We are not aware of how many dangers surround us every day. Perhaps that is why the immune system does a job that is not appreciated until the day it fails.
In this article we will review the main types of autoimmune diseases and the way they affect us. But first, let’s start with the simplest things.
The immune system is a group of cells coordinated with each other that specialize in protecting the body against external agents that could cause health deterioration, 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.
The problems become more acute when it is the immune system itself that does not function correctly. There are different failures of this system, such as the absence of response (immunodeficiency), an exaggerated response (hypersensitivity) or an attack on the body itself (autoimmune diseases). In this article I will focus on this last group.
immune tolerance
Autoimmune diseases have in common the loss of immune tolerance, that is, they 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 (immune system cell) is activated with its own 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 harm the body.
The immune system makes use of antibodies, molecules that bind to the aforementioned antigens, to signal the rest of the immune cells to attack them. The loss of tolerance is detected by the presence in the body of autoantibodies (antibodies that signal normal elements of the body as antigens) and autoreactive T lymphocytes (lymphocytes that recognize their own 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 greater prevalence than others. Many of them present similar symptoms (such as inflammation), which makes diagnosis difficult. Commonly, they are classified as complex diseases, since there is more than one factor to trigger the problem, such as hormonal, genetic or environmental components
I am not going to explain all the existing autoimmune diseases, but I will talk about the most recognized ones to expose different cases.
1. Type 1 Diabetes Mellitus (DM1)
Diabetes is one of the metabolic alterations that most affect human beings Already in 2015, 400 million cases had been diagnosed worldwide. There are different types of diabetes mellitus, one of them being of autoimmune origin. I’m talking about type 1 diabetes mellitus, which accounts for 5% of diagnosed cases.
The onset of DM1 normally occurs in adolescence, and what happens is that the immune system removes islet of Langerhans cells from the pancreas who are responsible for the production of the hormone insulin, causing the appearance of diabetes due to its lack.
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 covers 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 worldwide), and its symptoms are signs of failures in the transmission of information, such as fatigue, lack of balance, visual disturbances. and speech and tremors.
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, events caused by the attack of immune cells on 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 entire 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 presents very characteristic symptoms, such as butterfly-shaped redness on the face, photosensitivity or kidney failure. The latter can lead to the death of the patient
The reasons that trigger the disease are not known, although there is a strong genetic influence. In addition, it has also been seen that it is more common in women, and more specifically, in certain ethnicities. African American and Hispanic women are at higher risk for the disease than Caucasian women.
