Hypersensitivity Disorders

Questions and Answers

Which cells are primarily involved in Antibody-Dependent Cellular Toxicity (ADCC)?

T lymphocytes

B lymphocytes

Natural killer cells and macrophages (correct)

Dendritic cells

What is a key mechanism by which Antibody-Dependent Cellular Toxicity operates?

Complement activation

Lysis of cells coated with IgG antibodies (correct)

Phagocytosis of the target cell

Cytokine release by T cells

What complication occurs when an Rh (-) mother carries an Rh (+) infant?

Erythroblastosis Fetalis (correct)

Transfusion reaction

Autoimmune Hemolytic Anemia

Autoimmune Thrombocytopenic Purpura

In which condition does the mother develop IgG anti-Rh antibodies?

Erythroblastosis Fetalis Signup and view all the answers

Which of the following is a result of Antibody-Dependent Cellular Toxicity?

Destruction of cells coated with IgG antibodies Signup and view all the answers

What is a common clinical manifestation of Erythroblastosis Fetalis?

Jaundiced newborn Signup and view all the answers

Which disorder is characterized by the destruction of fetal red blood cells by maternal antibodies?

Erythroblastosis Fetalis Signup and view all the answers

Which of the following is NOT a condition associated with antibody-mediated cell destruction?

Myasthenia Gravis Signup and view all the answers

What effect does the antibody have in conditions like Myasthenia Gravis?

Inhibits Ach receptor binding Signup and view all the answers

What characterizes Grave’s disease?

Antibody-mediated stimulation of TSH receptors Signup and view all the answers

What is an example of localized immune complex disease described in the content?

Arthus reaction Signup and view all the answers

What leads to the dermal inflammatory reaction associated with immune complex diseases?

Small immune complexes deposited in tissues Signup and view all the answers

What does Type III hypersensitivity primarily involve?

Immune complex formation Signup and view all the answers

How did the Arthus reaction come to be recognized?

By injecting rabbits with horse serum Signup and view all the answers

What can happen with repeated injections of a foreign antigen in the context of immune complex diseases?

Formation of localized immune complexes Signup and view all the answers

What is the consequence of immune complexes not being removed promptly?

Tissue inflammation and disease Signup and view all the answers

What is a characteristic feature of immune complexes that leads to chronic inflammatory responses?

Small size Signup and view all the answers

What was a result of Nicholas Maurice Arthus's injections during his experiments?

Gangrene after repeated injections Signup and view all the answers

What conditions should you expect 4-10 days after someone receives a foreign serum vaccine for diphtheria?

Arthritis and skin rash Signup and view all the answers

How was serum sickness first recognized?

As a sequela after administration of large amounts of foreign serum Signup and view all the answers

What is the main factor that influences whether immune complex formation leads to tissue deposition and disease?

The factors determining tissue deposition are not fully understood Signup and view all the answers

What phase characterizes the immune complex formation in serum sickness?

Immune complex formation phase Signup and view all the answers

Which of the following symptoms is associated with serum sickness?

Rash and fever Signup and view all the answers

What was the source of serum used in the early vaccinations for diphtheria that led to serum sickness?

Serum from immunized horses Signup and view all the answers

What type of disease is serum sickness classified as?

Systemic immune complex disease Signup and view all the answers

Which symptom would least likely be associated with serum sickness?

Abdominal pain Signup and view all the answers

What is the timeline for the presentation of symptoms after serum administration?

4-10 days Signup and view all the answers

What is NOT typically observed in individuals suffering from serum sickness?

Chronic fatigue syndrome Signup and view all the answers

What type of lymphocytes are primarily involved in recognizing protein antigens in multiple sclerosis?

Cytotoxic lymphocytes Signup and view all the answers

Which antigen is specifically associated with myelin basic protein in the context of multiple sclerosis?

Protein antigens Signup and view all the answers

Which mechanism is used by cytotoxic lymphocytes for directional delivery of cytotoxic components?

Perforins and granzymes Signup and view all the answers

What is the result of Fas-Fas ligand interaction in the context of T-cell activity?

Cellular apoptosis Signup and view all the answers

Which inflammatory condition is linked with the presence of CD4+ T-cells?

Multiple sclerosis Signup and view all the answers

What substances do neutrophils release in response to immune complexes?

Prostaglandins Signup and view all the answers

What happens at the site of immune complex deposition during inflammation?

Tissue damage occurs Signup and view all the answers

Which clinical feature is NOT typically associated with systemic lupus erythematosus (SLE)?

Jaundice Signup and view all the answers

In autoimmune conditions like SLE, antibodies are primarily formed against which of the following?

Double-stranded DNA Signup and view all the answers

Where do antigen-antibody complexes predominantly deposit in cases of SLE?

Kidneys, skin, and joints Signup and view all the answers

What is one of the clinical symptoms indicating kidney involvement in SLE?

Proteinuria Signup and view all the answers

During which phase of the immune response do clinical symptoms like fever and rashes manifest?

Phase 3: Tissue injury and inflammation Signup and view all the answers

What type of inflammation is primarily associated with the deposition of immune complexes?

Acute inflammation Signup and view all the answers

Which condition is specifically mentioned as an example linked with immune complex deposition?

Systemic lupus erythematosus Signup and view all the answers

Which symptom is specifically related to systemic lupus erythematosus rather than general inflammation?

Rash Signup and view all the answers

What is the role of leukotrienes in the respiratory system?

They induce bronchial smooth muscle contraction leading to difficulty in breathing. Signup and view all the answers

Which of the following outcomes is directly related to the action of prostaglandin D2?

Induction of bronchospasm and increased mucus secretion. Signup and view all the answers

What condition can result from increased vascular permeability during inflammatory responses?

Urticaria or hives. Signup and view all the answers

What does class switching in B cells refer to?

The ability of B cells to change the type of antibody they produce. Signup and view all the answers

What is one consequence of increased fluid leakage into the interstitium due to vasodilation?

Formation of edema and swelling. Signup and view all the answers

Which of the following is NOT a typical action associated with leukotrienes in hypersensitivity reactions?

Decreased mucus production. Signup and view all the answers

What physiological effect results from the contraction of bronchial smooth muscles?

Difficulty of breathing due to narrowed airways. Signup and view all the answers

What primary symptom may arise from the interaction of prostaglandin D2 in the context of respiratory reactions?

Intense bronchospasm. Signup and view all the answers

What is the primary pathological effect of immune complex deposition in tissues?

Attraction of neutrophils and macrophages Signup and view all the answers

In the context of serum sickness, what is the typical timeline for symptom onset after exposure to foreign serum?

4-10 days Signup and view all the answers

Which of the following conditions is classified as a type of immune complex disease?

Systemic lupus erythematosus (SLE) Signup and view all the answers

What is primarily responsible for the inflammatory lesions seen in glomerulonephritis related to immune complex deposition?

Complement activation Signup and view all the answers

Which of the following is NOT a common site for the deposition of immune complexes?

Nervous system Signup and view all the answers

What directs the production of IgE antibodies in Type I hypersensitivity reactions?

Induction of Th2 cells Signup and view all the answers

Which process describes the coating of cells with antibodies to enhance phagocytosis?

Opsonization Signup and view all the answers

What serves as potent opsonins generated during the classical pathway of complement activation?

C3b and C4b Signup and view all the answers

Which clinical feature is NOT typically seen in Type I hypersensitivity reactions?

Chronic autoimmune response Signup and view all the answers

What is the primary action of mast cell mediators during Type I hypersensitivity?

Releasing inflammatory signals Signup and view all the answers

What is the role of inflammatory cells in Type I hypersensitivity reactions?

To accumulate at antigen deposition sites Signup and view all the answers

What occurs during the late phase of Type I hypersensitivity reactions?

Persistent eosinophil infiltration Signup and view all the answers

How do phagocytes recognize opsonized cells?

By binding to antibodies on the cell surface Signup and view all the answers

What is a consequence of the release of mast cell mediators in Type I hypersensitivity?

Increased symptoms of anaphylaxis Signup and view all the answers

What main type of antibody becomes elevated during Type I hypersensitive reactions?

IgE Signup and view all the answers

What key feature distinguishes Antibody-Dependent Cellular Toxicity (ADCC) from phagocytosis?

Engagement of natural killer cells Signup and view all the answers

Which disorder is characterized by Rh incompatibility between a mother and her fetus?

Erythroblastosis Fetalis Signup and view all the answers

What is the primary antibody involved in the hemolytic disease seen in Erythroblastosis Fetalis?

IgG Signup and view all the answers

What is a common clinical condition resulting from antibody-mediated cell destruction?

Autoimmune Hemolytic Anemia (AIHA) Signup and view all the answers

What occurs to an Rh (+) fetus while in an Rh (-) mother's womb?

The mother develops antibodies against the fetal blood cells Signup and view all the answers

Which cell type is least involved in the processes associated with Antibody-Dependent Cellular Toxicity?

B Lymphocytes Signup and view all the answers

What is the primary clinical manifestation of Goodpasture syndrome?

Hemoptysis and hematuria Signup and view all the answers

How does Myasthenia Gravis affect cell function?

It impairs cell function Signup and view all the answers

What type of hypersensitivity reaction is primarily involved in Autoimmune Hemolytic Anemia?

Type II Signup and view all the answers

Which of the following correctly describes the effect of antibodies in Grave’s disease?

Antibodies stimulate excessive cell function Signup and view all the answers

In which condition does maternal IgG antibody crossing the placenta result in fetal complications?

Hemolytic Disease of Newborn Signup and view all the answers

What is a sequela of direct cell lysis by antibodies in conditions like AIHA?

Jaundice Signup and view all the answers

What types of antibodies are primarily involved in Type II hypersensitivity reactions?

IgM and IgG Signup and view all the answers

What is characterized by the presence of antibodies against non-collagenous proteins in the basement membrane?

Goodpasture syndrome Signup and view all the answers

What factor is critical for the effective operation of natural killer cells in ADCC?

Recognition of the Fc region of antibodies Signup and view all the answers

Which organ systems are affected in Goodpasture syndrome as indicated by its mnemonic?

Lungs and kidneys Signup and view all the answers

In the context of autoimmune disorders, what is a common outcome of antigen-antibody interactions?

Destruction of healthy tissues Signup and view all the answers

What type of immune response is primarily associated with Type III hypersensitivity?

Formation of immune complexes Signup and view all the answers

Which condition involves both glomerulonephritis and pulmonary issues due to antibody-mediated mechanisms?

Goodpasture syndrome Signup and view all the answers

What type of antibodies are primarily implicated in the pathophysiology of both Grave’s disease and Myasthenia Gravis?

IgG Signup and view all the answers

Which type of hypersensitivity reaction is primarily IgE mediated?

Type I Signup and view all the answers

What is a common mechanism involving Type II hypersensitivity reactions?

Complement activation and inflammation Signup and view all the answers

Which of the following conditions is an example of Type IV hypersensitivity?

Tuberculosis Signup and view all the answers

What type of antibody is primarily involved in Type III hypersensitivity?

IgM Signup and view all the answers

Which immune cells are primarily involved in the cytotoxic process of Type IV hypersensitivity?

CD8+ cytotoxic T-lymphocytes Signup and view all the answers

What mechanism is commonly associated with the inflammatory response in Type II hypersensitivity?

Opsonization and phagocytosis Signup and view all the answers

In the context of hypersensitivity reactions, what does 'atopy' refer to?

A general term for allergies Signup and view all the answers

What role does IgE play in allergic responses?

Mediates immediate release of allergens Signup and view all the answers

Which condition exemplifies a Type II hypersensitivity reaction characterized by the destruction of red blood cells?

Autoimmune hemolytic anemia Signup and view all the answers

Which of the following is primarily involved in the inflammation associated with immune complex diseases?

Neutrophils Signup and view all the answers

Which mechanism is primarily involved in Goodpasture syndrome?

Complement and Fc receptor-mediated inflammation Signup and view all the answers

Which disease is characterized by antibody-mediated stimulation of the TSH receptor?

Graves disease Signup and view all the answers

What type of hypersensitivity is primarily involved in the tuberculin (PPD) reaction?

Type IV (Cell Mediated) Hypersensitivity Signup and view all the answers

What is a clinical manifestation associated with systemic lupus erythematosus (SLE)?

Nephritis Signup and view all the answers

Which target antigen is involved in myasthenia gravis?

Acetylcholine receptor Signup and view all the answers

Which disease is characterized by cytokine-mediated inflammation and chronic arthritis?

Rheumatoid Arthritis Signup and view all the answers

In which condition is opsonization and phagocytosis of platelets a primary mechanism?

Autoimmune thrombocytopenic purpura Signup and view all the answers

What is the primary mechanism through which cytotoxic T lymphocytes (CTLs) cause injury in Type I Diabetes Mellitus?

Direct cell lysis Signup and view all the answers

In which condition does demyelination occur due to the attack of pathogenic T cells?

Multiple Sclerosis Signup and view all the answers

Which type of hypersensitivity is systemic lupus erythematosus classified as?

Type III hypersensitivity Signup and view all the answers

What type of antigens are involved in the Arthus reaction?

Various foreign proteins Signup and view all the answers

Which of the following is a disease related to Type IV hypersensitivity that involves obstruction and chronic inflammation in the intestines?

Inflammatory Bowel Disease Signup and view all the answers

What is primarily targeted in autoimmune hemolytic anemia?

RBC membrane proteins Signup and view all the answers

What type of immune cells are primarily involved in the granulomatous reaction?

CD4+ T cells Signup and view all the answers

Which disease involves nephritis due to streptococcal antigens?

Poststreptococcal glomerulonephritis Signup and view all the answers

What clinical manifestation is associated with the inflammatory response due to myelin basic protein in multiple sclerosis?

Demyelination and paralysis Signup and view all the answers

Which of the following statements accurately describes the specificity of pathogenic T cells in Rheumatoid Arthritis?

They target collagen and citrullinated self-proteins. Signup and view all the answers

What effect do antibodies have in myasthenia gravis?

Inhibit acetylcholine binding Signup and view all the answers

Which outcome results from the T-cell mediated destruction of pancreatic beta cells in Type I Diabetes Mellitus?

Insulin deficiency and diabetes Signup and view all the answers

What is a common feature shared by the mechanisms of Type IV hypersensitivity reactions?

Involvement of CD4+ or CD8+ T cells Signup and view all the answers

Study Notes

Antibody-Dependent Cellular Toxicity (ADCC)

IgG antibodies coat target cells, enabling destruction by natural killer cells and macrophages.
Cell lysis can occur independently of phagocytosis.

Clinical Examples of Antibody-Mediated Destruction

Erythroblastosis Fetalis: Occurs when an Rh-negative mother carries an Rh-positive infant, leading to maternal IgG anti-Rh antibodies crossing the placenta and destroying fetal red blood cells.
Hemolytic Transfusion Reactions: Result from incompatible blood transfusions causing antibody-mediated destruction of red blood cells.
Autoimmune Hemolytic Anemia (AIHA): Antibodies target and destroy the body's own red blood cells.
Autoimmune Thrombocytopenic Purpura (AITP): Antibodies cause destruction of platelets.

Transfusion Reactions

Jaundice in newborns is a sign of erythroblastosis fetalis linked to Rh incompatibility.

Type II Hypersensitivity

Involves antibody-mediated reactions:
- Graves’ Disease: Excessive stimulation of the thyroid gland via antibodies against TSH receptors.

Type III Hypersensitivity: Immune Complex Diseases

Localized Immune Complex Disease:
- Arthus Reaction: Localized inflammation due to immune complexes from repeated exposure to foreign antigens, first described by Nicholas Maurice Arthus in 1903.
Serum Sickness:
- Prototype of systemic immune complex disease arising from foreign serum administration, first identified in 1906.
- Symptoms manifest 4-10 days post-exposure and include arthritis, skin rashes, fever, and lymphadenopathy.

Phases of Immune Complex Diseases

Phase 1: Formation of immune complexes and their deposition in blood vessels lead to inflammation.
Phase 2: Neutrophil activation results in the release of damaging substances at tissue sites.
Phase 3: Tissue injury and clinical symptoms arise, including fever, rashes, joint pain, and proteinuria.

Examples of Systemic Immune Complex Diseases

Systemic Lupus Erythematosus (SLE): Autoantibodies against double-stranded DNA and nuclear antigens lead to complex deposition in kidneys, skin, and joints.

Cytotoxic Lymphocyte Recognition of Antigens

Cytotoxic T-Cells utilize pathways for antigen recognition involving perforins and granzymes, leading to cell death in infected or dysfunctional cells.
Examples include multiple sclerosis and insulin-dependent diabetes, where myelin or pancreatic antigens are targeted by effector T-cells.

Hypersensitivity Reactions Overview

Hypersensitivity reactions are classified into four types: Type I (IgE-mediated), Type II (antibody-mediated), Type III (immune complex-mediated), and Type IV (cell-mediated).
Type I reactions involve allergen exposure leading to rapid immune response and can range from localized allergies to systemic anaphylaxis.

Key Mediators in Type I Hypersensitivity

Leukotrienes C4 and D4:
- Cause bronchial smooth muscle contraction and intense bronchospasm, resulting in difficulty breathing.
Prostaglandin D2:
- Induces vasodilation and increased mucus secretion, contributing to respiratory distress.

Pathophysiology of Type I Hypersensitivity

Process initiated by induction of Th2 cells leading to B cell class switching for IgE production.
Accumulation of eosinophils and mast cells results in inflammation, contributing to symptoms.

Antibody-Dependent Cellular Toxicity (ADCC)

ADCC involves destruction of antibody-coated cells by effector cells, independent of phagocytosis.
Primary effector cells include natural killer cells and macrophages.

Clinical Examples of Antibody-Mediated Conditions

Hemolytic Transfusion Reactions: Immune response to mismatched blood transfusion.
Autoimmune Hemolytic Anemia (AIHA): Destruction of red blood cells due to antibodies.
Erythroblastosis Fetalis: IgG anti-Rh antibodies from an Rh(-) mother attack Rh(+) fetal blood cells, leading to anemia.
Autoimmune Thrombocytopenic Purpura (AITP): Destruction of platelets due to antibodies.

Goodpasture Syndrome

Characterized by diffuse pulmonary hemorrhages and rapidly progressive glomerulonephritis due to antibodies against basement membrane proteins.
Presents with hemoptysis (coughing blood) and hematuria (blood in urine).

Autoimmunity: Grave’s Disease vs. Myasthenia Gravis

Grave’s Disease: Antigen-antibody interaction leads to overstimulation of cell function and hyperactivity of thyroid function.
Myasthenia Gravis: Antibodies inhibit neurotransmitter interaction, leading to muscle weakness.

Type II and Type III Hypersensitivity

Type II hypersensitivity is mediated primarily by IgG and IgM, involving direct cell destruction.
Type III hypersensitivity involves deposition of immune complexes in tissues, causing inflammation and tissue damage.

Clinical Implications of Immune Complex Deposition

Common diseases associated include serum sickness, systemic lupus erythematosus (SLE), post-streptococcal glomerulonephritis, and farmer's lung.
Deposited complexes activate the complement system, recruiting macrophages and neutrophils, leading to further tissue injury.

Type IV Hypersensitivity

Characterized by delayed response mediated by T cells rather than antibodies, contributing to conditions like contact dermatitis and graft rejection.

Types of Hypersensitivity Reactions

Type I: Immediate hypersensitivity, commonly known as allergy, mediated by IgE.
Type II: Antibody-mediated hypersensitivity, involves IgG and IgM antibodies.
Type III: Immune-complex mediated hypersensitivity; involves antigen-antibody complexes leading to disease effects.
Type IV: T-cell mediated hypersensitivity, characterized by delayed-type responses.

Mediators and Mechanisms

Type I hypersensitivity results in immediate release of vasoactive amines from mast cells upon IgE production.
Type II hypersensitivity employs IgG and IgM to target specific cells, leading to opsonization, phagocytosis, complement activation, and inflammation.
Type III involves the formation of antigen-antibody complexes that can lead to tissue deposition and inflammation.
Type IV relies on T cells (CD4+ and CD8+) for cytokine-mediated inflammation and cytotoxicity.

Examples of Hypersensitivity Reactions

Type I manifestations: Allergies, bronchial asthma, allergic rhinitis, anaphylaxis.
Type II includes autoimmune hemolytic anemia, autoimmune thrombocytopenic purpura, hemolytic transfusion reactions, and conditions like Goodpasture syndrome and Graves disease.
Type III examples: Systemic lupus erythematosus (SLE), poststreptococcal glomerulonephritis, acute glomerulonephritis, Arthus reaction, serum sickness.
Type IV reactions include tuberculosis, responses to viral infections, transplant rejection, and autoimmune conditions like rheumatoid arthritis and multiple sclerosis.

Disease Mechanisms and Target Antigens in Type II Hypersensitivity

Autoimmune hemolytic anemia targets RBC membrane proteins; leads to opsonization and phagocytosis.
Autoimmune thrombocytopenic purpura targets platelet membrane proteins; similarly results in opsonization.
Goodpasture syndrome involves antibodies against basement membrane proteins, leading to inflammation.
Myasthenia gravis targets acetylcholine receptors, inhibiting function and receptor regulation.
Graves disease involves TSH receptor stimulation by antibodies, causing hyperthyroidism.

Immune-Complex Mediated Diseases (Type III)

Systemic lupus erythematosus (SLE) targets DNA and nucleoproteins, manifesting as nephritis and vasculitis.
Poststreptococcal glomerulonephritis arises from streptococcal antigens causing kidney inflammation.
Acute glomerulonephritis includes responses to bacterial and tumor antigens.
Arthus reaction results from exposure to foreign proteins, causing cutaneous vasculitis.
Serum sickness arises from various proteins leading to systemic manifestations like arthritis and nephritis.

T-Cell Mediated Conditions (Type IV)

Tuberculin reaction: delayed hypersensitivity to tuberculin purified protein derivative (PPD).
Granulomatous reactions result from chronic inflammatory responses.
Transplant rejection is mediated by specific T cells recognizing foreign antigens.
Rheumatoid arthritis involves cytokine-mediated destruction of articular cartilage by pathogenic T cells targeting collagen.
Multiple sclerosis features demyelination within the CNS from T-cell-mediated inflammation targeting myelin proteins.
Type I diabetes mellitus results from CD8+ T cell-mediated destruction of insulin-producing pancreatic beta cells, leading to chronic inflammation and diabetes progression.

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Description

This quiz covers topics related to antibody-dependent cellular toxicity (ADCC) and clinical examples of antibody-mediated destruction. Key conditions such as erythroblastosis fetalis, hemolytic transfusion reactions, and autoimmune disorders are discussed. Test your understanding of these critical immunological concepts!