Levels of interleukin-6 and interleukin-8 in seminal fluid of men attending an andrological clinic

The presence of interleukins (IL) and other cytokines in seminal plasma was demonstrated in the literature. In particular, the levels of IL-6 were found to be related to male accessory gland inflammation. The close correlation to leucocyte count indicates a production of interleukins from the leucocytes and by the prostate gland. No relation of IL-6 levels to spermatogenic activity was quoted in the literature. We measured IL-6 and IL-8 in 454 men and compared the values with seminal parameters. The mean values of IL-6 30.7 +/- 101.2 pg ml-1 and IL-8 2023 +/- 1721 pg ml-1. The correlation analysis revealed a significant correlation of IL-6 and/or IL-8 to age, total fructose, immunoglobulin G (IgG) concentration and leucocyte count. The significant correlation of IL-6 and fructose levels indicates that also the seminal vesicles take part in the production of seminal IL-6. No correlation of the two interleukins measured to sperm parameters occurred. The calculation of a single harmonic trend revealed a significant trend over the year of the levels of IL-6 with a maximum in December and a peak-to-trough variation of 33% of the mean. It may be the consequence of a higher frequency of seminal tract inflammations in autumn and winter.