Erythroid progenitors in the peripheral blood of children with sickle cell disease.

Purpose: The goals of this study were (a) to determine the number of peripheral blood burst forming units-erythroid (BFU-E); (b) to define the relationship between circulating BFU-E number and fetal hemoglobin (HbF) level; and (c) to define the relationship between BFU-E number and age in pediatric sickle cell disease (SCD) patients.

Patients and methods: Fetal hemoglobin (HbF) level and peripheral blood BFU-E number were determined in children < 18 years of age with SCD in a steady state of their disease. These data were compared with those of normal children.

Results: An increased number of BFU-E was observed in the peripheral blood of children with SCD compared with normals (30.7 vs. 15.7 per 10(5) mononuclear cells, respectively; p = 0.009). Overall there was the suggestion of a direct relationship between HbF level and peripheral blood BFU-E number (regression coefficient = 0.445; p = 0.06). Additionally, a strong inverse relationship between BFU-E number and age (regression coefficient = -0.671; p < 0.0001) was observed.

Conclusions: In children with SCD (a) there are an increased number of peripheral blood BFU-E compared with normal children; (b) the inverse relationship between HbF level and BFU-E number observed in adult SCD patients is not seen in children; and (c) there is a strong inverse relationship between age and BFU-E number. This information may help to further clarify the relationship between peripheral blood BFU-E and erythropoietic stress.