ABO mismatch may affect engraftment in multiple myeloma patients receiving nonmyeloablative conditioning.
BACKGROUND
Blood group incompatibility does not appear to affect the overall outcome in patients undergoing myeloablative conditioning before allogeneic BMT. Data on ABO-mismatched transplantation in the nonmyeloablative setting are limited.


METHODS
A retrospective analysis of the effects of ABO mismatches in multiple myeloma patients who received a nonmyeloablative conditioning regimen was conducted.


RESULTS
Three of 27 patients received a minor ABO-mismatched graft, all with evidence of hemolysis before converting to donor ABO group on Days 10, 15, and 6. Six patients received a major ABO-mismatched graft; of these, three developed GVHD of more than grade 2 and subsequently converted to the ABO blood group of the donor on Days 38, 33, and 43. Of the three patients without GVHD, one rejected the allograft and had autologous reconstitution. One remained a mixed chimera to Day 100 despite three donor lymphocyte infusions, and one developed pure RBC aplasia. None of the ABO-matched patients rejected the graft, whether they developed GVHD or not. RBC transfusions were significantly higher in the major and minor ABO-mismatched patients than in the ABO-matched patients, with medians of 12 units (range, 2-35), 13 units (range, 5-18), and 4 units (range, 2-15), respectively (p = 0.02). ABO-matched patients had a similar incidence of GVHD, with 5 of 9 ABO-mismatched patients (56%) having more than grade 2 versus 10 of 18 (56%). Four of 9 ABO-mismatched patients (44%) were mixed chimeras up to Day 100 versus 2 of 18 ABO-matched patients (11%), and the difference was significant (p = 0.01).


CONCLUSIONS
Patients with ABO mismatch had problems with engraftment, including graft rejection, pure RBC aplasia, and mixed-lineage chimerism. RBC transfusions were significantly higher in the ABO-mismatched recipients. GVHD may play a role in engraftment, possibly by facilitating the disappearance of native ABO antibodies via graft-versus-plasma cell effect. A prospective study to evaluate the effects of ABO mismatch on engraftment in the nonmyeloablative setting is needed.
Badros
Ashraf
A
Myeloma and Transplantation Research Center, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA. abadros@umm.edu
Tricot
Guido
G
Toor
Amir
A
Morris
Christopher
C
Guo
Chuanfa
C
Munshi
Nikhil
N
Barlogie
Bart
B
Cottler-Fox
Michele
M
D000017:ABO Blood-Group System; D000328:Adult; D000368:Aged; D001787:Blood Group Incompatibility; D016026:Bone Marrow Transplantation; D017707:Erythrocyte Transfusion; D005260:Female; D006084:Graft Rejection / Q000453:epidemiology; D006085:Graft Survival; D006086:Graft vs Host Disease / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000628:therapy*; D012010:Red-Cell Aplasia, Pure / Q000453:epidemiology; D014019:Tissue Donors; D018183:Transplantation Chimera; D019172:Transplantation Conditioning; D014184:Transplantation, Homologous; D016896:Treatment Outcome
D000017:ABO Blood-Group System