Hypersensitivity Flashcards
What are the 4 types of hypersensitivities
Type 1
type 2
type 3
type 4
what is the most common type of hypersensitivity
Type 1
the initial exposure of an Antigen and production of antibodies to that Ag is called ?
sensitization
T/F All types of hypersensitivity MUST have sensitization of the Ag before a hypersensitive reaction can occur
True
Type I hypersensitivity is mediated by what antibody
IgE
How fast does the type 1 hypersensitivity occur after reexposures to an antigen/allergen
w/in minutes
FAST*
What are the 5 syndromes associated w/ type hypersensitivity
1 - systemic anaphylaxis 2 - hives/ wheel and flare 3 - Hay fever 4 - asthma 5 - food allergy
type 1 hypersensitivity is often referred to as an _______ hypersensitivity
allergy or immediate
The release of mast cells in type 1 hypersensitivity triggers a biphasic response, what does this mean
1 - Immediate effects : dilation of vessels, vascular permability
2 - late response - inflammation via cytokine prod.
During the immediate response of type I hypersensitivity, a mast cell will degranulate causing release of vasoactive amines, and lipid mediators. What are the 2 lipid mediators we are responsible to know
Prostanglandins - vasoconstrict lungs
Leukotrines - bronchoconstriction and increase vascular permeability
during the late phase of the type I hypersensitivity, cytokines are secreted, in particular which ones ? What is their main responsibility
IL-4, IL-5, IL-13
Recruit eosinophils, neutrophils, and monocytes
lipid mediators prostanglandins and leukotrines are derived from what ?
arachodonic acid
What is the role of ITAMS in type I hypersensitivity
start signal cascade leading to degranulation of mast cell
once ITAMS is activated, it activates Map Kinase. what does Map kinase activate
1 - PKC
2 - production of cytokines
One of the responsibilites of Map kinase in the Type I hypersensitivity pathway is to activate PKC. What are teh two roles of PKC ?
1 - signal for movement of mast cells to surface and release granules
2 - Activate PLA
what does PLA activate in the type I hypersensitivity reaction
PLA —-> arachodonic acid —-> lipid mediators
what are teh most common signs/symptoms of asthma
cough, wheezing, shortness of breath
what is the most common trigger for asthma
dust mites
-there are hundreds of others though
dust mites secrete what specific enzyme that can enter through tight junctions and trigger mast cell degranulation
Der p 1
What are the 2 treatments strategies for asthma
- inhaled corticosteroids
- leukotriene modifiers
what is the functional role of eosinophils
kill parasites
the most severe form of type 1 (immediate) hypersensitivity is _____ ? Why ?
anaphylaxis
- severe drop in BP
- severe bronchoconstriction
Type II hypersensitivity is involved w/ what antibody
IgG
In type I hypersensitivity mast cells are activated, what does the binding of an antigen in type II hypersensitivity activate ?
Complement system proteins
What are the 3 types of Type II hypersensitivities we need to know ?
1 - Autoimmune hemolytic anemia
2 - Myasthenia gravis
3 - Graves disease
Autoimmune hemolytic anemia targets what cells
fetal RBCs
Myasthenia gravis does what to cause type II hypersensitivity
blocks Ach receptor (results in muscle weakness/paralysis)
Graves disease does what to cause type II hypersensitivity
stimutates TSH receptor
What are the treament strategies for 1) Autoimmune hemolytic anemia 2) Myastenia gravis 3) Graves disease
1 - prednisone, blood transfusion or rhogam
2 - myasthenia gravis - cholinesterase inhibitors and corticosteriods
3 - graves disease - radioactive iodine or anti-thyroid drugs
what is unique about type 3 hypersensitivites when an Ag comes into contact with an Ab
form an immune complex and clump together forming deposits in vessels
which type of immune-complex clumps would cause a type III hypersensitive reaction, Large aggregates or excess small aggregates
small aggregates b/c can deposit in excess in vessels and tissues = obstruct flow = occluded vessels
how long does a type III hypersensitive reaction occur after reexposure
3-10 hours
type III hypersensitivy induces inflammation in what 2 mechanisms ?
1 - mast cell activation
2 - macrophage release of TNF-x and IL-1 (induce inflammatory cascade)
The arthus reaction is triggered in the skin by IgG, this is an ex of what type of hypersensitivity
type III
what are the 3 examples of type III hypersensitivity we need to know
1 - arthus reaction
2 - serum sickness
3 - SLE (systemic lupus erythmatous)
how would one be exposed to arthus reaction (type III hypersensitivity)
- repeated subcutaneous vaccinations
- high levels of IgG immune complexes
the classic example for a transient immune-complex mediated syndrome is called
serum sickness
what is unique about the duration and treatment of serum sickness (type III hypersensitivity)
self limiting and will resolve itself over time
the most severe of the type III hypersensitivities is what ? Why is this ?
SLE (systemic lupus erythmatous)
-b/c its IgG fighting against a SELF-Ag
What is unique about type IV hypersensitivities
involve T cells inducing macrophage infiltration
when does a type 4 hypersensitivity occur after reexposure to an Ag
2-3 days
*** DTH or delayed type hypersensitivity **
What are the 5 examples of type 4 hypersensitivities that bitch Stiner Jones wants us to know ?
1 - Tuberculin hypersensitivty 2 - contact dermatitis 3 - chronic asthma 4 - Crohns disease 5 - graft rejection
type 4 hypersensitivities are initiated by _______ with the help of APC’s
haptens
**haptens alone to small to elicit immune response ***
The tuberculin test is conducted by injecting Ag intradermally and then looking for a response w/in 2-3 days. If there was a response it would be mediated by what kind of t cells
TH1 cells
contact dermatitis is a type of type 4 hypersensitivity and occurs in 2 phases, what are they
1 - sensitization - exposure to Ag and formation of CD4 memory T cells
2 - elicitation - reexposure and T cells relaease IFN-gamma to recruit macs
chronic asthma is a type 4 hypersensitivity. What t cells mediate this reaction and what do they cause ?
Mast cell degranulation causes TH2 cells to increase eosinophils
Initial presentation of what type 4 hypersensitivity may be in the oral cavity
Crohns disease
-type of bowel disease
For all types of hypersensitivites, which of them occur b/c of soluble antigens ?
Which occur b/c of Ag found on cell surface
Type 1,3,4 find soluble antigens
Type 2 find cell surface Ag
