title: ABO mismatch may affect engraftment in multiple myeloma patients receiving nonmyeloablative conditioning.
abstract: 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.
authors.affiliation: Myeloma and Transplantation Research Center, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA. abadros@umm.edu
authors.forename: Ashraf
authors.initials: A
authors.lastname: Badros
authors.forename: Guido
authors.initials: G
authors.lastname: Tricot
authors.forename: Amir
authors.initials: A
authors.lastname: Toor
authors.forename: Christopher
authors.initials: C
authors.lastname: Morris
authors.forename: Chuanfa
authors.initials: C
authors.lastname: Guo
authors.forename: Nikhil
authors.initials: N
authors.lastname: Munshi
authors.forename: Bart
authors.initials: B
authors.lastname: Barlogie
authors.forename: Michele
authors.initials: M
authors.lastname: Cottler-Fox
mesh_terms: 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
chemical_list: D000017:ABO Blood-Group System