Sickle cell anemia with few painful crises is characterized by decreased red cell deformability and increased number of dense cells

The frequency and severity of the painful sickle cell crisis vary greatly among affected patients. Aside from a high level of Hb F(>20%) there is no established parameter which may modulate the clinical severity of the disease. In this paper we describe two groups of adult patients with homozygous SS and present their characteristics. The division into these two groups was on the basis of relatively low RBC deformability (≤37% of control) and high RBC deformability (>65% of control) in the steady state. None of the patients had α‐gene deletion and all had Hb F level