Increased IL‐18 Levels in Seminal Plasma of Infertile Men with Genital Tract Infections

Problem Interleukin (IL)‐18 is a novel cytokine, previously known as interferon (IFN)‐ γ inducing factor. We evaluated the levels of IL‐18 and IFN‐ γ in seminal plasma (SP) of fertile and infertile men. Method of study Semen samples were obtained by masturbation from 80 men, and were examined for the levels of IL‐18 and IFN‐ γ by enzyme‐linked immunosorbent assay. Seven groups were included: (i) fertile men ( n  = 18), (i) infertile men with genital tract infections ( n  = 17), (iii) with varicocele ( n  = 15), (iv) with Klinefelter syndrome ( n  = 6), (v) with cryptorchidism ( n  = 7), (vi) with mumps orchitis ( n  = 7), and (vii) with idiopathic testicular lesions ( n  = 10). Results Mean levels of IL‐18 were higher in SP from infertile men with genital tract infections compared with SP from other groups except Klinefelter syndrome ( P  < 0.05). However, no significant differences could be detected for IFN‐ γ . A significant positive correlations was found between IL‐18 and IFN‐ γ in total patient population ( P  < 0.001). Moreover, a negative correlation was observed between IL‐18 and sperm concentrations, and motility ( P  < 0.01 and <0.03, respectively). Furthermore, there was a positive and statistically significant association between IL‐18 and IFN‐ γ levels in SP of infertile men with genital tract infections ( P  < 0.0001). However, there was no relationship between IL‐18 and IFN‐ γ , and semen parameters in the same group. Conclusion SP IL‐18 levels were increased in men with urogenital infections. Thus, the elevated expression of IL‐18 in SP may be used as a diagnostic marker in the male genital tract infections.