Transplatns, grafts, rejection

Question 1

Major barrier for allografts is?

Answer 1

Rejection of transplants

Question 2

Cell and antibody-mediated hypersensitivity lasts for how long after transplants/

Answer 2

the rest of the patients life

Question 3

Immune recognition of allografts is a response to

Answer 3

MHC molecuels

Question 4

Host T cells recognize

Answer 4

foreign MHC molecules

Question 5

Donor APCs present Ag to host?

Answer 5

T-cells

Question 6

CD4 + recognizes?

Answer 6

delayed hypersensitivity reaction

Question 7

CD8 + recognizes?

Answer 7

cytotoxic T cells

Question 8

direction recognition

Answer 8

• Host T cells recognize foreign MHC molecules.
• Donor APCs present Ag to host T cells.
• CD4 + → delayed hypersensitivity reaction.
• CD8 + → cytotoxic T cells.

Question 9

Indirection recognition

Answer 9

• Host CD4 + T cells recognize donor MHCs presented by host APCs.
• Mainly activates DTH pathways.
• Also induces production of Abs against graft alloantigens.

Question 10

Host CD4 + T cells recognize donor MHCs presented by

Answer 10

host APCs

Question 11

Indirection recognition mainlt activates?

Answer 11

DTH pathways

Question 12

Indirection recognition also induces production of?

Answer 12

Abs against graft alloantigens

Question 13

what cells are involved in graft rejection in varying amounts?

Answer 13

T cells and Abs (antibodies)

Question 14

CD8+ T-cells Mediated Rejection

Answer 14

Parenchymal and endothelial cell death by removing blood supply *very effective

Question 15

CD4+ T-cells Mediated Rejection

Answer 15

Delayed hypersensitivity reactions → Destruction of graft cells and vasculature
*by a gamma interferin inflammatory event

Question 16

Graft alloantibodies Antibody-Mediated Rejection

Answer 16

Endothelial injury and thrombosis

Question 17

Platelet aggregation + coagulation result in

Answer 17

additional ischemia (Antibody-Mediated Rejection)

Question 18

Mechanisms of Graft Rejection

Answer 18

1) Hyperacute
2) Acute
- - Cellular
- - Humoral
3) Chronic

Question 19

Hyperacute Rejection has presence of preformed?

Answer 19

antibodies

Question 20

Hyperacute rejection takes how long to happen?

Answer 20

Immediate rejection (minutes to hours)

Question 21

Hyperacute rejection causes endothelial _____ and ______

Answer 21

destruction and thrombosis

Question 22

Hyperacute rejection has ____ necrosis

Answer 22

Fibrinoid necrosis

Question 23

Hyperacute rejection is rare due to?

Answer 23

screening and cross-matching

Question 24

Acute rejection takes how long?

Answer 24

• Days to weeks if nonimmunosuppressed.
• Months or years in presence of
  immuosuppression.

Question 25

Acute rejection by _____ and _____ responses? which one dominates?

Answer 25

Cellular and humoral

*BOTH occur at the same time, but one may dominate

Question 26

Acute cellular rejection happens within?

Answer 26

the first months

Question 27

Acute cellular rejection clinically presents with?

Answer 27

renal failure

Question 28

Acute Antibody-Mediated Rejection vasculitis due to?

Answer 28

antidonor Abs

Question 29

Vasculitis

Answer 29

Ischemic necrosis of renal parenchyma

Question 30

Less acute vaculitis

Answer 30

thickening of intima → infarction or renal cortical atrophy

Question 31

Chronic Rejection takes how long?

Answer 31

Months to years after transplantation

Question 32

Chronic rejection causes progressive increase in serum?

Answer 32

creatinine

Question 33

increased creatinine is due to a decrease in ____ function

Answer 33

kidney

Question 34

Methods of Increasing Graft Survival

Answer 34

1) Better matching of donor and recipient HLA molecules

2) Immunosuppression (cyclosporine, azathioprine)

Question 35

Immunosuppressions (cyclosporine, azathioprine) causes increases susceptibility to?

Answer 35

opportunistic infections and malignancies

*Ex: epsilon barr, HPV, lymphomas