title: Transfusion efficacy of ABO major-mismatched platelets (PLTs) in children is inferior to that of ABO-identical PLTs.
abstract: BACKGROUND
  ABO major compatibility is essential in transfusions of red blood cells but is not requisite in PLT transfusions. In adults there is some evidence that transfusion efficacy of ABO blood group-identical platelets (PLTs) is superior to major-mismatched PLTs. However, in children this question has not been investigated for more than 30 years.
  
  
  METHODS
  In a prospective study, the efficacy (based on the 1-hour percentage of PLT recovery [PPR(1hr)]) of 400 eligible ABO blood group-identical or out-of-group apheresis PLT concentrates (APCs), transfused mainly prophylactically to 50 children with hematologic malignancies, solid tumors, or aplastic anemia was investigated. The primary objective was to compare PPR(1hr) between ABO-identical and major-mismatched transfusions.
  
  
  RESULTS
  After ABO major-mismatched transfusions, PPR(1hr) was significantly lower than after ABO blood group-identical transfusions (median 21% vs. 32%; p = 0.034). Multivariate analysis showed major-mismatched transfusions to be significantly more often unsuccessful than identical transfusions (odds ratio [OR], 3.97; 95% confidence interval [CI], 1.52-10.39; p = 0.005). Using flow cytometry and fluorescent microscopy, it could be demonstrated that PLTs of subgroup A(1), significantly expressing A antigen on their surface, were rapidly cleared from the circulation of group O or B recipients. In contrast, major-mismatched transfusions of A(2) PLTs, expressing no detectable A antigen, were as successful as identical transfusions (OR, 1.13; 95% CI, 0.16-7.88; p = 0.90).
  
  
  CONCLUSIONS
  These data clearly indicate that in children ABO major-mismatched PLT transfusions result in inferior transfusion efficacy, with the only exception of group A(2) PLTs. ABO minor-mismatched PLTs showed comparable efficacy to identical transfusions.
authors.affiliation: Department of Pediatrics, University of Berne, Berne, Switzerland.
authors.forename: Friedgard
authors.initials: F
authors.lastname: Julmy
authors.forename: Roland A
authors.initials: RA
authors.lastname: Ammann
authors.forename: Behrouz Mansouri
authors.initials: BM
authors.lastname: Taleghani
authors.forename: Stefano
authors.initials: S
authors.lastname: Fontana
authors.forename: Andreas
authors.initials: A
authors.lastname: Hirt
authors.forename: Kurt
authors.initials: K
authors.lastname: Leibundgut
mesh_terms: D000017:ABO Blood-Group System; D000741:Anemia, Aplastic / Q000628:therapy*; D001788:Blood Grouping and Crossmatching; D001792:Blood Platelets; D002648:Child; D002675:Child, Preschool; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007223:Infant; D008297:Male; D009369:Neoplasms / Q000628:therapy*; D017713:Platelet Transfusion; D011446:Prospective Studies
chemical_list: D000017:ABO Blood-Group System