Single-center Pilot Study: Nano-rheological Biomarkers for Patients With Sickle Cell Disease (SCD) Versus Control Subjects (Other Constitutional Red Blood Cell Diseases and Healthy Subjects)

Numerous pathologies (sickle cell disease, thalassemia, spherocytosis, etc.) lead to changes in the rheological properties of the blood, in particular via alterations in the deformability of red blood cells. These alterations lead to circulatory complications of which an emblematic example is the sickle cell crisis which manifests itself by microcirculatory occlusions. Several authors suggest that the deformability of erythrocytes is a key parameter for the diagnosis and monitoring of patients. Numerous studies, especially in vitro, show that the mechanical properties of the red blood cell significantly influence its dynamics in flow (blood viscosity, distribution in capillary networks). Moreover, concerning the specific problem of vaso-occlusion, the proportion of the most rigid red blood cells is a determining factor of the probability of occlusion more than the average value of this rigidity which can hide great disparities.

There is no clinically usable test to assess the alteration of the fine rheology of the red blood cell in a patient. Functional tests such as ektacytometry require heavy equipment and teams of specialized biologists; this technique is therefore only available in 3 biological reference centers in France. "Mechanical phenotyping" seems to be a potentially simpler and more accessible technique, and has already shown promising prospects in other nosological settings than red blood cell pathologies.

Today, there is no specific marker of sickle cell vaso-occlusive crisis, nor marker of severity, that would be useful for pathophysiological understanding but also for clinical management.