The impact of antisperm antibodies on human male reproductive function: an update

Immune infertility occurs due to the presence of antisperm antibodies (ASA). This type of infertility has a relatively low prevalence (2.6-6.6% in infertile men), and its etiology, risk factors, targets, and consequences for male fertility are not completely understood. While it is largely accepted that abnormalities in the blood-testis barrier and/or blood-epididymal barrier are the main factors behind its etiology, and that sperm motility is the most frequently reported altered parameter, few are the well-defined risk factors and ASA targets only now started to be disclosed, with proteins involved in sperm-oocyte interaction rising as the most significant. The development of potential treatments is also limited, being the corticosteroids the more promising. Overall, there are still many knowledge gaps related to immune infertility. With this review, we aimed to gather all the information collected from studies developed in humans in the last decade. Despite the controversial results/inconsistencies, that are not only a result of the complexity of mechanisms/variables involved in ASA infertility but also from the technical approaches to assess ASA and the lack of a consensus regarding the thresholds to be used, this manuscript aims to bring a fresh update on the field. It has become clear that, to obtain more/reliable data, there is a need to assess ASA in all the routine seminal analyses, following WHO recommendations. In this way, it will be possible to obtain consistent and comparable information, that can add to current knowledge. Additionally, multicentric studies with large cohorts are also missing, and future research should take this into consideration.