Unlocking the Puzzle: Investigating the Role of Interleukin 17 Genetic Polymorphisms, Circulating Lymphocytes, and Serum Levels in Venezuelan Women with Recurrent Pregnancy Loss

In recurrent pregnancy loss (RPL), peripheral and local immune cells are activated, decreasing the leukocyte tolerogenic response in the uterus and decidua. The aim was to examine the role of IL-17 in RPL critically. The study included genetic polymorphism, the analysis of the number of circulating IL-17 lymphocyte populations, before and after cell priming, serum cytokine quantification, and the assessment of T-reg cells in a group of 50 RPL and 50 normal women from the admixed Venezuelan population. The study found no differences in the genetic polymorphisms rs2275913 and rs763780. However, when IL-17+ cell populations of controls and RPL patients were compared, a significant increase was observed in the cell populations CD3+ and CD4+ (p < 0.001), while the contrary was recorded in CD8+ and CD56+ cells. Upon cell priming, all IL-17+ populations were significantly decreased (p < 0.001) in RPL patients compared to controls. The increase in IL-17A in the serum of RPL patients may be due to the CD4+ population, while cell exhaustion after activation could be responsible for decreased CD8+ cell population. The number of CD4CD25 FoxP3+ cells was significantly reduced (p < 0.001), and the number of activated HLADR+ cells was significantly increased (p < 0.001) in RPL patients. The absence of differences in the genetic polymorphism compared to controls suggests that biological factors influence IL-17 levels in RPL patients. This finding has significant implications for the understanding and potential treatment of RPL.