title: The development of severe neonatal alloimmune thrombocytopenia due to anti-HPA-1a antibodies is correlated to maternal ABO genotypes.
abstract: BACKGROUND
  Maternal alloantibodies against HPA-1a can cross placenta, opsonize foetal platelets, and induce neonatal alloimmune thrombocytopenia (NAIT). In a study of 100, 448 pregnant women in Norway during 1995-2004, 10.6% of HPA-1a negative women had detectable anti-HPA-1a antibodies.
  
  
  METHODS
  A possible correlation between the maternal ABO blood group phenotype, or underlying genotype, and severe thrombocytopenia in the newborn was investigated.
  
  
  RESULTS
  We observed that immunized women with blood group O had a lower risk of having a child with severe NAIT than women with group A; 20% with blood group O gave birth to children with severe NAIT, compared to 47% among the blood group A mothers (relative risk 0.43; 95% CI 0.25-0.75).
  
  
  CONCLUSIONS
  The risk of severe neonatal alloimmune thrombocytopenia due to anti-HPA-1a antibodies is correlated to maternal ABO types, and this study indicates that the observation is due to genetic properties on the maternal side.
authors: Department of Laboratory Medicine, University Hospital of North Norway, 9038 Tromsø, Norway. therese.ahlen@unn.no
authors: Maria Therese
authors: MT
authors: Ahlen
authors: Anne
authors: A
authors: Husebekk
authors: Mette Kjær
authors: MK
authors: Killie
authors: Jens
authors: J
authors: Kjeldsen-Kragh
authors: Martin L
authors: ML
authors: Olsson
authors: Bjørn
authors: B
authors: Skogen
mesh_terms: D000017:ABO Blood-Group System / Q000235:genetics* / Q000276:immunology*; D016824:Antigens, Human Platelet / Q000276:immunology*; D005260:Female; D005838:Genotype; D006801:Humans; D007231:Infant, Newborn; D039661:Integrin beta3; D007518:Isoantibodies / Q000276:immunology*; D010641:Phenotype; D010976:Platelet Count; D011247:Pregnancy; D012720:Severity of Illness Index; D054098:Thrombocytopenia, Neonatal Alloimmune / Q000276:immunology*
chemical_list: D000017:ABO Blood-Group System; D016824:Antigens, Human Platelet; C061248:ITGB3 protein, human; D039661:Integrin beta3; D007518:Isoantibodies