ANTI SPERM IGA ANTIBODIES AGAINST THE EQUATORIAL SEGMENT OF THE HUMANSPERMATOZOON ARE ASSOCIATED WITH IMPAIRED SPERM PENETRATION AND SUBFERTILITY

Objective-To determine the prevalence of antibodies directed against t he equatorial segment of the spermatozoon in Ja) serum in both sexes i n relation to age and fertility status and (b) semen of infertile men with tail-to-tail sperm agglutination in relation to in vitro sperm pe nentration capacity. Material-Serum samples were obtained from 30 neon ates, 11 prepubertal children, 30 adolescents, GO adults aged 20-50 ye ars, and 60 adults over the age of 70. Semen samples were obtained fro m 62 men with normal sperm counts and sperm morphology but with tail-t o-tail agglutination. Methods-Sperm anitbodies were demonstrated with an immunoperoxidase assay. Sperm penetration capacity was measured wit h a modified Kremer capillary test. Results-Serum anti-sperm antibodie s were absent in children but appeared in teen-age boy (10%) and in ad ult men (20%) and women (30%). Lower prevalence of serum anti-sperm an tibodies was noted for old individuals of both sexes (6-10%). Among in dividuals with a history of infertility, a significantly higher freque ncy of anti-sperm antibody-positive men (P <.001) and (P <.05) was fou nd as compared to fertile controls. Presence of IgA antibodies bound t o the equatorial segment of spermatozoa was associated with impaired i n vitro sperm penetration capacity. No IgG or IgM anti-sperm antibodie s bound to the equatorial segment were demonstrable. Conclusions-Semin al IgA antibodies bound to sperm are associated with impaired sperm pe netration.