Immunology Quiz on Blood and Allergies

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Questions and Answers

Which immunoglobulin class is primarily responsible for mediating allergic reactions?

IgD

IgA

IgG

IgE (correct)

What type of hypersensitivity reaction is characterized by the formation of immune complexes that deposit in tissues?

Type IV

Type III (correct)

Type II

Type I

Which of the following is NOT a characteristic of a humoral immune response?

Directly targets intracellular pathogens (correct)

Involves B lymphocytes

Provides long-lasting immunity

Mediated by antibodies

Which blood group system is primarily responsible for the development of hemolytic disease of the newborn (HDN)?

Rh system (A) Signup and view all the answers

Which laboratory test is used to detect the presence of antibodies against red blood cells, even if they are not currently attached to the cells?

Indirect Coombs Test (A) Signup and view all the answers

If a person with type O- blood is exposed to type A+ blood, which of the following reactions could occur?

Agglutination of the donor's red blood cells (C) Signup and view all the answers

Which of the following blood types is the most prevalent?

O+ (C) Signup and view all the answers

What is the purpose of cross-matching blood before a transfusion?

To identify any potential antigen-antibody incompatibilities between the donor and recipient (D) Signup and view all the answers

Which of the following statements accurately describes the role of Coombs tests?

Coombs tests check for the presence of antibodies against red blood cells in the blood (A) Signup and view all the answers

Which of the following is a potential consequence of a transfusion reaction?

Acute kidney failure (D) Signup and view all the answers

A patient with Type A blood receives a transfusion of Type B blood. What is the most likely outcome?

The patient's immune system will attack the transfused red blood cells. (A) Signup and view all the answers

Which blood type is considered the universal donor, meaning it can be safely transfused to individuals with any other blood type?

Type O (A) Signup and view all the answers

A patient with Type AB blood needs a blood transfusion. Which blood type(s) can be safely transfused to this patient?

Type O, Type A, Type B, and Type AB (A) Signup and view all the answers

What type of blood is compatible with Type O blood?

Only Type O (C) Signup and view all the answers

A patient with a rare blood type needs a transfusion. They are only compatible with blood from individuals with the same rare blood type. What is the most likely reason for this limitation?

The patient has a genetic mutation that prevents their body from recognizing common blood types. (B) Signup and view all the answers

Which of the following statements accurately describes the function of antibodies in the ABO blood typing system?

Antibodies bind to specific antigens on red blood cells, triggering an immune response when incompatible blood types are mixed. (B) Signup and view all the answers

Which of the following blood products is specifically indicated for patients with bleeding and clotting factor deficiencies?

Fresh frozen plasma (FFP) (C) Signup and view all the answers

Which of the following laboratory tests is typically used to assess the function of the extrinsic pathway of coagulation?

Prothrombin time (PT)/International Normalized Ratio (INR) (A) Signup and view all the answers

Which of the following blood products would be most appropriate for a patient with a deficiency in Factor VIII and fibrinogen?

Cryoprecipitate (B) Signup and view all the answers

Which of the following blood products is typically used to treat patients with thrombocytopenia?

Platelets (B) Signup and view all the answers

If a patient has an INR of 1.8, which of the following blood products would be most appropriate to administer?

Fresh frozen plasma (FFP) (C) Signup and view all the answers

A patient presents with signs and symptoms consistent with immune-mediated hemolytic anemia. What laboratory test would be most appropriate to confirm this diagnosis?

Direct Coombs test (D) Signup and view all the answers

A pregnant woman is screened for antibodies against red blood cells. Which test is most commonly used for this purpose?

Indirect Coombs test (D) Signup and view all the answers

A patient requires a blood transfusion. What laboratory test would be performed to determine their blood type and identify any antibodies that could cause a reaction?

Type and Screen (D) Signup and view all the answers

What is the purpose of the 'Type and Cross' test?

To determine if the donor blood is compatible with the patient's blood (A) Signup and view all the answers

In a patient with a positive Direct Coombs test, what is the expected outcome when Coombs reagent is added to their red blood cells?

The red blood cells will clump together (B) Signup and view all the answers

Why are indirect Coombs tests performed when testing for antibodies in pregnant women?

To identify antibodies that could potentially cross the placenta and harm the fetus (D) Signup and view all the answers

Which of the following is a reason why packed red blood cells are preferred over whole blood for transfusion?

All of the above (D) Signup and view all the answers

What is the primary clinical indication for platelet rich plasma (PRP) transfusion?

Low platelet count (D) Signup and view all the answers

Which of the following statements about immunoglobulins is TRUE?

Immunoglobulin levels can be used to monitor the course of diverse immune conditions, but they are not always diagnostic. (A) Signup and view all the answers

Which immunoglobulin isotype is NOT directly involved in complement activation?

IgE (D) Signup and view all the answers

What is the primary function of IgE in the immune system?

Mediating allergic responses and fighting parasitic infections (B) Signup and view all the answers

Which of the following is a characteristic of Type II hypersensitivity reactions?

Involves the body recognizing its own cells as foreign. (C) Signup and view all the answers

Which of the following is an example of a Type III hypersensitivity reaction?

Post streptococcal glomerulonephritis (C) Signup and view all the answers

What is the difference between polyclonal and monoclonal antibodies?

Polyclonal antibodies bind to multiple epitopes of an antigen; monoclonal antibodies bind to a single epitope of an antigen. (C) Signup and view all the answers

Which of the following statements about IgG is FALSE?

Elevated IgG levels are always indicative of an autoimmune disorder. (B) Signup and view all the answers

Which of the following is NOT a function of IgG in the immune system?

Mediating allergic reactions (A) Signup and view all the answers

What is the main function of IgA in the immune system?

Protecting mucosal tissues from pathogens (D) Signup and view all the answers

Which immunoglobulin isotype is primarily responsible for ABO blood grouping?

IgM (A) Signup and view all the answers

Which immunoglobulin isotype is NOT directly involved in antibody-dependent cytotoxicity?

IgA (A) Signup and view all the answers

Which of the following describes a characteristic of Type IV hypersensitivity reactions?

Involves the delayed activation of T cells, leading to inflammation and tissue damage. (D) Signup and view all the answers

Which of these statements describes the primary difference between autoimmune disorders and immunodeficiency disorders?

Autoimmune disorders involve an overactive immune system attacking the body's own tissues; immunodeficiency disorders involve a weakened immune system susceptible to infections. (D) Signup and view all the answers

Which of the following statements about the Gell and Coombs system is TRUE?

The Gell and Coombs system is widely used, despite some questioning its clinical significance. (B) Signup and view all the answers

Which of the following conditions is NOT an example of a Type IV hypersensitivity reaction?

Graves' disease (B) Signup and view all the answers

Which of the following is NOT a characteristic of immunodeficiency disorders?

Often characterized by a strong inflammatory response (B) Signup and view all the answers

Study Notes

Immunology Overview

This is a subject matter overview covering different immunological concepts and components

Instructional Objectives

Inventory of antigens and antibodies (including IgA, IgD, IgE, IgG, and IgM) are detailed
Illustrations of the processes of the immune response are outlined
The different hypersensitivity types are examined
Comparison of autoimmune and immunodeficiency diseases is provided
HIV definition, transmission, and testing are discussed
Major blood group systems are compared, with a brief overview of other systems
Contrast of Rh antibody formation and hemolytic disease of the newborn (HDN) is presented
Different laboratory tests (Type and Cross Match, Type and Screen, Direct and Indirect Coombs) are explained
The role and indications of blood transfusions (red cell, cryoprecipitate, platelet, and fresh frozen plasma) and reactions are reviewed

Refresh on Immunity

Innate immunity is nonspecific, with physical/physiological barriers such as skin, GI lining, gastric acid, and phagocytes (neutrophils and macrophages)
Adaptive immunity is specific, focused on acquired responses with specific targets.
- Cell-mediated immunity: T-lymphocytes
- Antibody-mediated (humoral) immunity: B-lymphocytes

Immune Response (Simplified)

Local neutrophils encounter pathogens and begin phagocytosis, triggering cytokines
Cytokines cause vasodilation, attracting more neutrophils and monocytes
Monocytes differentiate into macrophages
Macrophages and neutrophils continue phagocytosis
Macrophages act as antigen-presenting cells (APCs), presenting to T-cells (cytotoxic, helper, and regulatory) and B-cells
Memory B-cells are dormant, enabling faster response to future pathogens
Plasma B-cells secrete antibodies (immunoglobulins)

Immunoglobulins (Antibodies)

Immunoglobulins are synonymously used with antibodies
Measured in blood, values vary by age
Used to monitor the progress of hypersensitivities, immune deficiencies, autoimmune diseases, and chronic infections
Serum Ig testing is not a sole diagnostic but can indicate disease
Electrophoresis separates them based on mass and charge
Five isotypes: IgG, IgA, IgM, IgE, IgD

Monoclonal vs Polyclonal Antibodies

Polyclonal antibodies bind to different epitopes of the same antigen
Monoclonal antibodies bind to one epitope of the same antigen
Differences are used in drug development, research and lab evaluations

Immunoglobulin G (IgG)

Constitutes approximately 75% of serum immunoglobulins
Key component of the immune response, including neutralization, opsonization, complement activation.
Plays an important role in antibody-dependent cytotoxicity against infected cells.
Involved in fighting infections and in many other disorders
Exists in four subclasses with varying actions in fighting infections

Immunoglobulin A (IgA)

IgA is approximately 15% of the body's immunoglobulin
Found in tears, blood, respiratory and gastrointestinal secretions
Supports mucosal tissue protection (maintains homeostasis) from pathogens
Increased levels are linked with various inflammatory conditions
Decreased levels are associated with conditions like leukemia and immunodeficiencies

Immunoglobulin M (IgM)

Primarily involved in ABO blood grouping and immediate responses to infections
Involved importantly in immune responses to many infections
Forms a pentamer, possessing 10 antigen-binding sites
Effective in antigen-antibody complex formation
Does not cross the placenta

Immunoglobulin E (IgE)

Mediates allergic response and parasitic diseases
Helps in detecting allergic and hypersensitivity diseases
Not a standalone test as it is frequently involved in other non-allergic conditions
Does not activate complement system for opsonization
Elevated levels can be indicative of various diseases

Immunoglobulin D (IgD)

Little is understood about IgD, with limited clinical evaluation
Potentially involved in B-cell function, but not in direct immune responses

Hypersensitivity

An exaggerated immune response, ranging from mild to fatal.
Classified into four types (Type I, Type II, Type III, and Type IV)
Type I: IgE-mediated, immediate hypersensitivity
Type II: Antibody-mediated, involves the killing of self-cells by the immune system
Type III: Immune complex-mediated, involves antigens and antibodies forming complexes and causing damage
Type IV: Cell-mediated, delayed hypersensitivity

Human Immunodeficiency Virus (HIV)

A virus that leads to a progressive immune system failure
Associated with an increased infection and cancer risk
CD4 is a protein on immune cells (especially helper T cells), playing a role in signaling
HIV leads to the progressive reduction of CD4+ T cells
CD4 test helps in tracking HIV and treatment efficacy
Lower CD4 counts correlate with increased risks of opportunistic infections
Increased CD4 count suggests successful treatment
CD4 counts below 200 indicate AIDS.

HIV Diagnosis and Treatment

HIV differentiation immunoassay (serology) confirms HIV type
HIV RNA quantification (viral load) quantifies HIV RNA after confirmation
Results from CD4 and viral load direct treatment

HIV Diagnosis Tests

ELISA (Enzyme-Linked ImmunoSorbent Assay) detects HIV antibodies
CBC (Complete Blood Count) can reveal leukopenia, lymphopenia, and thrombocytopenia, potentially caused by infections

Blood Types

ABO typing and Rh typing depend on inherited antigens on erythrocytes
Blood type compatibility is crucial to avoid adverse effects in transfusions
Antigens trigger immune responses; antibodies attack antigens

Rh Factor

An erythrocyte antigen first discovered in rhesus monkeys
Antibodies to the Rh factor typically develop after exposure to Rh-positive blood
There are many human erythrocyte antigen systems; in emergencies these are cross-matched before transfusion

Transfusion Reactions

Exposure to incompatible blood can lead to severe reactions in recipients
Two major types of antigen-antibody reactions occur
Often involves recipient's plasma antibodies and donor's erythrocyte antigens
Can cause severe complications like acute kidney failure

Hemolytic Disease of the Newborn (HDN)

Transfusion reactions
An important aspect to consider in pregnancy and blood transfusions

Coombs Tests

Used to detect antibodies against red blood cells (RBCs).
Two types: direct and indirect.
- Direct Coombs test detects antibodies directly on RBCs
- Indirect Coombs test detects antibodies in the serum

Type and Screen/Crossmatch

ABO grouping and Rh typing are checked
Other antibodies are also often screened.
Recipient plasma is added to donor blood to determine compatibility
Often performed before transfusions to reduce risk of reactions

Blood Product Indications

Whole blood: Not suitable for most patients, ideal for specific conditions
Packed red blood cells: Used for treating low hemoglobin, decreased oxygen saturation
Platelet-rich plasma (PRP): Used for patients with a risk of spontaneous bleeding and before high-risk procedures (e.g. surgeries)
Fresh frozen plasma (FFP): Contains clotting factors and used for those with bleeding and clotting deficiency
Cryoprecipitate: Contains high concentrations of clotting factors, including Factors VIII and XIII, fibrinogen, and von Willebrand factor, typically used when those specific clotting factors are low.

Midterm Topics

A listing of tested components of immunity, blood types, and diseases.

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Description

Test your knowledge on immunoglobulin classes, hypersensitivity reactions, and blood group systems. This quiz covers important concepts such as the humoral immune response and transfusion reactions. Perfect for students of immunology and related fields.