Relationship between local anti-sperm antibodies and sperm–mucus interaction in vitro and in vivo*

Abstract

Sperm-mucus interaction under in-vitro or in-vivo conditions can be affected by local anti-sperm antibodies (ASA). In a prospective study, a mixed antiglobulin reaction (MAR) test, using immunoglobulin-coated red cells and spermatozoa, was used to detect the presence of IgG and/or IgA on the spermatozoal surface in 209 males of infertile partnerships. The results of direct MAR tests range from 0 to 100% and a significant correlation between MAR % IgG and MAR % IgA (r = 0.74) was found. MAR positive semen samples were significantly more frequent in the group of patients with an inadequate outcome of postcoital testing (PCT). The sperm-mucus interaction in vitro, evaluated by means of the in-vitro sperm-cervical mucus penetration test (SCMPT) with cervical mucus (CM) of patients' partners, was particularly related to spermatozoal surface antibodies of the IgA class: MAR IgA positive ejaculates were seen in 13.9% of males with inadequate SCMPT versus 4.4% when SCMPT was adequate. The significant correlation between MAR IgA and the sperm penetration ability in vitro could also be proven when donors' CM was taken for the SCMPT, but not when a non-human material was used for in-vitro penetration testing. Microbial colonization of semen specimens did not interfere with the outcome of MAR testing. The pregnancy rate after 12 months was 23% (48/209) and was significantly lower when greater than 30% of spermatozoa were covered with surface ASA of the IgG or IgA class.(ABSTRACT TRUNCATED AT 250 WORDS)