Autoimmune diseases – the most common forms explained

It often starts slowly and insidiously. A sudden feeling of weakness, unexplained pain or seemingly unrelated symptoms. For those affected, the cause often remains unclear for a long time, until the diagnosis is finally made: autoimmune disease.

This involves a misdirection of the immune system. Instead of shielding the body from pathogens, the immune system turns against its own healthy cells.

In medical terms, this process is known as an autoimmune reaction. The resulting inflammation can cause permanent damage to the respiratory tract, intestines, skin, nervous system, kidneys, blood vessels and thyroid glands, among other things. People affected by this condition experience chronic discomfort due to a disruption in immune tolerance, which is the ability of the immune system to distinguish between foreign and its own cells.

The immune system serves as the body’s natural shield, protecting it against pathogens such as bacteria, viruses, parasites and fungi. It also defends against harmful substances from the environment and detects pathological changes in its own cells, enabling it to combat them. To achieve this, it distinguishes between the body’s own and foreign substances, specifically targeting harmful invaders.

If the immune system detects unknown substances, such as pathogens, it triggers an alarm response. This triggers the production of special defence substances, known as antibodies. These attach themselves to the foreign structures, known as antigens, enabling the immune system to render them harmless.

In autoimmune diseases, this process is disrupted. The immune system produces autoantibodies that mistakenly target healthy body tissue. These autoantibodies, along with activated immune cells, trigger inflammatory responses that can harm or destroy tissues and organs.

Experts distinguish between two main forms of autoimmune diseases:

• Organ-specific autoimmune diseases: In this case, individual organs or organ systems are affected, such as in Hashimoto’s thyroiditis or type 1 diabetes.
• Systemic autoimmune diseases: These affect multiple organs and tissues in the body, such as in systemic lupus erythematosus.

According to estimates, around five to eight percent of the global population is affected by one of the approximately 100 known autoimmune diseases. Women are four times more likely to develop the condition than men. The most common autoimmune diseases include:

The precise causes of autoimmune diseases haven’t been fully explained. Typically, a combination of various factors contributes to the development of the disease, with genetic predisposition increasing the risk. Additionally, viral infections, hormonal changes, environmental factors such as pollutants, and lifestyle choices like smoking can all play a role.

The symptoms of autoimmune diseases vary widely, depending on which organs or tissues are affected. Chronic pain is a common occurrence, such as joint pain in rheumatoid arthritis, abdominal pain in Crohn’s disease, or back pain in axial spondylitis.

Fever is also a common symptom, often arising from inflammatory processes. In chronic inflammatory bowel diseases, such as ulcerative colitis or coeliac disease, diarrhoea and impaired nutrient absorption are common, often resulting in fatigue and general exhaustion.

The eyes can also be affected, such as in the case of inflamed eyes in Bechterew’s disease. Itching, particularly with psoriatic arthritis, is also common and often occurs on the palms of the hands, soles of the feet or in skin folds. However, these symptoms can also be present in other diseases, such as infections or allergies, making diagnosis even more challenging.

Living with an autoimmune disease can present significant challenges for many of those affected. The symptoms and unpredictability of the disease can significantly impact daily life. Nevertheless, a life worth living is still possible.

A crucial factor is that those affected learn to accept the disease and actively engage with it. Regular visits to the doctor, adherence to treatment plans and a healthy lifestyle are crucial in this process.

Many patients report that interacting with others who share their experiences helps them better manage the emotional burden. Self-help groups or online communities provide a space for sharing experiences and tips. In addition to medical treatment, psychological counselling or stress management techniques can also significantly enhance the quality of life.

The life expectancy of individuals with autoimmune diseases is heavily influenced by the specific disease and individual circumstances. While some diseases, such as coeliac disease or Hashimoto’s thyroiditis, have minimal impact on life expectancy when properly treated, others, such as systemic lupus erythematosus or multiple sclerosis, can have more serious consequences.

The chances of recovery from autoimmune diseases are limited, as most of these diseases are chronic in nature. However, medical advances have significantly enhanced treatment options. Early diagnosis and consistent treatment can alleviate many symptoms and halt the progression of the disease.

New approaches, such as the cell therapy tested at Charité – Universitätsmedizin Berlin, could improve the chances of recovery in the future. This innovative treatment aims to propagate living cells in patients’ bodies, specifically targeting the auto-aggressive components of the immune system. The initial results of the therapy studies are promising, with patients reporting a significant improvement in their condition. There are even indications that a complete cure may be possible.

While Charité is focusing on the targeted fight against autoaggressive cells, scientists at UC Davis Health are testing a therapy that could potentially help people with lupus. With CAR-T cell therapy, immune cells are extracted from the blood and modified to target the cells responsible for the disease. Here, too, initial results appear promising. The symptoms improved, and no relapses occurred for two years.