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Flashcards in Hypersensitivity Deck (25):
1

Type 1 Hypersensitivity

Immediate
Mechanism: IgE
Main player: Antibodies
Mechanism of injury: Mast cells and their mediators

2

Type 2 Hypersensitivity

Antibody mediated
Mechanism: IgM, IgG. Against cell surface or ECM antigens
Main player: Antibodies
Mechanism of injury: Opsonization and phagocytosis, complement

3

Type 3 Hypersensitivity

Immune complex mediated
Mechanism: IgM or IgG + antigen
Main player: Antibodies
Mechanism of injury: Complement

4

Type 4 Hypersensitivity

T cell mediated
Mechanism: CD4+ T cells (cytokine-mediated inflammation)
CD8+ T cells (T cell mediated cytolysis)
Main player: T cells
Mechanism of injury: Recruitment and activation of leukocytes

5

Mast cells activated by cross-linking of ____

Fc-epsilon-RI molecules

6

Lipid mediators of type 1 hypersensitivity
Causes:

Prostaglandin D2, Leukotrienes C4, D4, E4
Vasodilation, increased vascular permeability, bronchoconstriction, mucus secretion

7

Cytokine mediators of type 1 hypersensitivity
Causes:

IL-4, IL-5, IL-13
Inflammation/late-phase reaction, IgE production, Eosinophil production/activation

8

Autoimmune hemolytic anemia

IgG against protein antigens on surface of RBCs

9

Acute Rheumatic Fever

Type 2 hypersensitivity
Molecular mimicry
Occurs 2-4 weeks after group A streptococcus pharyngitits

10

Post-streptococcal glomerulonephritis

Type 3 hypersensitivity
Immune complexes in glomeruli trigger inflammation
Occurs after skin or throat infection w/ group A streptococci
Very low serum C3

11

TH1 produce ____ which leads to ____

IFN-gamma
activate macrophages

12

TH17 produce ____ which leads to ____

IL-17
Recruit neutrophils

13

Poison ivy dermatitis

Type 4 hypersensitivity

14

AIRE gene mutations

Failure to delete autoreactive T cells

15

APECED

AIRE gene mutations
Autoimmune PolyEndocrinopathy, Candidiasis, Ectodermal Dystrophy
Hypoparathyroidism, adrenal insufficiency, hypogonadism

16

FAS gene mutations

Impaired apoptosis

17

ALPS

FAS gene mutations
Autoimmune LymphoProliferative Syndrome
Hemolytic anemia, thrombocytopenia (low platlets), neutropenia (low neutrophils)
Increased risk of lymphoma

18

FOXP3 gene mutations

Impaired regulatory T cells

19

IPEX

FOXP3 gene mutations
Immune dysregulation, Polyendocrinopathy, Enteropathy, X-linked
Chronic life-threatening diarrhea due to enteropathy, dermatitis

20

Systemic Lupus Erythematosus

Type 3 Hypersensitivity
IC deposition

21

Rheumatoid Arthritis
Cytokines:

Type 4 Hypersensitivity
T cell and Abs --> joint inflammation
Innate immune response in synovium
Proinflammatory cytokines: IL-17, TNF, IL-1

22

Diabetes Mellitus Type 1
Inflammation mediated by:

Type 4 Hypersensitivity
Immune-mediated destruction of pancreatic beta cells of islets of Langerhans --> insulin deficiency
Mediated by CD4 TH1 cells

23

Myasthenia Gravis

Type 2 Hypersensitivity
Abs against acetylcholine receptors at postsynaptic membrane of neuromuscular junction

24

Graves' Disease

Type 2 Hypersensitivity
Hyperthyroidism
Simulated by immune response

25

Hashimoto's Thyroiditits

Hypothyroidism
Autoimmune destruction of thyroid gland