{"id":759,"date":"2022-07-17T17:36:00","date_gmt":"2022-07-17T11:51:00","guid":{"rendered":"https:\/\/immunologynotes.com\/?p=198"},"modified":"2022-09-20T02:00:32","modified_gmt":"2022-09-19T20:15:32","slug":"autoimmune-disease","status":"publish","type":"post","link":"https:\/\/microbenotes.com\/autoimmune-disease\/","title":{"rendered":"Autoimmune Disease- Definition, Types, and Examples"},"content":{"rendered":"\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_65 counter-hierarchy ez-toc-counter ez-toc-custom ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title \" >Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #0a0a0a;color:#0a0a0a\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #0a0a0a;color:#0a0a0a\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/microbenotes.com\/autoimmune-disease\/#what-is-an-autoimmune-disease\" title=\"What is an Autoimmune disease?\">What is an Autoimmune disease?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/microbenotes.com\/autoimmune-disease\/#hypersensitivity-reaction\" title=\"Hypersensitivity Reaction\">Hypersensitivity Reaction<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/microbenotes.com\/autoimmune-disease\/#organ-specific-and-systemic-autoimmune-diseases\" title=\"Organ-specific and systemic autoimmune diseases\">Organ-specific and systemic autoimmune diseases<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/microbenotes.com\/autoimmune-disease\/#self-antigen-auto-antigen\" title=\"Self-antigen \/&nbsp;Auto-antigen\">Self-antigen \/&nbsp;Auto-antigen<\/a><\/li><\/ul><\/nav><\/div>\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"what-is-an-autoimmune-disease\"><\/span><strong>What is an <span style=\"color: #000000;\">Autoimmune disease<\/span>?<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p><span style=\"color: #000000;\"> <strong><span style=\"color: #000000;\">Autoimmune disease<\/span><\/strong> occurs when a specific adaptive immune response is mounted against self-antigens<\/span>. The normal consequence of an adaptive immune response against a foreign antigen is the clearance of the antigen from the body. Virus-infected cells, for example, are destroyed by cytotoxic T cells, whereas soluble antigens are cleared by the formation of immune complexes of antibody and antigen, which are taken up by cells of the mononuclear phagocytic system such as macrophages. When an adaptive immune response develops against self-antigens<span style=\"color: #000000;\">, however, it is usually impossible for immune effector mechanisms to eliminate the antigen completely, and so a sustained response occurs. The consequence is that the effector pathways of immunity cause chronic inflammatory injury to tissues, which may prove lethal. The mechanisms of tissue damage in autoimmune diseases are essentially the same as those that operate in protective immunity and in hypersensitivity diseases.<\/span><\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter\"><img decoding=\"async\" src=\"https:\/\/microbenotes.com\/wp-content\/uploads\/2018\/04\/Autoimmune-Disease.jpg\" alt=\"Autoimmune Disease\" class=\"wp-image-199\"\/><\/figure><\/div>\n\n\n\n<p><span style=\"color: #000000;\"><\/span><\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"hypersensitivity-reaction\"><\/span><span style=\"color: #000000;\"><strong><a href=\"https:\/\/microbenotes.com\/hypersensitivity-introduction-causes-mechanism-and-types\/\" target=\"_blank\" rel=\"noreferrer noopener\">Hypersensitivity Reaction<\/a><\/strong><\/span><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p><span style=\"color: #000000;\">There are four types of hypersensitivity reaction mediated by immunological mechanisms that cause tissue damage. Types I-III are antibody-mediated and are distinguished by the different types of antigens recognized and the different classes of antibody involved. <\/span><\/p>\n\n\n\n<ul><li><span style=\"color: #000000;\"><strong>Type I<\/strong> responses are mediated by IgE, which induces mast-cell activation, whereas types II and III are mediated by IgG, which can engage Fc-receptor and complement-mediated effector mechanisms to varying degrees, depending on the subclass of IgG and the nature of the antigen involved. <\/span><\/li><li><span style=\"color: #000000;\"><strong>Type II<\/strong> responses are directed against cell-surface or matrix antigens.<\/span><\/li><li><span style=\"color: #000000;\"><strong>Type III<\/strong> responses are directed against soluble antigens, and the tissue damage involved is caused by responses triggered by immune complexes. <\/span><\/li><li><span style=\"color: #000000;\"><strong>Type IV<\/strong> hypersensitivity reactions are T cell-mediated and can be subdivided into three groups. In the first group, tissue damage is caused by the activation of macro-phages by TH1 cells, which results in an inflammatory response. In the second, damage is caused by the activation by TH2 cells of inflammatory responses in which eosinophils predominate; in the third, damage is caused directly by cytotoxic T cells (CTL).<\/span><\/li><\/ul>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter\"><img decoding=\"async\" src=\"https:\/\/microbenotes.com\/wp-content\/uploads\/2018\/04\/Autoimmune-Disease1-1024x767.jpg\" alt=\"Autoimmune Disease\" class=\"wp-image-200\"\/><\/figure><\/div>\n\n\n\n<p><span style=\"color: #000000;\"><\/span><\/p>\n\n\n\n<p><span style=\"color: #000000;\">Adaptive immune responses are initiated by the activation of antigen-specific T cells, and it is believed that autoimmunity is initiated in the same way. T-cell responses to self-antigens can inflict tissue damage either directly or indirectly. Cytotoxic T-cell responses and inappropriate activation of macrophages by TH1 cells can cause extensive tissue damage, whereas inappropriate T-cell help to self-reactive B cells can initiate harmful autoantibody responses. Autoimmune responses are a natural consequence of the open repertoires of both B-cell and T-cell receptors, which allow them to recognize any pathogen. Although these repertoires are purged of most receptors that bind with high affinity to self-antigens encountered during development, they still include receptors of lower affinity reactive to some self-antigens. It is not known what triggers autoimmunity, but both environmental and genetic factors, especially MHC genotype, are clearly important. Transient autoimmune responses are common, but it is only when they are sustained and cause lasting tissue damage that they attract medical attention.<\/span><\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter\"><img decoding=\"async\" src=\"https:\/\/microbenotes.com\/wp-content\/uploads\/2018\/04\/Autoimmune-Disease2.jpg\" alt=\"Autoimmune Disease\" class=\"wp-image-201\"\/><\/figure><\/div>\n\n\n\n<p><span style=\"color: #000000;\"><\/span><\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"organ-specific-and-systemic-autoimmune-diseases\"><\/span><span style=\"color: #000000;\"><strong>Organ-specific and systemic autoimmune diseases<\/strong><\/span><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p><span style=\"color: #000000;\">The classification of disease is an uncertain science, especially in the absence of a precise understanding of causative mechanisms. This is well illustrated by the difficulty in classifying autoimmune diseases. It is useful to distinguish two major patterns of autoimmune disease, the diseases in which the expression of autoimmunity is restricted to specific organs of the body, known as <strong>&#8216;organ-specific&#8217;<\/strong> autoimmune diseases, and those in which many tissues of the body are affected, the <strong>&#8216;systemic&#8217;<\/strong> autoimmune diseases. Examples of organ-specific autoimmune diseases are Hashimoto&#8217;s thyroiditis and Graves&#8217; disease, each predominantly affecting the thyroid gland, and type I insulin-dependent diabetes mellitus (IDDM), which affects the pancreatic islets. Examples of systemic autoimmune disease are systemic lupus erythematosus (SLE) and primary Sj\u00f6gren&#8217;s syndrome, in which tissues as diverse as the skin, kidneys, and brain may all be affected.<\/span><\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"self-antigen-auto-antigen\"><\/span><span style=\"color: #000000;\"><strong>Self-antigen \/&nbsp;Auto-antigen<\/strong><\/span><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p><span style=\"color: #000000;\">Tissue injury in autoimmune disease results because the self-antigen is an intrinsic component of the body and, consequently, the effector mechanisms of the immune system are directed at the body&#8217;s own tissues. Also, because the adaptive immune response is incapable of removing the offending autoantigen from the body, the immune response persists, and there is a constant supply of new autoantigen, which amplifies the response. An important exception to this rule is type I IDDM, in which the autoimmune response destroys the target organ completely. This leads to a failure to produce insulin one of the major autoantigens in this disease. Lack of insulin is in turn responsible for the phenotype of diabetes mellitus.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>What is an Autoimmune disease? Autoimmune disease occurs when a specific adaptive immune response is mounted against self-antigens. The normal consequence of an adaptive immune response against a foreign antigen &#8230; <a title=\"Autoimmune Disease- Definition, Types, and Examples\" class=\"read-more\" href=\"https:\/\/microbenotes.com\/autoimmune-disease\/\" aria-label=\"Read more about Autoimmune Disease- Definition, Types, and Examples\">Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":656,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1026],"tags":[1071,1072,1073,58,1188,1350,1449,1477],"custom":{"td_video":"","featured_image":"https:\/\/microbenotes.com\/wp-content\/uploads\/2018\/04\/Autoimmune-Disease.jpg","author":{"name":"Sagar Aryal","avatar":"https:\/\/secure.gravatar.com\/avatar\/862472ea06500d4318f1ad82addb608e?s=96&d=mm&r=g"},"categories":[{"term_id":1026,"name":"Immunology","slug":"immunology","term_group":0,"term_taxonomy_id":1026,"taxonomy":"category","description":"<strong>Immunology is an emerging branch of medical science that deals with studies related to different aspects of the immune system like the cells, structure, function, response against antigens, and disorders.<\/strong>\r\n<ul>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">The immune system consists of a collection of cells, chemicals, processes, and mechanisms that function to protect the body from foreign antigens, such as microbes (organisms such as bacteria, fungi, and parasites), viruses, cancer cells, and toxins.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Beyond, the structural and chemical barriers which protect us from infection, the immune system consists of two lines of defense; innate immunity and adaptive immunity.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">The innate immunity represents the first line of defense against the antigen, and it is an antigen-independent defense mechanism used by the host immediately or within hours of encountering an antigen.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">On the other hand, adaptive immunity is antigen-dependent and antigen-specific and, therefore, includes a lag time between exposure to the antigen and maximal response.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Studies conducted in immunology are related to the measurement of physiological functioning of the immune system in both healthy and disease conditions, malfunctioning of the system in the case of disorders, and physical, chemical, and physiological characteristics of the cells of the immune system.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Immunology is fast becoming an important branch of clinical medicine as it has a close relationship with organ transplantation, oncology, virology, bacteriology, and even dermatology.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Immunology is focused on certain organs of the body like the bone marrow and the lymphatic system and the white blood cells found in the blood.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">These cells or organs producing these cells are responsible, directly or indirectly, for the defense mechanism of the body against a pathogenic agent or other antigens.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">These cells keep on circulating throughout the body via blood or lymph so that they can detect antigens entering the body from different sources.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">An important aspect of immunology is immunotherapy, where components of the immune system or antigens are used to treat a disease or disorder as a form of treatment.<\/span><\/li>\r\n<\/ul>","parent":0,"count":115,"filter":"raw","cat_ID":1026,"category_count":115,"category_description":"<strong>Immunology is an emerging branch of medical science that deals with studies related to different aspects of the immune system like the cells, structure, function, response against antigens, and disorders.<\/strong>\r\n<ul>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">The immune system consists of a collection of cells, chemicals, processes, and mechanisms that function to protect the body from foreign antigens, such as microbes (organisms such as bacteria, fungi, and parasites), viruses, cancer cells, and toxins.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Beyond, the structural and chemical barriers which protect us from infection, the immune system consists of two lines of defense; innate immunity and adaptive immunity.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">The innate immunity represents the first line of defense against the antigen, and it is an antigen-independent defense mechanism used by the host immediately or within hours of encountering an antigen.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">On the other hand, adaptive immunity is antigen-dependent and antigen-specific and, therefore, includes a lag time between exposure to the antigen and maximal response.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Studies conducted in immunology are related to the measurement of physiological functioning of the immune system in both healthy and disease conditions, malfunctioning of the system in the case of disorders, and physical, chemical, and physiological characteristics of the cells of the immune system.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Immunology is fast becoming an important branch of clinical medicine as it has a close relationship with organ transplantation, oncology, virology, bacteriology, and even dermatology.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Immunology is focused on certain organs of the body like the bone marrow and the lymphatic system and the white blood cells found in the blood.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">These cells or organs producing these cells are responsible, directly or indirectly, for the defense mechanism of the body against a pathogenic agent or other antigens.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">These cells keep on circulating throughout the body via blood or lymph so that they can detect antigens entering the body from different sources.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">An important aspect of immunology is immunotherapy, where components of the immune system or antigens are used to treat a disease or disorder as a form of treatment.<\/span><\/li>\r\n<\/ul>","cat_name":"Immunology","category_nicename":"immunology","category_parent":0}]},"_links":{"self":[{"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/posts\/759"}],"collection":[{"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/comments?post=759"}],"version-history":[{"count":0,"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/posts\/759\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/media\/656"}],"wp:attachment":[{"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/media?parent=759"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/categories?post=759"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/tags?post=759"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}