Role of the Immune System in Unexplained Male Infertility

Abstract

The immune system plays an important role in male infertility. The testis is an immune-privileged site. Sperm cell has several “nonself” antigens that develop during later stages of spermatogenesis. These “nonself” antigens are sequestered from the immune attack by the blood–testis barrier. The most frequent phenomenon of immune pathology in infertility is the development of antibodies directed to these “nonself” antigens that are relevant to sperm motility, function, fertilization, and fertility. There are several etiological factors and sites in the male genital tract that can induce antibodies to sperm. The antisperm antibodies (ASAs) can be detected by various methods, including the mixed antiglobulin reaction (MAR) test, immunobead binding test (IBT), and enzyme-linked immunosorbent assay (ELISA). The presence of ASAs has been shown to reduce fertilization rates in the in-vitro fertilization (IVF) procedure used for the treatment of male infertility. For the treatment of immunoinfertility, the suppression of antibody production using steroids (glucocorticoids) has not yielded successful results. Several in-vitro methods have been used to remove antibodies bound to sperm for treatment. Intracytoplasmic sperm injection (ICSI) technique has been successfully used to bypass sperm antibodies that are relevant to fertilization. However, the embryos may degenerate even after successful fertilization. In conclusion, the available data indicate that immunological factors, including ASAs, play an important role in pathogenesis of unexplained male infertility. As additional fertility-related sperm antigens and mechanisms become delineated, a larger subgroup of “unexplained infertility” is becoming a part of “immunoinfertility.”