2011 and May 2014 including thirty patients during vaso-occlusive crisis and thirty patients out of crisis. Also this study included twenty healthy children of matched age and sex as a control group. Serum TSP1 and PlGF levels were analyzed by ELISA. RESULTS: In SCA patients with crisis the mean serum Thrombospondin level was 902.5±280.89 ng/mL; in SCA patients out of crisis the mean serum Thrombospondin level was 462.5 ± 190.2 ng/mL and in controls the mean value was 236.66±58.29 ng/mL. In SCA patients with crisis the mean serum Placenta growth factor level was 19.97±1.28 pg/ml; in SCA patients out of crisis the mean serum Placenta growth factor level was 13.12 ± 1.82 pg/ml and in controls the mean value was 9.89 ± 1.20 pg/ml. All paired comparisons for Thrombospondin and Placenta growth factor reached statistical significance (P< 0.001). There was significant positive correlation between serum Thrombospondin and Placenta growth factor levels in sickle cell anemia patients during crisis (r=0.848, p=<0.001). CONCLUSIONS: This is the first study to show TSP1and PlGF concentration changes in patients with SCD in a large cohort study from Middle East, and to show correlation between both markers; therefore TSP1and PlGF may be useful VOC markers in SCD patients. RECOMMENDATION: To further assess TSP1 and PlGF as a marker of VOC in patients with SCD, further studies should be conducted to determine the exact point before VOC, when serum TSP1 and PIGF levels begin to increase. This requires monitoring of the TSP1 and PIGF levels in sickle cell patients out of crisis, showing how rapidly these levels increase just before VOC development.