Part 6: Immune Injury

Question 1

What are the 7 steps of Type I Immediate Hypersensitivity?

Answer 1

1. Allergen (antigen) enters body, binds to surface of 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 exposure — sensitized mast cell degranulates
6. Degranulation releases histamine and other vasoactive substances that act as inflammatory mediators causing vessel dilation, smooth muscle contraction
7. Individual experiences hives, itching, runny nose

Question 2

Atopy (atopic syndrome)

Answer 2

Clustering of eczema, allergic conjunctivitis, allergic rhinitis, asthma

Question 3

Anaphylaxis

Answer 3

Severe and rapid systemic allergic reaction to a trigger substance (allergen) to which individual is sensitized.

Question 4

What are the steps for Type II Cytotoxic reactions?

Answer 4

1. antigen and antibody (IgG) bind on the cell surface

2. Marked cells are destroyed by phagocytosis or complement which results in cell lysis

Question 5

Most cytotoxic diseases are

Answer 5

Hematological (blood related)

Question 6

Example of hematological disease

Answer 6

• Transfusion with wrong blood type

- Rh disease

Question 7

What is the result of transfusion with the wrong blood type?

Answer 7

Foreign erythrocytes are agglutinate by recipient’s antibody, complement is activated and RBCs are lysed

Question 8

Explain Rh disease?

Answer 8

Rh- mother gives birth to Rh+ baby. Baby’s blood enters mother’s body and mother produces antibodies against Rh antigens on her baby’s RBCs. The second pregnancy is also Rh+ and the antibody is able to pass through placenta to embryo where it leads to agglutination and destruction of RBCs

Question 9

What are the steps of TYP III immune complex reactions?

Answer 9

1. Large quantities of soluble antigen-antibody complexes form in the blood and are not completely removed by macrophages
2. Antigen-antibody complexes lodge in capillaries between endothelial cells and basement membrane
3. 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. Leukocytes discharge their lysozymes and promote massive inflammation leading to tissue death

Question 10

Streptococcal glomerulonephritis (renal disease) and lupus erythematosus, serum hepatitis and pneumonitis are examples of

Answer 10

Immune complex disease

Question 11

Autoimmune disorder in which antibodies are created against patients own DNA

Answer 11

Lupus erythematosus

Question 12

Acute hepatitis leading to liver failure

Answer 12

Serum hepatitis

Question 13

General term for inflammation of lungs if fungi is antigen

Answer 13

Pneumonitis

Question 14

Steps of Type IV delated hypersensitivity (cell-mediated) reaction

Answer 14

1. T cells interact with presented antigen
2. T cells proliferate and secrete cytokines
3. Macrophages are attracted and host cell destroyed

Question 15

Leprosy, histoplasmosis and chlamydia are examples of

Answer 15

Infectious delayed hypersensitivities