This document discusses autoimmune diseases, including their mechanisms, features, and different types. It begins with an introduction to autoimmunity and immunological tolerance. It then covers the general mechanisms of autoimmunity, including genetic and environmental triggers. The key features of autoimmune diseases are progressive damage, clinical/pathological manifestations tied to the immune response, and clinical overlaps between diseases. Specific diseases discussed include systemic lupus erythematosus, its diagnostic criteria and morphology, and other systemic diseases like Sjogren's syndrome and systemic sclerosis.

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2. TABLE OF CONTENTS
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 INTRODUCTION
 MECHANISMS OF AUTOIMMUNITY: General
principles, role of infections.
 GENERAL FEATURES OF AUTOIMMUNE
DISEASES.
 DIFFERENT AUTOIMMUNE DISEASES AND
THEIR MORPHOLOGY
 CONCLUSION
 CLINICAL CORRELATES
 REFERENCES

3. INTRODUCTION
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 Autoimmune 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.

4. CONT’D
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 Immunological 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

5. MECHANISMS OF
AUTOIMMUNITY
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 General principles
 Autoimmunity 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.

6. Pathogenesis of autoimmunity
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 Role of infections Many autoimmune diseases
are associated with infections, and clinical flare-
ups are often preceded by infectious prodromes.

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9. GENERAL FEATURES OF
AUTOIMMUNE DISEASES
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 Diseases 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.

10. DIFFERENT AUTOIMMUNE
DISEASES AND THEIR CLINICO
MORPHOLOGY
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 Organs Specific autoimmune diseases
Autoimmune hemolytic anemia
Autoimmune thrombocytopenia
Myasthenia gravis
Graves disease
Systemic autoimmune diseases
Systemic lupus Erythematosus(SLE)
Diseases caused by autoimmunity or by reactions to
microbial antigens
Polyarteritis nodosa
Others: Type 1 diabetes mellitus, multiple sclerosis,
Rheumatoid arthritis, Systemic sclerosis, Sjogren
syndrome, crohn etc…

11. SYSTEMIC LUPUS
ERYTHEMATOSUS
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 SLE 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

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 Revised criteria for classification of Systemic Lupus
Erythematosus
 MD SOAP N HAIR
 M-malar rash
 D-discoid rash
 S-serositis
 O-oral ulcers
 A-arthritis
 P-photosensitivity
 N-neurologic disorders
 H-hematologic disorders
 A-antinuclear antibodies
 I-immunological disorders
 R-renal disorder

13. Morphology
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 The 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.

14. MIcrospecimens
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16. Libman Sacks endocarditis of the
mitral valve
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17. Others: sjogren,
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18. Systemic sclerosis
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19. Systemic sclerosis
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20. CONCLUSION
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 AUTOIMMUNE 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 DESTRUCTION…
 ITS LIFE THREATENING LIKE IN THE CASE
OF SLE WHERE GLOMERULONEPHRITIS IS
THE MAIN CAUSE OF DEATH.

21. REFERENCES
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 PATHOLOGIC BASIS OF DISEASE BY
ROBBINS
 WIKIPEDIA.