Study of a Red Blood Cell Deformability Parameter in Patients With Sickle Cell Disease
Study of a Red Blood Cell Deformability Parameter in Patients With Sickle Cell Disease
Sickle cell disease is the most common genetic disease in the world. It results in the
 synthesis of an abnormal hemoglobin (HbS) which, in its deoxygenated form, polymerizes and
 causes structural changes in red blood cells (RBCs). They become more rigid and less
 deformable. The fragility of sickle-cell RBCs leads to their massive destruction, leading to
 chronic anemia (i.e. low hemoglobin in the blood) and to low tissue oxygenation. More rigid
 and less deformable, sickle-shaped RBCs tend to obstruct microvessels, leading to
 particularly painful vaso-occlusive crisis (VOC), which can cause organ failure (spleen,
 kidneys, brain, lungs, heart, liver, bone ...) and patient's lifethreatning. A preliminary
 work on red blood cells of sickle cell patients showed alteration of a parameter measuring
 the overall deformability of RBCs by assessing the nature of their movement in a shear flow.
 This parameter is altered sickle cell patients at basal state compared to a population of
 healthy individuals. This alteration is increased when sickle cell patients are in crisis.

 The main objective of this project is to study the evolution of this parameter in sickle cell
 patients according to their health status (basal state vs vaso-occlusive crisis). The
 investigators hypothesize that the alteration of the RBC deformability parameter is
 significant before symptoms of vaso-occlusive crisis (several hours to several days). The
 main objective is a weekly analysis of the evolution of the parameter in 30 sickle cell
 patients (SS or SB°) in the basal state and daily in at least 6 patients at the beginning,
 during and just after a vaso-occlusive crisis. The comparison between the parameter measured
 in a subject in the basal state and in the same subject in crisis will be performed. The
 criteria for the presence of a vaso-occlusive crisis were: the appearance of a attacks of
 pain affecting at least two territories +/- fever> 38.3 +/- dyspnea and / or sputum. The
 investigators will differentiate the moderate VOC managed at home with low-level analgesics
 and VOC requiring hospitalization. The number of days of hospitalization, the occurrence of
 thrombotic complications, the degree of anemia and hemolysis will be noted. The measurement
 of the parameter will be performed on a capillary sampling of 40 microliters performed at the
 fingertip, weekly outside crises and daily when a crisis occurs.
Inclusion Criteria:

 -  Homozygous SS or SB° sickle cell patients

 -  Person without regular blood transfusion

 Exclusion Criteria:

 -  Other general diseases

 -  Psychiatric disorder

 -  Alcoholics

 -  Minors

 -  Absence of informed consent

 -  Pregnant or lactating woman

 -  Person under guardianship

 -  Person living in a health or social institution

 -  Person in emergency

 -  Person out of healthcare system

 -  Person deprived of liberty

 -  Person who has received a blood transfusion in the previous 3 months

 -  Person with regular blood transfusion or in a blood transfusion program