title: Incidence of alloantibody formation after ABO-D or extended matched red blood cell transfusions: a randomized trial (MATCH study).
abstract: BACKGROUND
  Most incidentally transfused patients receive only ABO-D-compatible transfusions and antibodies are formed in up to 8%. The effect of extended (c, C, E, K, Fy(a) , Jk(a) , and S antigens) matched (EM) and ABO-D-matched red blood cell (RBC) transfusions on the incidence of new clinically relevant RBC antibody formation after a first elective transfusion event in surgical patients was studied.
  
  
  METHODS
  A multicenter randomized trial was performed in nontransfused patients who were scheduled to experience a single elective transfusion event of maximal 4 RBC units. The primary outcome was the incidence of newly formed warm reacting clinically relevant RBC alloantibodies measured in three follow-up (FU) samples taken at 7 to 10 days, 4 to 6 weeks, and 4 to 6 months posttransfusion.
  
  
  RESULTS
  A total of 853 patients were randomized, and of these, 333 patients were transfused with a total of 1035 RBC units. At least one FU sample was available from 97% of transfused patients. In intention-to-treat analysis, new antibodies were detected in 10 of 155 ABO-D and seven of 178 EM patients, respectively. Per-protocol analysis including 190 patients showed a nonsignificant absolute risk difference (ARD) of 5.3% (95% confidence interval [CI], -1.4% to 12%) in alloimmunization between study arms. In a post hoc analysis of 138 patients who received RBCs but no platelet (PLT) transfusions the ARD increased to significance, 8.0% (95% CI, 0.4-16.0).
  
  
  CONCLUSIONS
  Extended matching for selected antigens reduced the alloimmunization risk by 64% in surgical patients. Extended matching seems successful only if the patient did not receive accompanying nonmatched PLT transfusions.
authors.affiliation: Centre for Clinical Transfusion Research, Sanquin Research.|Jon J. Van Rood Centre for Clinical Transfusion Research, Sanquin-Leiden University Medical Centre, Leiden, The Netherlands.
authors.forename: Henk
authors.initials: H
authors.lastname: Schonewille
authors.affiliation: Centre for Clinical Transfusion Research, Sanquin Research.|Jon J. Van Rood Centre for Clinical Transfusion Research, Sanquin-Leiden University Medical Centre, Leiden, The Netherlands.
authors.forename: Áine
authors.initials: Á
authors.lastname: Honohan
authors.affiliation: Centre for Clinical Transfusion Research, Sanquin Research.|Jon J. Van Rood Centre for Clinical Transfusion Research, Sanquin-Leiden University Medical Centre, Leiden, The Netherlands.
authors.forename: Leo M G
authors.initials: LM
authors.lastname: van der Watering
authors.affiliation: LabWest, Haga Teaching Hospital, The Hague, The Netherlands.
authors.forename: Francisca
authors.initials: F
authors.lastname: Hudig
authors.affiliation: Department of Haematology, Erasmus Medical Centre, Rotterdam, The Netherlands.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Te Boekhorst
authors.affiliation: Department of Anesthesiology, Albert Schweitzer Hospital, Dordrecht, The Netherlands.
authors.forename: Ankie W M M
authors.initials: AW
authors.lastname: Koopman-van Gemert
authors.affiliation: Jon J. Van Rood Centre for Clinical Transfusion Research, Sanquin-Leiden University Medical Centre, Leiden, The Netherlands.|Department of Immuno-Hematology and Blood Transfusion, Leiden University Medical Centre, Leiden, The Netherlands.
authors.forename: Anneke
authors.initials: A
authors.lastname: Brand
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017707:Erythrocyte Transfusion / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007518:Isoantibodies / Q000097:blood / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012204:Rh-Hr Blood-Group System / Q000097:blood / Q000276:immunology
chemical_list: D007518:Isoantibodies; D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen