The immune system protects us from diseases. However, on certain occasions it turns against the body itself, causing the conditions itself. We are talking about autoimmune diseases, a group of pathologies that are increasingly common and more diagnosed.
“Our defenses suddenly begin to recognize structures, proteins from certain organs or parts of the body as foreign and attack them, producing an inflammatory response,” explains Patricia Fanlo Mateo, specialist in Internal Medicine, coordinator of the Systemic Autoimmune Diseases Unit of the Hospital Complex. of Navarra and president of the Spanish Multidisciplinary Society of Systematic Autoimmune Diseases (SEMAIS).
“The problem is that it is chronic inflammation. In an infection, an inflammatory process occurs to act against this aggression and, once resolved, there are mechanisms by which the inflammatory process is stopped. But the brake does not occur in these diseases and the inflammation tends to destroy the tissues in which it occurs,” adds Juan Carlos Nieto González, rheumatologist at the Gregorio Marañón Hospital and co-director of the Center for Immune-Mediated Inflammatory Diseases (CEIMI).
Virtually any part of the body can be affected, including the joints, muscles, skin and also vital organs such as the brain, heart, kidneys or lungs, giving rise to a heterogeneous group of diseases.
About 100 conditions of this type are known, including lupus, Crohn’s disease, rheumatoid arthritis, psoriasis or multiple sclerosis. According to the figures normally used, a little less than 5% of the population is affected, especially women, who represent 80% of the proportion.
However, the number of cases has increased over time and has done so “drastically in many parts of the world, probably as a result of changes in our exposures to environmental factors,” explains Frederick Miller, former director of the Group, in a review. of Environmental Autoimmunity of the National Institute of Environmental Health Sciences (NIEHS), attached to the American National Institutes of Health (NIH, for its acronym in English). Current projections suggest that they could soon occupy a prominent place among the predominant medical disorders, the expert adds.
In a systematic review published in the International Journal of Celiac Disease, which included 30 studies published in the last 30 years on the incidence and prevalence of these diseases, it was estimated that the proportion of the world’s population affected increased by more than 12% each year. New cases increased 19% annually.
In autoimmune diseases there is a very important genetic predisposition, although, in general, the precise mechanisms for their debut are still not clear, according to Nieto González. It is true that current evidence implies significant alterations in diet, pollution, infections, lifestyles, stress or climate change as causes of the recorded increases.
“Most genes are neither good nor bad, but rather their environments that make them that way. Furthermore, our genetic architecture, which has evolved over millennia to allow us to thrive in previous environments, may be, in many ways, inadequate to meet rapidly changing modern environmental challenges,” says Miller.
Fanlo Mateo emphasizes emotional stress, which is increasingly normalized. “We know that it alters the immune system and is one of the most important triggers in autoimmune diseases and their outbreaks. Many debut in a situation of family or work stress, a separation… Trying to lead a less stressful life or techniques such as mindfulness have been seen to work well,” explains the doctor.
Diet emerges as another trigger that triggers many of these pathologies. “There are eating habits that can have a significantly positive or very negative impact on inflammatory processes that can lead to diseases or make existing ones chronic,” says Beatriz Cabanillas, head of the allergy research group at the Hospital 12 Research Institute in October.
Cabanillas highlights the possible effect of consuming ultra-processed foods, those very far from the original form of the food, rich in added sugars, and refined flours and refined oils, the expert points out. These have already been associated with a higher risk of cardiovascular and cerebrovascular diseases, among others. Some research also indicates the presence of traces of chemicals and contaminants – xenobiotics – in what we ingest.
Air pollution has in turn been studied in relation to the appearance of problems with autoimmunity. There are also preliminary studies on the effects of climate change proposing hypotheses such as the alteration in our exposure to elements with which the immune system interacts or the modification of dietary patterns, among others.
The key point for the two doctors interviewed has, however, been the improvements in diagnosis. Professionals now have much more powerful diagnostic tools. Imaging tests such as PET (positron emission tomography) and genetic tests stand out here, “which 20 years ago did not exist,” in the words of Fanlo Mateo. This makes it possible to diagnose more and more patients earlier and earlier, who were missed a few years ago.
In parallel, progress in treatments has been key, not only to improve the quality of life of those affected, but to help understand the mechanisms by which inflammation occurs.
“Twenty years ago it was treated with corticosteroids and classic oral immunosuppressants. Today there is already precision medicine. These are biological therapies that block specific inflammatory molecules such as cytokines. They are much more targeted therapies that avoid the toxicity of corticosteroids and organic damage,” says the doctor.
Even so, there is still a way to go. “The immune system is very complicated, very personalized. […] We are still far from knowing how to predict which pro-inflammatory molecule we have to block in each patient, which would be ideal,” says Nieto González.
