Expression of FasR, Fas-L and Bcl-2 in CD4+ and CD8+ subpopulations of T lymphocytes in the cord blood of healthy full-term newborns, is gender of influence?

PURPOSE The expression of FasR, Fas-L and Bcl-2 on CD4+ and CD8+ T lymphocytes subpopulations from the cord blood were assayed. The results in blood from boys and girls were analyses separately and compared. MATERIAL AND METHODS Twenty four full-term newborns: 13 females and 11 males were included into the study. Blood from the umbilical vein was collected immediately after cutting the umbilical cord. The staining with monoclonal antibodies against CD4, CD8, FasR, Fas-L and Bcl-2 was performed within 2 hours after collection and followed with flow cytometry acquisition and analysis. RESULTS The percentage of CD4+ and CD8+ T lymphocytes and CD4+:CD8+ ratio was within normal range. The expression of FasR, Fas-L was higher on CD4+ T lymphocytes than on CD8+ T lymphocytes (10,36% vs 6,79% and 6,66% vs 5,63% respectively). The expression of Bcl-2 was comparable (91,9% and 93,75% respectively). The comparison between males and females showed higher percentage of CD4+ lymphocytes on lymphocytes from girls' blood (56% vs 38,69%, p=0.0003). The expression of FasR and Fas-L on CD4+ T lymphocytes was higher on CD4+ T lymphocytes from girls' blood (13,8% vs 7,53% and 6,8% vs 6,52% respectively) but without statistical significance. Bcl-2 expression was higher on CD4+ T lymphocytes from boys' blood (99,65% vs 89,7%) but without statistical significance. Similar pattern of FasR, Fas-L and Bcl-2 expression was noted on CD8+ T lymphocytes analysed separately for girls' and boys' blood origin cells. The difference in Bcl-2 expression was more prominent than on CD4+ T lymphocytes and reached statistical significance. CONCLUSIONS The lymphocytes from cord blood of boys showed the more immature immunophenotype than T lymphocytes from cord blood of girls'. Impaired apoptosis (as a consequence of low expression of FasR, Fas-L) in neonatal cells may contribute to prolonged inflammation in newborns after oxidative stress or infection.