title: Low incidence of D alloimmunization among patients with a serologic weak D phenotype after D+ transfusion.
abstract: BACKGROUND
  By consensus definition, the red blood cells (RBCs) of patients that react weak to 2+ in the serologic D test are classified as having the serologic weak D phenotype (weak D). The risk of D alloimmunization in patients with weak D is not well studied. This study retrospectively determined the incidence of D alloimmunization in patients with weak D who received D+ blood products.
  
  
  METHODS
  Patient records at four institutions were reviewed. Eligible patients had at least 1 D typing result with agglutination strength that was weak to 2+ result in gel or tube (Institutions 1-3) or weak to 2+ result in solid phase or a positive tube weak D test using antihuman globulin reagent (Institution 4). All patients received at least 1 D+ allogeneic RBC or platelet transfusion and had a subsequent antibody detection test performed at least 30 days after the first D+ transfusion.
  
  
  RESULTS
  The incidence of alloanti-D formation was 0.15% (6/4011, at Institutions 1-3) and 5.1% (3/59, at Institution 4; these incidences were significantly different [p = 0.0002]). There were 0.15% (6/4011) patients who had autoanti-D detected; all were at Institutions 1 to 3.
  
  
  CONCLUSIONS
  Until RHD genotyping is widely available, these data support the fact that patients with serologic weak D may be transfused with D+ RBCs if an urgent transfusion is required. At Institution 4, inclusion of a higher proportion of black patients compared to the other institutions may have affected the incidence of alloimmunization by perhaps including partial D recipients who are at risk of forming D antibodies.
authors.affiliation: Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania. myazer@itxm.org.|The Institute for Transfusion Medicine, Pittsburgh, Pennsylvania. myazer@itxm.org.
authors.forename: Mark H
authors.initials: MH
authors.lastname: Yazer
authors.affiliation: Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Brunker
authors.affiliation: Department of Clinical Pathology, The Cleveland Clinic, Cleveland, Ohio.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Bakdash
authors.affiliation: Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Aaron A R
authors.initials: AA
authors.lastname: Tobian
authors.affiliation: Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania.|The Institute for Transfusion Medicine, Pittsburgh, Pennsylvania.
authors.forename: Darrell J
authors.initials: DJ
authors.lastname: Triulzi
authors.affiliation: Bloodworks NW, Seattle, Washington.
authors.forename: Victorea
authors.initials: V
authors.lastname: Earnest
authors.affiliation: Bloodworks NW, Seattle, Washington.
authors.forename: Samantha
authors.initials: S
authors.lastname: Harris
authors.affiliation: Department of Laboratory Medicine, University of Washington.|Bloodworks NW, Seattle, Washington.
authors.forename: Meghan
authors.initials: M
authors.lastname: Delaney
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000937:Antigen-Antibody Reactions / Q000276:immunology; D017707:Erythrocyte Transfusion / Q000009:adverse effects*; D005260:Female; D006801:Humans; D015994:Incidence; D007518:Isoantibodies / Q000097:blood* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D017713:Platelet Transfusion / Q000009:adverse effects*; D012189:Retrospective Studies; D012204:Rh-Hr Blood-Group System / Q000276:immunology*; D012698:Serologic Tests; D055815:Young Adult
chemical_list: D007518:Isoantibodies; D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen