• Enzyme-linked immunosorbent assay;
  • human seminal plasma antigens;
  • immunologic infertility;
  • sperm agglutination

PROBLEM: To determine whether patients whose infertility remains unexplained (by routine physical and laboratory investigations including sperm antibody testing) exhibit significantly elevated humoral anti-seminal plasma immune responses in comparison to fertile individuals.

METHOD: Sera from 72 infertile couples were examined by ELISA for the presence of antibodies against normozoospermic seminal plasma (NSP). A group of 36 fertile individuals was used to determine the level of physiological reactivity. Kibrick's and Friberg's sperm-agglutination tests were employed to distinguish patients routinely diagnosed as immunologically infertile.

RESULTS: Anti-NSP reactivity was elevated in 18% of male and 26% of female patients. In the female patients, the prevalence rate for elevated anti-NSP reactivity was significantly higher among partners of positive men. In only 4% the positive anti-NSP results coincided with sperm-agglutinating antibodies.

CONCLUSION: NSP constituents other than sperm-coating antigens might interfere with infertility related autoimmune imbalance. The identification of the corresponding NSP antigens might help to resolve more cases of unexplained infertility.