Regulatory Τ-cell differentiation between maternal and cord blood samples in pregnancies with spontaneous vaginal delivery and with elective cesarian section.

Problem: The immunological mechanisms preventing fetal antigenic rejection during normal pregnancy and the extent to which the type of delivery influences lymphocyte reactions are elusive.

Method Of Study: Maternal peripheral blood and neonatal umbilical cord blood (CB) was collected upon labor after vaginal delivery or cesarian section. Leukocytes were analyzed with flow cytometry, focusing on regulatory and γ/δ T-cells.

Results: In CB from neonates delivered by vaginal delivery, natural killer cells were increased. On the other hand, in maternal blood, γ/δ T-cells were increased, and activated T-cells (cluster of differentiation [CD]4+/25(dim) /122+ cells) were decreased. Moreover, maternal blood presented increased levels of T regulatory cell subsets like CD4+/25(high) /45RO+, CD4+/25(high) /DR+, CD4+/25(high) /CD38+ and CD4+/25(high) /71+. In CB, CD19+, CD4+/25(high) /45RA+ and CD4+/25(high) /122+ cells were increased.

Conclusion: The effect of delivery type on lymphocyte immunophenotype was minimal. Mothers' and neonates' lymphocyte subsets differed significantly. Mothers' phenotype comprised significantly of lymphocytes involved in tolerance (memory and activated regulatory T-cells, γ/δ T-cells).