Antibodies to sperm, eggs or other body cells may be the cause of unwanted childlessness. This is called immunological sterility, where conception is prevented by the body's own immune system.

Unfulfilled fertility and the immune system

Our immune system has the task of protecting the body from pathogens. It can identify bacteria and viruses and then fight them effectively. For example, our intestines are able to differentiate between threatening pathogens and vital food. This ability also plays an essential role in reproduction. If the body recognises eggs or sperm as dangerous or foreign, pregnancy is prevented, which is also known as immunological sterility.

Male and female immunological sterility

When an egg is fertilised, foreign cells with male genetic material enter the woman's body. The body then mounts an immune response and begins to produce so-called Fc-blocking antibodies. These coat the embryo and suppress the body's own immune cells during pregnancy. If the body cannot produce enough of these antibodies, the embryo may be rejected during pregnancy. In order for the body to produce Fc-blocking antibodies, the woman must have a natural defence response to the embryo. However, if the immune response is too weak, insufficient antibodies are produced and the embryo is attacked by so-called killer cells or NK cells. Studies have shown that the immune response is particularly weak when the male and female cells are very similar. On the other hand, a fertilised egg can also cause the immune system to overreact. Within a very short time, the body produces many killer cells that attack the embryo, greatly increasing the risk of miscarriage.

In men, immunological sterility can also be caused by the immune system. For example, if an injury to the seminal ducts causes the sperm to come into contact with blood, an infection occurs, causing the sperm cells to clump together and significantly reduce their ability to move. If the ability of the man's semen to be fertilised is also reduced, he may become totally or partially infertile.

Symptoms

The first sign of immunological infertility is an unfulfilled desire to have children. As immunological testing is very complex, it is only carried out when all other causes of infertility have been ruled out. Some fertility centres also offer immunological blood tests as part of their routine diagnostics, and a so-called MAR test may also provide a first indication, as clumped spermatozoa under the microscope can indicate the presence of autoantibodies.

Diagnosis of immunological infertility

Many clinics offer what is known as an immunological consultation, which aims to identify the immunological causes of infertility following IVF. The individual situation is analysed and immunological, uterine, haemostaseological, endocrine, infectious and genetic abnormalities are examined. The doctor will also carry out a blood test to detect specific antibodies. Another possible method of detecting antibodies is the post-coital test. In this test, cervical mucus is taken twelve hours after sexual intercourse and then examined under a microscope. The antibodies can then be detected by the movement, number and arrangement of the sperm.

Therapy options and process

Once the diagnosis has been made, treatment is recommended. For example, immunoglobins (IVIg) may be given as an adjunct to IVF. Immunoglobins have the same function as antibodies that are normally produced naturally by the healthy body. They are given to help regulate or support the immune system. If previous IVF/ICSI treatments have been unsuccessful, infusion treatment is usually started before embryo transfer. If a patient has had several miscarriages without IVF, treatment is given from the time of a positive pregnancy test until the 24th week of pregnancy. Immunotherapy usually significantly increases the birth or pregnancy rate, even in women who have had multiple miscarriages.

Treatment with partner lymphocytes also has a more than 70 per cent chance of success, but very few specialists carry out this treatment, and the cost and side effects should also be considered. Cortisone is also commonly used. Cortisone can be used to suppress the body's own defences, and this ability is also used to weaken the activity of killer cells. Cortisone is most commonly used in IVF or ICSI treatment. If there is an immunological problem, the coagulation system may also be disturbed, which can be treated with anticoagulants such as heparin. In addition, the activity of killer cells can be reduced by using a fat emulsion containing omega-3 or omega-6 fatty acids. The side effects are very low and this option is also relatively inexpensive. Fat emulsion infusion is done very slowly and several sessions are needed. To maximise the success rate, it should be done before fertility treatment. The drug lenograstim can also be used to stimulate white blood cells. This takes place in the lining of the uterus and can have a positive effect on the implantation of the embryo. It can be given either by injection or directly into the uterus. Studies have shown that direct administration significantly increases pregnancy rates. If there is evidence of antibodies to the sperm, there is currently no effective treatment. However, newer methods should make it possible to identify the sperm components responsible for antibody formation. If the sperm components are intact, artificial insemination may be possible.

Potential risks

You should be particularly aware of side effects during pregnancy. When immunoglobulins are used in treatment, there is a risk that they may be transferred across the placenta to the embryo. Normally this is not a problem, but it should be monitored. The same applies to the use of cortisone. There are differences between the different preparations in terms of placental receptivity. For example, prednisolone is inactivated by the placenta and can only be detected in the embryo at very low doses. There are also no harmful side effects when granocytes are administered.