IMPACT OF IMMUNOGLOBULIN ISOTYPE AND SPERM SURFACE LOCATION OF ANTISPERM ANTIBODIES ON FERTILIZATION IN-VITRO IN THE HUMAN

Objective: To investigate the impact of immunoglobulin (Ig) isotypes a nd their location on the human sperm surface on fertilization in vitro . Design: Retrospective review and analysis. Setting: Reproductive end ocrine division of a level 3 academic center. Patients: Forty-eight co uples (80 IVF cycles) with males showing positive antisperm antibodies on the sperm surface by immunobead test, treated by IVF at the Norfol k Program. Main Outcome Measure: Evaluation of total fertilization rat e of preovulatory oocytes (metaphase II - metaphase I). Results: Immun oglobulin G and IgA. antibody levels have no significant correlation w ith total fertilization rate of preovulatory oocytes by logistic regre ssion. Immunoglobulin M, present in 44% of the couples, had a strong c orrelation with fertilization. When IgA showed very high levels of bin ding (>68%) and IgM binding was >40%, the fertilization rate dropped s ignificantly. A strong correlation between presence of antibodies and fertilization rate was seen when IgM was directed to the head or tail tip of the sperm. Immunoglobulin A induced a statistically significant reduction of fertilization only when it was present on the head. Conc lusion: Two male antisperm Ig isotypes significantly impaired fertiliz ation rates. Immunoglobulin A exerted its impact only when high level of binding was detected on the head. Immunoglobulin M, present in 44% of the males, was the Ig isotype that most significantly affected fert ilization rates when localized both at the head and at the tail tip le vel.