Correlation between PCNA expression and Cytokine Imbalance in First-Trimester Miscarriage: A Marker of Endometrial Deficiency

Background:The proliferation marker PCNA (proliferating cell nuclear antigen) is involved in early pregnancy decidualization. This process is crucial for endometrial development and implantation, and PCNA expression reflects the proliferative activity of DSCs. Immunity and inflammation are also of immense importance in maintaining pregnancy. We aimed in this study to assess expression of PCNA and its relationship with the main cytokines, IL-10 and TNF-α in first trimester miscarriage.Methods:Sixty-one women (17–39 years old) were subdivided into 3 groups: group 1 RM (Recurrent miscarriage) (N = 25), group 2 Non-RM (Non-recurrent miscarriage) (N = 15), and group 3 term pregnancy control (N = 21). The expression of PCNA in DSCs was assayed by immunohistochemistry (IHC), and PCNA positive cells were counted using light microscopy. The levels of IL-10 and TNF-α in maternal serum were measured by ELISA.Results: Mean value of PCNA-positive DSC percentages was significantly less for Group 1 (11.04±2.03) and Group 2 (15.3±2.7) compared with that of Group 3 (24.19±2.65) (p≤0.001). Both groups 1 and 2 also had a marked increase in TNF-α (p ≤0.001) as well as a marked decrease in IL-10, compared to the control group.Conclusion:Low expression of PCNA in first-trimester miscarriage and its related to proliferation of decidua cell. A simultaneous reduction of IL-10 and increase of TNF-α is an indication of an imbalance of the immune environment that could lead to pregnancy loss. PCNA and inflammatory cytokines are potential molecular markers for evaluating endometrial receptivity and immunity during the early pregnancy.