Sickle cell disease (SCD) is an autosomal recessive disorder resulting from a substitution in the β chain of hemoglobin (Hb) which causes hemoglobin S to polymerize when deoxygenated. SCD patients present immune abnormalities that have always been attributed to functional asplenia. It it is now being recognized that patients with SCD have a pro-inflammatory condition with altered immune system activation contributing to the pathology of SCD. Increased levels of neutrophils, monocytes or cytokines have been reported in SCD patients.