Immunology: Test 2: 1. Hypersensitivity Type I And Ii

Front 1

What is a type I hypersensitivity reaction?

Back 1

immediate hypersensitivity
allergy

Front 2

What type of antibody does Type II hypersensitivity rxn involve?

Back 2

IgG

Front 3

What does Type III involve?

Back 3

immune complex hypersensitivity

Front 4

What is Type IV hypersensitivity?

Back 4

Delayed Type Hypersensitivity (DTH) = Cell-mediated Hypersensitivity

Front 5

please describe a few common Type I reactions

Back 5

common seasonal allergic rhinitis, allergic asthma, atopic dermatitis, acute urticaria (hives), and in the extreme situation, anaphylactic reactions.

Front 6

what is a Hypersensitivity reaction

Back 6

excessive immune response that causes damage

Front 7

describe the term allergy

Back 7

Type I Hypersensitivity - refers to certain diseases in which immune responses to environmental antigens cause tissue inflammation and organ dysfunction

Front 8

what is an allergen?

Back 8

an antigen that induces allergic reaction

Front 9

what is atopy?

Back 9

Simply stated, atopy is allergy mediated by IgE antibody. Individuals exhibiting these immediate hypersensitivity responses are called atopic.

Front 10

what is the time frame and exposure necessary involved in type I reactions

Back 10

occur within minutes to hours after the second exposure to an allergen

Type I reactions are initiated when allergen binds to IgE on the surface of mast cells, causing degranulation with release of bioactive substances (e.g., histamine).

Front 11

where do IgE antibodies bind?

Back 11

bind to high affinity FCεRI on mast cells and basophils

Front 12

what should you think if you have elevated serum IgE

Back 12

elevated serum levels in atopic disease and parasitic infection

Front 13

does IgE activate a complement? cross the placenta? what is its structure?

Back 13

-No it does not activate a complement
-it does not cross the placenta
-it is only a monomer

Front 14

what additional domain does an IgE have?

Back 14

has an additional H-chain domain

Front 15

type I is associated with what Ab?

Back 15

IgE

Front 16

Type II uses what Ab?

Back 16

IgG

Front 17

What is another name for Type II HS rxns?

Back 17

Cytotoxic

Front 18

What do type III reactions use?

Back 18

immune complexes

Front 19

what are immune complexes (basically)

Back 19

the consequence of Ab mediated immune rxns

Front 20

what type of high affinity receptors do mast cells and basophils have? what do they like to bind to?

Back 20

FCεRI

binds IgE

Front 21

Hayfever, asthma, anaphylaxis, and atopic dermatitis are all examples of what type of hypersensitivity (HS) rxn?

Back 21

Type I

Front 22

What is atopy again?

Back 22

A genetically determined state of hypersensitivity to common environmental allergens, mediated by IgE antibodies

Front 23

what is atopy mediated by?

Back 23

IgE

Front 24

So if you can't see when there is tons of pollen, or if you sneeze like crazy in spring time, what kind of individual are you?

Back 24

an atopic

Front 25

what is Allergic Rhinitis (Hay fever)

Back 25

The most common clinical expression of atopic hypersensitivity

Front 26

Is atopy genetic?

Back 26

yes!

Front 27

if both parents are atopic, what percentage of children will be atopic?

Back 27

50%

Front 28

list the sequence of events for a type I rxn

Back 28

allergen presented to immune system

TH2 is produced (more in atopic ppl)

Start making more IgE ab

binds to FCepsillon1 receptor on mast cell

activation occurs

granules released from mast cell (histamine and enzymes)

get hypersensitivity rxn in minutes

Front 29

if atopic, what type of TH response will you have more than a non atopic person?

Back 29

TH2

TH2 leads to the release of IL-4

IL4 facilitates B-cell proliferation and IgE antibody expression

thus this makes sense

Front 30

What 2 cells have FCepsillon1 receptors?

Back 30

basophils and mast cells

Front 31

what is the most common clinical expression of atopic hypersensitivity

Back 31

Allergic rhinitis

Front 32

are mast cells found in the blood or tissue resident? basophil?

Back 32

mast cell: tissue
basophil: blood

Front 33

what preformed mediators are released by mast cell?

Back 33

Histamine
Enzymes (chymase, tryptase, esterase)

Front 34

what is anaphylaxis?

Back 34

is an acute, generalized allergic reaction with simultaneous involvement of several organ systems --- usually cardiovascular, respiratory, cutaneous, and gastrointestinal

In other words, it is a systemic, severe form of type I hypersensitivity.

Front 35

what is an Anaphylactoid reaction ?

Back 35

is one in which the symptoms and signs of anaphylaxis occur in the absence of an allergen-antibody mechanism. In this case, the endogenous mediators of anaphylaxis are released in vivo through a non-immunologic mechanism

Front 36

What are some of the causes of anaphylactoid reactions?

Back 36

drugs, insect venom, or food

Front 37

A 4-year old atopic girl (hypersensitive to various types of grass) is outdoors playing when the nextdoor neighbor starts mowing the grass.

She inhales the grass allergens and . . .

Back 37

. Allergen binds to IgE on mast cells causing degranulation and release of inflammatory mediators

Front 38

what do you do to treat anaphylaxis? 2

Back 38

Aqueous epinephrine given I.M. or S.C. and repeated if needed.

Antihistamines for urticaria, angioedema, and GI reactions

Front 39

what can be found in nasal secretions in a lab finding?

Back 39

eosinophils

Front 40

what is desensitization/hyposensitization

Back 40

inject small amounts of allergen into patient in increasing doses over time

over time they will have a decreased response to the allergen! yay! whooppieee!

Front 41

For type II HS, what are the key effector cells? 4

Back 41

macrophages, neutrophils, eosinophils and NK cells

Front 42

autoimmune responses are what kind of HS rxns?

Back 42

Type II

Front 43

Incompatible blood transfusion reactions is what type of HS rxn?

Back 43

type II

Front 44

Hemolytic disease of the newborn due to Rh-factor reactions is what type of HS rxn?

Back 44

type II

Front 45

Autoimmune hemolytic anemia, where the patient becomes sensitized to their own erythrocytes
is what type of HS rxn?

Back 45

type II

Front 46

Goodpasture's syndrome is what? and what type of HS rxn is it?

Back 46

antibody react against glomerular basement membrane

type II

Front 47

Pemphigus is what? what type of HS rxn?

Back 47

antibody react to desmosome proteins in skin (get blisters)

type II

Front 48

Myasthenia gravis is what type of HS rxn?

Back 48

type II