Does intraperitoneal insemination in the absence of prior sensitization carry with it a risk of subsequent immunity to sperm?

To evaluate the occurrence of antisperm antibodies in women, with no prior sensitization, 112 couples undergoing intraperitoneal insemination were tested for serum antisperm antibodies with the sperm immobilization test (SIT) and the immunobead test (IBT). A serum sample was taken from each of the 112 patients immediately before the first intraperitoneal insemination. Another sample was taken from 58 patients who underwent a second insemination procedure. In 16 of the 58 patients the IBT results were positive for one or more immunoglobulin classes. Five patients showed positive SITs. In 7 out of these 16 subjects (12%) the antibodies were bound to the head and to the shaft of the sperm tail. Five of the six patients submitted to a third intraperitoneal insemination procedure showed unchanged SIT values and IBT binding percentages. In one subject, SIT (6 months after the third insemination) became negative. Antibody production may be either a transient response to massive antigen stimulation or the first step toward systemic immunity.