title: A possible role for maternal HLA antibody in a case of alloimmune neonatal neutropenia.
abstract: BACKGROUND
  Alloimmune neonatal neutropenia (ANN) is caused by a reaction of maternal alloantibodies with paternally inherited antigens on the fetal neutrophils. While human neutrophil antigens (HNA) antibodies are found in half of ANN cases, specific antibodies have not been defined in the remaining cases.
  
  
  METHODS
  Reported here is a neonate with omphalitis due to neutropenia. To elucidate the cause of ANN, flow cytometric and PCR analyses were used. Reactions of the patient's and mother's sera with neutrophils, lymphocytes, and platelets were examined by lymphocytotoxicity test (LCT), anti-human immunoglobulin-LCT, and mixed passive hemagglutination test.
  
  
  RESULTS
  The maternal sera reacted with neutrophils, lymphocytes, and platelets of the patient and father. The platelet adsorption eliminated the reaction of the maternal serum with the patient's neutrophils. The HLA typing of the family and an LCT using a panel of lymphocytes of 20 HLA-typed donors showed HLA-A2 antigen as a target of antibodies in the maternal serum. According to anti-human immunoglobulin-LCT, the anti-HLA-A2 was present in the neonatal serum. On the other hand, HNA antibodies were not detectable in the patient's or the mother's serum.
  
  
  CONCLUSIONS
  These results suggest that the transplacental passage of the maternal HLA antibody caused neutropenia in this patient.
authors.affiliation: Department of Pediatrics, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Hagimoto
authors.forename: K
authors.initials: K
authors.lastname: Koike
authors.forename: K
authors.initials: K
authors.lastname: Sakashita
authors.forename: T
authors.initials: T
authors.lastname: Ishida
authors.forename: Y
authors.initials: Y
authors.lastname: Nakazawa
authors.forename: Y
authors.initials: Y
authors.lastname: Kurokawa
authors.forename: T
authors.initials: T
authors.lastname: Kamijo
authors.forename: S
authors.initials: S
authors.lastname: Saito
authors.forename: A
authors.initials: A
authors.lastname: Hiraoka
authors.forename: M
authors.initials: M
authors.lastname: Kobayashi
authors.forename: A
authors.initials: A
authors.lastname: Komiyama
mesh_terms: D000328:Adult; D005260:Female; D006680:HLA Antigens / Q000276:immunology*; D006801:Humans; D007231:Infant, Newborn; D007518:Isoantibodies / Q000276:immunology*; D008297:Male; D009503:Neutropenia / Q000209:etiology*
chemical_list: D006680:HLA Antigens; D007518:Isoantibodies