Exam 5 Full Study Guide Flashcards
(45 cards)
Define Hypersensitivity
An exaggerated immune response to a typically harmless antigen
What are the Four Categories of Hypersensitivity?
Type I, Type II, Type III, Type IV.
Compare Immediate vs. Delayed Hypersensitivity Reactions
Immediate occurs within minutes to hours; Delayed occurs 48-72 hours after exposure.
What mediates Type I Hypersensitivity?
IgE, Histamine, Heparin; mediated by Mast cells and Basophils.
What are the 3 phases of Type I Hypersensitivity?
Sensitization, Activation, Effector Phases.
Common allergens associated with Type I Hypersensitivity
Food allergies, Rhinitis, Asthma, Urticaria (“hives”) wheal-and-flare reaction, systemic anaphylaxis.
What is Anaphylaxis?
A severe and most immediate hypersensitivity, potentially life-threatening allergic reaction.
What treatments are available for Type I Hypersensitivity?
Antihistamines, Epinephrine pens, Allergy shots (AIT), In vivo skin tests: evaluates the cellular immune response, and Monoclonal anti-IgE antibody.
What is RAST testing?
Radioallergosorbent test used to detect specific IgE antibodies.
What characterizes Type II Hypersensitivity?
Cytotoxic reactions against cell surface antigens; mediated by IgG and IgM.
What are common examples of Type II Hypersensitivity?
Transfusion reactions, Hemolytic disease of the newborn (HDN), Autoimmune hemolytic anemias.
What tests are used for Type II Hypersensitivity?
Indirect Antiglobulin Test (IAT); Coombs’ test and Direct Antiglobulin Test (DAT).
What defines Type III Hypersensitivity?
Immune complex-mediated hypersensitivity, small antigen-antibody complexes precipitate out and deposit in tissue
Examples of diseases associated with Type III Hypersensitivity
Systemic Lupus Erythematosus (SLE), Rheumatoid Arthritis (RA), Glomerulonephritis.
What are common tests for Type III Hypersensitivity?
Rheumatoid Factor (RF), Complement levels, Antinuclear Antibody (ANA) testing.
What is Type IV Hypersensitivity?
Delayed-type hypersensitivity mediated by T-cells. Hypersensitivity peaks 48 to 72 hours after antigen exposure
What are common examples of Type IV Hypersensitivity?
Contact (dermatitis) allergies- poison ivy, poision oak, nickel salts, materials in cosmetics and hair dyes, latex
Infections with intracellular pathogens- tuberculosis and herpes simplex virus
Tuberculin skin test (Mantoux test).
What does a positive PPD test indicate?
Exposure to M. tuberculosis.
Define Autoimmune Disease and Autoantibody
A condition where the immune system attacks the body’s own tissues.
Antibody produced against an antigen found in an individual’s own cells, tissues, or organs
What are ANAs?
Antinuclear antibodies that target substances within the nucleus of cells.
Includes: Anti-ds DNA (Lupus-specific) and Anti-Sm (Smith antigen) specific for SLE
What is the IIF test?
The most widely used, highly sensitive, inexpensive, wide range of Ab, easy to perform
It incubates patient serum with Hep-2 cells fixed onto a microscope slide
(Hep-2 cells are a human epithelial cell line; used because of their large nuclei)
It washes and incubates fluorescein- labeled anti-human IgG
What are the ANA patterns associated with SLE?
Homogeneous, Peripheral (Rim), and Fine/Coarse Speckled.
What is Rheumatoid Arthritis (RA)?
An autoimmune disease characterized by joint inflammation, chronic arthritis of peripheral joints that can progress to joint deformity and disability.
What antibodies are associated with RA?
Rheumatoid Factor (RF): IgM autoantibody directed against the Fc portion of IgG (capillary swelling, inflammation, deposits of immune complexes; initiates complement cascade) and Anti-Citrullinated Protein Antibodies (Anti-CCP).
