Exam 3 part 2 - hypersensitivity Flashcards
type 1 hypersensitivity
allergic reaction
causative mechanism type 1 hypersensitivity
allergen causes formation of IgE antibodies from B lymphocytes. They attach to mast cells. (Mast cells are connective tissue cells that are present in large numbers in mucosa of the respiratory and digestive tracts.) upon re-exposure to the allergen, the allergen attaches to the IgE on the mast cells causing the release of histamine. Histamine causes an inflammatory response
s/s type 1 hypersensitivity
- general, sudden vasodilation resulting in a rapid drop in blood pressure
- edema of the mucosa
- constriction of the bronchioles occurs obstructing airflow.
- hives (urticaria) and rashes (atopic dermatitis)
- Itching
- skin erythema
- Vomiting
- Abdominal cramping
- allergic rhinitis (hay fever - redness and inflammation of nose and eyes)
type 2 hypersensitivity
Antibody mediated
- Complement- and antibody-mediated cell destruction, inflammation, cell dysfunction
type 2 hypersensitivity causative mechanism
IgG or IgM binds antigens on cell surfaces
- On red (AB or Rh) or white blood cells
– Transfusion reactions
– Drug reactions (heparin induced thrombocytopenia)
- On tissues
– Goodpasture syndrome (antibodies attack basement membrane in lungs and kidneys), Graves disease, myasthenia gravis
Complement and antibody mediated cell destruction (type 2)
- Blood incompatibility understand blood typing
- Drug reaction Hemolytic anemia from penicillin
Complement and antibody mediated inflammation (type 2)
Antibodies deposited on extracellular tissue tissue damage results from inflammation
- Rejection of organ grafts
- Goodpasture syndrome (condition when antibodies are deposited on basement membrane - inflammation)
– Deposit of antibodies on basement membrane in lungs and kidneys
Antibody mediated cellular activation or destruction (type 2)
- Graves disease - change in cell function
– Antibody bonds to receptors on thyroid gland hyperthyroidism - Myasthenia gravis - binds to Ach receptor destroying the receptor
type 3 hypersensitivity
immune complex hypersensitivity
type 3 hypersensitivity causative mechanism
- Free-floating antigen + antibody
- Immune complexes deposit on walls of blood vessels and activate complement inflammation and blood vessels damage
Systemic type 3
Autoimmune vasculitis, glomerulonephritis, serum sickness (serum sickness immune complex is deposited in blood vessels, joints, heart and kidney tissue protein from non-human sources venom, antibodies)
systemic type 3 s/s
urticaria (hives), patchy or generalized rash, extensive edema and fever
local type 3
- Arthus reaction - localized tissue necrosis - certain drug reaction
- Administration of antibiotics CANNOT cause this
type 4 hypersensitivity
cell-mediated delayed hypersensitivity (only one with t cells) takes days for adverse ration to happen
type 4 causative mechanism
- Cell-mediated: sensitized T cells attack antigen
- Direct cell-mediated cytotoxicity
– Cytotoxic T cells directly kill antigen containing cell
— Viral reactions - cytotoxic T cells kill viral infected cells - Delayed-type hypersensitivity
– Response to soluble protein antigen
– Macrophages, T helper cells
type 4 examples
Tuberculin test, allergic contact dermatitis, hypersensitivity pneumonitis, poison ivy, transplant rejection, MS, rheumatoid arthritis, IBD, type I diabetes, Hashimoto’s thyroiditis
