Increased levels of interferon-gamma in seminal plasma of infertile men.

The role of the cell-mediated immunity in male infertility is still far from clear. Interferon-gamma (INF-gamma), a secretory product of activated T cells and natural killer cells, has been hypothesized to have a toxic effect on sperm function. The presence of INF-gamma was investigated in seminal plasma of fertile and infertile subjects, using a specific enzyme-linked immunosorbent assay, in order to study its role in male infertility. Forty-one subjects were studied; 20 had proven fertility and normal semen quality (fertile group) and 21 showed male infertility for at least 2 years and poor semen quality (infertile group). INF-gamma was present in significantly higher levels in the seminal plasma of infertile subjects (6.36 +/- 0.72 fmol ml-1) compared to fertile subjects (3.68 +/- 0.30 fmol ml-1). Moreover, a significant negative correlation between INF-gamma levels and sperm count, motility and morphology was detected, whereas no correlation between INF-gamma levels and leukocyte count was found. These findings (i) confirm INF-gamma to be present in seminal plasma; (ii) show increased INF-gamma secretion in the infertile group; (iii) demonstrate negative correlations of INF-gamma with the main spermiogram parameters and (iv) no correlation with leukocyte count. INF-gamma may therefore play an important role in male infertility.