Regulatory T cells are of utmost importance for tolerating the fetus. In some pregnancy complications such as pre-eclampsia, the frequency of CD4+CD25+Foxp3+ regulatory T cells is altered, but there is no consistency regarding the results. Besides, little is known about the frequency of CD8+CD25+Foxp3+ Treg cells in pregnancy complications. Therefore, we aimed to investigate the frequency of both CD4+ and CD8+ regulatory T cells in the peripheral blood of women afflicted by preeclampsia. Ten non-pregnant, ten healthy pregnant, and ten preeclamptic women participated in this study. Four colors flow cytometry method was used to identify the frequency of the CD4+ and CD8+ regulatory T cells in the peripheral blood. Results indicated that the frequencies of CD4+CD25+Foxp3+ and CD8+CD25+Foxp3+ cells were significantly lower in preeclamptic women compared to healthy pregnant and non-pregnant ones (p<0. 05). A positive correlation was also observed between CD4+ and CD8+ regulatory T cells (R=0. 532, p=0. 002). Moreover, CD4+ regulatory T cells negatively correlated with systolic and diastolic blood pressures (R=-0. 760 and-0. 753, respectively; p<0. 001). CD8+ regulatory T cells also had a negative correlation with systolic (R=-0. 503, p=0. 001) and diastolic (R=-0. 590, p=0. 005) blood pressures. In conclusion, a reduction in the frequencies of both CD4+ CD25+ Foxp3+ and CD8+CD25+Foxp3+ regulatory T cells might be important in the pathogenesis of pre-eclampsia.

Immune responses are pivotal in hepatitis B virus (HBV) infection, where Regulatory T cells (Treg) can contribute to sustaining the infection by suppressing immune responses. Forkhead box P3 (Foxp3) is the central regulator of Treg cells. In this case-control study, we investigated the role of Foxp3 -3279 (rs3761548) C/A polymorphism in the context of HBV infection. The study encompassed 140 healthy individuals as the control group and 70 individuals with chronic hepatitis B virus (CHBV) as the case group. The rs3761548 polymorphism was analyzed using the restriction fragment length polymorphism-PCR (PCR-RFLP) method. Furthermore, we evaluated Foxp3 gene expression in both HBV-positive and control groups using Real-Time PCR. The results revealed that the frequency of the AA genotype in the case and control groups was 52.9% and 44.3%, respectively, yielding an odds ratio (OR) of 1.411 with a 95% confidence interval (CI) ranging from 0.793 to 2.509. However, this difference did not achieve statistical significance (P = 0.242). Notably, the AC genotype was significantly more prevalent in the control group compared to the case group (P = 0.000). Moreover, Foxp3 gene expression was significantly higher in CHBV infection cases compared to the control group (P = 0.000). These findings suggest that the observed polymorphism may play a role in the pathogenesis and persistence of HBV infection. Nevertheless, further research is warranted to comprehensively investigate this phenomenon.