Antisperm Antibodies
Immune antibodies that target sperm and can affect fertility
Quick Facts
- Type: Immunologic fertility factor
- Key test: Antisperm antibody testing
- Common triggers: Vasectomy, testicular injury or infection
- Main impact: Reduced sperm movement and binding
Overview
Antisperm antibodies are proteins made by the immune system that attach to sperm. Normally the body keeps sperm separated from the immune system by a barrier in the testicles, so the immune system does not treat sperm as foreign. If that barrier is breached, the body may produce antibodies against sperm, in either a man or his partner.
These antibodies can interfere with fertility by reducing sperm movement, causing sperm to clump together, or making it harder for sperm to reach and fertilize an egg. Antisperm antibodies are one of several possible contributors to difficulty conceiving and are usually considered as part of a wider fertility evaluation. Their presence does not make pregnancy impossible, and treatments are available.
Symptoms
Antisperm antibodies do not themselves cause noticeable symptoms. They are detected through testing, usually carried out because a couple is having trouble conceiving.
- Usually no symptoms at all
- Difficulty conceiving despite otherwise normal findings
- Sperm that clump together (agglutination) seen on a semen analysis
- Sometimes a history of an event that could trigger antibodies, such as a vasectomy or testicular injury
Because there are no outward signs, the antibodies are typically found only when fertility is being investigated.
Causes
Antisperm antibodies usually develop when something allows the immune system to come into contact with sperm.
- Vasectomy: A common reason, especially relevant when a man later wishes to reverse the procedure.
- Testicular injury or surgery: Trauma or operations that disrupt the protective barrier.
- Infection or inflammation: Of the testicles or reproductive tract, such as after certain infections.
- Blockages: Of the tubes that carry sperm.
In some cases no clear trigger is found. Antibodies can also occur in the female partner, where the immune system reacts to sperm.
Risk Factors
- Previous vasectomy or vasectomy reversal
- Injury or surgery to the testicles
- Past infection of the testicles or reproductive tract
- Twisting of the testicle (testicular torsion) in the past
- Undescended testicle or other reproductive tract abnormalities
Diagnosis
Antisperm antibodies are identified with specific laboratory tests, often prompted by clues on a routine semen analysis.
- Semen analysis: May show sperm clumping together or poor movement, raising suspicion of antibodies.
- Antisperm antibody testing: Laboratory tests, such as the mixed antiglobulin reaction (MAR) test or immunobead test, detect antibodies attached to sperm.
- Evaluation of both partners: Testing may be considered in the male and, in some cases, the female partner.
Treatment
Treatment focuses on helping sperm reach and fertilize the egg despite the antibodies, often through assisted reproduction.
- Sperm washing with intrauterine insemination (IUI): Preparing sperm in the lab and placing them directly in the uterus may help in milder cases.
- In vitro fertilization (IVF): Bringing egg and sperm together outside the body.
- Intracytoplasmic sperm injection (ICSI): Injecting a single sperm directly into an egg, which can bypass the effect of antibodies and is often the most effective option.
- Treating underlying causes: Such as addressing an infection or blockage where present.
A fertility specialist can recommend the approach most likely to succeed based on antibody levels and other findings.
Prevention
Antisperm antibodies cannot always be prevented, but some measures may reduce the chance.
- Promptly treat infections of the testicles or reproductive tract
- Seek timely care for testicular injury or torsion
- Discuss fertility implications before a vasectomy if future fertility may be desired
When to See a Doctor
Consider a fertility evaluation if you and your partner have not conceived after a year of regular, unprotected sex, or six months if the female partner is over 35. Testing for antisperm antibodies may be suggested if a semen analysis shows clumping or unexplained problems, or if there is a history of vasectomy, testicular injury, or infection. Seek prompt care for sudden, severe testicular pain, which can signal an emergency such as torsion.
Frequently Asked Questions
What are antisperm antibodies?
They are immune system proteins that attach to sperm and can interfere with fertility by reducing sperm movement, causing sperm to clump, or making it harder for sperm to reach and fertilize an egg. They can occur in a man or, less commonly, in his partner.
What causes the body to attack its own sperm?
Sperm are normally kept apart from the immune system by a barrier in the testicles. When that barrier is breached, such as by a vasectomy, testicular injury or surgery, infection, or blockage, the immune system may begin to produce antibodies against sperm.
Do antisperm antibodies make pregnancy impossible?
No. They can reduce fertility but do not always prevent pregnancy. Treatments such as sperm washing with insemination, IVF, and especially ICSI can help overcome their effect, and many couples go on to conceive.
How are they detected?
They are found with specific laboratory tests, such as the mixed antiglobulin reaction (MAR) or immunobead test, that detect antibodies attached to sperm. Suspicion is often first raised by sperm clumping or poor movement on a routine semen analysis.
What is the most effective treatment?
Intracytoplasmic sperm injection (ICSI), in which a single sperm is injected directly into an egg during IVF, is often the most effective option because it bypasses the antibodies. Milder cases may respond to sperm washing with intrauterine insemination.
References
- American Society for Reproductive Medicine (ASRM).
- Urology Care Foundation, American Urological Association.
- MedlinePlus, U.S. National Library of Medicine.
- Mayo Clinic. Male infertility.