Influence of delivery on numbers of leukocytes, leukocyte subpopulations, and hematopoietic progenitor cells in human umbilical cord blood.

Abstract

Human umbilical cord blood (UCB) may be used as an alternative source of bone marrow repopulating cells in allogeneic bone marrow transplantation. The quality and quantity of UCB harvests for transplantation is affected by several factors. In this study we analyzed the influence of delivery, in particular stress during delivery, on the numbers of leukocytes and leukocyte subsets in UCB. Four groups of women with different types of deliveries were included in the study, and from each group samples of UCB were analyzed. Blood samples from healthy adults were used as control. In UCB there was a higher absolute number of leukocytes than in peripheral blood (PB). UCB leukocytes were highest after deliveries with a prolonged second stage of labor, which was mainly due to granulocytosis. The percentage of T cells in UCB was lower than in PB, in particular when stress during delivery was higher. In all groups, however, the absolute concentration of T cells per milliliter of UCB was higher than in adult PB. The differences in T cells in stressful deliveries were mainly due to a relative decrease in CD3+/CD4+ cells in UCB. The relative frequency and absolute concentration of the CD56+ cell population in UCB was higher than in PB, which was mostly due to an increase of CD2-/CD56+ cells, in particular in stressful deliveries. The absolute number of CD34+ cells as well as hematopoietic progenitor cells as determined in semisolid medium cultures was high in UCB and was increased in cases of prolonged secondary stage of labor. This study demonstrates that the quality of UCB transplants is influenced by the course of delivery, in particular by stress during delivery.