The body's immune system is our first and major line of defense against diseases and invading germs. It is comparable to soldiers stationed at the borders of a country, always ready to defend against any form of attack. The body's immune system has the intelligence to differentiate between the normal body cells and foreign/invading cells. It can trigger off a local or widespread alarm response or attack against invading microbes. It can also keep memories of these offending cells, so that it can repel them if they ever show up next time. The body's immune system works like a perfectly set up machine. However, it does have its shortcomings. There may be times when, for some reason, it breaks down and leaves the body at the mercy of invading microbes. There could also be times when the ability to differentiate between body cells and foreign cells goes sour and the immune system will turn its arsenal of attack against normal healthy body cells it is suppose to protect, causing damage to the body system.
The immune system plays a vital role in normal body functioning and the reproductive system is not excluded. Several cells of the immune system help in the reproductive process. For example, some inflammatory cells and their secretory products are important in ovulation and in the preparation of the endometrium of the uterus for the implantation of the fertilized egg. It is therefore not surprising to learn that any dysfunction of the immune system would interfere with the normal reproductive process and by extension, fertility.
As a matter of fact, it is estimated that up to 20% of otherwise 'unexplained' infertility in couples have an immune factor involved. There is not so much scientific evidence to link immune factors to infertility; however, there is a solid scientific evidence to implicate the formation of antibodies against sperm cells as an important infertility factor.
Normally, the sperm cells are protected from the reach of the immune system by tight connections between the cells lining the male reproductive tract, a natural protective mechanism known as the 'Blood Testes barrier'. This protects the testes from having any contact whatsoever with the blood, where the majority of immune cells are housed. Any injury or condition that compromises this barrier gives the immune cells access to the sperm cells. The immune system, not familiar with these sperm cells, because of the barrier separating them, treats the sperm cells as foreign cells and anti sperm antibodies may be formed.
Anti sperm antibodies tend to be commoner in infertile men. Almost 10% of all infertile men have anti sperm antibodies compared to about 1% of fertile men.
The most profound risk factor happens to be surgery on the reproductive tract. Nearly 70% of all men who have undergone a vasectomy reversal would have anti sperm antibodies present on their sperm. Other factors that may also contribute to this condition include:
- Varicocele or dilation of the veins surrounding the spermatic cord
- Testicular torsion or twisting of the testicle
- Undescended testes
- Cancer of the testes
- Infections like prostatitis
- Inguinal hernia surgical repair, especially before puberty.
It is amazing to note, however, that several men with anti sperm antibodies have none of these conditions. This shows that every man with fertility problems is at risk of this condition, especially when no other reason has been diagnosed for the infertility.
Women also stand a risk of anti sperm antibodies. It is believed that about 5% of women with fertility problems could have these antibodies. What is not clear is who is at risk for their formation. Fortunately, intra uterine insemination, which involved placing 'treated sperm cells' into the uterine cavity of a woman, has not been shown to cause the formation of anti sperm antibodies.
The immune system has also been found to affect the ability to carry pregnancy in some women. In women with recurrent pregnancy loss, there is a group of antibodies that appear to attack an early developing pregnancy, resulting in either a miscarriage or severe preeclampsia with risk of intrauterine growth retardation or even foetal death. These antibodies are collectively called anti phospholipid antibodies and testing for them should be an integral part of the work up for recurrent pregnancy loss. It is still unclear if these antibodies affect the ability to get pregnant, but some physicians are of the opinion that the presence of these antibodies may decrease the chances for pregnancy through an invitro fertilization.
There are still several controversial areas as regards immunological factors and infertility. However, what is clear is that the immune system really does affect your fertility when things go wrong.
Michael Russell
Your Independent guide to Infertility