Autoimmune Diseases: When Your Defense System Revolts

What happens when the human body's own defense mechanism turns rogue? Why does it happen and what could be the possible solution? Dr Arti Dumbrepatil takes us through the basics again

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By Arti Dumbrepatil
The never-ending  COVID-19 “Infodemic” has made every one of us think about a thousand ways to boost our immune system. To add in the tsunami of information the frenzied markets are filled with immune-boosting products from teas to cooking oils. One sees and reads about COVID-19, then sees and reads more, which not only overwhelms but wears one down. All this talk about the immune system has forced us to ask the dreadful question:
“What happens when the immune system attacks your own body?”
The immune system is supposed to be defending the body against viruses, bacteria, and other illness-causing organisms. The immune system response to an infectious agent can be enhanced administration of vaccines but other factors can lead to malfunctioning of the immune system. This breakdown of the immune response leads to an attack on healthy cells, tissues, and organs of the host. Immune system disorders can be caused due to abnormally low activity or overactivity. In 1901, Paul Ehrlich speculated that the immune system might act against the host by targeting its tissues. He coined the term “horror autotoxicus”. Even though tremendous progress has been made in our understanding of the mechanisms of autoimmune diseases, the development of highly effective and targeted treatments remains elusive. Autoimmune diseases affect millions of people around the world generating a treatment market of ~ $108 billion, much bigger than Cancer and Heart disease.
What are the causes of autoimmune diseases?
The exact cause of autoimmune diseases remains unknown. Studies have shown that both genetic and changing environmental factors contribute to the rise in the incidence of autoimmune diseases. Current scientific evidence has established important environmental alterations in particular dietary and microbial exposure, whether pathogen or otherwise to be one of the underlying causes for autoimmune diseases. Other factors such as drugs, chemical irritants also have been shown to cause the malfunctioning of the immune system. Autoimmune diseases often run in families and are much more common in women than men.
Most common autoimmune diseases
100 -plus autoimmune diseases have been identified so far worldwide. Recent years have seen a significant rise in autoimmune diseases. The most common indicators for autoimmune diseases are fatigue, fever, general malaise, joint pain, and skin rash. In most cases, symptoms aggravate during outbursts and reduce during remission. Some commonly occurring autoimmune diseases include:
  • Type I diabetesThis is different from the more popularType II diabetes that accounts for 95% of total diabetes cases (in which the body becomes resistant to insulin). With Type 1 diabetes (also known as juvenile or insulin-dependent diabetes) there is little or no production of insulin by the pancreas. An immune attack damages the part of the pancreas that produces insulin. Frequent urination and excessive thirst are common problems associated with Type I diabetes, but it can lead to complications and damage organs such as kidneys and eyes.
  • Celiac diseaseCeliac disease targets the small intestine. Gluten consumption leads to an immune reaction that damages the small intestine and impairs normal digestion. Other problems, such as rash, joint pain, and fatigue might develop.
  • Inflammatory bowel syndrome: This is an umbrella term describing disorders of the digestive tract due to chronic inflammation.Types of IBD include:
  • Ulcerative colitis A condition that causes inflammation and ulcers in the innermost lining of the large intestine and rectum
  • Crohn’s disease – This disease is characterized by the inflammation of the lining of the digestive tract.
  • Thyroiditis: The thyroid gland produces hormones that control the body’s growth and metabolism. Thyroiditis refers to inflammation of the thyroid gland causing unusually high or low levels of thyroid hormones in the body. Hashimoto’s thyroiditis is common in the Indian population.
  • Multiple Sclerosis: Multiple Sclerosis is a condition where the immune system targets the central nervous system. The myelin fibers that protect the nerves carrying messages to and from the brain are targeted by the immune system.
  • Rheumatoid arthritis: Condition causing inflammation of multiple joints. It leads to the development of stiff and painful joints. Might lead to inflammation in other organs such as lungs or eyes. Population over 40 years of age are highly prone to this disease.
  • Lupus: Lupus is a systemic autoimmune disease caused by inflammation in multiple parts of the body, especially the joints, skin, lining of the lungs, and kidney.
  • Vasculitis:This term means “inflammation of vessels” and refers to a family of conditions in which blood vessel inflammation leads to bothersome symptoms and, in some cases, organ damage. Examples include temporal arteritis, granulomatosis with polyangiitis, and hypersensitivity vasculitis.
Diagnosis and treatment for autoimmune diseases
Symptoms of the autoimmune diseases vary from being mild to severe.  The different degrees of symptoms are mostly affected by multiple factors such as genetics, environment, and personal health. Autoimmune diseases share similar symptoms such as fatigue, joint pain, and swelling, skin problems, abdominal pain or digestive issues, recurring fever, swollen glands. To further complicate the situation, autoimmune diseases are hard to diagnose because the symptoms overlap with common conditions. Hence, blood tests looking auto-antibodies (antibodies that attack your cells, tissues, and organs) and inflammation and organ function tests are performed for the diagnosis of the autoimmune diseases.
Most autoimmune diseases are treated with medications that suppress or alter the immune system with a hope to reduce the immune response mounted in the body. Treatment consists of drugs that bring down inflammation or reduce the pain. Drugs such as nonsteroidal anti-inflammatory drugs (NSAIDs) and immune-suppressing drugs are commonly used. A better understanding of the immune system has led to the identification of specific immune cells (such as the antibody-producing B-cells) or chemical messages (such as tumor necrosis factor, or TNF). These have helped in the development of targeted drugs such as rituximab, an anti-B cell treatment as well as infliximab, an anti-TNF drug.
The bottom line for autoimmune diseases
Autoimmune diseases vary in severity in different populations. The mysterious incidence of autoimmune diseases has hampered the development of highly targeted and effective treatments. The treatment for these diseases is expensive. Cumulative research efforts from academic and pharmaceutical research labs are needed not only for better understanding of the rising global incidence of autoimmune diseases but for the development of targeted therapies since no specific cures are currently available for these painful conditions.

About Author: Arti Dumbrepatil is a scientist and a science writer. She has worked at the University of Michigan, Ann Arbor, MI, USA, as a postdoctoral researcher. During her tenure at the University of Michigan, she also worked as a Science Communication Fellow and as a Science Communication Writer. She is the lead author in several peer-reviewed scientific journals such as the Journal of Biological Chemistry, Proteins, and Applied and Environmental Microbiology. Arti continues to write as a contributing author to Microbiome Digest, American Society for Biochemistry and Molecular Biology.