Interleukins‐6 and −8 Levels in Sera and Cervical Mucus of Fertile, Idiopathic Infertile, and Immunoinfertile Women: Implication in Infertility

PROBLEM: The purpose of this study was to investigate the levels of interleukin-6 and -8 (IL-6 and IL-8) in sera and cervical mucus of infertile (idiopathic and immunoinfertile) women and to compare the levels with those in age-matched normally cycling fertile women. METHODS: Levels of IL-6 and IL-8 were measured in the sera and cervical mucus of fertile and infertile women by the enzyme-linked immunosorbent assay (ELISA). A non-parametric Mann-Whitney test was used to evaluate significance between the means. Linear regression analysis of IL-6 and IL-8 concentrations in serum versus cervical mucus and with antisperm antibody titers was performed by condition as well as all groups together. P < 0.05 was considered significant. RESULTS: Both IL-6 and IL-8 were detected in sera and cervical mucus of fertile as well as infertile groups. Although serum levels of IL-6 and IL-8 were significantly different between fertile and infertile groups, the differences were more pronounced in the cervical mucus samples. Cervical mucus of idiopathic and immunoinfertile women demonstrated significantly (P = 0.002 to < 0.0001) greater concentrations of IL-6 and IL-8 compared to fertile controls. In general, there was no significant correlation between the serum and cervical mucus IL-6 and IL-8 levels, whether analyzed by condition or all groups together. CONCLUSIONS: Elevated levels of IL-6 and IL-8 in cervical mucus of infertile groups may play a role in etiology of idiopathic and immunologic infertility. These findings suggest that the measurements of cytokines (especially IL-6 and IL-8) in cervical mucus may provide a tool for specific diagnosis and possibly treatment of infertility, especially idiopathic infertility.