Peripartum alterations of maternal and neonatal leukocytes

The aim of this study was to identify the influence of labor on maternal and neonatal lymphocyte subpopulations. Peripheral blood was taken from 20 healthy women at vaginal delivery and 3 days later concomitantly with cord and peripheral blood from their newborns. Lymphocyte immunophenotyping was done by 3-color flow-cytometry. All lymphocyte subsets, except for the cytotoxic T cells and cytotoxic T cells with NK activity, were higher in their absolute counts in umbilical blood, but three days later only the levels of T helper and B lymphocytes were higher in newborns than in parturients . There was an expected predominance of naive phenotype in newborns. However, the absolute count of CD4+CD45RO+ cells was as high in umbilical blood as in peripheral blood of parturients at delivery. Of maternal CD8+ cells, an especially high proportion of CD45RA+ and CD45RA+RO+ was found during labor, and three days later the absolute numbers of maternal and neonatal naive CD8+ cells were equal.