Impact of immunoglobulin isotype and sperm surface location of antisperm antibodies on fertilization in vitro in the human

Abstract

To investigate the impact of immunoglobulin (Ig) isotypes and their location on the human sperm surface on fertilization in vitro. Restrospective review and analysis. Reproductive endocrine division of a level 3 academic center. Forty-eight couples (80 IVF cycles) with males showing positive antisperm antibodies on the sperm surface by immunobead test, treated by IVF at the Norfolk Program. Evaluation of total fertilization rate of preovulatory oocytes (metaphase II-metaphase I). Immunoglobulin G and IgA antibody levels have no significant correlation with total fertilization rate of preovulatory oocytes by logistic regression. Immunoglobulin M, present in 44% of the couples, had a strong correlation with fertilization. When IgA showed very high levels of binding (> 68%) and IgM binding was > 40%, the fertilization rate dropped significantly. 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. Two male antisperm Ig isotypes significantly impaired fertilization 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 fertilization rates when localized both at the head and at the tail tip level.