Autoimmune diseases

Definition

Autoimmune diseases are conditions where the immune system mistakenly attacks the body’s own healthy cells, tissues, or organs, viewing them as foreign invaders. This misdirected immune response can lead to inflammation, tissue damage, and impaired function of the affected areas. Understanding how this process occurs involves knowledge about the immune system's cells and tissues, as well as recognizing the various disorders and hypersensitivity reactions that can arise from such failures in immune regulation.

5 Must Know Facts For Your Next Test

1. Autoimmune diseases can affect any part of the body and are categorized into systemic autoimmune diseases (like lupus) and organ-specific diseases (like Type 1 diabetes).
2. The exact cause of autoimmune diseases is often unclear, but genetic, environmental, and hormonal factors are believed to contribute to their development.
3. Women are disproportionately affected by many autoimmune diseases compared to men, with some conditions being up to 10 times more common in females.
4. Common symptoms of autoimmune diseases include fatigue, joint pain, skin issues, and organ dysfunction, which can vary widely depending on the specific disease.
5. Diagnosis often involves serological tests to detect autoantibodies, along with clinical evaluations to assess symptoms and organ involvement.

Review Questions

• How do T cells contribute to the development of autoimmune diseases?
  • T cells play a crucial role in the immune response, including recognizing and attacking pathogens. In autoimmune diseases, T cells can become dysregulated, mistakenly identifying the body's own cells as foreign invaders. This leads to an inappropriate immune response where T cells attack healthy tissues, causing inflammation and damage, which is a hallmark of many autoimmune conditions.
• Discuss how autoantibodies are involved in the pathophysiology of autoimmune diseases.
  • Autoantibodies are antibodies produced by the immune system that incorrectly target and bind to a person's own tissues. Their presence is a key feature in many autoimmune diseases, leading to chronic inflammation and damage in affected organs. The mechanisms by which these autoantibodies cause harm can vary but often involve complement activation and recruitment of inflammatory cells, contributing significantly to tissue destruction and dysfunction.
• Evaluate the impact of environmental factors on the onset of autoimmune diseases in genetically predisposed individuals.
  • Environmental factors such as infections, toxins, and dietary components can significantly influence the onset of autoimmune diseases in individuals with a genetic predisposition. For example, certain viral infections may trigger an autoimmune response by mimicking self-antigens or by causing an inappropriate activation of the immune system. This interplay between genetics and environmental triggers underscores the complexity of autoimmune disease development and suggests potential avenues for prevention and treatment.

Related terms

T cells: A type of white blood cell that plays a central role in cell-mediated immunity and can become dysregulated in autoimmune diseases.

autoantibodies: Antibodies produced by the immune system that mistakenly target and react with a person's own tissues, often seen in autoimmune diseases.

hypersensitivity: An exaggerated immune response to an allergen or foreign substance that can overlap with mechanisms seen in some autoimmune diseases.