title: Serologic analysis of three cases of neonatal alloimmune thrombocytopenia associated with HLA antibodies.
abstract: BACKGROUND
  Neonatal alloimmune thrombocytopenia (NAIT) is caused when maternal alloantibodies react with paternally inherited antigens present on the fetal PLTs, a reaction mainly due to antibodies against human PLT antigens. Cases in which NAIT has been caused by HLA antibodies are relatively rare. In this study, three cases of NAIT associated with HLA antibodies that occurred in a 1-year period are reported.
  
  
  METHODS
  The presence of HLA antibodies in these three NAIT case studies was elucidated by examining reactions of the neonatal and maternal sera with lymphocytes, PLTs, and beads from an HLA antibody screening test (FlowPRA, One Lambda Inc.). Absorption and elution tests with paternal cells were also conducted. In addition, the influence of titer and specificity of HLA antibodies on NAIT was analyzed in light of 24 other documented cases in Japan.
  
  
  RESULTS
  In the three case studies presented herein, antibodies against human PLT antigens were found in neither the maternal nor neonatal sera, while specific HLA antibodies were identified in both sera. Absorption of maternal serum with paternal PLTs eliminated the reactivity against paternal PLTs and lymphocytes.
  
  
  CONCLUSIONS
  Transplacental passage of maternal HLA antibodies was observed in the three neonates cited in the present study.
authors.affiliation: Department of Legal Medicine, Shinshu University School of Medicine, Matumoto, Japan. stsaito@poplar.ocn.ne.jp
authors.forename: Satoshi
authors.initials: S
authors.lastname: Saito
authors.forename: Masao
authors.initials: M
authors.lastname: Ota
authors.forename: Yumi
authors.initials: Y
authors.lastname: Komatsu
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ota
authors.forename: Shigeru
authors.initials: S
authors.lastname: Aoki
authors.forename: Kenichi
authors.initials: K
authors.lastname: Koike
authors.forename: Izumi
authors.initials: I
authors.lastname: Tokunaga
authors.forename: Takahisa
authors.initials: T
authors.lastname: Tsuno
authors.forename: Goro
authors.initials: G
authors.lastname: Tsuruta
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Kubo
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Fukushima
mesh_terms: D000327:Adsorption; D000918:Antibody Specificity; D016824:Antigens, Human Platelet / Q000276:immunology; D001788:Blood Grouping and Crossmatching; D001792:Blood Platelets / Q000276:immunology*; D005220:Fathers; D006680:HLA Antigens / Q000276:immunology*; D015235:HLA-B Antigens / Q000276:immunology; D059947:HLA-B40 Antigen; D006650:Histocompatibility Testing; D006801:Humans; D007231:Infant, Newborn; D007518:Isoantibodies / Q000276:immunology*; D007519:Isoantigens / Q000276:immunology; D008297:Male; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D013921:Thrombocytopenia / Q000276:immunology*
chemical_list: D016824:Antigens, Human Platelet; D006680:HLA Antigens; D015235:HLA-B Antigens; D059947:HLA-B40 Antigen; C035270:HLA-B5 antigen; D007518:Isoantibodies; D007519:Isoantigens