The comparison of CD4(+);CD25(high); Foxp3(+); regulatory T cells between neonatal cord blood and adult peripheral blood.

Objective: To quantify the proportion of CD4(+);CD25(high); Foxp3(+); regulatory T cells (Treg) in neonatal cord blood and adult peripheral blood, and to explore the clinical significance of Treg in neonatal cord blood.

Methods: The percentage of CD4(+); T cells, and ratio of CD4(+);CD25(+);/CD4(+); and CD4(+);CD25(high);/CD4(+);T cells in mononuclear cells in 30 neonatal cord blood and 27 adult peripheral blood were examinea with flow cytometry (FCM). The expression of Foxp3(+); in CD4(+);CD25(+); and CD4(+);CD25(high); T cells was examined with FCM and RT-PCR, respectively RT-PCR.

Results: Compared with adult PBMC, the percentage of CD4(+); T cells was increased in neonatal cord blood(P<0.01); the percentage of CD4(+);CD25(+);/CD4(+); and CD4(+);CD25(high);/CD4(+);T cells were decreased in neonatal cord blood(P<0.05). The percentage of Foxp3(+); cells in CD4(+);CD25(+); and CD4(+);CD25(high); T cells in neonatal cord blood were both lower than that in adult peripheral blood(P<0.01) and the expression level of Foxp3 mRNA was also lower than that in adult peripheral blood(P<0.05).

Conclusions: There are certain amount CD4(+);CD25(high); Tregs in neonatal cord blood, but the expression levels of Foxp3 are lower than that in adult peripheral blood, which indicate that Tregs might play a distinct role of immunoloregulation.