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12/27/20131

AUTOIMMUNE DISEASES

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TABLE OF CONTENTS12/27/20132INTRODUCTIONMECHANISMS OF AUTOIMMUNITY: General principles, role of infections.GENERAL FEATURES OF AUTOIMMUNE DISEASES.DIFFERENT AUTOIMMUNE DISEASES AND THEIR MORPHOLOGYCONCLUSIONCLINICAL CORRELATESREFERENCES

INTRODUCTION12/27/20133Autoimmune diseases arise from an abnormal immune response of the body against substances and tissues normally present in the body (autoimmunity). This may be restricted to certain organs(autoimmune thyroiditis) or involve a particular tissue in different places.Immunological tolerance: Immunological tolerance is th phenomenon of unresponsiveness to an antigen as a result of exposure of lymphocyte to that antigen. Self tolerance refers to lack of responsiveness to an individuals own antigens, and it underlies our ability to live in harmony with our cells and tissues.

CONTD12/27/20134Immunological tolerance can be broadly classified into two groups; Central tolerance and Peripheral tolerance.Central tolerance: In this process, immature self reactive T and B lymphocyte clones that recognize self antigens during their maturation in the central (or generative) lymphoid organs (the thymus for T cells and the bone marrow for B cells) are killed or rendered harmless.Peripheral tolerance: Several mechanisms silence potentially autoreactive T and B cells in peripheral tissues, these are best defined for T cells

MECHANISMS OF AUTOIMMUNITY12/27/20135General principlesAutoimmunity arises from a combination of the inheritance of susceptibility genes, which may contribute to the breakdown of self-tolerance and environmental triggers, such as infections and tissue damage, which promote the activation of self-reactive lymphocytes.

Pathogenesis of autoimmunity12/27/20136

12/27/20137Role of infections Many autoimmune diseases are associated with infections, and clinical flare-ups are often preceded by infectious prodromes.

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GENERAL FEATURES OF AUTOIMMUNE DISEASES12/27/20139Diseases caused by autoimmunity have some important general features.

1.Once autoimmune disease have been induced it tends to be progressive, sometimes with sporadic relapses and remissions, and the damage becomes inexorable. Another reason for the persistence and progression of autoimmune disease is the phenomenon of epitome spreading.2.The clinical and pathologic manifestations of an autoimmune disease are determined by the nature of the underlying immune response.3.Different autoimmune diseases show substantial clinical, pathologic, and serologic overlaps.

DIFFERENT AUTOIMMUNE DISEASES AND THEIR CLINICO MORPHOLOGY12/27/201310Organs Specific autoimmune diseases Autoimmune hemolytic anemiaAutoimmune thrombocytopeniaMyasthenia gravisGraves disease Systemic autoimmune diseasesSystemic lupus Erythematosus(SLE)Diseases caused by autoimmunity or by reactions to microbial antigensPolyarteritis nodosaOthers: Type 1 diabetes mellitus, multiple sclerosis, Rheumatoid arthritis, Systemic sclerosis, Sjogren syndrome, crohn etc

SYSTEMIC LUPUS ERYTHEMATOSUS12/27/201311SLE is the prototype of a multisystem disease of autoimmune origin, characterised by a vast array of autoantibodies, particularly antinuclear antibodies (ANAs). Acute and insidious in its onset, it is a chronic, remitting and relapsing,often febrile illness characterised principally by injury to the skin, joints, kidney, and serosal membranes.Spectrum of Autoantibodies in SLE: The hallmark of the disease is the production of autoantibodies. Some antibodies recognize diverse nuclear and cytoplasmic components of the cell that are neither organ nor species specific and others are directed against the cell surface antigens of blood cells.

12/27/201312Revised criteria for classification of Systemic Lupus ErythematosusMD SOAP N HAIRM-malar rash D-discoid rashS-serositisO-oral ulcersA-arthritisP-photosensitivity N-neurologic disordersH-hematologic disordersA-antinuclear antibodiesI-immunological disordersR-renal disorder

Morphology12/27/201313The morphologic changes in SLE are extremely variable, as are the clinical manifestations and the course of disease. The constellation of clinical serologic, and morphologic changes are essential for diagnosis. The most xteristic lesions result from immune complexes depositing in blood vessels, kidneys, connective tissue, and skin. An acute necrotizing vasculitis involving capillaries, small arteries, arterioles may be present in any tissue. The arteritis is xterised by fibrinoid deposits in the vessel walls. In chronic stages, vessels undergo fibrous thickening with luminal narrowing.

MIcrospecimens12/27/201314

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Libman Sacks endocarditis of the mitral valve12/27/201316

Others: sjogren,12/27/201317

Systemic sclerosis12/27/201318

Systemic sclerosis12/27/201319

CONCLUSION12/27/201320AUTOIMMUNE DISEASES MAINLY AFFECTS WOMEN THAN MEN ESPECIALLY WOMEN OF CHILDBEARING AGE. ITS MAINLY CHARACTERISED BY THE DESTRUCTION OF ORGANS, TISSUES.ITS THE BODYS OWN IMMUNE SYSTEM CARRY OUT THE DESTRUCTIONITS LIFE THREATENING LIKE IN THE CASE OF SLE WHERE GLOMERULONEPHRITIS IS THE MAIN CAUSE OF DEATH.

REFERENCES12/27/201321PATHOLOGIC BASIS OF DISEASE BY ROBBINSWIKIPEDIA.