Transfusions and Blood Groups Flashcards
IMHA treatment
- remove underlying cause
- immunosuppressive therapy
- anticoagulant therapy
- supportive care
Transfusion
Process of receiving blood products into one’s own circulation
Types of blood products
- fresh whole blood
- packed red blood cells
- fresh frozen plasma
- platelet concentrates
Indications for transfusions
- anemia: hemorrhage, hemolysis, non-regenerative
- disorders of hemostasis/coagulation
- deficiencies of plasma components
RBC transfusions
- any cause of life-threatening anemia
- acute hemorrhage
- hemolysis
- severe non-regenerative anemia
- neonatal isoerythrolysis
Blood groups
Inherited antigens on RBC surface
- species specific
- vary in immunogenicity and clinical significance
RBC antigens
- contribute to self recognition
- elicit the production of antibodies when introduced to an animal whose RBCs lack that antigen
Canine blood types
Dog erythrocyte antigen (DEA) system
- 1.1, 1.2 - 8
- 1.1, and 1.2 are considered important in transfusion medicine (produce the greatest immune response)
DEA 1.1
Extremely antigenic
- DEA 1.1 positive express the antigen
- 42% of dogs
What is the first antibody class that is synthesized by the primary immune response
IgM
- efficient at binding complement
What is produced during a secondary immune response?
IgG
Red cell alloantibodies
IgM, IgG, or IgE antibodies that could cause hypersensitivity reactions to blood products
Do dogs have naturally occurring alloantibodies?
NO Requires sensitization (transfusion) for alloantibodies to develop
Transfusion with similar DEA antigens and no alloantibodies
Less likely to mount an immune response
Transfusion with recipient positive DEA 1.1 and donor negative DEA 1.1
DEA 1.1 negative does not express 1.1 antigen, so less likely to mount an immune response
Transfusion with recipient negative DEA 1.1 and donor positive DEA 1.1
Will become sensitized and produce an anti-DEA 1.1 alloantibody
- does not happen immediately
Previously transfused patients
At risk for developing transfusion reactions
- risk complement destroying transfused blood immediately (acute hemolysis)
Blood typing
RBC antigens and plasma antibody interaction can be used to assess compatibility
Agglutination
Antibody-mediated clumping of cells that express antigen on their surface
Will the very first transfusion a dog receives cause a reaction?
No, since there are no antibodies free floating in the body at this point
Major crossmatch
Determine compatibility between donor and recipient
- donor RBCs are incubated with recipient serum and observed for agglutination or hemolysis
- if no agglutination/hemolysis then you are safe to transfuse
Minor crossmatch
Compatibility: donor plasma and recipient
Feline blood types
3 main blood types
- A
- B
- AB
Feline type A
Predominant blood type
- varies with breed and location
- type B: devon rex, and british shorthair
Do cats have naturally occurring alloantibodies?
Yes
- some A cats have antibodies against B blood
- MOST B cats have antibodies against A blood
What happens if you give a B recipient A type blood?
Will get an immediate hemolytic response
Actue hemolytic transfusion reactions
Develops when transfused RBCs interact with preformed circulating antibodies in the recipient that are naturally occurring or acquired
- can activate complement and cytokines = systemic inflammatory response
AHTRs
- reaction severity is directly related to number of RBCs destroyed
- dogs: reactions are predominantly IgG
- cats: reactions are predominantly IgM
AHTR clinical signs
- fever
- restlesness
- salivation
- incontinence
- shock
Febrile non-hemolytic transfusion reactions
- temperature increase associated with a transfusion without other explanation
- leukocyte derived cytokine and/or circulating anti-leukocyte antibodies in the recipient
