Circulating anti-follicle-stimulating hormone immunoglobulin A in women: a sperm-prone reaction of mucosal tolerance?

Antibodies against follicle-stimulating hormone (anti-FSH) are present in infertile female sera. Follicle-stimulating hormone as antigen is present in female sera and introduced to the genital tract mucosa as a constituent of semen. The female immune system is activated by semen constituents during insemination to induce mucosal tolerance. We found that circulating anti-FSH IgA correlated with IgA against sperm surface antigens in female patients undergoing IVF. Our results suggest that anti-FSH and anti-sperm IgA could share antigenic origin, being induced possibly by mucosal tolerance to semen.