title: Anti-D investigations in individuals expressing weak D Type 1 or weak D Type 2: allo- or autoantibodies?
abstract: BACKGROUND
  Whether anti-D produced by individuals with a weak D phenotype are allo- or autoantibodies remains a matter of debate even though blood transfusion practice is impacted. The aim of our study was to determine the serologic features of anti-D in individuals expressing the most frequent weak D type in Caucasians that are weak D Type 1 or weak D Type 2, to assess whether anti-D were allo- or autoantibodies.
  
  
  METHODS
  Serologic D typing and molecular analysis enabled the including of 121 weak D Type 1 individuals and 99 weak D Type 2 individuals in our study. Serologic features of anti-D included autologous controls, direct antiglobulin test, elution, and titration of anti-D before and after adsorption of serum on autologous red blood cells (RBCs).
  
  
  RESULTS
  Serologic D typing showed a variable reactivity of RBCs expressing weak D Type 1 or weak D Type 2 (4+ to 0). Anti-D was identified in six weak D Type 1 and six weak D Type 2 individuals, respectively. The serologic data were in favor of autoantibodies.
  
  
  CONCLUSIONS
  A complete anti-D investigation in individuals with a D variant (weak D or partial D identified by molecular analysis) should be systematically performed before any valid conclusion on the nature of the antibody. Transfusing weak D Type 1 or weak D Type 2 patients with D+ RBC units should be recommended. Weak D Type 1 or weak D Type 2 pregnant women do not need anti-D immunoprophylaxis.
authors.affiliation: Institut National de la Transfusion Sanguine, CNRGS-INSERM U665, Paris, France. bnpham@ints.fr
authors.forename: Bach-Nga
authors.initials: BN
authors.lastname: Pham
authors.forename: Michèle
authors.initials: M
authors.lastname: Roussel
authors.forename: Thierry
authors.initials: T
authors.lastname: Peyrard
authors.forename: Marylise
authors.initials: M
authors.lastname: Beolet
authors.forename: Véronique
authors.initials: V
authors.lastname: Jan-Lasserre
authors.forename: Dominique
authors.initials: D
authors.lastname: Gien
authors.forename: Maryline
authors.initials: M
authors.lastname: Ripaux
authors.forename: Sébastien
authors.initials: S
authors.lastname: Bourgouin
authors.forename: Sandrine
authors.initials: S
authors.lastname: Kappler-Gratias
authors.forename: Philippe
authors.initials: P
authors.lastname: Rouger
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Le Pennec
mesh_terms: D001323:Autoantibodies / Q000097:blood* / Q000276:immunology; D001788:Blood Grouping and Crossmatching / Q000379:methods*; D017707:Erythrocyte Transfusion / Q000009:adverse effects; D004912:Erythrocytes; D005260:Female; D015870:Gene Expression; D006801:Humans; D007518:Isoantibodies / Q000097:blood* / Q000276:immunology; D008297:Male; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000097:blood / Q000276:immunology / Q000517:prevention & control; D012204:Rh-Hr Blood-Group System / Q000097:blood* / Q000235:genetics* / Q000276:immunology; D044465:White People
chemical_list: D001323:Autoantibodies; D007518:Isoantibodies; D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen