LAUSR

Most of the findings have focused on the importance of CD4+HLA-G+ and CD8+HLA-G+ regulatory T cells (Treg) during pregnancy. It has been demonstrated that these HLA-G+ T cell subsets could induce maternal immune tolerance against semi-allogenic conceptus during pregnancy. There are only a few experiments regarding the Treg cells in the context of unexplained infertility (UI). Thirty-five participants including 18 primary unexplained infertile and 17 fertile females were enrolled in this study. A total of 3–5 ml blood samples were taken, and peripheral blood mononuclear cells (PBMCs) were separated by using Ficoll. Using a flow cytometer, the frequency of CD4+HLA-G+ and CD8+ HLA-G+ T cells was assessed in the peripheral blood samples of primary unexplained infertile and fertile females. Our results showed that the frequency of CD8+HLA-G+ Treg cells was significantly lower in primary unexplained infertile females than fertile females (P = 0.048). Although the frequency of CD4+HLA-G+ Treg cells in the primary unexplained infertile females was lower than fertile females, the difference was not statistically significant (P = 0.25). Regarding the important role of CD8+HLA-G+ Treg cells during pregnancy and its decrease in females with primary UI, it seems that reduced CD8+ HLA-G+ Treg cells could be a leading immunological factor in the context of infertility. Nevertheless, more researches are needed in this field.