Lecture 27 (Transplantation and Transfusion) Flashcards
What is transplantation?
process of taking cells, tissues, or organs, called a graft, from one individual and placing them into a different individual
donor vs. recipient for transplants
donor: provides the graft (tissue, cells, etc.)
recipient: receives the graft (tissue, cells, etc.)
from one individual to the same individual
a) autologous transplant
b) syngeneic transplant
c) allogeneic transplant
d) xenogeneic transplant
a) autologous transplant
between two genetically identical individuals
a) autologous transplant
b) syngeneic transplant
c) allogeneic transplant
d) xenogeneic transplant
b) syngeneic transplant
between genetically different individuals of the same species
a) autologous transplant
b) syngeneic transplant
c) allogeneic transplant
d) xenogeneic transplant
c) allogeneic transplant
between individuals of different species
a) autologous transplant
b) syngeneic transplant
c) allogeneic transplant
d) xenogeneic transplant
d) xenogeneic transplant
why is MHC an important antigen in transplants
-highly polymorphic; unlikely to be similar between individuals
-polymorphic variants; can be recognized as foreign antigens when shared between individuals
-they are proteins themselves; highly antigenic
-potent stimulators of immune responses
transplant reactions are divided into what three different types of reactions?
-hyperacute reactions
-acute reactions
-chronic reactions
occur within minutes
a) hyperacute reaction
b) acute reaction
c) chronic reaction
a) hyperacute reaction
due to the presence of preformed antibodies within the recipient
a) hyperacute reaction
b) acute reaction
c) chronic reaction
a) hyperacute reaction
directed against graft vasculature
a) hyperacute reaction
b) acute reaction
c) chronic reaction
a) hyperacute reaction
how are hyperacute rejections/reactions avoided?
crossmatch procedure; blood typing
occur within days to weeks
a) hyperacute reaction
b) acute reaction
c) chronic reaction
b) acute reaction
mediated by T-cells and antibodies specific for alloantigens
a) hyperacute reaction
b) acute reaction
c) chronic reaction
b) acute reaction
c) chronic reaction
what is the most important alloantigen?
MHC II
occur over months to years
a) hyperacute reaction
b) acute reaction
c) chronic reaction
c) chronic reaction
directly kill graft cells
a) CD8+ CTLs
b) CD4+ cells
a) CD8+ CTLs
secrete cytokines and induce inflammation
a) CD8+ CTLs
b) CD4+ cells
b) CD4+ cells
t/f: RBC’s do not have MHC
true
RBC’s do not have MHC but rather have a variety of _____________ membrane proteins
glycosylated
t/f: animals may make antibodies to foreign blood group antigens even though they have never had a transfusion
true
what two species have natural antibodies to blood?
cats and humans
what are human blood types?
A, B, AB, O
what are feline blood types?
A, B, AB
87% of domestic cats are blood type ____
A
N-glycolyl-neuraminic acid
a) type A blood
b) type B blood
a) type A blood
N-acetyl-neuraminic acid
a) type A blood
b) type B blood
b) type B blood
t/f: there is no null-type to feline blood groups
true
75-90% of cats are A+; about 1/3 of type A cats have low level antibody against type ___
B
type B cats hav a high level of antibody against type _____
A
*crossmatching is critical
t/f: type AB cats do not develop anti-A or anti-B
true
what happens to cats with type B blood that receive type A blood?
normally immediate anaphylactic reaction
what happens to cats with type A blood that receive type B blood?
-first time may be minor reaction
-second time anaphylactic reaction
t/f: feline blood typing kits only determine major blood type
true
how many blood group antigens do dogs have?
13
how are dog blood types designated?
DEA 1.1, 1.2, 3-8
t/f: only DEA 1 is of clinical significance in dogs
true
which allele is the most antigenic in dogs?
DEA 1.1+
what percentage of dogs are DEA 1.1+?
~32-67%
if you have a DEA 1- dog who has had a prior transfusion with + blood, the dog becomes _____________
sensitized
sensitization of - dam if bred to + male, may lead to ________ disease of newborns
hemolytic
DEA ___ and ___ appear on ~98% of canine RBCs
4 and 6
t/f: dogs generally have iso-antibodies to incompatible blood groups
false - do not have iso-antibodies until an initial exposure
antibodies against incompatible blood can form in ___ to ___ days
5 to 7
t/f: the half-life of compatible blood will be shorter than incompatible blood
false - the half-life of incompatible blood will be shorter than comparable blood
what is the universal donor for canine blood typing?
DEA 1.1- is the best but also 1.2- and 7-
horses have at least ___ blood groups
7
what are equine blood types?
A, C, D, K, P, Q, U
_____ and ______ are the most antigenic blood type variants in equine
Aa and Qa
t/f: horses do not have preformed antibodies
true
_________ ____________ is the most clinically relevant issue associated with equine blood types
Neonatal Isoerythrolysis
Reasons for a blood transfusion
-anemia
-blood loss
-hemolysis
-massive hemorrhage
-etc.
what does cross-matching blood types detect?
detects the presence of serum antibody to RBC antigens
donor serum is mixed with recipient RBC
a) minor reaction
b) major reaction
a) minor reaction
donor RBC is mixed with recipient serum
a) minor reaction
b) major reaction
b) major reaction
for crossmatching when you do a major reaction (donor RBC is mixed with recipient serum), what would denote a positive cross reaction?
precipitation in the tubes
what are the 4 reasons MHC proteins are such important antigens in transplants?
- Highly variable - unlikely to be similar in host & donor
- Recognizable as foreign by immune system
- Highly antigenic proteins (like most protein)
- Expressed in high numbers on cell surfaces
which reactions to a transplant are targeted by current immunosuppressive therapies?
acute
*hyperacute reaction is avoided by cross matching blood type // chronic reaction is not subject to the therapy
what is the important antigen for transfusions?
erythrocyte proteins (Glycosylated membrane proteins // “blood types” antigens)
besides being born with them or being sensitized by a prior mismatched blood transfusion, why else might an animal have antibodies to a given blood type?
-Molecular mimicry (pathogen epitopes similar to their given blood antigens)
-Pregnancy related (HDN mechanism)
what happens if you give a mismatched blood transfusion to a Type A cat?
-first time: may only have a minor reaction (only 1/3 of A cats have anti-B immunoglobulins), or could be the unlucky third
-second time: immediate anaphylactic reaction; lysis, hypotension, and shock
what happens if you give a mismatched blood transfusion to a Type B cat?
first time you will have the immediate anaphylactic reaction because 100% of Type B cats are born with anti-A-immunoglobulins
what is the most antigenic allele in regards to canine blood type?
DEA 1.1+
what is the clinically significant locus in canine blood type genes?
DEA1 locus
approximately what percent of dogs will be DEA1.1+
33-67%
if a DEA1- dog receives a first transfusion, but the blood is mismatched what will happen?
the dog will become sensitized for future transfusion and using non-matched blood will no longer be a plausible option clinically
*relatively safe once since no preformed antibodies but worried about molecular mimicry or HDN issues
the two most antigenic erythrocyte antigens for equine blood types are:
Aa and Qa
in a Major Cross-Match you use the Recipients __________________ & the donor’s _______________. Mix them, incubate them, and check for precipitation if reactive
Recipient’s Serum; Donor’s RBCs
dogs have blood volumes of ______% of their body weight
7-9%
*~70-90 ml/kg blood volume
cats have blood volumes of _____% of their body weight
6-7%
*~60-70 ml/kg blood volume
how do you calculate RBC volume?
blood volume x patient’s PCV%
what needs to be monitored on a patient during transfusion?
-rectal temp
-pulse rate
-capillary refill time
-demeanor
-hives
preformed antibodies can lead to ______________ reactions
hyperacute
donor white blood cells and foreign proteins (cytokines) can lead to __________ reactions
acute
