Chapter 12: Hypersensitivities

Question 1

Anergy

Answer 1

reduced/complete loss of lymphocyte response to an antigen

occurs in immunodeficiency

Question 2

Hypersensitivities

Answer 2

reactions differ based on which components (cells) of immune system are activated, onset of symptoms, and mechanism of injury
Type 1-3 = humoral mediated (B cells)
Type 4 = cell-mediated (T cells)

Question 3

Allergies

Answer 3

reaction to harmless environmental antigen

Question 4

Autoimmune Diseases

Answer 4

production of autoantibodies = autoreactivity

Question 5

Type 1 - Immediate (Allergic) Response

Answer 5

Antibody: IgE
develops rapidly
Cells involved: Type 2 helper T cells and mast cells (release histamine)
Can be localized: contact dermatitis, allergic rhinitis
or systemic: asthma, anaphylaxis

Question 6

Type 2 helper T cells

Answer 6

helps differentiate B lymphocytes into plasma B cells which produce antibodies

Question 7

Eosinophilic Chemotactic Factor

Answer 7

attracts eosinophils to areas

Question 8

Type II - Antibody-Dependent Cell Cytotoxicity (ADCC)

Answer 8

Antibodies: IgG and IgM
intermediate acting - within 24 hours
antibodies bind to antigen on the surface of a specific cell type
stimulates activation of the complement system, NK cells, and macrophages
basis of many autoimmune disorders

Question 9

Examples of Type II Hypersensitivity Reaction

Answer 9

rheumatic fever, hemolytic anemia
Goodpasture syndrome
Inhibiting target: myasthenia gravis
Stimulating target: Graves disease

Question 10

Type III: Immune Complex (Complement) Mediated

Answer 10

Antibodies: IgG and IgM
intermediate acting - within 24 to 48 hours
antibodies bind to antigens within the plasma (free-floating)
triggers the complement system and inflammation results

Question 11

Examples of Type III Hypersensitivity Reactions

Answer 11

SLE
serum sickness
rheumatoid arthritis, nephritis, vasculitis
Arthus reaction

Question 12

Type IV: Cell-Mediated

Answer 12

no antibodies involved - involves T lymphocytes
delayed response > 3 days
Cells involved: Type 1 helper T lymphocytes (CD4) and cytotoxic T lymphocytes (CD8)

Question 13

Type 1 helper T lymphocytes

Answer 13

release cell damaging cytokines such as interferon which stimulates macrophages to produce granulomas

Question 14

Examples of Type IV Hypersensitivity Reactions

Answer 14

Contact dermatitis
Mantoux test (TB screening test)
Transplant rejection