Anti-sperm antibodies are not associated with sperm DNA damage: a prospective study of infertile men

Infertile men have poorer sperm DNA integrity than do fertile men, and this damage may contribute to reducing male reproductive potential. However, the etiology of this damage has not been fully characterized. We sought to examine the relationship, if any, between anti-sperm antibodies and sperm DNA damage in a consecutive series of non-azoospermic, infertile men in order to determine whether anti-sperm antibodies (ASAs) may contribute to sperm DNA damage. We conducted a prospective study on consecutive semen samples obtained from men (n=75) presenting for infertility evaluation. Sperm concentration, motility, strict morphology, ASA levels (by direct mixed agglutination reaction, expressed as the percentage of spermatozoa with IgG or IgA antibodies) and sperm DNA damage (by sperm chromatin structure assay) were evaluated. Mean (+/-SD) sperm concentration and progressive motility were significantly lower in ASA-positive (>40% of sperm coated with ASAs) compared to ASA-negative samples (23.4+/-13.1 x 10(6)/mL and 27+/-15% vs. 74.6+/-61.2 x 10(6)/mL and 46+/-18%, respectively, P<0.05). Sperm progressive motility was inversely correlated with the percentage of IgG-bound (r=-0.33) and IgA-bound spermatozoa (r=-0.25). In contrast, sperm %DNA fragmentation index and percent normal forms were not significantly different in ASA-positive compared to ASA-negative samples (17.5+/-17.9% and 7.5+/-3.0% vs. 17.4+/-13.5% and 6.5+/-2.6%, respectively). The data indicate that ASAs are not associated with sperm DNA damage and suggest that ASAs are unlikely to have a significant direct or indirect effect on sperm DNA integrity.