Problem: To determine the prevalence and characteristics of gonadotropin autoantibodies (GAB) associated with unexplained infertility, and to assess the relationship between ovarian autoantibodies (OVAB) and GAB.
Method of study: Ovarian antibodies and GABs in sera of patients with unexplained infertility (n = 53) and a comparison (population) group from a blood bank (n = 40) were detected by immunoassay. Patients with unexplained infertility had either no prior gonadotropin treatment (n = 15) or two or more gonadotropin cycles to induce ovulation (n = 38).
Results: The GABs were detected in 67% of women with treatment, 27% of women without treatment and 8% of women in the population. The GABs recognized follicle stimulating hormone (FSH) and luteinizing hormone (LH) and their alpha and beta subunits and to a lesser extent thyroid stimulating hormone (TSH) and prolactin. There was no significant difference in OVAB prevalence between gonadotropin treated or untreated women while GABs were significantly more frequent in gonadotropin treated women (P < or = 0.01).
Conclusion: Gonadotropin antibodies may represent a separate marker of ovarian autoimmunity in unexplained infertility as they are correlated with OVAB and are present in patients not treated with gonadotropin. However, as a higher frequency of GAB is associated with gonadotropin treatment, patients with ovarian autoimmunity may tend to have an immune response to gonadotropins in addition to an endocrine response.