ABSTRACT
Disorders in immune system regulation may result in pregnancy abnormalities such as recurrent spontaneous abortion [RSA]. This study aims to determine the ratio of regulatory T [Treg] and T helper [Th] 17 cells in unexplained RSA [URSA] women during proliferative and secretory phases of their menstrual cycles compared to healthy non-pregnant women. In this case control study, 25 women with URSA and 35 healthy, non-pregnant women were enrolled. The percentage of Th17 and Treg cells in participants peripheral blood were determined by flow cytometry. The percentage of Th17 cells and their related cytokines in serum [IL-17A] were higher in the proliferative and secretory phases of the menstrual cycles of URSA women compared to the control women. However, a lower percentage of Treg cells and their related cytokines in serum, transforming growth factor [TGF] beta1 and interleukin [IL]-10 were detected in the proliferative but not the secretory phase of the URSA group. The ratio of Th17/CD4+ Treg was higher in the URSA group than the control group. We observed an increased ratio of Th17/CD4+ Treg during the proliferative and secretory phases in URSA women. The imbalance between Th17 and Treg cells during the proliferative phase of menstrual cycles in the URSA group may be considered a cause for spontaneous abortion