Clinical Research Directory

Transfusion Exchanges and Cognition in Sickle Cell Disease

DREPA-COG is an observational study evaluating the effect of exchange transfusions on cognitive function in adults with severe sickle cell disease (SS or Sβ0). Information processing speed is assessed at three time points during the transfusion cycle using the Symbol Digit Modalities Test (SDMT) and additional validated neuropsychological measures. This minimal-risk, fully remote study aims to identify processing speed as a reproducible marker for clinical monitoring and future therapeutic trials.

Study of a Deformability Parameter of Red Blood Cell

Sickle-cell disease is one of the most common severe monogenic disorders in the world, it results in the synthesis of abnormal hemoglobin (HbS) instead of hemoglobin A. When deoxygenated, the sickle haemoglobin (HbS) polymerizes inducing the sickling of red blood cells (RBCs) and leading to decreased deformability and increased fragility. Therefore, sickle RBCs exhibit a reduced lifespan associated with intravascular hemolysis, hemolytic anemia and low tissue oxygenation. Sickle RBCs, which exhibit abnormal adhesive properties to endothelial cells, can block the microcirculation, causing the occurrence of painful vaso-occlusive crisis (VOC), acute chest syndrome (ACS), acute and chronic organ damage (heart, lung, liver, spleen, kidney, bone…) and shortened life span. A preliminary study performed on RBC from sickle cell patients (Hb SS) has shown an alteration of a parameter measuring the overall deformability of RBCs by evaluating the nature of their movement in a shear flow. This parameter is significantly lower in sickle cell patients in steady state compared to a population of healthy individuals. The parameter is also significantly lower in sickle cell patients during VOC when compared to patient in steady state. The main objective of this study is to evaluate the performance of the method for measuring the deformability of RBCs on an experimental prototype. Measurements will be performed on blood samples from subjects with a normal hemoglobin electrophoretic profile, from heterozygous carriers of sickle cell disease and from patients with sickle cell disease. Samples from paediatric patients will also be tested to study any specificity in comparison to adult subjects.