Help the development of the site, sharing the article with friends!

VERIFIED CONTENTAuthor: Katarzyna Wieczorek-Szukała, MD, PhD, medical biotechnologist, Medical University of Lodz

Autoimmune diseases are diseases in which the human immune system begins to attack its own he althy tissues. Symptoms of this type of ailments are not specific, they often appear and disappear, so proper diagnosis can take years. Unfortunately, most autoimmune diseases are incurable, and modern medicine can only alleviate the accompanying ailments.

The genesisof autoimmune diseasesis not fully understood, but it is suspected that for the so-called autoimmunity is mostly due to genetic factors and some viral or bacterial infections. There are currently over 100 types of autoimmune diseases that affect almost every part of the human body. Among the best known are Hashimoto's disease, Crohn's disease, MS, RA and many others.

Where do autoimmune diseases come from?

According to statisticsautoimmune diseasesoccur rather rarely - they affect on average 3 to 8% of the population. They can develop at any age, but are mostly diagnosed in women. It is still not fully known what the exact cause of this type of pathology is, although many theories have emerged about it.

A common feature of all diseases resulting from autoimmunity is the disturbance of special mechanisms regulating autotolerance - that is, telling the cells of the immune system which antigens (e.g. proteins) are the enemy and which are not. Physiologically, in T lymphocytes of this type, tolerance is maintained on the basis of 3 different biological mechanisms:

  • positive selection,
  • anergii,
  • suppression.

Selection involves the removal of overly reactive T lymphocytes at the site of their formation and maturation, i.e. the thymus. In this gland, cells of the immune system "learn" to recognize their own surface proteins, otherwise they are directed to the so-called pathway. apoptosis, i.e. controlled and programmed destruction of the body's own cells.

In turn, lymphocyte anergy consists in the presentation of antigens with the participation of other molecules (so-called coactivators). If the co-activator is absent, the lymphocyte will not be able to enter the excited (active) state and will therefore remaintolerant to antigens from the same organism.

Suppression - this is the suppression of T lymphocyte responses by other types of immune system cells - mainly regulatory (Treg) and suppressor (Ts) lymphocytes, secreting cytokines that inhibit activation. It has been shown that a frequent cause of the development of autoimmune diseases is the weakening of Treg lymphocyte function.

Disturbances in the functioning of the innate immune system are, of course, not the only possible causes of diseases related to autoimmunity. An important role in their development is also played by the cells of the acquired immune system, in particular disorders of the secretion of pro-inflammatory and anti-inflammatory cytokines, e.g. interleukins, NF-κβ factor, or interferons.

Viral or bacterial infections are a very important factor that can "trigger" the growing autoimmune system. Infection with a pathogen can stimulate the development of autoimmunity (that is, an over-response of the immune system against its own tissues) through several different mechanisms.

An example may be rheumatic fever - developing after infection with bacteria from the Streptococcus group - streptococci that cause angina. One of the latent symptoms of this condition is inflammation of the heart, manifested by fever, shortness of breath and weakness.

This complication appears as a result of autoimmunity, resulting from the similarities in structure between the bacterial antigen (a specific membrane protein) and myosin - a protein characteristic of the human heart muscle.

Similar infections, e.g. with the influenza virus, can activate a nonspecific immune response that gives rise to one of the diseases considered to be civilization - type 1 diabetes.

Other known links between a specific pathogen and the development of autoimmune diseases include infection with the Klebsiella pneumoniae strain inducing arthritis or the bacterium Proteus mirabilis - associated with the development of rheumatoid arthritis (RA).

Individual genetic predisposition is also associated with a higher probability ofautoimmune diseases . Each of us may have a slightly different variant of genes (the so-called allele) conditioning the formation of MHC (Major Histocompatibility Complex) proteins.

The complex of these molecules is also known as the histocompatibility complex and is responsible for the presentation of individual antigens to T lymphocytes. in such diseases as:

  • type 1 diabetes,
  • multiplescattered,
  • systemic lupus erythematosus,
  • pemphigus common,
  • ankylosing spondylitis (AS, Bechterew's disease).

Some of the above ailments (e.g. systemic lupus) typically run in families - their genesis is clearly related to genetic factors.

Based on many studies, it has also been concluded that harmful environmental factors contribute to the development of many autoimmune diseases:

  • chemicals,
  • hazardous industrial waste,
  • pesticides,
  • air and water pollution,
  • food preservatives,
  • UV radiation.

Compounds of this type disturb the natural balance of the intestinal flora of the mouth and intestines, and also trigger an increased immune reactivity of tissues, although the mechanism of these changes is not fully understood.

As you can see, autoimmune diseases constitute a very extensive and heterogeneous group of diseases. Although they stem from the autoimmune immune system acting on its own cells, the very basis of their formation can vary significantly.

Examples of autoimmune diseases

Crohn's disease

This disease is one of the subtypes of the so-called inflammatory bowel diseases (such as ulcerative colitis). The resulting inflammatory changes may affect all sections of the gastrointestinal tract - most often, however, they affect the final section of the ileum and the small intestine, and less frequently the large intestine. As with many autoimmune diseases, the symptoms of progressive Crohn's disease are not specific and general, including:

  • fever,
  • general weakness,
  • gradual weight loss,
  • stomach pains,
  • anemia.

These ailments mainly result from poor absorption of nutrients from the intestines and insufficient nutrition of the body. Local symptoms are related to the localization of inflammatory changes. Frequent diarrhea occurs in more than half of patients, in more serious cases it takes the form of the so-called fatty diarrhea (associated with impaired digestion and absorption of fats from the gastrointestinal tract).

Treatment of Crohn's disease is chronic and persistent. It is primarily about alleviating acute ailments and preventing relapses. The presence of this condition also increases the likelihood of developing colorectal cancer in the future.

Multiple Sclerosis

Multiple sclerosis (Latin sclerosis multiplex - MS) is a progressive disease of the centralnervous system, which most often appears in young adults between 20 and 40 years of age. It consists in the disappearance of the myelin sheath around neurons (called demyelination) - which results in faulty signal transmission along nerve fibers and extensive damage to the brain and spinal cord.

The second part of the name of the disease - "disseminated" refers to a vast area of ​​pathological processes and occurrence in the form of foci in various parts of the nervous system. The dynamics of the progress of changes is often very individual, and the most common symptoms include:

  • impaired coordination of movements,
  • muscle weakness,
  • visual and speech disorders,
  • sensory disturbance,
  • chronic fatigue,
  • acute pain syndromes.

One of the most common variants of multiple sclerosis manifests itself in the form of the so-called relapses - that is, a sudden worsening of symptoms followed by periods of disease stabilization (lasting even several months or years).

Rheumatoid arthritis

Rheumatoid Arthritis (RA) is one of the most common systemic diseases and affects up to 1.5% of the Polish population. This rheumatic disease is also known as arthritis or chronic progressive rheumatism. It is a systemic disease of the connective tissue that manifests itself clinically as chronic arthritis. As with multiple sclerosis, RA has periods of remission and exacerbation.

Usually thisautoimmune diseasedevelops slowly and is accompanied by general symptoms similar to the common cold (feeling weak, low-grade fever, muscle pain, loss of appetite and weight loss) . In the next, more typical stages of RA, there are:

  • joint pain and stiffness,
  • symmetrical swelling,
  • joint tenderness to pressure,
  • restriction of mobility.

This disease does not only affect the joints, but also affects other organs. The untreated form of RA may manifest itself with the so-called rheumatoid nodules, as well as a significantly higher probability of atherosclerosis, ischemia, strokes and heart attacks.

Systemic Lupus Erythematosus

Lupus is a systemic disease of connective tissue resulting from disorders of the immune system. Changes resulting from the disease can affect virtually any tissue in the body, although they most often affect the skin, kidneys or joints.

People who are genetically susceptible to falling ill may develop symptoms of the disease after the action of certain environmental factors - drugs,UV radiation, infections with retroviruses, hormonal factors.

Lupus is about 10 times more common in women, which could potentially be associated with fluctuations in the level of hormones such as estrogen and prolactin in subsequent life cycles. One of the most characteristic symptoms of systemic lupus is erythema on the face in a butterfly shape.

This type of redness may be chronic, often accompanied by erosions of the mouth or nose. These lesions are especially susceptible to sunlight, which exacerbates symptoms. Other symptoms that most patients experience also include:

  • chronic joint pain,
  • traveling muscle pains,
  • ischemic skin ulcers,
  • dry eye syndrome,
  • recurring lung infections,
  • nonspecific abdominal pain.

Due to the complex of many systemic symptoms, lupus is difficult to distinguish from other connective tissue diseases and requires careful diagnosis.

Hashimoto's disease

Hashimoto's disease is a chronic lymphocytic thyroiditis and the most common cause of primary hypothyroidism. Under the influence of autoimmune disorders, the thyroid parenchyma gradually fibrosis and atrophy, and the proper secretion of thyroid hormones may also be inhibited.

This condition can develop insidiously at a young age and gradually worsen symptoms. Severe hypothyroidism can result in heart disease and even coma. Initial symptoms that may indicate the development of Hashimoto's disease include:

  • feeling too cold,
  • sleepiness,
  • mood swings,
  • weight gain,
  • dry skin and hair,
  • menstrual disorders or infertility.

As in the case of systemic lupus, this disease affects several times more often women and people suffering from other diseases related to autoimmunity.

Psoriasis

Psoriasis is a chronic disease with a characteristic appearance of skin lesions. It is often confused with atopic dermatitis. Psoriatic lesions most often appear around the elbows and knees, the sacrum or buttocks, on the scalp and the skin of the feet and hands.

They take the form of round red-brown spots, which sometimes become covered with a grayish "scale" as a result of excessive keratinization of the diseased epidermis. The severity of the disease may vary significantly, but in more severe cases it is associated with difficult-to-heal skin exudates or complications in the form of inflammation.joints.

Treatment of autoimmune diseases

Unfortunately, the overwhelming majority of autoimmune diseases are chronic in nature and the methods of their final cure are unknown. Therapies are most often used to relieve persistent symptoms, pain and acute relapses.

Thus, it manipulates in some way the response of the body's immune system, while maintaining the patient's ability to fight diseases that he may encounter on a daily basis.

Traditional treatment options may include immunosuppressants to reduce the overall immune response and inflammation, including non-steroidal anti-inflammatory drugs (NSAIDs) and glucocorticoids.

In therapy, vitamin or hormonal supplements are also often used, which provide the body with components missing from the development of the disease (insulin, vitamin B12, thyroid hormone, etc.). In modern medicine, great hopes are associated with the so-called targeted therapies that would be more specific to specific molecules and less harmful side effects.

They use, for example, monoclonal antibodies that block pro-inflammatory cytokines. Physiotherapy is an invaluable addition to the treatment of autoimmune diseases affecting joints and muscles (such as RA or systemic lupus).

Help the development of the site, sharing the article with friends!

Category:

Immune system