Hypersensitivity 1 and 2 Flashcards Preview

POD Exam II > Hypersensitivity 1 and 2 > Flashcards

Flashcards in Hypersensitivity 1 and 2 Deck (31):
1

Hypersensitivity:

An exaggerated response resulting i harm to the host.

2

Type I hypersensitivity results in:

Release of mediators from IgE-sensitized mast cells.

3

Components of Type I hypersensitivity immediate reaction (5):

1. Allergen specific IgE.
2. Mast cells.
3. Allergen.
4. Eosinophils.
5. CD4+ Th2 cells

4

Type I hypersensitivity late-phase:

Develops more slowly, characterized by the accumulation of neutrophils, eosinophils and macrophages.

5

Type I hypersensitivity - sensitization (4):

1. First exposure to allergen.
2. Antigen activation of Th2 cells and stimulation of IgE class switching in B cells (IL-4).
3. Production of IgE.
4. Binding of IgE to FC receptors on mast cells.

6

Mediators of the Type I hypersensitivity immediate reaction:

- Vasoactive amines (histamine).
- Lipid mediators.

7

Mediators of the Type I hypersensitivity late-phase reaction:

Cytokines.

8

Biologic effects of histamines (2):

1. Vasodilation.
2. Vascular leak.

9

Biologic effects of lipid mediators (2):

1. Broncho-constriction.
2. Intestinal hypermotility.

10

Biologic effects of cytokines:

Inflammation.

11

Biologic effects of enzymes:

Tissue damage.

12

Type I hypersensitivity late phase reaction(3):

- IL-5 from mast cells and Th2 cells recruit and activate eosinophils.
- Eosinophils release additional mediators.
- Begins within 4-8 hours and lasts 1-2 days.

13

Disease states caused or affected by Type I hypersensitivity (6):

1. Allergic rhinitis.
2. Allergic asthma.
3. Eczema or atopic dermatitis.
4. Some food allergy.
5. Some drug allergy.
6. Insect venom allergy.

14

Allergic march:

Progression of allergic symptoms with age.

15

Allergen-specific serum IgE test:

1. Plate (solid phase) coated with allergen.
2. Patient's serum added.
3. Labeled anti-IgE added.

16

Serum IgE levels - ELISA method:

1. Solid surface coated with anti-IgE antibody.
2. Patient's serum added.
3. Labelled anti-IgE added.

17

Type II hypersensitivity:

- Antibody mediated hypersensitivity.
- Involves IgM or IgG antibodies.
- Involves a circulating antibody and its target antigen.
- Antigen is located either on the surface of a cell in circulation or in a tissue.

18

Antibody-dependent cell-mediated cytotoxicity:

ADCC
- IgG antibodies serve as "bridges" to link target cells to effector cells.

19

Mechanisms of Type II hypersensitivity (3):

1. Complement and Fc receptor mediated inflammation (ADCC).
2. Opsonization and phagocytosis.
3. Abnormal physiologic responses without cell/tissue injury.

20

Disease associations of Type II hypersensitivity (6):

1. Transfusion reaction.
2. Hemolytic disease of the newborn.
3. Autoimmune hemolytic anemia.
4. Goodpasture syndrome.
5. Pemphigus vulgaris.
6. Rheumatic fever.

21

Direct Coombs test:

Picks up antibodies directly on the surface of the red blood cell:
- Pt's blood added to anti-Ig leads to agglutination of RBC.

22

Direct Coombs test is used to diagnose (3):

1. Hemolytic disease of the newborn.
2. Autoimmune hemolytic anemia.
3. Transfusion reaction.

23

Indirect Coombs test:

Measures anti-RBC antibodies in the serum.
- Uncoated RBCs added to serum from pt with antibodies, anti-Ig added, agglutination of RBC.

24

Main use of indirect Coombs test:

Blood banking:
- Cross-matching.
- Blood typing.
- Ab detection.
- Ab identification.

25

Clinical symptoms of a transfusion reaction (4):

1. Fever.
2. Low BP.
3. Nausea and vomiting.
4. Back and chest pain.

26

Hemolytic disease of the newborn:

Erythroblastosis fetalis:
- Dramatic type II reaction.
- Antigen present on the surface of the red cell, RhD.
- Occurs in second pregnancy of woman who is RhD- and has RhD+ baby.

27

Hemolytic disease of the newborn if untreated causes (4):

1. Elevated bilirubin.
2. Large liver and spleen.
3. Petechiae.
4. Positive direct Coombs test.

28

Autoimmune hemolytic anemia:

AIHA
- Pt's produce anti-RBC antibodies.
- Can cause hemolysis of RBCs.
- Positive direct Coombs test.

29

Pemphigus vulgaris:

- Disease of skin and mucous membranes.
- Causes blisters all over body.
- Autoantibodies against intercellular cement substance of skin and mucous membranes.

30

Goodpasture's syndrome:

- Targets basement membranes of kidney glomeruli and lung alveoli.
- Leads to acute glomerulonephritis and pulmonary hemorrhage.

31

Acute rheumatic fever:

- Follows a throat infection with group A strep.
- Symptoms present about 2-4 weeks following onset of infection.
- JONES
- Molecular mimicry with cardiac antigens.