HLTH module 3: hypersensitivity and transplants

Question 1

hypersensitivity meaning

Answer 1

aka allergic reactions; can be unusual and harmful immune responses to normally harmless substances; reactions stimulate an inflammatory response

Question 2

what are the most common transplants?

Answer 2

skin, cornea, bone, kidneys, lungs, hearts, and bone marrow

Question 3

organ rejection

Answer 3

primarily involves a type IV cell-mediated hypersensitivity reaction (and small humoral response); this causes inflammation and tissue necrosis, eventually destroying the organ

Question 4

what organs are less rejection associated with?

Answer 4

corneas and cartilage because they lack a blood supply

Question 5

why do better transplants occur in young infants?

Answer 5

because their immune system in not yet mature and does not respond to the foreign tissue

Question 6

two types of rejection

Answer 6

host-verus graft disease and graft-verus host disease

Question 7

host-verus-graft disease

Answer 7

occurs when the host’s immune system rejects the graft

Question 8

graft-versus-host disease

Answer 8

occurs when the graft tissue contains T cells that attack the host cells; common in bone marrow transplants

Question 9

hyperacute rejection

Answer 9

rejection occurs immediately as circulation to the site is reestablished

Question 10

acute rejection

Answer 10

occurs after several weeks when unmatched antibodies cause a reactionc

Question 11

chronic or late rejection

Answer 11

occurs after months or years, with gradual degeneration of the blood vessels

Question 12

how can rejection be treated?

Answer 12

immunosuppression techniques that reduce the immune response; involves drugs such as cyclosporine, Imuran, and a glucocorticoid

Question 13

concern with treatment of rejection

Answer 13

immunosuppression increases the risk of infection because the normal body defences are now limited

Question 14

allergen

Answer 14

the antigen causing the allergic reaction; can be a food, drug, plant, pollen, or chemical

Question 15

atopic hypersensitivity reaction

Answer 15

tendency for allergic conditions to be inherited, and this is the manifestation name

Question 16

what antibodies are associated with a type I hypersensitivity?

Answer 16

IgE antibodies from B lymphocytes; these attach to mast cells, creating a sensitized mast cell

Question 17

where are mast cells abundnat?

Answer 17

mucosa of the respiratory and digestive tracts

Question 18

what occurs in a type I hypersensitivity reaction?

Answer 18

the allergen attaches to the IgE antibody on the mast cell, stimulating the release of chemical mediators such as histamine; this causes vasodilation and increased capillary permeability at the site, resulting in swelling and redness, and sometimes itching

Question 19

what are other chemical mediators involved in type I hypersensitivity reactions?

Answer 19

prostaglandins and leukotrienes; these are released at the second phase of the reaction

Question 20

when are hay fever signs present?

Answer 20

when the antigen-antibody reactions occurs in the nasal mucosa

Question 21

what does the first exposure to an antigen do?

Answer 21

does not cause a reaction but causes the formation of antibodies and sensitized mast cells

Question 22

hay fever

Answer 22

an allergic reaction in the nasal mucosa that causes frequent sneezing, water secretions from the nose, and itching; causes red eyes as well; usually associated with plant pollens

Question 23

common signs of a food reaction

Answer 23

nausea, vomiting, diarrhea, and rash/hives

Question 24

eczema other name

Answer 24

atopic dermatitis

Question 25

eczema

Answer 25

often genetic and common in young children; forms a skin rash on the face, trunk, or extremities and is often associated with foods, irritating fabrics, and a dry atmosphere

Question 26

anaphylaxis

Answer 26

a severe, life-threatening hypersensitivity reaction resulting in airway obstruction, decreased BP, and hypoxia

Question 27

what is anaphylaxis commonly caused by?

Answer 27

latex materials, insect stings, nuts, shellfish, penicillin, or local anesthesia

Question 28

signs of anaphylaxis

Answer 28

itching, tingling, coughing, and difficulty breathing initially, then weakness, dizziness, or fainting; edema may also occur around the eyes, lips, tongue, hands or feet, as well as hives; low BP and airway obstruction also occur

Question 29

why does itching occur in allergic reactions?

Answer 29

histamine and chemical mediators irritate sensory nerves

Question 30

treatment of anaphylaxis

Answer 30

epinephrine injection; antihistamine drugs or chlorpheniramine may be useful in the early stages as they block histamine release

Question 31

type II hypersensitivity other name

Answer 31

cytotoxic hypersensitivity

Question 32

type II hypersensitivity

Answer 32

occurs when the antigen is present on the cell membrane, reacting with circulating IgG antibodies which cause destruction of the cell by phagocytosis or releasing cytolytic enzymes

Question 33

example of a type II hypersensitivity

Answer 33

a incompatible blood transfusion; ex. type A blood has A antigen and anti-B antibodies in the blood, and type B blood will cause a reaction due to anti-A antibodies

Question 34

another name for type III hypersensitivity

Answer 34

immune complex hypersensitivity

Question 35

type III hypersensitivity

Answer 35

occurs when the antigen combines with the antibody, forming a complex that is deposited in tissue, often vessel walls, activating complement which causes inflammation and tissue destruction

Question 36

what diseases are believed to be caused by type III hypersensitivties?

Answer 36

glomerulonephritis and rheumatoid arthritis

Question 37

serum sickness

Answer 37

refers to the systemic reaction that occurs when the immune complex is deposited in many tissues

Question 38

type IV hypersensitivity other name

Answer 38

cell-mediated or delayed hypersensitivity

Question 39

type IV hypersensitivity

Answer 39

is a delayed response by sensitized T lymphocytes to antigens, resulting in the release of lymphokines or other chemical mediators that cause an inflammatory response and destruction of the antigen

Question 40

what is type IV hypersensitivity associated with?

Answer 40

organ transplants

Question 41

test for checking of prior exposure of the organism causing tuberculosis

Answer 41

tuberculin test

Question 42

contact dermatitis

Answer 42

is an allergic skin reaction and is caused by a type IV reaction often by cosmetics, dyes, soaps, metals, or poison ivy

Question 43

signs of a type IV hypersensitivity reaction

Answer 43

often skin reactions that damage the mucous membranes; signs can be asthma, hives, anaphylaxis, as well as red and itchy skin