Transplantation

Question 1

Autograft

Answer 1

Self-tissue transplanted from one site to another on the same individual

Question 2

Isograft

Answer 2

Tissue is transferred between genetically identical individuals

Question 3

Allograft

Answer 3

Tissue is transferred between non-identical members of the same species

Question 4

Xenograft

Answer 4

Tissue is transferred between individuals of two different species

Question 5

Greatest barrier to transplantation

Answer 5

Immunological recognition of graft as foreign

Question 6

Immune mediators of allograft rejection

Answer 6

T cells and antibodies

Question 7

Immune mediators of xenograft rejection or mismatched blood antigens

Answer 7

Antibodies and complement

Question 8

Which factors influence rate of rejection?

Answer 8

Closeness of genetic match
Tissue location
Solid organ vs cellular engraftment

Question 9

Strongest driver of rejection

Answer 9

Mismatches at MHC alleles (different haplotypes)

Question 10

Which subtypes of T cells contribute to allograft rejection?

Answer 10

CD4 and CD8

Question 11

Direct allograft rejection

Answer 11

Dendritic cells from the donor trigger immune responses against donor tissue

Question 12

Indirect allograft rejection

Answer 12

Recipient dendritic cells process donor cell proteins and present foreign epitopes to T cells

Question 13

Minor histocompatibility antigens

Answer 13

Antigens involved in histocompatibility that operate outside of MHC allele matching

Question 14

Hyperacute graft rejection: time for rejection

Answer 14

Minutes to hours

Question 15

Hyperacute graft rejection: primary mediators

Answer 15

Natural antibodies

Complement-mediated lysis

Question 16

Acute graft rejection: time for rejection

Answer 16

Hours to days

Question 17

Acute graft rejection: primary mediators

Answer 17

Antibodies, NK cells, CD8 T cells

Question 18

Chronic graft rejection: time for rejection

Answer 18

Weeks to months

Question 19

Chronic graft rejection: primary mediators

Answer 19

Antibodies, CD4 T cells, CD8 T cells

Question 20

Hyperacute rejection: cause and mechanism

Answer 20

Blood type mismatches, xenotransplants

Mechanism: rapid binding of antibody and complement activation

Question 21

Acute rejection: cause and mechanism

Answer 21

Reaction against alloantigens

Damage to vascular endothelial cells and tissue cells

Question 22

Chronic rejection: cause and mechanism

Answer 22

Type 3 or type 4 hypersensitivity

Restriction in blood supply to graft tissue as blood vessels thicken

Question 23

Hematopoietic stem cell transplantation

Answer 23

Stem cells from donor bone marrow or blood are infused into recipient
Only curative option for blood cancers, autoimmune diseases, and certain genetic disorders

Question 24

Major obstacle of hematopoietic stem cell transplantation

Answer 24

Chronic graft vs host disease: donor T cells attack immunocompromised host because they identify host as foreign

Question 25

First match to be made for transplantation

Answer 25

Blood type (ABO)

Question 26

Second match to be made for transplantation

Answer 26

MHC alleles (matched as best as possible)
Can tolerate some mismatch depending on tissue

Question 27

Induction of graft recipient tolerance

Answer 27

Give recipient donor antigens ahead of surgery

Question 28

Avoiding hyperacute rejection in xenotransplantation

Answer 28

Create transgenic animal (eg pigs) that expresses human CD59 and decay accelerating factor

Question 29

Luminex assay

Answer 29

Most common test for recipient antibodies against donor MHC antigens
Used to determine MHC compatibility between donor and recipient