Hypersensitivity reaction Flashcards by Jesutofunmi Ogunbona

in hypersensitivity reaction the body responds to new antigens in an excessive manner
T or F

F
renewed contact with an antigen it already knows

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according to gell and coombs classify hypersensitivity reactions

anaphylactic
cytotoxic/cytolytic
immune/toxic complex reaction
cell mediated hypersensitivity

or can be called type 1-4
first 3 require antibodies
last one requires T cells and macrophage

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Hypersensitivity is the excessive pathogenic reaction of a SENSITIZED body to renewed contact with the SENSITIZING antigen.
T or F

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antigens in type 1 H.R are usually called

allergens
examples include
tree grass and weed pollens
cat and other animal antigens
dust mite fecal pellets antigens
mold spores

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individuals that inherit genes that make them susceptible to allergens is manifested by their ability to make what kind of responses?

strong Th2 responses and subsequent production of igE against allergens

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mast cells and basophils are implanted on FcR of IgE in type 1 H.r
T or F

F
it is the other way round
igE on FcR of mast and basophils

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first implantation of igE on mast cells causes ____

priming of mast cells
2nd and subsequent exposure causes cross linking of IgE on surface of mast cells

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in type 1 H.R complement system is involved
T or F

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what are the 3 ways allergens might be introduced to the body

inhalation
ingestion
injection

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what helper cell is involved in type 1 hypersensitivity

Th2 cells
because they secrete il4 which attracts igE

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example of a chemokine produced locally which attracts eosinophils is

eotaxin

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what’s the function of il13 secreted by Th2 cells in type 1 H.R

stimulation of epithelial cells to produce mucous

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mast cells receptors with high affinity for the __a__ portion of igE are called __b__

a. Fc
b. FceRI

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Basophils which are the circulating counterparts of mast cells have a role in type 1 hypersensitivity
T or F

F
their role in H.R 1 is not established

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FceRi receptors are expressed in what 3 cells

mast cells
basophils
eosinophils

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on 1st exposure priming of mast cells occur while on subsequent exposure degranulation occurs
T or F

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list 3 locations where mast cells can be found

blood vessels
skin
lungs

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list 2 mediators of type 1 H.R

histamine - responsible for the wheal and flare as well as edema
serotonin

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systemic anaphylaxis is an example of type 1 H.R
T or F

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local anaphylaxis also called __a__ is an example of __b__ H.R

a. atopy
b. type 1

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Hives is a clinical manifestation of food allergy
T or F

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hay fever(allergic rhinitis) is presented clinically as pulmonary edema and mucous in nasal mucosa
T or F

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wheel and flare allergic reaction can occur due to insect bites
T or F

insect stings and snake venom can cause systemic anaphylaxis
T or F

autoimmune hemolytic anemia pernicious anemia graves disease ALL these are examples of type 2 hypersensitivity T or F

Type 2 h.r can be divided into 3 list them

1.complement dependent cytotoxicity e.g autoimmune hemolytic anemia 2.antibody dependent cytotoxicity e.g Pernicious anemia 3. anti receptor antibody e.g graves disease where antibody stimulate thyroid gland oversecretion

list 4 diseases under complement dependent cytotoxicity

transfusion reaction due to blood incompatibility erythroblastosis fetalis (igG mediated) attack of glomerular basement membrane type 4 collagen (Goodpasture syndrome) autoimmune hemolytic anemia

in antibody-dependent cytotoxicity there is presence of inflammatory cells such as Nk cells and monocytes and they phagocytize the cell T or F

F they do not phagocytize the cell they cause it to lyse

NOT A QUESTION difference between complement mediated and antibody mediated cytotoxicity is that in complement mediated there is activation of complement with subsequent formation of MAC which lyses the cell while in antibody mediated there's no complement activation and inflammatory cells like nk and monocytes are the ones lysing the cells

Joy is coming

least 3 example of antibody mediated cytotoxicity

Transplant rejection immune reaction against parasite immune reaction against neoplasm pernicious anemia

in anti receptor antibody, the complement system is involved T or F

T they mediate the destruction of the receptors while antibodies mediate either the inhibition or unregulated activity of the receptor

anti receptor antibody type 2 h.r can sometimes be called

Type 5 hypersensitivity seen in myasthenia Gravis where antibody block Nm and prevents stimulation other reactions where this can be seen include graves disease pernicious anemia(they also listed it under antibody mediated cytotoxicity I don't know why)

Type 3 hypersensitivity reaction is mediated by immune complexes which promote tissue damage primarily through complement activation T or F

in type 3 h.r immune complexes are formed then are deposited in tissue due to inflammation/ disease T or F

in type 2 h.r serum complement is reduced because it is used up in this process T or F

F type 3 reaction not type 2

type 3 H.R is due to high level of circulating soluble immune complexes containing igG or igM T or F

T this high amount overwhelm the ability of the mononuclear system to remove them thus depositing in various tissues and activate complement

in type 3 h.r the antigen is not an intrinsic component of the target cells T or F

T it's in slide

chemotactic complement for neutrophils release of prostaglandins, kinin and free radicals factor 12 activation platelet aggregation All these occur in hypersensitivity type 3 reactions T or F

in type 3 H.R systemic immune complex diseases, smaller immune complexes are quickly phagocytized by macrophages and removed, but large to intermediate complexes formed with antigen excess may escape removal T or F

F swap small and large i.e the small to intermediate ones escape phagocytosis

NOT A QUESTION the immune complexes in type 3 h.r can be systemic or localized

list 3 example of systemic immune complex disease

vasculitis glomerulonephritis serum sickness

example of local immune complex disease(type 3) is

Arthus reaction usually happens when given tetanus injection with a characteristics vasculitus near/at the site of injection another example is hypersensitivity pneumonitis(farmers lungs)

type 4 H.R is mediated by SENSITIZED Th2 lymphocytes T or F

F Th1 lymphocytes

list 3 disease where type 4 H.R is found in

Virus granuloma Tumor

Cd4+ T cell reaction are specifically called

Delayed type hypersensitivity and inflammation

Cd8+ T cell reaction are specifically called

cell mediated cytotoxicity for some reason slide called it cytotoxicity no be me

in delayed type hypersensitivity there is accumulation of mainly cd4+ T cell but with persistent or non degradable antigens the predominant cell eventually becomes macrophages T or F

In delayed type hypersensitivity the macrophages are activated and become ____

epitheloid cells

an aggregation of epitheloid cells surrounded by a collar of lymphocytes are called

granulomas

contact with urushiol(antigeniccomponent of poison ivy/oak) can cause a delayed hypersensitivity reaction called

Contact or vesicular dermatitis

list 2 examples of cell mediated cytotoxicity h.r disease

diabetes type 1 graft rejection

cytotoxic T lymphocytes secrete 3 enzymes into cells in cell mediated cytotoxicity h.r list them

perforins granzyme serglycin nb: CTL also express Fas ligands which can bind to death receptors on target cells

cd8+ T cells produce IFN-Y T or F

transplant rejection is also under type 4 h.r reaction T or F

NOT A QUESTION Contact dermatitis despite involving allergens is not classified under type 1 h.r but it is under type 4

Poison ivy (catechols) Nickel Formaldehyde Latex Chromium Dyes in clothing and cosmetics are all examples of contact allergens T or F

T contact allergens are allergens that can cause contact dermatitis

in Cytotoxic T lymphocyte (CTL) mediated responses cytokines are not involved T or F

T it's in slide class 1 HLA molecules play a role though