Antisperm antibodies are present in 7-10% of men with fertility problems, and can cause for them a significant reduction in fertility. While this does not necessarily mean an absolute prevention of conception, the likelihood of the occurrence of pregnancy has an inverse relationship with the concentration of antibodies. At levels above 40%, natural conception is highly unlikely to occur.
Direct contact between a man’s blood and sperm is prevented by the blood/testis barrier in the testes. This barrier is composed of Sertoli cells, which lie closely to each other and form tight junctions that protect developing sperm cells from being in contact with blood and circulating antibodies. This barrier can be breached during physical injury or infection.
When foreign antigens are found in the bloodstream, white blood cells such as T and B cells produce antibodies such as IgG, IgA and IgM: immunoglobulins which bind to the antigens found on the surfaces of the sperm cells.
The antibodies may be found in the blood, or secreted by various tissues of different organ systems. Thus, having high levels of antibodies in the blood do not mean that the antibodies will automatically find their way to the testicular tissues where they can affect the sperm. The concentration of IgG is much higher in the blood compared to the reproductive organs, while levels of IgA are higher in the reproductive secretions than in the blood. IgA and IgG are found in the semen, whereas IgM are not.
When antisperm antibodies have formed and detected the antigens that would trigger an attack, there are several ways they can affect sperm cells. Some cause agglutination, whereas other antibodies can trigger attack by the natural killer cells. Other antibodies can cause a reaction between the sperm membrane and cervical mucus, or even block the sperm’s ability to bind to the zona pellucida of an oocyte.
A number of diagnostic tests are available in the local Philippine setting to detect the presence of sperm antibodies. These include enzyme-linked immunoabsorbent assay (ELISA), the Franklin-Dukes sperm agglutination assay, and the Immunobead Binding Test (IBT), which can detect antibodies present in the blood serum, in cervical mucus or on the surface of the sperm cell membrane. These tests can help increase IVF success in the Philippines.
In-vitro fertilization (IVF) with intracytoplasmic sperm injection (ICSI) is the most viable option for conception in the presence of significant antisperm antibodies. Each egg is injected with a single sperm, avoiding any antibody response. Antisperm antibodies effect on pregnancy and birth rates are the same as in cases where IVF is performed for reasons other than infertility found in the male partner. Instead of intrauterine injection (IUI), in the Philippines, IVF with ICSI is the treatment of choice for these couples.