Type I Immunopathology and Parasite Immunity

Question 1

What is the true role of IgE and Th2?

Answer 1

Fighting parasites

Question 2

Is IgG produced in a person infected with worms?

Answer 2

Yes. and it activates complement and recruits neutrophils

Question 3

Are neutrophils able to kill helminths?

Answer 3

No they lack a helminthocidal mechanism

Question 4

When a mast cell binds antigens to it FcR the mast cell degranulates what does it release?

Answer 4

Anti-helminth IgE
Histamine
Prostaglandins
Leukotrienes

Question 5

What does histamine do to the smooth muscle of the gut?

Answer 5

Increases contraction and violent peristalsis

Question 6

What do the prostaglandins and leukotrienes do (released as ECF=A2)?

Answer 6

Attract eosinophils in large numbers

Question 7

Eosinophils have Fc receptors that recognize IgG. How does that help it recognize the worm it needs to kill?

Answer 7

Because IgG is already opsonizing the worm at this point

Question 8

What do the eosinophils do after the Fc receptor binds the IgG + helminth?

Answer 8

It releases the content of its granules Including Major Basic Protein which is highly toxic the the helminth

Question 9

What is the role of Th2-like Tfh cells?

Answer 9

They go to the lymph node and help B cells switch to IgE production

Question 10

What is the role of Th2 cells in helminth infection?

Answer 10

They go to the site of infection and attract both eosinophils and macrophages

Question 11

What do Th2 cells produce to recruit eosinophils and macrophages?

Answer 11

IL-4
IL-5
IL-13

Question 12

What do IL-4, IL-5, and IL-13 do to macrophages?

Answer 12

Activate them to the alternative M2 pathway where they heal damage and wall off M1-resistant invaders

Question 13

Eosinophilia in the blood is indicative of what?

Answer 13

1. Parastie infection

2. Type II immunopathology

Question 14

What are allergens?

Answer 14

Antigens that cause allergy

Question 15

When will a mast cell degranulate?

Answer 15

When two adjacent IgE molecules are bound to the same antigen

Question 16

What does histamine do the the bronchial smooth muscle?

Answer 16

Causes contraction

Question 17

Is it common to see a type I immunopathology reaction to an antigen that can penetrate intact skin?

Answer 17

Uncommon

Question 18

What is allergic rhinitis?

Answer 18

Seasonal (August and September) allergy to ragweed

Causes runny nose and itchy eyes

Question 19

What is eczema?

Answer 19

Chronic dry and easily irritated skin, itch, and rash caused by an allergen

Secondary bacterial infections are common

Question 20

What is oral allergy syndrome?

Answer 20

Almost immediate allergy to foods that causes tingling lips and tongue, itching, and swelling of the lips

ONLY oral cause stomach acid causes degradation of allergen

Question 21

Asthma is considered both __________ and _________.

Answer 21

broncoconstrictive and inflammatory

It is important to avoid fibrosis

Question 22

What is hyper IgE syndrome?

Answer 22

Autosomal Dominant condition
Inability to make INF gamma
So Th2 dominant
High IgE, skin abscesses and fungal and Pseudomonas pneuonia

Question 23

What percentage of people experience allergic symptoms at some time in their life?

Answer 23

15%

Question 24

A newborn with two parents who have allergies has a _____% of developing allergies.

Answer 24

65

Question 25

Is the incidence of asthma on the rise or decline?

Answer 25

Rise

Question 26

Give an example of a cross-reaction.

Answer 26

Cantaloupes cross-react with ragweed; people with ragweed rhinitis can have cantalouope oral allergy syndrome

Question 27

What is atopic state?

Answer 27

Prone to develop any of the range of allergic syndroms Infant with eczema can go on to have allergies to fish or milk, or develop asthma

Question 28

Production of IgE is dependent upon what?

Answer 28

Tfh/ IL-4

Question 29

IgE binds to that two cells that have Fc(epsilon)RI?

Answer 29

Basophils (found in blood) Mast cells (found in tissue) SUPER HIGH BINDING AFFINITY

Question 30

What does degranulation release?

Answer 30

histamine heparin enzymes TNF

Question 31

What clinical symptoms does histamine produce?

Answer 31

Itch Blood vessel dilation leakiness

Question 32

What occurs in the late phase reaction?

Answer 32

Phospholipase PLA2 cleaves arachidonic acid from membrane phospholipids Converted into prostaglandins by COX and leukotrienes by lipoxygenase

Question 33

What is the role of prostaglandins and leukotrienes?

Answer 33

They initiate inflammation, constrict bronchioles, and are together called "eosinophil chemotactic factor of anaphylaxis"

Question 34

What are the two phases of Type I reactions?

Answer 34

Immediate phase | Late phase

Question 35

Describe immediate phase

Answer 35

Due to histamine, so can be blocked by antihistamines Antihistamines are receptor antagonists

Question 36

Describe late phase

Answer 36

Onset: 4-10 hours Dependent on prostaglandins, leukotrienes, and cytokines

Question 37

Eosinophils are attracted to ECF-A and IL-4 what are these mediators produced by?

Answer 37

ECF-A is produced by Mast cells IL-4 is produced by Th2

Question 38

Name some things that can trigger bronchospasms in hyperreactive lungs.

Answer 38

Dry air Irritants in the air Viral infections Cold

Question 39

What is chronic spontaneous urticaria CSU?

Answer 39

IgG antibody against the Fc(epsilon)R1 on mast cells >>>>Chronic stimulation of histamine release Tx: mAb omalizumab (binds to Fc or IgE so it can't bind to mast cells)

Question 40

What is the most important diagnostic tool for diagnosing allergy?

Answer 40

History

Question 41

Does a positive skin test conclusively mean that the patient is allergic to that allergen?

Answer 41

No. Cross-reactivity could be occuring

Question 42

ImmunoCAP-FEIA is used to diagnose a specific allergen, but is it safe?

Answer 42

Yes. CAP testing is completely safe, unlike skin test which have some risk

Question 43

What is asthma?

Answer 43

Reversible bronchoconstricitive disease with progressive inflammation leading to fibrosis

Question 44

How is asthma diagnosed?

Answer 44

Spirometry-measures air flow Measure FEV1- volume of air that can be forcibly exhaled from full lungs in 1 second Then you measure FEV1 again once they get a bronchodilator treatment

Question 45

Th2 in the lungs is proinflammatory. Why is this bad? How can you treat it?

Answer 45

Inflammation leads to fibrosis which is irreversible Glucocorticoids

Question 46

Antihistamines are effective for what phase of a type I reaction?

Answer 46

Immediate

Question 47

How does epinephrine help treat anaphylaxis?

Answer 47

Constricts blood vessels, but dilates bronchial smooth muscle

Question 48

What is the role of the following in the treatment of type I reactions: - Glucocorticoids - Leukotriene Inhibitors - Rescue Inhalers - LABAs (Lone-Acting Beta-2 Agonists) - IgE blocker - Immunotherapy

Answer 48

- Glucocorticoids: Local anti-inflammatory. Systemic has a lot of side effects. Block PG and LT synthesis and cause apoptosis in eosinophils - Leukotriene Inhibitors: Block either synthesis (Zileuton) or binding (Montelukast) - Rescue Inhaler: Short-acting beta-2 antagonist - LABAs: reduce bronchoconstriction (Fluticasone/salmeterol - IgE blocker: Omalizumab Immunotherapy: Dilute solution of allergen extracts mechanism not clear. Oral desensitization. Peanut allergen skin patch

Question 49

What is the role of Nucala (mepolizumab)?

Answer 49

Humanized interleukin-5 antagonist monoclonal antibody. Reduces severe asthma attacks by reducing the levels of blood eosinophils