Seminal plasma immunoglobulin concentrations in autoimmune male subfertility

The presence of anti-sperm antibodies (ASAs) in seminal plasma is associated with infertility. They have been shown to reduce sperm motility, interfere with cervical mucus penetration and gamete interaction, and have been shown to reduce spontaneous fertilization and pregnancy rates. Although some causes can be determined, in the majority of cases the initial event causing the immune sensitisation and the reasons for the continuing antibody secretion remains unknown. Quantitative determination of total IgG, IgA and IgM within seminal plasma had not been previously reported in patients with and without specific ASAs. Semen samples from 512 men presenting with infertility were analyzed. One hundred and forty-six men (28.5%) had seminal fluid ASAs as determined by the MAR or TAT tests. The total seminal plasma IgG and IgA concentrations were significantly elevated in the ASA-positive groups compared with ASA-negative groups (IgG: 8.83 mg/100 ml vs. 7.15, P = 0.0008; and IgA: 2.88 mg/100 ml vs. 1.64, P = 0.0001). Only 19 samples showed seminal fluid IgM, and there was no difference between the ASA positive or ASA negative samples. The significance of these findings is discussed.