Serologic changes and transfusion
requirements after ABO
incompatible stem cell transplant
Kimberly W. Sanford, M. D.
Associate Medical Director of Transfusion Medicine
Virginia Commonwealth University Health System
Objectives




Review basic ABO serology
Define the types of incompatible ABO transplants
Serologic changes in recipient
Discuss transfusion strategies
Page 2
Antigen
Substance capable of inducing immune response
 Protein, carbohydrate, lipid
 Can be cell bound or free floating
ANTIGEN
RBC
Page 3
Antibody
A protein synthesized by B lymphocyte in response to antigen
and resides in the plasma

Expected antibody –


Naturally occurring
Example


Anti A, Anti-B antibodies
Unexpected antibody



Exposure to donor blood through transfusion
Exposure during pregnancy
Example:

Anti-D, Anti-Kell antibodies
Page 4
ABO System

The antigens present on the
surface of RBC are numerous


ABO system





Several hundred antigens
present on surface
A antigen
B antigen
AB antigen
O lacks both A and B antigen
RBC
Rh system


49 antigens make up the Rh
system
5 antigens most important:

D, C,E,c,e
Page 5
ABO system
Group A
Group
AB
Group
B
Group O
Page 6
ABO antibodies
RULES:
WE FORM ANTIBODIES TO THE ANTIGENS WE LACK
WE DO NOT FORM ANTIBODIES TO OUR OWN
ANTIGENS
Page 7
Blood Group A

Patient has A antigen on RBC

Patient lacks B antigen

Therefore patient will form
Anti-B antibodies, but NOT
Anti-A antibodies.
Page 8
Blood Group B

Patient has B antigen on
RBC

Patient lacks A antigen

Therefore patient forms Anti-A
antibodies but NOT Anti-B
antibodies
Page 9
AB group

Patient have both A and B
antigen on RBC

Therefore patient does NOT
form any AB antibodies.
Page 10
O Blood Group

Patient lacks both A and B
antigen

Patient forms both:

Anti-A antibody

Anti-B antibody
Page 11
HLA & ABO inherited separately

HLA: Chromosome 6 (6p21.3) contains 200 genes,
expressed on WBC

ABO: located on Chromosome 9, expressed on RBC

Patient & donor may be 6/6 HLA match but disparate
ABO groups
Page 12
HLA system



Human Leukocyte Antigen
system expressed on all
nucleated cells
Mature circulating RBCs do
not have nuclei, do not express
HLA antigens
Look at HLA antigens to
determine if donor is a match



Class I: HLA A, B, C
Class II: HLA DP, DQ, DR
HLA-A, B, DRB1 (Cw) are
most important for matching
Page 13
HLA and ABO Antigens

HLA compatibility

Strongest predictor for occurrence of severe GVHD

Single most important factor to consider in selecting donor
Page 14
ABO mismatch transplant

ABO mismatch does not:



Affect engraftment since stem cells do not have ABO antigens
The lack of the ABO antigens allow for homing and engraftment
of stem cells regardless of ABO incompatibility
Does NOT affect neutrophil, platelet engraftment, graft failure or
rejection.
Page 15
ABO mismatched transplants

Complications

Require more transfusion


Acute RBC hemolysis





Acute hemolysis of RBC with infusion of HPC product
Delayed RBC hemolysis


Delayed RBC engraftment or RBC aplasia
After engraftment, marrow produces donor RBC incompatible with
recipient antibodies.
After engraftment, ABO antibodies produced against recipient RBC
Patient develops a positive DAT and hemolysis
Can be life threatening
Complex transfusion requirements
Page 16
Intravascular hemolysis



Antibody binds intravascular to RBC activating complement
Complement causes pores in RBC membrane
Free hgb escapes, hgb drops, LDH increases, haptoglobin decreases



Complement activation generates




Anaphylatoxins, C3a & C5a
Proinflammatory cytokines activated


Binds NO2
Renal vasoconstriction, ischemia, tubal necrosis, renal failure
IL-1, IL-6, IL-8, TNF
Fever, Hypotension, Activate WBC and clotting cascade
Disseminated Intravascular coagulation
Death
Page 17
Intravascular Hemolysis
Page 18
ABO incompatibilities in transplant

Major


Minor


Recipient has ABO antibodies directed against donor RBC
Donor has ABO antibodies directed against recipient RBC
Bidirectional: Major and Minor ABO Incompatibility:

Recipient has ABO antibodies directed against donor red cells
AND

Donor has ABO antibodies directed against recipient red cells.
Page 19
Major mismatch: O recipient & A donor
O recipient: Anti-A, Anti-B antibodies and O RBCs
Donor RBCs: A antigen RBC
Complications




R
Immediate hemolysis of donor RBC at transplant
R
R
R
D
R
R
R
D
R
R
Page 20
Delayed complications

Delayed hemolysis after RBC engraftment

Persistent recipient anti-A abs



Hemolyze donor A RBC produced from marrow.
Delay RBC engraftment


120-605 days post transplant
20% of patients experience
RBC aplasia (severe)


Reticulocytopenia persists > 60 days
RBC precursors not present in marrow aspirate
Page 21
Minimize Risk

Apheresis collections can minimize RBC contamination of
product to hematocrit < 2-3%.

Remove RBCs from the graft below 10-20 ML during
processing of stem cell product
Page 22
Minor Mismatch: A recipient & O donor



Recipient A : A RBC and Anti-B abs
O donor: infusion of Anti-A abs into recipient
Complication

Delayed hemolysis (1-2 wks) after donor lymphocyte engraftment
D
R
D
D
D
R
R
R
R
R
Page 23
Minimize Risk

Remove donor plasma and antibody from graft to prevent
hemolysis at transplant

Biggest risk is 5-14 days after transplant, the donor
lymphocytes create antibodies against recipient RBC cells.



Positive DAT and hemolysis of RBC
Severe hemolysis can lead to multisystem organ failure
Death
Page 24
Passenger donor lymphocytes

“Passenger” donor lymphocytes proliferate within the
marrow and produce ABO antibodies.
R
Page 25
Bidirectional Mismatch: A recipient & B donor



Recipient: A RBC’s with Anti-B antibodies
Donor: B RBC’s with Anti-A antibodies
R
Complication: immediate hemolysis of donor cells, delayed hemolysis
after lymphocyte engraftment of recipient RBC and RBC aplasia
D
R
D
D
R
D
R
Page 26
Minimize Risk

Deplete the donor graft of RBC and plasma.

Biggest risk is 5-14 days after transplant, the donor
lymphocytes create antibodies against recipient RBC cells.





Delayed RBC engraftment, pure RBC aplasia
Positive DAT and hemolysis of RBC
Can lead to multisystem organ failure
Death
Bidirectional ABO incompatibility have significantly
increased risk of mortality over major and minor
incompatibilities
Page 27
Transfusion support

Difficult to select components



Recipient antibodies can persist for weeks or months after
transplant and engraftment
Donor lymphocytes produce antibodies against recipient RBC
Patients are chimeras



Patient has 2 distinct blood group RBC populations
Donor RBC production increases after engraftment, incompatible
with persistent recipient antibody
Concerns




Intravascular hemolysis in major and bidirectional mismatches
Delayed hemolysis in minor mismatches
Select product that will not exacerbate hemolysis
Transfusion support can affect overall survival
Page 28
ABO/Rh incompatible transplant transfusion


Phase I: Prior to transplant
Phase II: Transplant until engraftment



Recipient antibodies are still detectable
Chimera: recipient and donor type RBC detectable
Front and back types don’t match


Interpret as undetermined type
Phase III: Complete engraftment



Patient RBC type like donor RBCs
Patient ABO antibodies are same as donor.
Requires confirmed new blood type on 2 separate occasions to
switch blood products to donor type
Page 29
ABO selection of products

Major Incompatibility: O recipient receives A donor

PRBC



Transfuse with recipient type RBC until recipient antibodies are no
longer detectable.
Then switch to donor type RBC
Plasma

Continue with donor type plasma
Page 30
ABO Selection of PRBC

Major incompatibility: O recipient & A donor


Recipient has Anti-A or Anti B antibody against donor A RBC
Transfuse with recipient type, O RBC
R
D
Page 31
ABO Selection of Plasma products

Major incompatibility: O recipient & A donor


Recipient has Anti-A or Anti-B antibody against donor A RBC
Transfuse with donor type A plasma
R
D
R
Page 32
Transfusion for Major Incompatiblity
Recipient
Donor
RBC/WBCs
Platelets/FFP
O
A
O
A, AB
O
B
O
B, AB
A
AB
A
AB
B
AB
B
AB
O
AB
O
AB
Page 33
ABO selection of products

Minor Incompatibility: A recipient receives O donor

PRBC


Transfuse with donor type RBC until engraftment
Plasma

Continue with recipient type plasma until recipient RBCs are no
longer detectable, then switch to donor type
Page 34
Minor Mismatch: A recipient & O donor

RBC: provide donor type O RBC start immediately after transplant
and continue after engraftment.
Page 35
Minor Mismatch: A recipient & O donor

Plasma: provide recipient type A or AB plasma until recipient red
blood cells are no longer detected, then switch to donor type plasma.
Page 36
Minor ABO Incompatibility
Recipient
Donor
RBC/WBCs
Platelets/FFP
A
O
O
A, AB
B
O
O
B, AB
AB
O
O
AB
AB
A
A
AB
AB
B
B
AB
Page 37
Bidirectional Mismatch: A recipient & B donor

Bidirectional Incompatibility

PRBC


R
Provide O PRBC
FFP

Provide AB plasma products
D
R
D
D
R
D
R
Page 38
Bidirectional (Major and Minor) ABO Incompatibility
Continue until offending RBC antigens and antibodies are no longer
detected.
Recipient
Donor
RBC/WBCs
Platelets/FFP
B
A
O
AB
A
B
O
AB
Page 39
RBC Alloantibody incompatibility

Have major and minor incompatibilities of other antigens



Rh system: Anti- D, C, E
Anti – Kell or Kidd abs are particularly bad
Major: Recipient has antibodies to donor antigens


Minor: Donor has antibodies to recipient RBC antigen


Ex: Kell antigen + donor, recipient with Anti-Kell abs
Ex: donor with Anti-E abs, E antigen + recipient
HPC product



Keep low hct during collection
Remove plasma from HPC product
Provide antigen negative, crossmatch compatible RBC for
transfusion.
Page 40
Alloimmunization to RBC antigens



Despite immunosuppression, may still see immune
response to foreign RBC antigens.
Complicates transfusion by now requiring antigen negative
blood in addition to ABO transfusion requirements.
2 studies have demonstrated red cell alloimmunization of
2-8% in patients undergoing stem cell transplant.


Perseghin P, Balduzzi A, Galimberti et al. Bone Marrow Transplant 2003;32:231-6.
Abou-Elella AA, Camarillo TA, Allen MB et al. Transfusion 1995;35:931-5.
Page 41
Rh Negative Transplant patients



Minimize exposure to Rh positive products
Rh positive platelets contain about 2 ml of RBC/dose
Risk of forming Anti-D is low, 0-22%

22 adult patients, none alloimmunized


35 pediatric patients, none alloimmunized


Cid J, Ortin X, Elies E, et al. Transfusion 2002;42:173-6.patients
Molnar R, Johnson R, Sweat LT, Geiger TL. Transfusion 2002;42:177-82.
98 adult patients, received 445 D+ RBC units

22 formed anti-D, 22%

Yazer MH, Triulzi DJ. Transfusion 2007;47:2179-2201.
Page 42
Rh Incompatible Transplants
Recipient
Donor
Transfusion Protocol
Rh Positive Rh Negative Rh Negative cells
Rh Negative Rh Positive Transfuse Rh Negative red cells; switch to Rh
positive cells once the transplanted BM or PBSC
begins producing Rh Positive red cells
Page 43
Summary






Complex transfusion requirements
See acute and delayed hemolysis
Lower overall survival in minor and bidirectional
mismatched grafts.
Delayed RBC engraftment or red blood cell aplasia.
ABO doesn’t affect engraftment of stem cell product,
lymphocytes or granuloctyes
Studies have found ABO incompatibility bigger risk of
mortality in certain cases:



based on disease condition
reduced intensity conditioning
receiving unrelated grafts.
Page 44
References


Szczepiorkowski ZM. Transfusion Support for Heamotpoietic Transplant Recipients.
In: Roback J. Ed. Technical manual 16th ed. Bethesda MD: American Association of
Blood Banks, 2008. 679-96.
Tormey CA, Synder EL. Transfusion Support for the Oncology Patient. In: Toby L.
Simon et al. Ed. Rossi’s Priniciples of Transfusion Medicine 4th ed. American
Association of Blood Banks, 2008. 482-97.


Perseghin P, Balduzzi A, Galimberti et al.Red blood cell support and
alloimmunization rate against erythrocyte antigens in patients undergoing
hematopoietic stem cell transplantation. Bone Marrow Transplant 2003;32:231-6.
Abou-Elella AA, Camarillo TA, Allen MB et al. Low incidence of red cell and HLA
antibody formation by bone marrow transplant patients. Transfusion 1995;35:931-5.
Page 45