Antibodies that are directed against spermatozoa antigens are found to cause infertility in both men and women. Anti-spermatozoa antibodies (ASA) are known to fight against man’s sperm in the blood, semen, or vaginal fluids. These can cause an immune system response that can either damage or even kills sperm in the bodies of men or women. The use of anti-spermatozoa antibodies is widely recommended in the diagnosis of immunological disorders of fertility.

There is evidence to indicate that if elevated levels of sperm antibodies come into contact with sperm they can make it very difficult or even impossible for the sperm to fertilize an egg (often referred to as immunologic infertility). Women can produce sperm antibodies through an allergic reaction to the partner’s semen, whereas in men if the sperm comes into contact with his immune system this can lead to the production of sperm antibodies.

Human ASA can also be applied for clinical practices to the diagnosis of infertility in men. Please note: the terms anti-sperm antibodies, anti-spermatozoa antibodies, and sperm antibodies are equivalent.