Hypersensitivity and Mechanisms of Autoimmune Disease Flashcards
Type 1 Hypersensitivity
- What is the mechanism of action behind this type of hypersensitivity?
In type 1 hypersensitivity, injury is caused by what cells?
TH2 cells, mast cells, and IgE antibodies
What are the common features of antigens that elicit a T1H Rxn?
With regards to T1HRxns, when a person experiences a repeat exposure following sensitization, what are the phases of response they experience?
Immediate (within 1 hour of exposure)
Late (2 - 24 hours post exposure)
What is allergic skin testing?
What is systemic anaphylaxis?
Immediate hypersensitivty reaction characterized by edema, decrease in BP due to vasodilation and vascular leakage
What is the treatment for anaphylaxis?
Epinehprine –> causes vasoconstriction, bronchodilation, increased CO
What are the major outcomes of systemic anaphylaxis?
SHOCK
Diarrhea
Hives
Excess broncial mucus (due to bronchoconstriction)
What clinical syndromes are associated with T1H Rxn?
Allergic rhinitis
Food allergies
Bronchial asthma
Anaphylaxis
What is atopy? What role does it play in forming allergies?
What is the concept of an allergy “vaccine”?
What is type 2 hypersensitivity?
T2H Rxn is caused by antibodies that recognize either normal cell tissue as foreign or exogenous antigens. What 2 principles underlie the reason why this Rxn incorrectly recognizes normal protein as antigen?
Rheumatic fever is an example of […] hypersensitivity.
Type 2
Systemic lupus erythematosus is an example of […] hypersensitivity.
Type 2
In rheumatic fever, the body produces antibodies against […], which then cross react with heart tissue causing the disease.
Streptococcal cell wall
Type 2 hypersensitivity is associated with causing some auto-immune conditions. If the antibodies attack self antigen without causing injury or inflammation, what type of condition is the T2H causing then?
Cellular dysfunction - Abs directed against cell surface proteins and impair function w/o causing injury / inflammation
Graves’ disease and myasthenia gravis are examples of […] hypersensitivity.
Type 2
One outcome of a type 2 hypersensitivity reaction is opsonization / phagocytosis. What kind of damage does this cause?
Responsible for depletion of cells coated with Abs
By what means does a type 2 hypersensitivity rxn cause inflammation and what is the resultant injury to the tissue?
Note here that it is the individual ANTIBODIES depositing in tissue and causing inflammation via complement activation (classical) and activating neutrophils
What is type 3 hypersensitivity?
What processes is this specific to?
What are the possible outcomes of this reaction?
Describe the mechanism of action of type 3 hypersensitivity.
What is type 4 hypersensitivity?
