> See also: > - [[Systemic Autoimmune Rheumatic Diseases (SARDs)]] # Autoimmunity ## Immune Tolerance - Central Tolerance - Peripheral Tolerance ### Defenses Against Autoimmunity > See also: [[Programmed Cell Death]] Programmed cell death protein 1 (PD-1) **Autoimmune Regulator (AIRE)** is a protein [[Transcription|transcription factor]] expressed in the medulla of [[the thymus]] that is part of the mechanism which elimates self-reactive T cells https://en.wikipedia.org/wiki/Autoimmune_regulator ## Autoimmune Disorders In **autoimmune disorders**, the mechanisms of [[Anki Flashcards/Courses/Molecular Biology II/Chapter 17 - The Genetic Code|the immune system]] are turned against the host and inflict harm. Some examples of these mechanisms are: - The production of autoantibodies which target - [t cell mediated autoimmune diseases](https://www.immunopaedia.org.za/immunology/advanced/9-t-cell-mediated-autoimmune-diseases/) > [!NOTE]- Autoimmunity vs Autoimmune Diseases > Autoimmunity is the production of anti-self antibodies. It is often a natural progression as we age, and can be induced by certain drugs or pathogens. The presence of these antibodies alone doesn't indicate autoimmune disease. Tissue damage must result for this term to be correct. There are two major classifications of autoimmune disorders - An autoimmune disease that targets a specific organ is said to be **organ-specific**. ### Mechanisms of Autoimmune Reactions There are many different mechanisms that can influence the development of autoimmune reactions: - **Molecular Mimicry:** Occurs when the epitope - Defective elimination and/or control of self-reactive lymphocytes A common theme between these mechanisms is an "imbalance between effector and regulatory immune responses". ### Common Autoimmune Diseases **Autoimmune Disorders (AIDs)** - A diverse group of disorders potentially caused by genetic and/or environmental factors AIDs is different from AIDS **Acquired Immunodeficiency Syndrome (AIDS)** - Caused by the Human Immunodeficiency Virus (HIV) **Autoimmune Hepatitis (AIH)** https://my.clevelandclinic.org/health/diseases/17867-autoimmune-hepatitis