Density distribution of red cells and prognostic significance in 50 patients with homozygous sickle-cell disease.

The sickle cell disease is characterized by a heterogeneous clinical and biological expression. In order to evaluate the prognostic significance of the red blood cell density distribution: D50 (median cell density of the distribution), R60 (middle density range in which 60% of the cells can be found), F4 and F5 (proportion of cells with density higher than 1.110 and 1.120 g/ml, respectively) have been determined in 50 patients with homozygous sickle cell disease. The alpha gene status was determined in 27 patients. All patients have been included in an original score of severity fitted to infancy and childhood. A positive correlation has been found between D50 and the clinical score. This result illustrates the potential clinical importance of this parameter as well as other biological indices such as the haemoglobin F level, the alpha gene status and the haplotypes of the beta-like gene cluster.