Immunology and autoimmune

This page is reference information compiled from the cited sources. It is not medical advice. For any decision about health, diagnosis or care, consult a qualified professional.

What it is

An autoimmune disease is a condition causing disease that results from an anomalous response of the adaptive immune system. It mistakenly targets and attacks healthy, functioning parts of the body as if they were foreign organisms. Autoimmune diseases are a separate class from autoinflammatory diseases. A key difference is a malfunction of the innate immune system in autoinflammatory diseases, whereas in autoimmune diseases there is a malfunction of the adaptive immune system. These diseases represent a vast and diverse category of disorders that share some common symptomatic threads as a result of the body's immune system mistakenly attacking its own cells and tissues.

Key facts

It is estimated that there are more than 80 recognized autoimmune diseases, with recent scientific evidence suggesting the existence of potentially more than 100 distinct conditions. Nearly any body part can be involved, and commonly affected areas include blood vessels, connective tissues, joints, muscles, red blood cells, skin, and endocrine glands. Symptoms can significantly vary based on the specific type of disease and the body part it affects, and they are often diverse and fleeting, fluctuating from mild to severe. Common symptoms include fatigue, low-grade fever, malaise, muscle aches, joint pain, and skin rashes. A UK study found that 10% of the population were affected by an autoimmune disease, and women are more commonly affected than men. The exact causes remain unclear and are likely multifactorial, involving both genetic and environmental influences.

When to seek professional help

The appearance of signs and symptoms can provide clues for the diagnosis of an autoimmune condition, often in conjunction with tests for specific biological markers. Diagnosing autoimmune diseases can be challenging due to their diverse presentations and the transient nature of many symptoms. Symptoms can be diverse and can comprise low-grade fever, fatigue, general malaise, joint pain, skin rashes, or neurological symptoms. Some autoimmune diseases may present with more specific symptoms such as increased thirst, frequent urination, and unexplained weight loss in type 1 diabetes, or severe diarrhea, abdominal pain, fatigue, and weight loss in inflammatory bowel disease. The specific presentation of symptoms largely depends on the location and type of autoimmune response, and an individual may simultaneously have more than one autoimmune disease, further complicating the symptomatology.

Source: Autoimmune disease (CC BY-SA 4.0 (Wikipedia)), retrieved 2026-08-27.