Hypersensitivites

Question 1

Overview of Type 1:

Answer 1

Sensitized phase: Exposed to Ag. Plasma cells secrete IgE, which bind to FcR on mast cells. When exposed to Ag again, Ag will bind to receptor on mast cell = degranulation.

Could lead to asthma, urticaria(hives), eczema, or anaphylaxis.

Question 2

Overview of Type II:

Answer 2

Antibody mediated cytotoxic response. Tissue specific.
Abnormal IgG and IgM produced against specific tissues.

1-3 All involve complement
1-4 Involve cytotoxic cell killing

1. Complement mediated lysis = hemolytic disease of newborn.
2. Opsonization and phagocytosis
3. Neutrophil mediated.
4. ADCC. Cytotoxic cells with FcR bind to the Fc portions of the Antibodies that are bound to Ag.
5. Indued cell malfunction. Myasthenia gravis, graves.

Question 3

Overview Type III: Immune Complex (Ag: Ab)

Answer 3

Ab-Ag complexes get stuck in kidney, vessel walls, or other filtration tissues. Usually IgG or IgM.

1. Systemic: Serum, raynauds.
2. Localized: Arthus. Farmers Lung.
3. Immune Diseases: Infectious or Autoimmune (SLE, AR)
4. Ocular manifestations (uveitis, scleritis)

Question 4

Overview Type IV: Delayed/Cell mediated

Answer 4

Mediated by T cell lymphocytes.
Direct: CTLs
Indirect: Th1 activates MO

1. Environmental- contact dermatitis.
2. TB skin test
3. Autoimmune- Chrons, MS, type I diabetes
4. Ocular. Uveitis, scleritis, optic neuritis.

Question 5

2 main categories of hypersensitives

Answer 5

1-3: Immediate. Ab mediated.

4: Delayed. Does not involve Ab.

Question 6

Symptoms of type 1 sensitivity

Answer 6

Puritis (itching) 
Angioedema 
Urticaria (hives) 
Conjunctivitis 
Rhinitis (stuffy nose) 
Hypotension Low BP
Bronchospasm 
Dysrhthmias
GI cramps

Question 7

2 treatments of type 1 hypersensitivity

Answer 7

1. Desensitization: Will increase threshold, but you will still be allergic.
2. Tolerance: Longer term change. No longer allergic.

Question 8

What does anaphylaxis do to the body? How does an epipen help?

Answer 8

Anaphylaxis causes blood vessels to dilate due to histamine, BP drops.

Constrict blood vessels, relaxes smooth muscle, stimulates Heart beat and reduces swelling.

Question 9

3 Chronic diseases of Type I

Answer 9

Allergic asthma (bronchioles constrict and have increased secretions) 
Chronic urticaria (hives) 
Eczema

Question 10

Type II. Example of complement mediated lysis?

Answer 10

Hemolytic disease of the newborn

Question 11

How does Type II cause induced cell malfunction

Answer 11

Ab attack self and change the function. Causes increase or decrease in cell activity. Problematic for cells that need to turn on or off.

Question 12

Type II induced cell malfunction Myasthenia Gravis

Answer 12

Abs block Ach receptors on muscle cell at NMJ. Prevents ACh release. Causes muscles to become weak. Ptosis, diplopia, trouble swallowing, and easily fatigued.

Question 13

Type II induced cell malfunction Graves

Answer 13

Ab stimulate thyroid cells to over produce thyroid hormone. Causes goiter, increased metabolism, lid retraction and increased sympathetic activity.

Question 14

Type II. 3 examples that involve complement

Answer 14

1. Complement mediated lysis
2. Opsonization/Phagocytosis
3. Neutrophil mediated

Question 15

Type II. 4 examples that involve Cytotoxic cell killing.

Answer 15

1. Complement mediated lysis
2. Opsonization/Phagocytosis
3. Neutrophil mediated
4. ADCC.

Question 16

Requirements for hypersensitivity

Answer 16

Have to be genetically predisposed.

Initial exposure alters immunologic homeostasis.

Question 17

Anaphylaxis mild reactions and severe reactions

Answer 17

Mild:
Itching, hives, erythema (red skin), Contraction of bronchioles

Severe (multi-organ):
Laryngeal edema, vascular collapse, death

Question 18

Type II
Infections (1)
Autoimmune (2)
Alloimmune (2)

Answer 18

Infections: rheumatic fever
Autoimmune: Myasthenia gravis, graves
Alloimmune: Graft rejection, hemolytic disease of the newborn.

Question 19

Key about type II

Answer 19

IgM or IgG directed against antigens on SPECIFIC tissues/cells.

Question 20

Type III immune complexes are cleared how?
Large
Small
Intermediate

Answer 20

Large: MO
Small: Renal
Intermediate: Deposit in tissues

Question 21

Type III Systemic (2)

Answer 21

1. Serum. IV drugs

2. Raynauds. Temp dependent immune complex deposition in peripheral (cooler) capillary beds.

Question 22

Type III localized

Answer 22

Arthus rxn- farmers lung

Question 23

Type III autoimmune diseases

Answer 23

SLE, RA, Sjogrens

Question 24

Ocular manifestations of Type III

Answer 24

Uveitis, scleritis, ischemic optic neuropathy, peripheral ulcerative keratitis

Question 25

Type III infectious

Answer 25

1. Poststreptococcal glomerulonephritis causes compromised kidney function due to strep infection.
2. Polyarteritis nodosa
3. Reactive Arthritis

Question 26

Environmental antigens
Type I 
Type II
Type III
Type IV

Answer 26

I: pollens, mold, fungi, foods, animals

II: Antibiotics, latex. PCN binds to plasma membranes on RBCs or platelets. Usually against happens that bind to the surface of cells. IgG or IgM response.

III: Vaccines, Arthus (Farmer’s Lung- mold related in lungs)

IV: Plant resins, metal, chemicals. Mostly happens. Usually proteins found in skin.

Question 27

Most allergies are Type

Answer 27

I