What is the immune system?
The immune system is the body's defence network — a complex system of cells, tissues, and proteins that identifies and destroys pathogens like bacteria, viruses, and parasites. Under normal conditions it is extraordinarily precise: it distinguishes between foreign invaders and the body's own healthy tissue.
This distinction is called "self-tolerance." The immune system learns during early development which cells belong to the body and which are foreign threats. This process takes place largely in the thymus gland and bone marrow, where immune cells are trained and tested before being released into circulation.
When self-tolerance breaks down
In autoimmune diseases, self-tolerance fails. The immune system misidentifies healthy tissue as a threat and mounts an attack against it. This can happen for several reasons — genetic predisposition, environmental triggers, infections, or a combination of all three.
The result is chronic inflammation and progressive tissue damage. Because the immune response is self-sustaining, autoimmune diseases do not go away on their own. They require management to reduce immune activation and protect the tissues under attack.
The autoimmune spectrum
There are over 80 recognised autoimmune diseases. Some are organ-specific — attacking a single tissue — while others are systemic, affecting multiple organs simultaneously.
Examples include: Type 1 diabetes (attacks pancreatic beta cells), Hashimoto's thyroiditis (attacks the thyroid), rheumatoid arthritis (attacks joint linings), multiple sclerosis (attacks the myelin sheath of nerves), lupus (attacks multiple organs), and celiac disease (attacks the small intestine's lining in response to gluten).
Autoimmune conditions frequently cluster together. Having one autoimmune disease significantly increases the risk of developing another.
Celiac disease as an autoimmune condition
Celiac disease is unique among autoimmune conditions because its trigger is known and avoidable. When a genetically susceptible person ingests gluten — a protein found in wheat, barley, and rye — the immune system produces antibodies (primarily anti-tissue transglutaminase, or tTG-IgA) that attack the lining of the small intestine.
The resulting inflammation destroys the villi — tiny finger-like projections that absorb nutrients. This causes malabsorption, nutritional deficiencies, and a wide range of systemic symptoms. Strictly removing gluten from the diet allows the intestine to heal, though full recovery can take months to years depending on the degree of damage.
Genetic basis
Almost all people with celiac disease carry one or both of two specific gene variants: HLA-DQ2 and HLA-DQ8. These genes are found on chromosome 6 and play a central role in how the immune system presents gluten peptides to T-cells — the white blood cells that orchestrate the immune attack.
However, carrying these genes is necessary but not sufficient for developing celiac disease. Approximately 30–40% of the general population carries HLA-DQ2 or HLA-DQ8, yet only about 1% develops celiac disease. Additional genetic factors and environmental triggers are required for the disease to manifest.
Can autoimmune diseases be cured?
Most autoimmune diseases, including celiac disease, cannot currently be cured — but they can be effectively managed. For celiac disease, the treatment is a strict, lifelong gluten-free diet. This removes the trigger, halts the immune attack, and allows the intestine to heal.
For other autoimmune conditions, management typically involves immunosuppressant medications, anti-inflammatory drugs, or biologic therapies that modulate specific immune pathways. Research into more targeted treatments is ongoing, and several clinical trials are investigating new approaches to restoring immune tolerance in celiac disease specifically.