ch 20 Tolerance and Autoimmunity

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Questions and Answers

What is the term used to describe the failure of the host's immune systems to distinguish self from non-self?

Humoral immune system

Horror Autotoxicus (correct)

Cellular immune system

Autoimmunity

What can be the result of autoimmunity?

Increased immune response

Tissue and organ damage (correct)

Enhanced self-recognition

Improved host defense

What does autoimmunity refer to?

Failure of the immune system against non-self components

Enhanced host defense mechanisms

Self-recognition by the immune system

Inappropriate response of the immune system against self-components (correct)

Which of the following is the primary mechanism for deleting T or B clones before maturity if they have receptors that recognize self-antigens with great affinity?

Central tolerance Signup and view all the answers

Where does peripheral tolerance kill lymphocytes?

Secondary lymphoid tissue Signup and view all the answers

What regulates the life span of lymphocytes?

Apoptosis regulation Signup and view all the answers

Which mechanism exists to protect individuals from self-reactive lymphocytes by killing lymphocytes in the secondary lymphoid tissue?

Peripheral tolerance Signup and view all the answers

Central tolerance is a primary mechanism that deletes T or B clones before maturity if they have receptors that recognize self-antigens with great affinity.

True Signup and view all the answers

Peripheral tolerance kills lymphocytes in primary lymphoid tissue.

False Signup and view all the answers

The life span of lymphocytes is regulated by mitosis.

False Signup and view all the answers

What is the main function of T Recognize cells in inducing peripheral tolerance?

Recognize and suppress immune response against self-antigens Signup and view all the answers

How do T reg cells contribute to peripheral tolerance?

Induce cell death in some immune cells Signup and view all the answers

Which type of antigens can produce tolerance and are not considered immunogens?

Tolerogens Signup and view all the answers

Which of the following is correct promotes tolerance rather than stimulation of the immune system by a given antigen?

All of the above Signup and view all the answers

What is the term used to describe unresponsiveness to antigenic stimulus due to apoptotic cell death?

Clonal anergy Signup and view all the answers

What type of antigens are ignored by the immune system, resulting in clonal ignorance?

Self antigens Signup and view all the answers

Whaich of the following is correct Auto or Self antigens?

Both a and b Signup and view all the answers

What can alter one's own cells to become non-self antigens?

Action of bacteria, viruses, chemicals, or drugs Signup and view all the answers

Which of the following is TRUE an Auto antibody?

Both a and b Signup and view all the answers

Which of the following is correct Auto Immunity?

All of the above Signup and view all the answers

Which of the following is correct cause of tissue injury in autoimmune diseases?

A+B Signup and view all the answers

How does the immune system normally respond to self-cells?

The immune system not attacks self-cells. Signup and view all the answers

In autoimmune diseases, the immune system attacks:

Both specific tissues and a large number of tissues. Signup and view all the answers

Which of the following statements about autoimmune diseases is true?

Autoimmune diseases can be caused by humoral or cell mediated immune responses. Signup and view all the answers

Which of the following is correct cause of autoimmune diseases?

All of the above Signup and view all the answers

In which autoimmune disease are high levels of both class I and class II MHC molecules expressed by pancreatic beta cells?

Insulin-dependent diabetes mellitus (IDDM) Signup and view all the answers

Which tissue can induce auto-antibody formation in some men after a vasectomy?

Eye lens protein Signup and view all the answers

Which autoimmune disease is characterized by the expression of Class II MHC molecules on the membranes of thyroid acinar cells?

Graves' disease Signup and view all the answers

What can induce nonspecific polyclonal B-cell activation?

Gram-negative bacteria Signup and view all the answers

Which genes show the strongest associations with autoimmunity?

HLA genes, especially class II HLA genes Signup and view all the answers

Which of the following is correct relase of sequestered Antigen ?

All of the above Signup and view all the answers

Genetic factors, especially HLA genes, are strongly associated with autoimmunity.

True Signup and view all the answers

Which of the following correct Classification of Autoimmune Diseases Broadly classified ?

All of the above Signup and view all the answers

Which type of blood components can be targeted by autoantibodies in haemolytic autoimmune diseases?

RBCs, Platelets or Leucocytes Signup and view all the answers

What causes the lysis of red blood cells in autoimmune hemolytic anemia?

Production of autoantibodies against the RBC-antigens. Signup and view all the answers

Which form of autoimmune anemia is drug-induced?

Hemolytic anemia caused by certain medications like Penicillin or Anti-hypertensive agents like methyldopa Signup and view all the answers

What is the characteristic half-life of RBCs of haemolytic autoimmune diseases?

120 days Signup and view all the answers

Haemolytic autoimmune diseases are caused by destruction of blood components by autoantibodies.

True Signup and view all the answers

The immunodiagnostic test for autoimmune hemolytic anemias generally involves a Coombs test.

True Signup and view all the answers

Which autoimmune disease attacks the myelin coating of nerve axons?

Multiple sclerosis Signup and view all the answers

What is the specific target of Myasthenia gravis?

Nerve-muscle junction Signup and view all the answers

Which autoimmune disease attacks the insulin-producing cells?

Juvenile diabetes Signup and view all the answers

Which autoimmune disease attacks the Thyroid?

Thyroiditis Signup and view all the answers

What is Hashimoto's thyroiditis?

An autoimmune condition where an individual produces antibodies and sensitized TH1 cells specific for thyroid antigens. Signup and view all the answers

What is the physiological response to hypothyroidism in Hashimoto's thyroiditis?

Visible enlargement of the thyroid gland Signup and view all the answers

Which of the following is primary targets of antibodies formed in Hashimoto's thyroiditis?

Thyroglobulin and thyroid peroxidase Signup and view all the answers

All of the following is correct characteristic is most frequently observed in individuals with Hashimoto’s thyroiditis except?

High expression of MHC molecules in pancreatic beta cells Signup and view all the answers

What is the primary cause of insulin-dependent diabetes mellitus (IDDM)?

Autoimmune attack on the pancreas Signup and view all the answers

What is the specific target of the autoimmune attack in insulin-dependent diabetes mellitus?

Beta cells of the islets of Langerhans Signup and view all the answers

What is the consequence of the autoimmune attack in insulin-dependent diabetes mellitus?

Destroyed beta cells leading to decreased insulin production Signup and view all the answers

What is the physiological effect of decreased insulin production in insulin-dependent diabetes mellitus?

Elevated levels of glucose in the bloodstream Signup and view all the answers

What is insulin-dependent diabetes mellitus (IDDM) caused by?

An autoimmune attack on the pancreas Signup and view all the answers

What regulates the production of thyroid hormones?

Thyroid-stimulating hormone (TSH) Signup and view all the answers

What is the role of autoantibodies in Graves' disease?

They bind the receptor for TSH and mimic the normal action of TSH Signup and view all the answers

Which of the following is consequence of unregulated autoantibodies in Graves' disease?

Stimulation of thyroid and development of hyperthyroidism Signup and view all the answers

Which of the following is Correct the primary cause of Myasthenia Gravis?

Autoantibody against muscle antigen that binds acetylcholine receptor antigen Signup and view all the answers

Which of the following is the characteristic feature of Myasthenia Gravis?

Progressive muscular weakness Signup and view all the answers

Which of the following is Correct the consequence of Myasthenia Gravis on the neuromuscular junction?

Severe impairment of the neuromuscular junction Signup and view all the answers

Which of the following is Correct the eventual cause of death in Myasthenia Gravis?

Respiratory failure Signup and view all the answers

What are the early signs of Myasthenia Gravis?

Drooping eyelids and inability to retract the corners of the mouth Signup and view all the answers

How does a person with Myasthenia Gravis appear?

Snarling Signup and view all the answers

Which autoimmune disease can harm the kidneys, heart, brain, lungs, and skin?

Systemic Lupus Erythematosus Signup and view all the answers

What is the cause of Rheumatic fever?

A+C Signup and view all the answers

Which of the following is Correct characteristic feature is OBSERVED in Systemic Lupus Erythematous (SLE)?

Blood red spots over the bridge of nose & cheeks Signup and view all the answers

In Systemic Lupus Erythematous (SLE), which type of reaction develops when immune complexes of auto-antibodies are deposited along the walls of small blood vessels?

Type III hypersensitive reaction Signup and view all the answers

What is the main consequence of immune complexes in Systemic Lupus Erythematous (SLE) activating the complement system and damaging the walls of blood vessels?

Vasculitis and glomerulonephritis Signup and view all the answers

Which tissue antigens are affected in Systemic Lupus Erythematous (SLE)?

DNA, histones, RBCs, platelets, leukocytes, and clotting factors Signup and view all the answers

Systemic Lupus Erythematous (SLE) is characterized by fever, weakness, arthritis, skin rashes, pleurisy, and kidney dysfunction.

True Signup and view all the answers

In SLE, the immune complexes activate the complement system and generate membrane-attack complexes that damage the walls of the blood vessels.

True Signup and view all the answers

What is the primary target of the autoimmune attack in Multiple Sclerosis (MS)?

Myelin coating of nerve axons Signup and view all the answers

Which of the following is Correct the characteristic feature of Myasthenia Gravis?

Neuromuscular junction dysfunction Signup and view all the answers

What disease causes inflammation along the myelin sheath of nerve fibers, leading to various neurological dysfunctions?

Multiple Sclerosis (MS) Signup and view all the answers

Which of the following is Correct severe symptoms of Multiple Sclerosis (MS)?

Paralysis and loss of vision Signup and view all the answers

Which of the following is correct Mild symptoms of Multiple Sclerosis (MS)?

numbness in the limbs Signup and view all the answers

All of the following is FALSE characteristics of rheumatoid arthritis except?

Increased number of T-cells and macrophages in synovial fluid, and inflammatory changes in the synovial membrane Signup and view all the answers

What is the primary cause of tissue injury in rheumatoid arthritis?

Deposition of IgM-IgG complexes in the joints Signup and view all the answers

Rheumatoid Arthritis is a systemic disease of the joints.

True Signup and view all the answers

Rheumatoid factors in individuals with rheumatoid arthritis are reactive with determinants in the Fc region of IgG.

True Signup and view all the answers

The synovial fluid of patients with rheumatoid arthritis contains increased numbers of T-cells and macrophages.

True Signup and view all the answers

Rheumatoid Arthritis is characterized by atrophy of bones.

True Signup and view all the answers

Which of the following is correct auto immune diseases diagnosed?

By identifying autoantibodies in the serum Signup and view all the answers

Which of the following is Correct used to demonstrate autoantibodies?

Immunofluorescent antibody test Signup and view all the answers

Which of the following is Correct used to demonstrate Autoantibodies ?

All of the above Signup and view all the answers

Which of the following is examples of broad-spectrum immunosuppressive treatments?

Corticosteroids, azathioprine, cyclophosphamide, methotrexate Signup and view all the answers

How do broad-spectrum immunosuppressive treatments work?

Both a and b Signup and view all the answers

Which mediator, playing a role in autoimmune inflammatory processes, is widely used to treat rheumatoid arthritis, psoriasis, and Crohn’s disease?

TNF-α (adalimumab) Signup and view all the answers

Which therapy is a monoclonal antibody against the B cell-specific antigen CD20 that provides short-term benefit for patients with RA?

Rituximab Signup and view all the answers

What is the specific treatment for rheumatoid arthritis?

Anti-inflammatory drugs Signup and view all the answers

Which medication is used to treat Myasthenia Gravis?

Choline esterase inhibitors Signup and view all the answers

What type of drugs are used to treat Thyrotoxicosis?

Antithyroid drugs Signup and view all the answers

Which medication is used to treat Lupus Erythematous?

Immunosuppressive drugs Signup and view all the answers

Autoimmune diseases primarily affect men more than women.

False Signup and view all the answers

Hemolytic anemia: Treated with VitB12

True Signup and view all the answers

Lupus Erythematous : Treated with immunosuppressive or antimitotic drugs such as Corticosteroid, Cyclophosphamide and azathioprine.

True Signup and view all the answers

True or False: Autoimmune diseases can only be diagnosed based on clinical symptoms.

False Signup and view all the answers

What happens to the red cells if IgG auto-antibodies are present?

They become agglutinated by the antiserum Signup and view all the answers

How does the interference of auto-antibodies with iodine uptake affect the production of thyroid hormones?

It decreases the production of thyroid hormones Signup and view all the answers

What happens when immune complexes accumulate in tissues?

A+B Signup and view all the answers

Study Notes

Immune System and Autoimmunity

Autoimmunity refers to the failure of the host's immune system to distinguish self from non-self, resulting in an immune response against the body's own cells, tissues, and organs.
Autoimmune diseases occur when the immune system mistakenly attacks and damages its own cells, tissues, and organs.

Central Tolerance

Central tolerance is a primary mechanism that deletes T or B clones before maturity if they have receptors that recognize self-antigens with great affinity.
This process occurs in the thymus for T cells and bone marrow for B cells.

Peripheral Tolerance

Peripheral tolerance kills lymphocytes in secondary lymphoid tissues, preventing an immune response against self-antigens.
T regulatory cells (Tregs) contribute to peripheral tolerance by killing lymphocytes in secondary lymphoid tissues.

Autoimmune Diseases

Autoimmune diseases are caused by the immune system attacking the body's own cells, tissues, and organs.
Examples of autoimmune diseases include rheumatoid arthritis, lupus, multiple sclerosis, type 1 diabetes, and Hashimoto's thyroiditis.

Causes of Autoimmune Diseases

Genetic factors, especially HLA genes, are strongly associated with autoimmunity.
Environmental triggers, such as infections, can also contribute to the development of autoimmune diseases.

Effects of Autoimmune Diseases

Autoimmune diseases can cause tissue injury and organ damage, leading to various symptoms and complications.
Examples of tissue injury and organ damage include joint inflammation in rheumatoid arthritis, demyelination in multiple sclerosis, and thyroid inflammation in Hashimoto's thyroiditis.

Diagnosis and Treatment of Autoimmune Diseases

Autoimmune diseases are diagnosed based on a combination of clinical symptoms, laboratory tests, and imaging studies.
Treatment of autoimmune diseases involves managing symptoms, suppressing the immune system, and replacing damaged cells and tissues.

Examples of Autoimmune Diseases

Rheumatoid arthritis: An autoimmune disease that attacks the lining of the joints, leading to inflammation and pain.
Lupus: An autoimmune disease that can affect various organs, including the skin, joints, kidneys, and nervous system.
Multiple sclerosis: An autoimmune disease that attacks the myelin coating of nerve axons, leading to neurological symptoms.
Hashimoto's thyroiditis: An autoimmune disease that attacks the thyroid gland, leading to hypothyroidism.
Type 1 diabetes: An autoimmune disease that attacks the insulin-producing cells in the pancreas, leading to insulin deficiency.

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Description

Explore the concepts of tolerance and autoimmunity and their impact on the immune system. Learn about horror autotoxicus and the consequences of autoimmunity, including tissue and organ damage.