engleski

Peripartum alterations of maternal and neonatal leukocytes: possible causes and consequences

Adjustment of maternal immunoreactivity which involves a selective immune tolerance is necessary for successful pregnancy. Infections whose resolution depends on specific cellular immunity are more frequent in pregnant women. Intrauterine infection and proinflammatory cytokines are implicated in the pathogenesis of preterm labor and associated with an increased occurrence and severity of some neonatal diseases. Cytokines and immune cells are part of a complex regulatory network orchestrated by hormones within the fetoplacental-maternal unit. Many data support the hypothesis that labor is an inflammatory process. Parturition is associated with leukocyte invasion and proinflammatory cytokine production in the cervix, myometrium and decidua, but also in umbilical blood and maternal peripheral blood. Labor significantly affects the distribution and proportion of certain maternal peripheral blood and cord blood leukocyte subpopulations. In order to identify lymphocyte subpopulations that change the most in the short postpartum period immunophenotypes of 20 healthy women and their newborns at childbirth and again 3 days later were analyzed by flow cytometry. This study included uneventful vaginal deliveries on term. Total leukocytes were significantly higher at delivery than three days later in mothers and in newborns. Additionally, NK cells and NK cells with CD8+ antigen were greatly increased in their relative and absolute counts in both mothers and newborns (p < 0.001). A higher proportion of T cells with NK activity (CD3+CD16/CD56+) was found in mothers at delivery. The relative and absolute count of T helper cells was reduced in mothers at delivery. In newborns a lymphocytosis was present at birth. Despite significantly decreased percentages of T and T helper cells in cord blood in comparison with peripheral blood three days later, the absolute counts of T cells were increased in cord blood and the absolute T helper cell values were similar in both samples. An increased proportion of CD45RA+ cells was detected in mothers at delivery time. An especially high proportion of maternal CD8+ cells was CD45RA+ or CD45RARO+ during labor. There was an expected predominance of naive phenotype in newborns. However, the percentage of CD4+ cells bearing CD45RO marker and the absolute count of CD4+CD45RO+ cells was significantly increased at birth. This questions the usefulness of increased memory helper T cells in cord blood as an indicator of connatal infection and points to the importance of quantitative antigen expression.

parturition ; lymphocyte immunophenotype ; newborns

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