The 6 main types of autoimmune diseases

We are not aware of how many dangers surround us every day. Perhaps that is why the immune system performs a job that is not appreciated until the day it fails.

In this article we will review above the main types of autoimmune diseases and the way they affect us. But first, let's start with the simplest.

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What is the immune system?

The immune system is a group of cells coordinated with each other that specialize in protecting the body against external agents that could cause deterioration in health, such as infections or diseases. Like everything, it is not perfect, and some of these agents manage to penetrate the defense and cause discomfort, infections, etc.

Problems are exacerbated when the immune system itself is not working properly. There are different failures of this system, such as a lack of response (immunodeficiency), an exaggerated response (hypersensitivity) or an attack on the body itself (autoimmune diseases). In this article I will focus on the latter group.

Immune tolerance

Autoimmune diseases have in common the loss of immune tolerance, that is, that detect antigens (substances that are detected by the immune system and cause it to activate) of the body. Tolerance is a series of mechanisms that exist to avoid this; For example, if a lymphocyte (cell of the immune system) is activated with a self antigen at the time it is generated in the producing organ (spleen and thymus), the organ itself is responsible for eliminating this cell so that it does not damage the Body.

The immune system makes use of antibodies, molecules that bind to the aforementioned antigens, to signal the rest of the immune cells that attack them. Loss of tolerance is detected by the presence in the body of autoantibodies (antibodies that signal as antigens elements normal body) and autoreactive T lymphocytes (lymphocytes that recognize self antigens), which for some reason have not been eliminated.

Main types of autoimmune diseases

Up to 80 types of autoimmune diseases are known today, some with a higher prevalence than others. Many of them have similar symptoms (such as inflammation), which makes the task of diagnosis difficult. In a common way, they are classified in complex diseases, since there is more than one factor to trigger the problem, such as hormonal, genetic or environmental components.

I will not dedicate myself to explaining all the existing autoimmune diseases, but I will talk about the most recognized to expose different cases.

1. Type 1 Diabetes Mellitus (DM1)

Diabetes is one of the metabolism disorders that most affect humans. By 2015, 400 million cases had been diagnosed worldwide. There are different types of diabetes mellitus, one of them being of autoimmune origin. I am talking about type 1 diabetes mellitus, which translates into 5% of the cases that are diagnosed.

The onset of DM1 usually occurs in adolescence, and what happens is that the immune system removes cells from the islets of Langerhans from the pancreas, who are responsible for the manufacture of the hormone insulin, causing the appearance of diabetes due to the lack of it.

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2. Multiple sclerosis

It is a type of chronic demyelinating autoimmune disease of the central nervous system. In this case, the cells of the immune system, lymphocytes and macrophages, destroy the myelin that cover the nerve fibers, which has an important function in maintaining the nerve impulse. Without her, the neuron is unable to send correctly information.

It is one of the most common diseases that affects the nervous system in the world (2.5 million cases diagnosed in the world), and its Symptoms are signs of failure to transmit information, such as fatigue, poor balance, sight and speech disturbances, and tremors

• Related article: "Multiple sclerosis: types, symptoms, and possible causes"

3. Rheumatoid arthritis

This type of autoimmune disease affects the joints, a place that the immune system progressively destroys. It has a high prevalence (between 0.5 to 1% of the world population), with a higher frequency in women.

Rheumatoid arthritis causes joint pain, swelling, and stiffness, facts caused by the attack of the immune cells to this tissue. The exact causes of the disease are unknown, although hormonal, environmental and genetic components have been found.

4. Systemic Lupus Erythematosus (SLE)

SLE, or simply lupus, is one of the most prevalent autoimmune diseases. In Spain it is estimated that 9 out of every 10,000 inhabitants suffer from it. It is a systematic disease, in other words, the whole body is attacked by the immune system. This is because autoantibodies are generated against nucleic antigens (ANA), that is, they target elements of the cell nucleus, such as DNA or histones.

Lupus is a type of autoimmune disease that has very characteristic symptoms, such as redness in the shape of a butterfly on the face, photosensitivity or kidney failure. The latter can lead to the death of the patient.

The reasons for the disease are not known, although there is a strong genetic influence. In addition, it has also been seen that it is more frequent in women, and more specifically, in certain ethnicities. African American and Hispanic women are at higher risk for the disease than Caucasian women.