Section VI: Immune Injury

Question 0

What is Type I- immediate hypersensitivity

Answer 0

1: allergen enters body and binds surface antibody on B cell
2: B cell differentiates into plasma cells that produce IgE which binds to mast cell
3: Allergens bind to IgE on mast cell
4: Individual is now sensitized to allergen
5: 2nd time exposed to allergen sensitized mast cell degranulates
6: Degranulation releases histamine and other vasoactive substances that act as inflammatory mediators causing vessel dilation and smooth m contraction
7: Individual experiences hives, itching, runny nose

Question 1

How are hypersensitivities categorized

Answer 1

according to which parts of the immune response are involved and how quickly the response occurs

Question 2

What is atopy

Answer 2

The clustering of eczema, allergic conjunctivitis, allergic rhinitis, and asthma in certain individuals. There appears to be a strong hereditary component

Question 3

What is anaphylaxis

Answer 3

a severe and rapid systemic allergic reaction to a trigger substance to which the individual is sensitized

Question 4

What is a Type II-Cytotoxic reaction

Answer 4

1: Antigen and antibody (IgG) bind on cell surface
2: Marked cells are destroyed by phagocytosis or complement which results in cell lysis

Question 5

What are most cytotoxic diseases due to

Answer 5

hematological

• transfusion with the wrong blood type
• Rh disease

Question 6

What are Type III- Immune complex reactions

Answer 6

1: large quantities of soluble antigen-antibody complexes form in the blood and are not completely removed by macrophages
2: The antigen-antibody complexes lodge in the capillaries between the endothelial cells and the basement membrane
3: The antigen-antibody complexes activate the classical complement pathway leading to vasodilation
4: complement proteins and antigen-antibody complexes attract PMN leukocytes to the area
5: The leukocytes discharge their lysozymes and promote massive inflammation, leading to tissue death.

Question 7

What are Type IV- Delayed Hypersensitivity

Answer 7

1: T cells interact with presented antigen
2: T cells proliferate and secrete lymphokines
3: macrophages are attracted and host cell destroyed