Tolerance and Autoimmune Disorders

The ability of the immune system to specifically avoid attacking the body's own cells and tissues.

A type of tolerance that eliminates self-reactive lymphocytes within the thymus or bone marrow, preventing them from entering the bloodstream.

A type of tolerance that operates in peripheral tissues, suppressing or neutralizing any remaining self-reactive lymphocytes that escaped central tolerance.

A mechanism of peripheral tolerance that renders self-reactive lymphocytes functionally inactive, preventing them from attacking self tissues.

A type of immune cell that suppresses the activity of other lymphocytes, crucial for preventing autoimmune reactions.

Self-reactive lymphocytes that are eliminated through cell death (apoptosis), a mechanism of peripheral tolerance.

A mechanism where certain tissues physically isolate their antigens from the immune system, preventing recognition and attack.

A group of diseases that occur when the immune system mistakenly targets and attacks the body's own tissues, causing inflammation and damage.

A key component of the immune system that ensures it functions correctly, preventing the development of autoimmune diseases.

Genes that increase the susceptibility to developing autoimmune disorders due to their role in regulating immune responses.

T cell anergy is a state where T cells become unresponsive to their specific antigen. This can be broken by upregulating costimulatory molecules on antigen-presenting cells (APCs), leading to T cell activation.

A failure of T cell mediated suppression, as seen in AIDS, can lead to autoimmune disease. This occurs because the body loses the ability to control its immune response properly.

Molecular mimicry occurs when a microbe shares an amino acid sequence with a self-antigen. The immune response against the microbe can cross-react with the self-antigen, causing tissue damage.

Rheumatic heart disease is an example of molecular mimicry. Antibodies against streptococcal proteins cross-react with heart proteins, causing myocarditis. This is an autoimmune reaction.

Polyclonal B cell activation can be triggered by various microorganisms (like EBV). Some of these activated B cells may be autoreactive, leading to autoimmune disease.

Trauma or inflammation can release sequestered self-antigens (like lens proteins of the eye or sperm), exposing hidden epitopes and triggering autoimmune reactions.

Certain genetic predispositions, such as those involving HLA alleles, can increase susceptibility to autoimmune diseases.

Ankylosing spondylitis is strongly associated with the HLA-B27 allele. Individuals with this allele have a greatly increased risk of developing the disease.

Genetic defects in apoptotic pathways can contribute to the development of autoimmune diseases. This is because faulty apoptosis can allow self-reactive lymphocytes to survive and attack.

Viral infections can contribute to autoimmune diseases by modifying self-antigens, sharing similar epitopes (molecular mimicry), or inducing inflammation that exposes hidden antigens.

A type of autoimmune disease that targets specific organs or tissues, like the thyroid gland or pancreas.

A type of autoimmune disease that affects various organs and tissues throughout the body.

A type of autoimmune reaction where antibodies bind to and destroy specific cells, like red blood cells in autoimmune hemolytic anemia.

A type of autoimmune reaction where immune complexes, formed by antibodies and antigens, deposit in tissues, causing inflammation.

Antibodies that bind to and block receptors on cells, interfering with their function. Example: Myasthenia gravis where antibodies block acetylcholine receptors on muscle cells.

A type of autoimmune disease where the immune system attacks thyroid tissue, causing either hyperthyroidism (Grave's disease) or hypothyroidism (Hashimoto's thyroiditis).

An autoimmune disease that destroys insulin-producing cells in the pancreas, leading to insulin deficiency and diabetes.

An autoimmune disease affecting the neuromuscular junction, where antibodies block acetylcholine receptors on muscle cells, leading to muscle weakness and fatigue.

A systemic autoimmune disease characterized by inflammation and damage to multiple organs, including joints, skin, kidneys, and heart.