ABO discrepancies & transfusion in transplantation

Question 1

a) Discrepancy: Pt has anti-reagent Aby to _(3- what are they)
b) resolution (solution)

Answer 1

a) dyes in anti-A or anti-B; preservatives in reagent Aby or RBC preps
b) Wash pt/ reagent cells & resuspend in saline

Question 2

Type II discrepancy:
a) What is chimerism?
b) resolutino (solution)

Answer 2

a) patient has 2 different populations of RBC present
- Natural
- Acquired: out-of-group transfusions; BM/SC transplant; exchange transfusion
b) check pt history & molecular methods to ID chimera

Question 3

Describe the natural chimerism
a) multiple birth (twin, triplets etc) ;
b) dispermy
c) fetal-maternal bleed

Answer 3

a) blood flows b/w twins-> HSC engraft in BM -> 2 sets of cells
b) 2 sperm fertilise 2 maternal nuclei & zygote fuse = on body
c) baby blood cross placenta & circulates in mum’s blood

Question 4

Scenarios that describe a MAJOR mismatch (ABO incompatibles transplants)

Answer 4

• Foreign Ag on donor cells
• Recipient produces Aby against donor cells i.e. O recipient gets A cells
• Recipient lyses donor RBC - removed before transplantation

Question 5

Scenarios that describe a MINOR mismatch (ABO incompatibles transplants)

Answer 5

• foreign Aby in donor sample
• donor produces Aby against recipient cells e.g. A recipinet gets O cells
• Aby in residual donor plasma lyse recipient RBCs
• passenger lymphocyte syndrome: donor lymphocytes infused in recipient & make Aby -> haemolysis

Question 6

What transfusion products might you give a pt undergoing HPC (progenitor) engraftment in a MAJOR mismatch (e.g. Orecipient & A donor) & why

Answer 6

RBC: same group as recipient (e.g. O) until recipient Aby clears (-A, -B, -AB)
PLT/FFP/Plasma: same group as donor
bc contains Aby that lyse donor cells (e.g. A)
*don’t want to lyse DONOR cells. Remember O group will eventually change to A group

Question 7

What transfusion products might you give a pt undergoing HPC (progenitor) engraftment in a MINOR mismatch (e.g. A recipient & O donor) & why

Answer 7

RBC: same group as donor (e.g. A) & will have Anti-B aby
PLT/FFP/Plasma: same group as recipient (e.g. O)
bc contains Aby that lyse recipient cells
*don’t want to lyse RECIPIENT cells. Remember A group will eventually change to O group

Question 8

What transfusion products might you give a pt undergoing HPC (progenitor) engraftment in a bidirectional mismatch (e.g. A recipient & B donor or vise versa)

Answer 8

RBC: Group O
PLT/FFP/PLasma: group AB