Hypersensitivities part 2

Question 1

Describe a Type 2 hypersensitivity response.

Answer 1

Responses characterized by IgG or IgM antibodies binding to tissues, cells or ECM leading to their damage; Antigen is NOT soluble.

Question 2

What can the Type 2 antibodies bind to?

Answer 2

1. Self antigens on CM or collagen
2. Allergens absorbed onto cells.
3. Donor cells
4. Fetal cells

Question 3

Discuss autoimmune hemolytic anemia.

Answer 3

Erythrocyte membrane proteins are opsonized by antibodies causing hemolysis and anemia

Question 4

Discuss Thrombocytopenic purpura

Answer 4

Antibodies made for platelet membrane proteins; Presents as bleeding

Question 5

Describe Grave’s disease

Answer 5

Antibodies made for Thyroid stimulating hormone receptor; Hyperthyroidism

Question 6

Describe Myasthenia gravis

Answer 6

Antibodies made for acetylcholine receptor; Muscle weakness and paralysis.

Question 7

Discuss Rheumatic Fever

Answer 7

Antibody for strep cell wall antigen cross reacts with myocardial antigen; Myocarditis and arthritis

Question 8

Discuss Type 2 diabetes

Answer 8

Antagonistic antibody against insulin receptor; Insulin resistance and obesity.

Question 9

What is the main concern in an ABO incompatibility in pregnancy?

Answer 9

Can affect the first pregnancy

Question 10

Discuss Type 3 hypersensitivity

Answer 10

Formation of soluble immune complexes (IgG or IgM) that get stuck in small vascular spaces and cause tissue damage.

Question 11

What are type 3 hypersensitive antibodies binding to?

Answer 11

1. Soluble self antigens
2. Drugs
3. Bacterial or viral antigens
4. Antibodies for immunotherapy.

Question 12

Discuss Systemic Lupus Erythematosus

Answer 12

Antibody against DNA and nucleoproteins. Causes nephritis.

Question 13

Describe strep glomerulonephritis

Answer 13

Antibody to strep cell wall antigen; Nephritis

Question 14

Discuss Serum sickness

Answer 14

Antibodies against foreign antibodies; Systemic vasculitis

Question 15

What are the treatments for antibody mediated hypersensitivities?

Answer 15

1. Anti-inflammatory pharmaceuticals
2. Anti-microbial treatments
3. Plasmapheresis to reduce the level of circulating immune complexes (severe cases)

Question 16

Describe Type 4 hypersensitivity

Answer 16

Caused by Th1 or Th17 cells attacking self-antigens. Can be acute or chronic.

Question 17

What are the TCRs binding to in Type 4?

Answer 17

1. Unmodified/Modified self protein
2. Bacterial/viral proteins
3. Donor proteins in transplants

Question 18

Describe a contact hypersensitivity clinically

Answer 18

Blisters present

Question 19

Describe a tuberculin type hypersensitivity clinically.

Answer 19

A hard raised swelling with granuloma formation in the dermis.