5 - Immunology of Infertility

Abstract

Recent research on immunological infertility in men and women is reviewed and the possibilities for therapeutic success in this area are assessed. Surface antigens of the acrosome and main tail piece appear to provoke antibodies of special relevance to male and female infertility and are recognized by circulating sperm-immobilizing antibodies in women and by immobilizing and agglutinizing antibodies in men. Assessment methods have focused on the development of tests of local immunity to sperm. Antisperm antibodies have been tested via sperm microagglutination, the gelatin agglutination test, the sperm immobilization test, and immunofluorescence techniques. In addition, measurement has focused on antibodies in cervical mucus, antibodies in seminal plasma, and cell-mediated immunity. Methods involving both partners include postcoital test, the sperm-cervical mucus penetration test, and the sperm-cervical mucus contact test. There remains a need for the development of specific radioimmunoassys for the precise detection and quantitation of antibodies to sperm antigens, especially those of cell membrane origin. In males, autoimmunity to sperm antigens can be related to infertility by 2 main pathogenic mechanisms: 1) the adverse effects of antibodies directly on spermatozoa, and 2) the association with disordered spermatogenesis resulting in oligospermia and azoospermia. In women, the effector pathways of local immunization mediate both systemic and cell-mediated immune responses. Local antibodies can interfere with the reproductive process by arming macrophages and enhancing phagocytic clearance of spermatozoa from the genital tract, mediating cytotoxic effects on sperm, preventing sperm from adequately penetrating cervical mucus, intefering with sperm capacitation, and influencing sperm selection within the female genital tract. Between 5-10% of infertile men and women show evidence of anitbodies to sperm. Treatment has included occlusion therapy, intrauterine insemination, immunosuppression, and spermatogenesis suppression. There is a need for prospective controlled assessment of the therapeuatic approaches currently in use, as well as for research on the role of cell-mediated immunity.