General Pathology Lecture 10: Hypersensitivity Type I

What is an immune response that leads to tissue injury/disease?

Hypersensitivity

What can hypersensitivity be synonymous with?

Allergy

Which hypersensitivity is Immediate-type and Anaphylaxis?

Type I

Which hypersensitivity is Antibody-mediated?

Type II

Which hypersensitivity is Immune Complex-mediated?

Type III

Which hypersensitivity is Cell-mediated Disease?

Type IV

What do plasma cells produce in Type I hypersensitivty?

IgE antibodies (sensitization)

What two cells does IgE activate?

1. Mast cells (Tissues)

2. Basophils (Blood)

What do cells bind to on antibodies for it to release cytokines?

Fc receptor

What activates mast cells and basophils?

Antigen/IgE Cross-linking

How long does it take for mast cells and basophils to start releasing mediators?

Minutes

What do mast cells and basophils release?

Proinflammatory mediators

How long does it take for immediate reactions in hypersensitivity to resolve?

Within 1 hour

What are late reactions in hypersensitivity stimulated by?

Cytokines

What mediator recruit/activate various WBCs?

Cytokines

Which two mediators promote leakage and edema?

1. Histamine

2. Leukotrienes

What mediator causes bronchospasm?

Prostaglandins

Which type I reaction is due to chronic local allergy?

Atopy

Which type I reaction is due to acute severe systemic reaction?

Anaphylaxis

What is the risk percentage of anaphylaxis?

2%

What is the death rate per year of anaphylaxis?

63-99 deaths

What are the three respiratory responses to mediators?

1. Hayfever

2. Asthma

3. Bronchoconstriction

What are the two digestive responses to mediators?

1. Vomiting

2. Diarrhea

What are the three skin responses to mediators?

1. Urticaria

2. Pruritus

3. Redness

What is the cardiovascular response to mediators?

Systemic vasodilation

What is the response to mediators that causes symmetrical swelling?

Angioedema

What allergy can cause urticaria?

Penicillin allergy

Is urticaria usually symmetrical or asymmetrical?

Symmetrical

What is the center swollen area of skin in urticaria called?

Wheal

What is the surrounding red skin caused by vasodilation in urticaria called?

Flare

What are the three features of angioedema?

1. Swelling tongue

2. Swelling uvula

3. Swelling of face

If only one lip is swelling, what is it likely due to?

Oral infection

What does anaphylaxis promote?

Massive mast cell degranulation

How does anaphylaxis affect bronchiole smooth muscle?

Contraction

What are the two results from the contraction of bronchiole smooth muscle?

1. Dyspnea

2. Shock

What are the two things that help manage anaphylaxis?

1. Epinephrine

2. Antihistamine

What does epinephrine inactivate?

Mast cell degranulation

What should be the first thing to ask a patient before prescribing medication?

If they are allergic to the medication

What are the four allergic reactions that patients should watch out for?

1. Shortness of breath

2. Difficulty swallowing

3. Rash

4. Facial swelling

How many unrelated drug intolerances or allergies causes multiple drug intolerance syndrome?

> 3

What are the four risk factors for multiple drug intolerance syndrome?

1. Age

2. Females

3. Repeated exposures to medications

4. Depression

What are the two allergies that are high risk for multiple drug intolerance syndrome?

1. Penicillins

2. Quinolones

Is true allergies to local anesthesia common or rare?

Rare

Which local anesthesia causes the most allergic reactions?

Ester type

What is the currently used ester type local anesthesia?

Amide-based

What are the two factors that cause non-true allergic reactions for local anesthesia?

1. Vasovagal syncope

2. Previous inclusion of methylparaben

What are the four actual allergic features for local anesthesia allergies?

1. Sudden facial swelling

2. Burning sensation

3. Redness

4. Anaphylaxis

What syndrome represents potentially severe hypersensitivity reaction?

Alpha-gal syndrome

What is Alpha-gal syndrome associated with?

Lone star tick

What is the allergen in tick saliva?

Complex oligosaccharide

What subsequent exposure after tick saliva promotes hypersensitivity?

Epitope

What is a substance recognized by antibody that promotes cross-reactivity?

Epitope

What is the main allergy response to alpha-gal syndrome?

Anaphylaxis

What are the five substances that may promote alpha-gel syndrome?

1. Red meats

2. Milk proteins

3. Gelatin

4. Glycerol

5. Excipients

What are the five medical products that may promote alpha-gel syndrome?

1. Bone graft

2. Gelatin capsules

3. TMJ

4. Sutures

5. Dental products

What is the allergy test that uses injection of diluted allergens?

Intradermal testing

What is the allergy test that uses surface contact of allergen?

Patch testing

What is the allergy test that uses specific antigen/IgE antibodies in blood?

Serologic testing

What are the two complications with allergy testing?

1. False positives/negatives

2. Risk of anaphylaxis

What allergy is related to dental products?

Latex allergies

What treatment is performed for severe allergies?

Immunotherapy

What is the complication for immunotherapy?

Anaphylaxis