Autoimmune diseases are recording an increasing presence in health systems around the world, amid scientific attempts to understand the reasons for the high rates of some of them, and the role of environmental changes, lifestyle, infection, and the great development in diagnostic tools in detecting diseases that medicine was not aware of a few years ago.
Recent estimates indicate that autoimmune diseases of various types may affect between 5% and 10% of the world’s population. In a large study that included the health records of about 22 million people in Britain, it was found that the 19 autoimmune diseases included in the study collectively affected about 10% of the population.
Not all of these diseases move in the same direction; The prevalence and infection rates vary from one disease to another and from one region to another, but recent studies indicate that the total burden of immune diseases is likely to rise in the coming decades, with increasing numbers of cases and changing exposure to environmental factors and lifestyles.
How does it happen?
Autoimmune diseases occur when the immune system loses its natural ability to distinguish between components of the body and foreign agents, so it directs its response against healthy cells and tissues, leading to chronic inflammation that may, over time, cause organ damage or disturb their functions.
The exact cause of most of these diseases is still unknown, but evidence points to a complex interaction between genetic predisposition and external factors that may include infection, smoking, certain chemicals, diet, obesity, altered microbiome, pollution, and other factors related to lifestyle and environment.
At the same time, advances in genetics and gene sequencing technologies have identified rare, previously unknown immune disorders. This does not necessarily mean that they appeared suddenly in recent years. Rather, some of them may have been present for a long time, but patients were classified under other diagnoses before the responsible genetic cause was discovered.
The most prominent of these cases are VEXAS, SAVI, and COPA syndromes, which are rare diseases that differ in their mechanisms and classification from traditional autoimmune diseases, and some of which are more accurately classified as autoinflammatory diseases or diseases that combine autoinflammation and autoimmunity.
VEXAS syndrome
VEXAS syndrome did not enter the medical dictionary until 2020, after the discovery of acquired mutations in the UBA1 gene in a group of patients who suffered from severe systemic infections and blood disorders.
The syndrome is essentially classified as an acquired autoinflammatory disease that begins in adulthood, and not a traditional genetic disease that is necessarily transmitted from parents to children.
The majority of cases affect men after the age of fifty, and may cause fever, fatigue, weight loss, and infections of the skin, cartilage, joints, and blood vessels, in addition to lung problems and blood disorders that may be severe.
A study that relied on data from more than 163,000 people estimated the presence of mutations causing the disease in approximately one in every 13,591 people, while the estimate rose to one in every 4,269 men over the age of fifty.
The association of the disease with age means that the aging of the population may increase the number of cases that appear before doctors, but the most important factor behind its recent entry into the medical dictionary is the development of genetic diagnosis, which allowed the grouping of symptoms that seemed separate under one disease.
SAVI syndrome
Years earlier, specifically in 2014, scientists identified SAVI syndrome, a rare autoinflammatory disease resulting from mutations that lead to overactivity of the STING protein, which is responsible for one of the immune defense pathways.
The disease often begins in infancy or early childhood, and leads to persistent inflammation of the blood vessels, especially small vessels. Severe skin injuries may appear in the face, ears, nose, fingers, and toes, in addition to injury to the lungs and joints.
SAVI remains extremely rare, and therefore knowledge about its course and the diversity of symptoms is still limited compared to more common immune diseases.
COPA Syndrome
As for COPA syndrome, it was described in 2015 and is associated with mutations in a gene of the same name, and can affect both the innate and adaptive immune systems.
Its symptoms often begin in childhood, and are particularly concentrated in the lungs, joints, and kidneys. Patients may develop interstitial lung disease or pulmonary hemorrhage, arthritis, and glomerulonephritis.
One of the striking characteristics of the syndrome is that the presence of a mutation does not necessarily mean the disease will appear in its carrier, a phenomenon known as incomplete penetrance, which indicates the possibility that other genetic or environmental factors may contribute to determining who develops symptoms.
New diseases or new diagnosis?
The emergence of the names of these syndromes in the last decade does not mean that people suddenly began to develop diseases that did not exist before.
The expansion of the use of genetic sequencing and the study of cells and immune pathways has enabled researchers to identify the causes of disorders in which some patients were previously diagnosed with unspecified rheumatic, inflammatory, or blood diseases.
At the same time, there is evidence that the prevalence of many autoimmune and autoinflammatory diseases is rising in different regions of the world, an increase that is too rapid to be explained by human genetic changes alone, leading researchers to look increasingly to environmental and lifestyle factors.
PFAS substances under a microscope
Chemicals known as perfluoroalkyl substances (PFAS), or sometimes known as “forever chemicals,” are among the environmental factors receiving increasing attention.
These compounds have been widely used for decades in products that are water, grease, heat and stain resistant, and are difficult to degrade and able to persist in the environment and accumulate.
In April 2026, the Archives of Toxicology published a review of 51 studies examining the relationship between PFAS exposure and autoimmunity.
Thirty-three studies found an association between high exposure and some autoimmune markers or diseases, with the strongest evidence for celiac disease and inflammatory bowel disease, while evidence remained weaker or inconclusive for other diseases.
The researchers stressed that most of the available studies do not allow proving a direct causal relationship, and that the field needs more long-term studies.
Agricultural pesticides
Pesticides are another area of research, but the evidence also calls for caution. Studies have linked some types of pesticides to an increased risk of developing certain immune diseases, such as lupus, Sjögren’s syndrome, rheumatoid arthritis, and inflammatory bowel diseases, but the results vary depending on the substance used, the duration of exposure, and the population under study.
In an American study that included more than 54,000 people who work in the agricultural field or live with its workers, the use of some pesticides was associated with an increased risk of developing lupus or Sjögren’s syndrome, while the association did not appear with other types, which confirms the complexity of the relationship and the inability to deal with all pesticides as a single factor.
Covid and autoimmunity
Viral infections are among the most studied immune triggers, including Epstein-Barr virus, cytomegalovirus, and the coronavirus that causes COVID-19.
A large study that relied on data from South Korea and Japan showed that people who were infected with “Covid-19” were more likely to subsequently be diagnosed with immune-inflammatory rheumatic diseases compared to people who were not infected with the virus or had influenza, and more severe infections were also associated with a higher risk.
As for long-term Covid, estimates of its prevalence vary widely according to the case definition, population, and follow-up period. An analysis published in 2026 and including more than 200,000 participants concluded a combined average of 30.8%, but the researchers stressed that there was huge variation between studies, warning against treating this percentage as a fixed global average.
An unfinished puzzle
No single factor can be held responsible for the increase in autoimmune diseases or the emergence of new immune syndromes. Genes determine part of susceptibility, while infections, pollutants, smoking, diet, obesity, changing microbiome and other environmental factors may interact over years.
In contrast, the revolution in genetics and diagnosis made medicine more capable of naming diseases that already existed but were unidentified.
Thus, the growing list of immune diseases reveals not only a change in the human immune system, but also a change in our ability to see it and understand its malfunctions, in a scientific race that is still far from reaching the full picture.