Intrauterine growth restriction and prematurity influence regulatory T cell development in newborns

Abstract Purpose The aim of this study was to determine the relationship of birth weight and gestational age with regulatory T cells (T regs ) in cord blood of human newborns. Methods Cord blood mononuclear cells (CBMCs) of 210 newborns were analyzed using flow cytometry to identify T regs (CD3 + , CD4 + , CD25 high , FoxP3 high ) and measure FoxP3 mean fluorescence intensity (MFI). Suppressive index (SI) was calculated as FoxP3 MFI per T reg . Results Mode of delivery had no significant effect on T regs at birth. Term babies with growth restriction had fewer T regs than their appropriate weight counterparts but equivalent SI. Preterm babies had higher percentages of T regs , but lower SI than term controls. SI steadily increased through gestation. Conclusions Intrauterine growth restriction is correlated with fewer circulating T regs and prematurity with decreased functionality of T regs compared to term appropriate weight infants. This may have implications in diseases such as necrotizing enterocolitis that disproportionately affect premature and lower birth weight infants.