Immunophenotypic evaluation, and physiological and laboratory correlations of hematopoietic stem cells from umbilical cord blood

ABSTRACT

The use of umbilical cord blood stem cells is an efficient alternative for the transplantation of hematopoietic progenitor cells. A number of factors can influence the volume and amount of CD34+ cells, which are considered as immature and capable of proliferation. Quantification of CD34+ cells, evaluation of CD38 and c-kit molecules on these cells, as well as correlations of such factors as maternal age, gestational age, newborn sex and weight, umbilical cord length, placental weight with increased volume and concentration of immature cells, among others, were performed in 70 blood samples from term newborns. The mean volume of umbilical cord blood collected was 53.8±33.6 mL, where 30.96±18.9 CD34+/mL UCB cells were found, of which 16.66±8.32% were CD34+CD38- cells, and 47.23±24.0% were CD34+CD117cells. Newborn weight and placental weight were positively correlated with increased volume of collected UCB. The volume of collected blood was found to affect the absolute count of CD34+ cells and the relative value of these among total nucleated cells, as well as the percentage of CD34+CD117+ and CD34+CD117cells. CD34+ cells were positively correlated with leukocytes, and gestational age was negatively correlated with the number of CD34+ cells. Our results confirm the importance of the accurate quantification of CD34+ cells and their subsets, and that many factors may be related to the higher number of hematopoietic stem cells, which are crucial for successful transplantation.