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Fertility and the immune system: how it affects

fertility immune system

Fertility and the immune system: a dance for two

 

During the last decades, it has become increasingly evident that immunological factors contribute substantially to infertility situations.

 

El The body's immune system has among its functions that of distinguishing between what is its own and what is foreign. In this way, it is able to identify any invasion by foreign microorganisms -which can create an infection- or to identify cells that are not behaving as they should -which could trigger cancer-. 

 

In some cases, the immune system can make a mistake in this task. And when there is an error, it also begins to react against its own tissues, generating an autoimmune pathology. 

 

Approximately 7% of the population suffers from an autoimmune disease at some point in their life. And some of them suffer from autoimmune diseases for life, such as insulin-dependent diabetes or rheumatoid arthritis.

 

The immune system has "memory", it stores a memory after each battle. It's like having a hard drive with a huge database of identified criminals. 

 

This is a very useful feature to gain efficiency against future attacks. 

 

Vaccines are based on this system: they teach the immune system to respond effectively and efficiently by confronting different attenuated pathogens. Once vaccinated, when said pathogen appears, the immune system will be better prepared to act. 

 

This memory function resides in so-called antibodies. This very useful memory system can become a problem when, in the case of suffering from an autoimmune pathology, antibodies are created to go against your own cells and tissues. In these cases, memory also acts and favors the perpetuation of the pathology. 

 

Pregnancy and immune system

Pregnancy is a unique and very particular situation, which requires the immune system to self-limit its functions. 

A new cell, with at least 50% of its composition from something "foreign" (the man's genetic information) and growing abnormally fast, begins to invade and spread throughout the body's tissues. 

 

On paper, this cell would undoubtedly be a target of the immune system. However, it is not so. 

 

For a pregnancy to occur, the immune system must increase its immune tolerance enormously. The state of the mother's immune system is essential to establish a relationship between the mother and the viable fetus for both.

 

This immunological tolerance begins with a chip change. The immune system has two very different ways of acting. 

 

Types of action of the immune system

This immunological tolerance begins with a chip change. The immune system has two very different ways of acting. 

 

Type 1 or cellular and type 2, humoral or by antibodies. 

 

Depending on what type of invasion the body is receiving, the immune system uses one tool or another, as it sees fit. 

 

During pregnancy, since the new cell is a foreign cell agent, the body prioritizes the type 2 way of working and, in this way, the new cell will not be a target of the immune system. It will be able to implant and grow properly. 

   

This chip change means that some autoimmune diseases, which involve a predominantly cellular immune reaction (type 1), such as rheumatoid arthritis, tend to improve during pregnancy. But it also means that antibody-driven autoimmune diseases like lupus can get worse. It has been seen that there are specific antibodies that can have harmful effects on both the placenta and the fetus.

 

Dictionary of Immunological Terms 

The immune system is such a vast thing that understanding it and its implications for fertility can be difficult. For this reason, it is interesting to decipher some of these terms in order to improve immunity and fertility.

Natural Killers or natural killer cells

There are two types of immune system: innate and adaptive. The first is more ancient and we could say that "it comes from the factory". The second is, as its name suggests, learned, adaptive and specific. 

 

It is formed as it confronts foreign elements and forms the immunological memory. 

 

All the natural killers or natural killer cells are a type of white blood cell (lymphocyte) that are part of the innate immune system. Its ability to kill is also closely related to cellular or type 1 immunity. 

 

As such, they are potentially very threatening to a developing pregnancy.

 

However, they are the main type of immune cell found in the uterus. Their number increases throughout the menstrual cycle and reaches its peak at the time of implantation of an embryo. If an embryo implants, the number of natural killers it further increases to 70 percent of all cells. 

 

The amount of Natural Killers begins to decrease at 20 weeks of pregnancy. Finally, they are nonexistent at the end of pregnancy. This relationship makes it more than likely that these killer cells are intimately involved in the success or failure of embryo implantation, causing infertility and miscarriage. 

 

However, this extreme has not yet been scientifically proven. 

 

Antiphospholipid syndrome

In antiphospholipid syndrome (APS), women have “anticardiolipin antibodies” or the “lupus anticoagulant.” If these antibodies occur in women with reproductive failure and no other clinical problems, it is called primary APS. If there are also other autoimmune diseases, such as systemic lupus erythematosus or Sjögren's syndrome, it is called secondary APS.

 

It is not yet clear whether antiphospholipid antibodies have an effect on fertility. While they are most often found in women undergoing IVF, they can be found in 4% of the healthy population. 

 

The problem is that they can directly attack placental cells. They are often used as markers of a possible immunological disorder, but are mostly evaluated in the context of pregnancy loss. 

 

Consequences of the presence of antiphospholipid antibodies 

Antiphospholipid antibodies are reliable predictors of adverse pregnancy outcomes and are associated with early and late fetal loss, pregnancy-induced hypertension, intrauterine growth retardation, prematurity, and arterial and venous thrombosis during pregnancy. However, we must emphasize that these associations are not seen in all women, nor in all pregnancies.

 

It would be advisable to measure them in cases such as: two or more pregnancy losses in the first trimester, loss of one or more pregnancies in the second trimester, repeated or severe preeclampsia, intrauterine growth retardation, thromboembolic disease in pregnancy. 

 

And, without a doubt, in any woman who has a systemic autoimmune disease and wants to get pregnant.

 

Aspirin and heparin (Clexane) treatment has been shown to be safe and effective in women with recurrent pregnancy loss and reduces the risk of miscarriage. It is not known whether or not this therapy reduces the risk of pre-eclampsia or intrauterine growth retardation.

 

antipaternal antibodies

The theory of anti-paternal antibodies is still very much in question. It would be about antibodies that would protect the embryo, so they should be high and not low. 

 

But there are defenders and detractors. 

 

On the one hand, there are studies that affirm that there are certain blocking antibodies against the white blood cells of the partner. That is, they help the mother's immune system to tolerate the fertilized embryo, which contains both maternal and paternal molecules, and therefore could be recognized as foreign. 

 

If so, it would generate an immune reaction that would make correct embryo implantation impossible. These antibodies can be propitiated with an inoculation of paternal leukocytes before pregnancy as a vaccine. 

 

This theory supports the idea that having sexual intercourse on a regular basis favors fertility, since the mother's immune system will be better able to recognize the male material as its own and not attack to this paternal composition of the embryo.

 

On the other hand, there are detractors who claim that the activity of the immune system in the maternal-embryonic and maternal-fetal environment is very different from general immune activity and that these premises are not correct. 

 

They say that these antibodies, if they have any toxic activity, would fall on the T lymphocytes. And today it seems to have been confirmed that immune tolerance in the face of embryo implantation does not fall so much on the activity of these lymphocytes but rather on the Natural Killers that we have mentioned before. 

 

If so, the efficiency of the anti-paternal vaccine would be questioned. In addition, they emphasize that this vaccine could be an impediment to possible organ transplants to the woman by her husband (if she was compatible) or by many other people if necessary.  

 

anti sperm antibodies

It is still impossible for science to prove how certain antibodies can cause damage to the tissues of the testicles as well as the ovaries. In addition, these antibodies have been detected both in people with ovarian or testicular insufficiency and in men and women without this pathology. 

 

So it is not known if they are the cause or the effect of the problem. 

 

Its measurement is also complex and not entirely reliable, which is why it has been relegated to a more theoretical than practical level. By the time these antibodies are identified, it is usually too late and the damage to the sexual organs is usually irreparable.

 

In this case, the problem would be having them too high. The therapies used for its treatment, until recently, included immunosuppressive therapy, sperm washing, followed by artificial insemination or IVF. However, in the setting of unexplained infertility, the current treatment of choice is ICSI (intracytoplasmic injection), where a single sperm is injected into a single egg.

 

Antibodies affecting the fetus

Another way that autoimmunity can affect the fetus is through the passive transfer of an antibody that has pathogenic effects. Examples include neonatal thyrotoxicosis, neonatal lupus, and neonatal myasthenia gravis. 

 

All improve as the level of maternal antibodies decreases, so the treatment will go through treating the mother. 

 

Women with lupus will need specific tests to screen for specific antibodies that can cause fetal heart block and heart failure.

 

Treatment of immunological causes of infertility

Genetic bias for autoimmune pathologies exists and is difficult to avoid. Chinese medicine proposes a combination of acupuncture points for genetic filtering in month 3 and month 6 of pregnancy, so that genetic pathologies are not transmitted from parents to children. 

 

It is an ancestral knowledge, supported by the fact that it has lasted over time until our days, but no scientific studies have been carried out to confirm or deny it.

 

On the other hand, until today, the only immunological condition that is widely accepted as a treatable diagnosis is antiphospholipid syndrome, which would be treated with aspirin and clexane. 

 

Although, even aware that both the test and the treatment are still very experimental, it can be very interesting to investigate the activity of the cells natural killers in women with a history of infertility. 

 

The treatment would consist of some type of immunosuppressive therapy, with all that this may entail. During pregnancy these options would include progesterone, clexane, prednisolone, or intravenous immunoglobulin (IVIG).

 

On the other hand, if one of the functions of the immune system is to distinguish what is its own from what is foreign to the body, the creation of antibodies to its own cells or tissues is undoubtedly a failure in the immune function. 

 

The hyperactivity of certain cells of the immune system such as natural killers, meanwhile, is also a failure in immune function. 

 

There is a belief that the more work we give the immune system, the more likely it is to make mistakes. 

 

In this sense, leading a healthy and healthy life, in which there is no low-grade inflammation, in which there are no infections, in which the use of antibiotics is limited and in which the microbiota is taken care of, will help limit the work that the immune system is exposed to and will minimize its chances of being wrong. 

 

Live as healthy a life as possible for you and your fertility.

 

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