Nigerians with Sickle Cell Trait (Hb AS) have more Haematopoietic Stem Cells in Circulation than those with Hb AA

Abstract

Background: The outcome of haematopoietic stem cell (HSC) transplantation depends on the yield of CD34+ cells among other factors, but correlates of CD34+ cells have not been studied among Nigerians.

Aim and Objectives: This study determined the CD34+ cell count, haematological profile of cord blood and peripheral blood of apparently healthy non-mobilized Nigerian adults; and assessed the relationship between these parameters.

Materials and Methods: Fifty apparently healthy non-mobilized adults and 50 apparently healthy women in the third trimester of pregnancy were studied after informed consent. Full blood count (FBC) was obtained from peripheral blood of adults and cord blood (SFRI-H18 Medical Diagnostic) together with CD34+ cell count (Cyflow; Partec SL-3).

Results: The mean CD34+ cell count of cord blood (8.71 ± 8.87/µL) was significantly higher than that of adult blood (1.90 ± 1.43/µL; p = 0.0001). Adults with sickle cell trait (SCT; Hb AS; 18%) had significantly higher CD34+ cell counts (2.92 ± 1.75/µL) than Hb AA individuals (1.68 ± 1.27/µL; p = 0.016). Cord blood of newborns from mothers with SCT (32%) had a significantly higher CD34+ cell counts (12.32 ± 11.27/µL) than those with Hb AA (7.01 ± 7.05/µL; p = 0.047). Cord blood CD34+ cell count weakly correlated with Hb concentration (r = 0.300; p = 0.034) and Hct (r = 0.335; p = 0.017). Adult blood CD34+ cell count weakly correlated, but inversely with platelet count (r = -0.326; p = 0.021).

Conclusion: Non-mobilized adults andnewborns of mothers with SCT are more likely to have a higher CD34+ cell yield than those with Hb AA.