8 Hypersensitivities (1 Hour)

Question 1

Type 1 hypersensitivities are mediated by

Answer 1

Ab

Question 2

What hypersensitivity is atopic?

Answer 2

Type 1

Question 3

What cells are immediately activated in Type I responses?

Answer 3

Mast, eosinophil, basophil

Question 4

What receptors facilitate Type 1 hypersensitivity?

Answer 4

FC(epsilon)

Question 5

Mast cells are found

Answer 5

In skin and mucosa

Question 6

What is the high affinity Fc receptors for IgE found on Mast cells called?

Answer 6

Fc(epsilon)RI or CD23a

Question 7

What do IL4 and IL13 stimulate?

Answer 7

Th2 response

Question 8

What, from mast cells, stimulates and promotes eosinophil activation?

Answer 8

IL3, IL5, GM-CSF

Question 9

What does CCL3 do?

Answer 9

Attracts monocytes, macrophages, and neutrophils

Question 10

What does IL-5 induce on eosinophils?

Answer 10

FC(epsilon)RI

Question 11

What is in high number during chronic allergic inflammation?

Answer 11

Eosinophils

Question 12

What is the major contributor to tissue damage?

Answer 12

Eosinophils

Question 13

What has the same mechanism as histamine but lasts longer and has stronger action? Who makes it?

Answer 13

Leukotrienes

Eosinophils

Question 14

What is the most potent leukotriene? What do they do?

Answer 14

LTB4

They increase capillary permeability and increase mucus production

Question 15

What causes class switching of B cells?

Answer 15

IL4

Question 16

What does IL4 increase on cell surface of leukocytes?

Answer 16

VCAM-1 for adhesion

Question 17

What cells have Fc(epsilon)R

Answer 17

Basophils and mast cells

Question 18

What are the properties of allergens?

Answer 18

They require a tiny dose, they are very stable and can exist for a long period of time, small and highly soluble

Question 19

What is the first exposure to an allergen? What happens?

Answer 19

Priming

No allergic reaction

Question 20

How are allergens taken up?

Answer 20

They diffuse across mucosal epithelium and are processed and presented by Th2 and B cells make IgE against them

These IgE bind to Fc(epsilon)RI on mast cells

Question 21

What happens immediately in an acute atopic response?

Answer 21

Cross linking of mIgE
Degranulation of mast cells
Sneezing, congestion, pruritis, rhinorrhea

Question 22

What happens in the late phase of atopic responses?

Answer 22

After 4-12 hours there is an influx and activation of eosinophils, neutrophils, basophils and Th2

10 fold increase of mast cells w/ increased Fce receptors

Question 23

What happens in atopic asthma?

Answer 23

Contraction and relaxation of smooth muscle in bronchioles

Question 24

What causes systemic anaphylaxis?

Answer 24

Allergens introduced directly into the blood, systemic act. of mast cells, increase in vascular perm., huge drop in BP

Question 25

What are Type 2 hypersensitivities called? What do they react against?

Answer 25

IgG or IgM against cell surface or ECM

Question 26

What causes damage in Type 2 HS?

Answer 26

Complement binding (binds to both IgG and IgM) NK through ADCC

Question 27

In Type 2 HS, Ab against cell surface are ___________ but Ab against internal Ag are ____________

Answer 27

Pathogenic, non-pathogenic

Question 28

What causes the bystander damage during Type 2 HS?

Answer 28

Phagocytes want to connect to the cells and phagocytose them but they can’t so they release lytic particles “at” the cells causing widespread damage

Question 29

What is a penicillin “allergy?” What does penicillin bind to?

Answer 29

It is a Type 2 HS the penicillin binds to the surface of RBC and gets lysed because it is recognized as non-self

Question 30

What type of HS are transfusion reactions?

Answer 30

Type 2

Question 31

What is given to protect fetal RBC from maternal Ab in second pregnancy?

Answer 31

Rhogam, it prevents B cell activation to Rhesus factor

Question 32

Anti CD20 is used in

Answer 32

B cell non-Hodgkin’s lymphoma

Question 33

What is anti-CD52 used in?

Answer 33

Chronic B & T cell leukemias Immunosuppressants for BMT

Question 34

What are Type 3 hypersensitivities known as?

Answer 34

Immune complex

Question 35

What do Ab react to in Type 3 HS?

Answer 35

Soluble Ag This happens when there is too much Ab and not enough Ag

Question 36

How do Type 3 cause acute inflammation repsonse?

Answer 36

Phagocytes can’t chew up complexes so they release enzymes at the cells and the cells are damage and release internal contents, this leads to DAMPs and resultant activation

Question 37

Rheumatic fever is caused by what? What does it react to?

Answer 37

Streptococcal cell wall Ag This is similar to the heart wall and we get cross reactivity

Question 38

What causes myasthenia gravis?

Answer 38

Anti-Ach receptor Ab

Question 39

What causes grave’s disease (hyperthyroidism)?

Answer 39

Antibody stimulates TSH binding to receptor and you get overactivation of thyroid

Question 40

What causes SLE?

Answer 40

Ab against nucleic acids, nucleoproteins

Question 41

What does SLE cause?

Answer 41

Nephritis, arthritis, and vasculitis

Question 42

What causes serum sickness?

Answer 42

Type 3 HS against various components of whole blood

Question 43

What do Type 2 and 3 HS have in common?

Answer 43

They are both Ab mediated Complement is major mediator in both

Question 44

What are Type 4 HS also called?

Answer 44

Delayed type HS

Question 45

What mediates DTH?

Answer 45

Ag-specific CD4

Question 46

What are the 3 types of DTH?

Answer 46

Contact (Ni, poison ivy, latex) Tuberculin (Tb test) Granulomatous (look for presence of granulomas)

Question 47

What are the two stages of DTH?

Answer 47

Sensitization - antigen uptake by DC - present on class 2 HLA Elicitation - recruit CD4 T cells - pro-inflammatory cytokines - Th1 cells

Question 48

What is a quick and dirty way to measure cell mediated immunity?

Answer 48

Reaction of CD4 to something you know they were previously exposed to

Question 49

What causes granulomatous DTH? What T responds?

Answer 49

Intracellular organism able to resist macro killing, macro walls it off with several layers, can form necrotic center, associated with Th1 response happens in Tb

Question 50

What causes MS

Answer 50

Type 4 HS against myelin proteins

Question 51

What causes RA?

Answer 51

Type 4 HS in joints

Question 52

What causes IDDM?

Answer 52

Type 4 HS against pancreatic islet ag