Abstract
Our study aimed to study regulatory T cells (Tregs) and their expression of CD45RA, HLA-DR, and CD39 in preterm and full-term infants. In an observational study, we used a three-color flow cytometry for determination of Tregs and their expression of CD45RA, HLA-DR, and CD39 in preterm and full-term infants. The percentages of CD4(+)CD25(+high)Foxp3(+), CD39(+) Tregs, HLA-DR+ Tregs and the expression of Foxp3(+) in CD4(+)CD25(+high)Foxp3 Tregs cells were significantly lower in neonates when compared to healthy adult controls. The levels of naive resting Tregs (CD45RA(+)Tregs) were significantly higher in neonates than controls. The percentages of CD4(+)CD25(+high)Foxp3(+)Tregs, total CD4(+)CD25(+) and CD4(+)CD25(+high) were significantly higher in preterm infants when compared to the full-term group. Moreover, CD45RA(+)Tregs were significantly higher in preterm than in term infants. We found significant inverse correlations between the gestational age and the levels of both Tregs (r=-0.395, p=0.017) and CD45RA(+)Tregs (r=-0.422, p=0.010). Relative to full-term, the frequencies, and phenotypes of Tregs were affected by prematurity. A larger longitudinal study with a sufficient number of newborns is needed to investigate the Treg pool of term and preterm infants thoroughly and to explore the association between the Treg pool and clinical variables.