COPY: Tolerance and Autoimmune Disorders

Type II and Type III hypersensitivity reactions.

Autoimmune diseases are chronic and progressive, characterized by relapses and remissions.

Age, hormones, and environmental factors can influence symptoms.

<p>Grave's disease or Hashimoto thyroiditis.</p> Signup and view all the answers

<p>Systemic lupus erythematosus, which affects multiple organs throughout the body.</p> Signup and view all the answers

<p>Clinical manifestations are overlapping and affect classification, complicating accurate diagnosis.</p> Signup and view all the answers

<p>Autoreceptor antibodies can interfere with normal cellular functions, as seen in Myasthenia gravis.</p> Signup and view all the answers

<p>An individual may have more than one autoimmune disease simultaneously.</p> Signup and view all the answers

<p>Blood vessels, connective tissues, joints, muscles, skin, and endocrine glands.</p> Signup and view all the answers

<p>Organ-specific diseases target individual organs, while systemic diseases affect multiple body systems.</p> Signup and view all the answers

<p>The upregulation of costimulatory molecules on antigen-presenting cells (APCs) causes the breakdown of T cell anergy and activates T cells.</p> Signup and view all the answers

<p>Molecular mimicry occurs when a microbe shares an amino acid sequence with a self-antigen, leading to cross-reactive immunological reactions that target self-antigens.</p> Signup and view all the answers

<p>Polyclonal B cell activation can lead to the stimulation of autoreactive lymphocytes, promoting the development of autoimmune diseases.</p> Signup and view all the answers

<p>Defective regulatory T-cell development can fail to maintain peripheral and central tolerance, increasing susceptibility to autoimmunity.</p> Signup and view all the answers

<p>Release of sequestered self antigens exposes hidden epitopes, often due to tissue trauma or inflammation, triggering immune responses.</p> Signup and view all the answers

<p>Certain HLA alleles, like HLA-B27, are strongly associated with increased incidences of autoimmune diseases such as ankylosing spondylitis.</p> Signup and view all the answers

<p>Infections may cause autoimmune diseases by modifying self-antigens, leading to cross-reaction, and inducing necrosis and inflammation.</p> Signup and view all the answers

<p>A familial increase in certain autoimmune diseases, such as systemic lupus erythematosus (SLE), indicates a genetic predisposition to autoimmunity.</p> Signup and view all the answers

<p>Failure of T cell-mediated suppression can lead to increased immune activation and the potential development of autoimmune conditions.</p> Signup and view all the answers

<p>The complex, multigenic patterns suggest that autoimmune diseases cannot be attributed to single gene mutations but rather interactively involve multiple genetic defects.</p> Signup and view all the answers

<p>Immunologic tolerance is the inability of the immune system to respond to a specific antigen, crucial for preventing autoimmune reactions against self-antigens.</p> Signup and view all the answers

<p>Central tolerance involves clonal deletion of autoreactive lymphocytes in the thymus or bone marrow, while peripheral tolerance addresses autoreactive cells that escape central tolerance through mechanisms like anergy and suppression by regulatory T cells.</p> Signup and view all the answers

<p>Regulatory T cells inhibit lymphocyte activation and effector mechanisms through the secretion of cytokines like IL-10, contributing to peripheral tolerance.</p> Signup and view all the answers

<p>Antigen sequestration involves certain tissues hiding their antigens behind blood-tissue barriers, preventing autoreactive lymphocytes from interacting with them.</p> Signup and view all the answers

<p>The failure of self-tolerance in autoimmune diseases can result from inherited susceptibility genes and environmental triggers such as infections.</p> Signup and view all the answers

<p>Clonal deletion involves the apoptosis of autoreactive T and B lymphocytes during their development in the thymus or bone marrow.</p> Signup and view all the answers

<p>Anergy refers to the irreversible functional inactivation of autoreactive cells that escape central tolerance, preventing them from mounting an immune response.</p> Signup and view all the answers

<p>Mutations in apoptosis genes can lead to inadequate deletion of autoreactive lymphocytes, resulting in autoimmune lymphoproliferative disorders.</p> Signup and view all the answers

<p>Environmental factors, like infections, can interact with genetic susceptibility genes, leading to the breakdown of self-tolerance and subsequent autoimmune reactions.</p> Signup and view all the answers

<p>Disturbances in immunologic tolerance can lead to various autoimmune diseases, including rheumatoid arthritis, lupus, and type 1 diabetes.</p> Signup and view all the answers