2020B14 Briefly outline the potential immunological effects of transfusing packed red cells.

 

Immediate:

Febrile non-haemolytic

     Donor blood storage -> cytokine accumulation (IL-1, IL-6, TNF-α)

     Fever, malaise, dyspnoea

     Not harmful

Febrile haemolytic

     Due to incompatible transfusion

     RBC > platelets > FFP

     (Normal) prior alloimmunisation due to molecular mimicry by gut flora

     Donor antigen vs recipient antibody

     ABO IgM-> intravascular haemolysis (DIC, renal failure, death)

     RhD IgG-> extravascular haemolysis (haemolytic anaemia)

Anaphylaxis

     Type 1 hypersensitivity

     FFP and platelets > RBC

     Donor protein vs recipient IgE

     Especially IgA vs IgA-deficient host

     Mast cell degranulation -> vasodilation, bronchospasm, angioedema

TRALI

     Transfusion-related acute lung injury

     FFP and platelets > RBC

     ? Donor antibody vs recipient lung antigen

     ? Illness-related priming of neutrophils and endothelium

     Non-cardiogenic pulmonary oedema

     Major cause of mortality

     FFP and platelets > others

     Onset during transfusion or < 6 hours

 

Delayed:

Alloimmunisation

     First exposure to antigen during transfusion or childbirth

     Alloantibodies produced

     Second exposure results in antibody-mediated destruction

Delayed haemolytic reaction:

     Especially if recurrent transfusion

     Antibodies: Kell, Kidd, Duffy

     Diminishing antibody titre -> re-exposure -> anamnestic response

     Extravascular haemolysis -> haemolytic anaemia

Haemolytic disease of the newborn:

     RhD+ foetus vs RhD- mother; or Kell(+) foetus vs Kell(-) mother

     IgG crosses placenta -> severe haemolysis

     Prevented by anti-D at 28/40 and 34/40 in RhD- women

Post-transfusion purpura:

     Donor platelet vs recipient alloantibodies

     Consumption of both donor platelets and bystanders

Immunomodulation

     Mechanism unclear - ? donor WBC or mediators

     ↑Post-op infection, ↑cancer recurrence

     Rationale for cell salvage use in major cancer surgery

Graft vs host

     Donor WBC multiplies in immunocompromised host -> tissue damage

     Affects skin (rash), marrow (suppression), liver (↑LFT), GIT (diarrhoea)

     Rare, fatal, untreatable

     Prevented by gamma irradiation of blood product

 

 

Feedback welcome at ketaminenightmares@gmail.com