Immune Imbalance in Th1/Th2 and Th17/Treg as a Contributor to Endometrial Polyps: A Prospective Laboratory-Based Study

Background: From an immunological perspective, changes in cytokine levels can shift the immune response, potentially affecting the development of endometrial polyps (EPs). The relationship between the balance of T helper 1 (Th1)/T helper 2 (Th2) and T helper 17 (Th17)/Regulatory T (Treg) cytokines and the pathogenesis of EPs is an area of ongoing research. This study aims to investigate the role of Th1/Th2 and Th17/Treg immune imbalances in the pathogenesis of EPs. Methods: A total of 79 patients were included in this prospective laboratory-based study. The experimental group included 20 patients with single EPs, 20 with multiple EPs, and 19 with postmenopausal EPs. The control group included 20 individuals with proliferative endometriums. Immunohistochemical staining was performed to investigate the expression of interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-6 (IL-6), interleukin-17 (IL-17), tumor necrosis factor-α (TNF-α), interferon-gamma (IFN-γ). Results: The levels of TNF-α, IFN-γ, IL-17 and transforming growth factor-β (TGF-β) in the single EP group were higher than in the control group (pTNF-α = 0.001, pIFN-γ < 0.001, pIL-17 < 0.001, pTGF-β < 0.001), while the level of IL-6 in the stroma was lower than in the control group (pIL-6 < 0.001). The levels of IL-2, IFN-γ, IL-4, IL-17 and TGF-β in the glands of the multiple EPs group were higher than in the glands of the control group (pIL-2 = 0.041, pIFN-γ < 0.001, pIL-4 = 0.044, pIL-17 < 0.001, pTGF-β < 0.001). The levels of IL-4, IL-6, TNF-α, and IL-17 in the postmenopausal single polyp group were lower than in the total control group (pIL-4 = 0.020, pIL-6 = 0.002, pTNF-α < 0.001, pIL-17 = 0.006), while the levels of IL-2, IFN-γ and TGF-β in the glands were higher than in the control group (pIL-2 = 0.002, pIFN-γ = 0.002, pTGF-β = 0.005). Conclusion: Th1/Th2 and Th17/Treg immune imbalances are one of the causes of EPs.