Cytokine expression in the seminal plasma and its effects on fertilisation rates in an IVF cycle

Cytokines are released by various immunocompetent cell subsets in the male urogenital tract and are thought to affect sperm cell function and reproductive process. The aim of the study was to evaluate the levels and a possible role of seven seminal plasma cytokines with fertilisation rates in men attending an in vitro fertilisation (IVF) programme. A total of 36 men of couples who were undergoing traditional IVF in a regional reproductive medicine unit were recruited into this prospective study. Cytokines such as interleukin (IL)-6, IL-8, IL-10, IL-11, IL-12, tumour necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma) in the seminal plasma were determined using enzyme linked immunosorbent assay. IL-6, IL-8, IL-10, IL-11 and IFN-gamma were detected in all samples. IL-12, and TNF-alpha were detected in most samples. Levels of IL-11 were significantly higher in the good fertiliser group (P <= 0.05). Positive correlation between cytokines such as IL-6 and IL-8 (P < 0.03), IL-10 and IL-11 (P < 0.001) and IFN-gamma and IL-10 and IL-11 (P < 0.04 and P < 0.0001 respectively) were found. Our study confirms that the six cytokines other than IL-11 do not affect spermatozoon-oocyte interaction and fertilisation rates in IVF. IL-11 could have a role in the fertilising capacity of the spermatozoa. Significant correlation exists among these cytokines which shows that cytokines rarely act in isolation but rather in a network.