Naturally-occurring antisperm antibodies in men: interference with fertility and clinical implications. An update.

Naturally-occurring anti-sperm antibodies (ASA) in men can affect fertility by various mechanisms. Some of them are mainly related to the extent of the sperm autoimmunization (e.g., sperm-agglutination and impaired cervical mucus penetration); others are also related to immunoglobulin (Ig)-isotype (e.g., complement-mediated sperm injury through the female genital tract), or to antigenic specificity of ASA (e.g., interference with gametes interaction). The unavailability of current diagnostic tests to determine the antigenic specificity of ASA, and the difficulty in quantifying the antibody density on the sperm surface make it hard to establish in each individual patient, whether, or to what extent, these interfering effects occur, apart from sperm-agglutination and the impairment of cervical mucus penetration. However, the rational use of current ASA-tests can be effective in screening and quantifying sperm autoimmunization relevant to infertility. The degree of sperm-autoimmunization is the only empirical (rather effective) criterion in choosing more or less invasive assisted reproductive techniques (ART) for couples, where male immunological infertility is diagnosed. A more rational treatment strategy would be possible with the development of tests detecting ASA directed against defined fertilization-related antigens. In this article, the growing knowledge in this field is reviewed.