chapter 19: diagnosis associated w/ immune system

Question 1

type I (anaphylactic) hypersensitivity (w/ example)

Answer 1

IgE binds to mast cells or basophils; causes degranulation of mast cell or basophil and release of reactive substances (histamine)
- ex) anaphylactic shock from drug injections/ insect venom; allergic conditions (hay fever, asthma)

Question 2

type II (cytotoxic) hypersensitivity (w/ example)

Answer 2

antigen causes formation of IgM and IgG antikndies that bind to target cell; when combined with action of complement, destroys target cell
- ex) transfusion reactions; Rh incompatibility

Question 3

type III (immune complex) hypersensitivity (w/ example)

Answer 3

antibodies and antigens form complexes that cause damaging inflammation
- ex) arthus reactions, serum sickness

Question 4

type IV (delayed cell-mediated / delayed hypersensitivity) hypersensitivity (w/ example)

Answer 4

antigens active CTLs that kills target cell

- ex) rejection of transplanted tissues; contact dermatitis (poison ivy); chronic diseases (tuberculosis)

Question 5

allergic sensitization

Answer 5

outcome of a complex interplay between the allergen and the host in a given environmental context

Question 6

allergic desensitization

Answer 6

increasing dosages of antigen injected beneath the skin; produces IgG which act as blocking antibodies to intercept & neutralize antibodies

Question 7

ABO blood groups

Answer 7

• A ➡ anti-B
• B ➡ anti-A
• AB ➡ neither anti-A or anti-B
• O ➡ anti-A and anti-B

Question 8

Rh factor

Answer 8

Rh factor antigen (Rh +) found on RBCs of 85% of the population; Rh+ blood given to an Rh- recipient will stimulate anti-Rh antibodies in the recipient

Question 9

hemolytic disease of the newborn (HDNB)

Answer 9

Rh- mother w/ Rh+ fetus causes mother to produce anti-Rh antibodies; second Rh+ fetus will receive anti-Rh antibodies, damaging fetal RBCs

Question 10

autoimmune disease

Answer 10

immune system responds to self antigens, causing damage to the organs; autoimmunity = loss of self-tolerance (ability to discriminate self from non-self); failure of clonal deletion in the thymus

• ex) multiple sclerosis= immune system attacks the myelin sheaths of long nerve axons ➡ fatigue, weakness, paralysis
• rheumatoid arthritis= immune complexes (chains of antibodies stuck to epitopes) are deposited in the joints ➡ chronic inflammation & destruction of joints

Question 11

immunodeficiency

Answer 11

failure of the immune system to protect the body adequately from infection, due to the absence or insufficiency of some component process or substance; can be congenital (born with it) or acquired (get it over course of life)

• ex) severe combined immunodeficiency (SCID)= congenital lack of B & T cells - need to be isolated from everything until getting a bone marrow transplant (life in sterile bubble)
• acquired immunodeficiency syndrome (AIDS) = HIV virus attacks various cells (mostly CD4+ helper T cells) & macrophages