Module 7 Hypersensitivity Flashcards
Hypersensitivity is a normal immune response that is… (3)
Inappropriately triggered, excessive, or produces undesirable effects on the body
2 basic mechanisms that trigger hypersensitivity
antigen-antibody reaction or antigen-lymphocyte interaction
Four types of hypersensitivity: 1-3
mediated by antibodies produced by B cells, specifically plasma cells
Hypersensitivity type 4 is mediated by
T cells
B lymphocytes are immature until
they come across antigen and become a mature plasma cell
Types 1-3 is an
immediate reaction
type 4 will take longer because
T cells don’t have the immediate reaction like B cells do
Type 1 hypersensitivity
IgE mediated reaction
IgE is in response to someone developing an
allergy (ex: pet dander, pollen)
antibodies aka
immunoglobulins
Type 1 hyper sensitivity can become
anaphylactic
Type 1 hypersensitivity is
immediate
Type 1 hypersensitivity requires a
previous exposure to the antigen
Most allergens are
proteins
Type1 : If 1 parent is allergic
30% chance offspring will be allergic
Type 1: If both parents allergic
50% chance offspring will be allergic
Key cells involved in type 1 sensitivity
B lymphocytes, IgE antibodies, mast cells
allergy medications block chemical mediator release by blocking
histamine
allergic rhinitis
runny nose
uticaria
hives
asthma have
overactive mast cells
systemic release of chemical mediators
anaphylaxis
During anaphylaxis
bronchial constriction, airway obstruction, vascular collapse from widespread vasodilation (low BP)
type 2 hypersensitivity
cytotoxic reaction
type 2 hypersensitivity exposure to a
foreign tissue or cell type, antigens are located on cell surface
example of a type 2 hypersensitivity
organ transplant
in type 2 hypersensitivity
antigen-antibody complex attacks foreign cells, lyses them, and then phagocytes clean up
cells involved in type 2 hypersensitivity
IgG and IgM, phagocytes, complement cells (kill the foreign cells)
Examples of type 2 hypersensitivity
blood, diabetes, erythroblastosis fetalis
erythroblastosis fetalis
hemolytic anemia in the fetus, rh factor
type 2 hypersensitivity leads to
kidney damage because the small blood vessels are clogged AND less RBCs so no oxygen supply
Autoimmune disorders than can cause type 2 hypersensitivity
hemolytic anemia, myasthenia gravis, graves disease
medication used to treat rh factor
rhogam
signs and symptoms of a blood transfusion reaction
fever, chills, flushing, tachycardia, hypotension, chest or back pain, nausea, vomiting, restlessness, anxiety, headache
we take patient’s
temperature before and after a blood transfusion because this is one of the first signs
type 3 hypersensitivity
immune complex reaction
example of type 3 reaction
RA
type 3 hypersensitivity reaction step 1
antigen-antibody complex circulate in body and deposit into various tissues
type 3 hypersensitivity reaction step 2
the antigen-antibody complex causes inflammation in the tissue that it is lodged in and this is the type 3 reaction we see
etiology of hypersensitivity type 3
autoimmune attack, low grade infection, inhaled antigens from molds or contaminated plants, bacteria or viruses
key cells involved in type 3 hypersensitivity
IgG, IgM, complement, neutrophils, mast cells
neutrophils release toxins and chemical mediators that
cause tissue destruction
mast cells dump chemical mediators that cause the
inflammatory response
Type 3 clinical manifestations (3)
rheumatoid arthritis (joints), glomerulonephritis (kidney failure), systemic lupus erythematous (skin)
in type 2 hypersensitivity, the complexes attack the foreign cell
directly
in type 3 hypersensitivity, the complexes do NOT destroy the foreign cells, they
cause inflammation in tissues where the complexes are stuck and the inflammation is what causes the tissue to be destroyed
type 4 hypersensitivity
delayed hypersensitivity
examples of type 4 hypersensitivity
poison ivy, TB skin test, jelly fish sting, jewelry reaction, crohn’s disease
in type 4 hypersensitivity
there are no antibodies involved
key cells in type 4
T cells, cytokines, mast cells, macrophages
steps of type 4 hypersensitivity
hapten comes through skin and created complete antigen, t cells recognize and attack to release cytokines (inflammation), macrophages clean up
type 4 generally peak in
48-72 hours
two most common type 4 reactions
contact dermatitis, and tuberculin hypersensitivity
3 pharmacology options
immunosuppressants, antihistamines, epinephrine
suppress histamine mediator activity
antihistamines
suppress cell mediated immunity and inflammatory response
immunosuppressants and corticosteroids
halts mediator activity
epinephrine
epinephrine works on
alpha and beta receptors
where are alpha receptors
arteries
where are beta receptors
in the heart, lungs, arteries, skeletal muscles
for epi subcut use a
TB syringe
teach patients when taking epinephrine to
take exactly as directed and to contact HCP immediately after taking it
