Hypersensitivity Reactions: Type 1, IgE Mediated

Questions and Answers

Which type of hypersensitivity reaction involves the release of histamine and prostaglandins?

Type II

Type I (correct)

Type IV

Type III

What is the main treatment for Type I hypersensitivity reaction?

Epinephrine, antihistamines, and corticosteroids (correct)

Corticosteroids and cyclosporine

Medication to prevent maternal antibody development

Ensuring blood compatibility

Which of the following is an example of Type II hypersensitivity reaction?

Blood transfusion reaction (correct)

Hay fever

Anaphylaxis

Erythroblastosis fetalis

What is the mechanism of Type III hypersensitivity reaction?

Antigen-antibody complexes accumulate and deposit in tissue Signup and view all the answers

Which type of hypersensitivity reaction is cell-mediated?

Type IV Signup and view all the answers

What is the primary response of Type IV hypersensitivity reaction?

Release of lymphokines Signup and view all the answers

What is an example of an autoimmune condition that is an example of Type III hypersensitivity reaction?

Systemic lupus erythematosus Signup and view all the answers

What is the primary difference between Type I and Type IV hypersensitivity reactions?

Cell-mediated vs. antibody-mediated Signup and view all the answers

Which of the following is NOT a maladaptive coping strategy?

Relaxation Signup and view all the answers

What is the main function of the first line of defense in the immune system?

To prevent pathogens from entering the body Signup and view all the answers

What is an antigen?

A substance that triggers an immune response Signup and view all the answers

Which of the following is a physical barrier of the first line of defense?

Skin Signup and view all the answers

What is the main function of the inflammatory response?

To isolate and destroy pathogens Signup and view all the answers

What is the role of pyrogens in the immune system?

To induce fever Signup and view all the answers

What is the primary function of interferons?

To inhibit viral replication Signup and view all the answers

Which of the following is a characteristic of the immune system?

It is a complex system that can adapt to new threats Signup and view all the answers

What is the likely mechanism of transplant reaction?

Antibodies and complements deposit in vessel walls of transplanted tissue Signup and view all the answers

Which type of transplant reaction is more likely to be fatal?

Graft vs host disease Signup and view all the answers

What is the main characteristic of autoimmune disorders?

Directed against host tissue Signup and view all the answers

What is the common feature of autoimmune disorders and systemic lupus erythematosus?

More prevalent in females Signup and view all the answers

What is the likely cause of systemic lupus erythematosus?

Activated B cells Signup and view all the answers

What is the characteristic of disease progression in systemic lupus erythematosus?

Progressive and remitting Signup and view all the answers

What is the requirement for diagnosing systemic lupus erythematosus?

Four or more of the following criteria Signup and view all the answers

What is the main difference between host vs graft disease and graft vs host disease?

Direction of the immune response Signup and view all the answers

What is the most successful type of transplant?

Autologous Signup and view all the answers

Which type of transplant rejection occurs immediately or within 3 days after the transplant?

Hyperacute rejection Signup and view all the answers

What type of rejection is most common and occurs between 4 days and 3 months after a transplant?

Acute rejection Signup and view all the answers

Which transplant type involves donor and recipient being identical twins?

Syngenic Signup and view all the answers

What is the cause of hyperacute rejection?

The complement system Signup and view all the answers

Chronic rejection typically occurs how long after a transplant?

4 months to years Signup and view all the answers

What is the primary role of interferon production?

To protect other cells from viral infections Signup and view all the answers

How do plasma proteins function in the immune response?

They enhance the action of antibodies Signup and view all the answers

Which type of immunity is acquired through vaccinations?

Acquired immunity Signup and view all the answers

What defines active immunity?

It can develop from having a disease or vaccinations Signup and view all the answers

What is the primary characteristic of hypersensitivity?

An exaggerated immune response to a foreign substance Signup and view all the answers

How does autoimmune response alter immunity?

It causes the body to attack its own cells Signup and view all the answers

What causes immunodeficiency in the immune system?

Diminished or absent immune response Signup and view all the answers

Which cells are primarily involved in cell-mediated immunity?

T cells Signup and view all the answers

Study Notes

Coping Strategies

Relaxation, distraction, and biofeedback are positive coping strategies.
Maladaptive coping strategies include smoking, substance abuse, and overeating.

Immune System Overview

Functions: Self-regulated, self-limiting, defending, and attacking.
Ability to distinguish self from non-self is crucial.
Antigens are foreign agents that trigger immune responses.

First Line of Defense (Nonspecific)

Main role is distinguishing self from non-self without targeting specific pathogens.
Consists of physical barriers (skin, mucous membranes) and chemical barriers (skin secretions, stomach acid, and enzymes in tears/saliva).

Physical Barriers

Skin acts as a primary defense against pathogens.
Mucous membranes line body cavities and trap pathogens.

Chemical Barriers

Slightly acidic secretions on the skin inhibit bacteria.
Hydrochloric acid in the stomach destroys many ingested pathogens.
Lysozyme in tears and saliva breaks down bacterial cell walls.

Second Line of Defense

Targets antigens that breach the first line of defense.
Includes inflammatory response, pyrogens, interferons, and complement proteins.

Inflammatory Response

Triggered by mast cells releasing histamine and prostaglandins.
Symptoms: redness (erythema), swelling (edema), pain, and warmth.

Pyrogens

Molecules that induce fever, produced by macrophages.
Create an environment less favorable for bacterial growth.

Interferons

Proteins released by virus-infected cells.
They bind to uninfected cells to inhibit viral replication, preventing the spread of infection.

Complement Proteins

Approximately 20 plasma proteins that enhance antibody functions.
Activated by antigens, aiding immune responses and inflammation.

Third Line of Defense (Specific)

Develops over time and utilizes a memory system.
Distinguishes between self, non-self, and various pathogens.

T Cells and B Cells

T cells are involved in cell-mediated immunity, including helper, suppressor, and killer T cells, playing roles in viral infection and cancer prevention.
B cells are responsible for humoral immunity, producing antibodies and forming memory cells.

Acquired Immunity

Active Immunity: Developed from infections or vaccinations, long-lasting but takes time to become effective.
Passive Immunity: Acquired via maternal transfer or breastfeeding, providing temporary protection.

Alterations in Immunity

Hypersensitivity: Exaggerated immune responses to foreign substances.
Autoimmune: Immune system attacks the body's own tissues, perceiving them as foreign.
Immunodeficiency: Diminished immune response leads to increased susceptibility to infections.

Types of Hypersensitivity Reactions

Type I: IgE mediated, triggers immediate responses (e.g., allergies, anaphylaxis); treated with epinephrine and antihistamines.
Type II: Tissue-specific, involves IgG or IgM antibodies causing cell lysis (e.g., blood transfusion reactions); treated by ensuring blood compatibility.
Type III: Immune complex-mediated, leads to accumulation of antigen-antibody complexes (e.g., lupus); treatment is disease-specific.
Type IV: Delayed hypersensitivity reaction, involves T cells leading to tissue destruction (e.g., contact dermatitis).

Transplant Considerations

Successful transplants rely on matching tissue antigens.
Types of transplants: Allogenic, syngenic, autologous, xenogenic.

Transplant Rejection Patterns

Hyperacute rejection: Immediate response post-transplant due to the complement system.
Acute rejection: Common and treatable, occurs days to months post-transplant.
Chronic rejection: Develops over months to years, likely antibody-mediated affecting graft function.

Transplant Reaction Classifications

Host vs. Graft Disease: Recipient’s immune system attacks donor cells.
Graft vs. Host Disease: Donor immune cells attack the recipient’s tissues, often in bone marrow transplants.

Autoimmune Disorders

Characterized by the immune system failing to recognize self, leading to tissue damage.
Frequently affects women and is often triggered by physical or psychological stressors.

Systemic Lupus Erythematosus (SLE)

Chronic inflammatory condition with unpredictable remission and exacerbation periods.
Primarily affects connective tissues and varies from mild to severe symptoms.
Associated with B-cell activation and autoantibody production attacking the body’s tissues.

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Description

Learn about Type 1 hypersensitivity reactions, also known as IgE mediated reactions, which produce immediate responses and can be local or systemic.Discover the role of IgE, mast cells, and the complement system in these reactions.