Hypersensitivity Reactions and Transplant Rejection EC Flashcards Preview

ZImmunology > Hypersensitivity Reactions and Transplant Rejection EC > Flashcards

Flashcards in Hypersensitivity Reactions and Transplant Rejection EC Deck (12):
1

Type I Hypersensitivity

Anaphylactic/atopic
Antigen cross links IgE on sensitized mast cell--> Histamine
Rapid response with preformed antibody
"Wheel and flair" reaction

2

Type II Hypersensitivity

Cytotoxic (antibody mediated) - IgM, IgG bind fixed antigen which leads to cellular destruction
~opsonization w/ phagocytosis
~complement activation and lysis
~Antibody mediated killing via NK cells

3

Type III Hypersensitivity

IgG immune complexes deposit

Serum sickness- Immune complexes deposit in membranes where they fix complement

Arthus reaction- Intradermal injection of antigen leads to deposition of complexes in the skin (edema necrosis, complement activation)

4

Type IV Hypersensitivity

Delayed (T-Cell mediated)
Sensitized T-Lymphocytes recognize antigen and release lymphokines

5

Examples and Presentation of Type I Hypersensitivity

Anaphylaxis (bee sting, food/drug allergies)
Allergic/atopic disorders (rhinitis, hay fever, eczema, hives, asthma)

Immediate anaphylactic

6

Examples and Presentation of Type II Hypersensitivity

Autoimmune hemolytic anemia, Pernicious anemia, ITP, Erythroblastosis fetalis (Rh mismatch w/ mother), Acute hemolytic transfusion reactions, Rheumatic fever, Goodpasture's, Bullous pemphigoid, Pemphigus vulgaris

Specific to tissue or site where antigen is found (local)

7

Examples and Presentation of Type III Hypersensitivity

SLE, Polyarteritis nodosa, Poststrep. glomerulonephritis, Serum sickness, Arthus reaction

Vasculitis and systemic manifestations

8

Examples and Presentation of Type IV Hypersensitivity

MS, Guillain-Barre, GVH, PPD, Contact dermatitis (poison ivy, Nickel allergy)

Response is delayed and does NOT involve antibodies (T-Cell mediated)

9

Rejection of transplant within minutes with occlusion of graft vessels causing ischemia and necrosis.

Hyperacute graft rejection

Antibody mediated (type II)
Presence of preformed anti-donor antibodies

10

Rejection of transplant weeks later with vasculitis of graft vessels with dense interstitial lymphocytic infiltrate.

Acute graft rejection

Cytotoxic T-cell reaction to foreign MHC
Reversible with immunosuppressants

11

Rejection of transplant months to years later. Irreversible T-cell and antibody mediated vascular damage.

Chronic graft rejection

Class-I MHC(nonself) is perceived by CD8 cells as self presenting non-self antigen.

12

Maculopapular rash, jaundice, hepatosplenomegaly, diarrhea following transplant.

GVH disease

Grafted immunocompetent T cells proliferate and reject foreign (host) cells. Severe organ dysfunction.