Determination of soluble interleukin-2 receptor in human seminal plasma

T-helper 2 type cytokine and soluble interleukin-2 receptor levels in seminal plasma of infertile men

PROBLEM

The role of cell-mediated immunity (CMI) in unexplained male infertility and impaired sperm function has been explored.

METHOD OF STUDY

The presence of cytokines, namely, interleukin-4 (IL-4), interleukin-6 (IL-6), and the soluble interleukin-2 receptor (SIL-2R), was investigated in seminal plasma of 18 fertile and 20 infertile subjects, using specific enzyme-linked immunoadsorbent assays.

RESULTS

IL-4 was not detected. SIL-2R was detected, but the concentration difference between the fertile and infertile group was not significant. IL-6 was detected with significantly higher levels in the infertile group compared to the fertile group. IL-6 levels in seminal plasma correlated positively with leukocyte count and negatively with sperm count, motility, and morphology.

CONCLUSIONS

These findings show: a) a lack of IL-4 in seminal plasma; b) similar SIL-2R levels in fertile and infertile seminal plasma; c) increased IL-6 secretion in seminal plasma of infertile subjects; and d) specific correlations of IL-6 with the main semen parameters.

Interleukin-2 in seminal plasma of fertile and infertile men

The role of cell-mediated immunity in the etiopathogenesis of male infertility is far from being defined. The cytokine interleukin-2 (IL-2) has a key role in T-cell mediated immune responses. The aim of this study was to confirm the presence of IL-2 in human seminal plasma, to show eventual differences between IL-2 concentrations in fertile and infertile subjects, and to show potential relationship between IL-2 amounts in semen and spermiogram parameters. Forty-three subjects entered the study, 20 with proven fertility and normal semen quality (fertile group) and 23 with male infertility of at least 2 years and poor semen quality (infertile group). IL-2 levels of seminal plasma in infertile subjects (444.3 +/- 40.5 fmol/mL) were significantly higher than those in fertile subjects (251.3 +/- 42.7 fmol/mL). There was a significant negative correlation between IL-2 levels and sperm count, motility, and morphology. No correlation was found between IL-2 levels and leukocyte count. These findings confirm IL-2 to be in seminal plasma, show increased IL-2 secretion in the infertile group, demonstrate negative correlations of IL-2 levels with main spermiogram parameters, and indicate no correlation with leukocyte count. IL-2 concentration in seminal plasma may therefore be considered as a potential marker in male infertility.