Relationship between seminal plasma interleukin-6 and tumor necrosis factor alpha levels with semen parameters in fertile and infertile men.

The levels of two proinflammatory cytokines, namely tumor necrosis factor alpha (TNF-alpha) and interleukin 6 (IL-6), were investigated in seminal plasma (SP) of proven fertile (n=24) and infertile (n=55) men to evaluate the relationship between diagnosis and semen parameters in a prospective study. Infertile men were divided into four groups as follows: (1) varicocele (n=23), (2) 3 months after varicocelectomy (post-varicocele, n=14), (3) male accessory gland infection (MAGI, n=10) and (4) bilateral testicular atrophy (n=8). IL-6 and TNF-alpha levels were similar in the SP of fertile and infertile men. There was a strong correlation between the levels of TNF-alpha and IL-6 in all groups (P<0.001). IL-6 levels were not correlated with seminal parameters (P>0.05). TNF-alpha levels were negatively correlated with the sperm motility and morphology (P<0.05), but there was no correlation with total sperm counts (P>0.05). The mean levels of IL-6 in the SP of the MAGI group was higher than in the other groups but did not reach statistical significance. No variation was found in the SP levels of the proinflammatory cytokines studied between the varicocele and the post-varicocele groups. Our results suggest that IL-6 and TNF-alpha are involved in male fertility. However, their measurement in SP seem to be unsuitable for routine infertility work, perhaps with the exception of men with inflammatory genital diseases.