Evaluation of thrombomodulin (THBD) plasma levels in sickle cell disease and correlation with disease severity

Abstract Background Endothelial dysfunction is a hallmark of sickle vasculopathy. Thrombomodulin (THBD) is a transmembrane protein expressed on vascular endothelial cells suppressing blood coagulation and exerting anti-inflammatory effects. It is a known biomarker of endothelial injury and its elevated serum levels with subsequently, reduced endothelial function have been implicated in various disorders. We aimed to quantify THBD plasma levels in a cohort of Egyptian patients with SCD and investigate THBD levels’ association with disease severity and other inflammatory markers. Methods Plasma THBD levels were measured for 70 SCD patients and 70 healthy control subjects using an Enzyme-Linked Immunosorbent Assay (ELISA) kit that captures all THBD domains. Patients’ demographic, clinical, and laboratory characteristics were retrieved from their archived files. Results The mean THBD plasma level of our studied SCD patients was 5.23 ± 3.05 ng/ml (range 1.25–16.56 ng/ml) and it was significantly higher in comparison to controls ( p -value = 0.001). Thrombomodulin levels were elevated in SCD patients experiencing SCD-related complications and those requiring hospital admissions, denoting disease severity ( p -value = 0.004 and 0.017, respectively). A significant positive correlation was observed between thrombomodulin levels and patients’ age ( r = 0.359, p -value = 0.002). However, there were no statistically significant correlations with HbF ( p = 0.075) between thrombomodulin levels and the studied laboratory parameters in our SCD patients ( p -value > 0.05). Conclusion Steady-state SCD patients exhibited higher thrombomodulin plasma levels than controls. Thrombomodulin levels may increase with age and might be applied as a marker of disease severity among patients with SCD.