Mhc, Organ Transplantation, And Rejection

Front 1

What is the function of the MHC?

Back 1

1. Display peptide fragments for recognition by antigen-specific T cells

Front 2

What are the classes of MHC?

Back 2

1. I

2. II

3. III

Front 3

Where are class I MHC molecules present?

Back 3

1. All nucleated cells

Front 4

What encodes for MHC I?

Back 4

1. HLA-A

2. HLA-B

3. HLA-C

Front 5

What is the structure of MHC I?

Back 5

1. Heavy a-chain linked to B2-microglobulin

Front 6

To what do MHC I molecules present?

Back 6

1. CD8 cells

Front 7

Where are MHC II found?

Back 7

1. Only on antigen-presenting cells

Front 8

What encodes for MHC II?

Back 8

1. HLA-DP

2. HLA-DQ

3. HLA-DR

Front 9

What is the structure of MHC II?

Back 9

1. a-chain

2. B-chain

Front 10

To what does MHC II present?

Back 10

1. CD4 cells

Front 11

How are HLA genes linked together?

Back 11

1. Haplotype on chromosome 6

2. Inherited en bloc

Front 12

What is responsible for tissue compatibility between donor and recipient?

Back 12

1. MHC molecules

Front 13

What is cellular rejection?

Back 13

1. T cell mediated graft rejection

2. Destruction by CD8 cells

3. Type IV HSR triggered by CD4 cells

Front 14

What do T cells recognize in direct cellular rejection?

Back 14

1. MHC molecules on APCs in the graft

2. CD8 cells destroy

Front 15

What do T cells recognize in indirect cellular rejection?

Back 15

1. MHC antigens of graft donor after they are presented by recipient's own APCs

2. CD4 cells enter graft and recognize antigens

Front 16

What are the classifications of renal graft rejection?

Back 16

1. Hyperacute

2. Acute

3. Chronic

Front 17

What are the characteristics of hyperacute rejection?

Back 17

1. Ab mediated

2. Abs present in blood of recipient

3. May have arisen from prior transfusion, pregnancies, or previous transplants

Front 18

What is the consequence of a hyperacute rejection?

Back 18

1. Irreversible

2. Graft must be removed

Front 19

What is the histopathology of hyperacute rejection?

Back 19

1. Complement and Ig are deposited in vessel wall, causing endothelial injury and thrombi in renal vessels

2. Variable infiltrate of leukocytes in glomeruli, peritubular capillaries, and interstitium

Front 20

Back 20

1. Hyperacute rejection

Front 21

In what patients does acute rejection occur?

Back 21

1. Recipients not previous sensitized to transplantation antigens

2. Exposure to donor HLA antigens may provoke production of Abs which initially target graft vasculature

Front 22

What are the possible mediators of acute rejection?

Back 22

1. Ab (humoral)

2. T cell (cellular)

Front 23

When can acute rejection occur? What are the signs of acute rejection?

Back 23

1. Anytime

2. Most often seen in first few months

3. Ssx: Abrupt onset of decreasing urine output and increasing BUN/creatinine

Front 24

What is the reversibility of acute rejection?

Back 24

1. Possibly reversible with appropriate immunosuppressive tx

Front 25

What is the histopathology of acute humoral rejection?

Back 25

1. Damage to blood vessels---

2. Necrotizing vasculitis

3. Necrosis of renal parenchyma

Front 26

Back 26

Acute rejection capillaritis

Front 27

Back 27

Acute rejection vasculitis

Front 28

When does chronic rejection occur?

Back 28

1. Several years after transplantation

2. Several episodes of acute rejection

3. MC after initial 6-12 mos.

Front 29

What is the reversibility of chronic rejection?

Back 29

1. Irreversible

Front 30

What is the presentation of chronic rejection?

Back 30

1. Progressive renal failure

2. Rise in serum creatinine over 4-6 mos.

Front 31

What is the histopathology of chronic rejection?

Back 31

1. Vascular changes

2. Interstitial fibrosis

3. Tubular atrophy

4. Glomerular scarring

Front 32

Back 32

Chronic rejection

Front 33

Back 33

Chronic rejection

Front 34

What is graft v. host disease?

Back 34

1. Immunocompetent lymphocytes engrafted in bone marrow or liver may reject tissues of recipient

Front 35

Where does GVH disease usually occur?

Back 35

1. Skin

2. GI tract

3. Liver

Front 36

What are the ssx of acute and chronic GVHD?

Back 36

1. Acute-- rash, diarrhea, abdominal cramps, anemia, liver dysfunction

2. Chronic-- dermal sclerosis, dry eyes and mouth (Sicca), immunodeficiency

Front 37

Back 37

1. GVHD

Front 38

How do you increase graft survival?

Back 38

1. HLA-match donor and patient

2. Screen donor for preformed antibodies

3. Immunosuppressive tx

4. Pretreatment of graft with antithymocyte globulin

Front 39

What are the reasons for HLA testing?

Back 39

1. Pre-transplantation workup-- find a close match

2. Determine risk of certain diseases--- HLA-related diseases

Front 40

What should you do in pre-transplant testing?

Back 40

1. ABO and Rh

2. HLA recipient and donor lymphocytes

3. Look for pre-formed Abs

4. Test recipient's serum against donor's lymphocytes

Front 41

What organs do not require HLA testing?

Back 41

1. Heart

2. Lung

3. Liver

4. Pancreas

5. DO CHECK FOR ABO

Front 42

Corneal transplant. What's the deal?

Back 42

1. MC transplant

2. Don't need to test HLA or ABO

3. MC lost graft