title: Primary autoimmune neutropenia in children in Taiwan.
abstract: BACKGROUND
  Autoimmune neutropenia in children is caused by granulocyte-specific autoantibodies. These antibodies react to the patient's own neutrophils but disappear when the neutropenia spontaneously remits. This study reviewed our experience with autoimmune neutropenia in children and investigated possible associations with HLA-DR and HLA-DQ alleles.
  
  
  METHODS
  From 1993 to 2006, our laboratory received 155 blood samples from children with neutropenia. Of these samples, 55 had granulocyte-specific autoantibodies on the indirect granulocyte immunofluorescence test. As the children had no other disorders associated with neutropenia, they were diagnosed with primary autoimmune neutropenia. HLA-DRB1 and -DQB1 allele typing was performed in 31 cases, and the results were compared with those of 190 normal healthy unrelated Taiwanese controls.
  
  
  RESULTS
  The mean ages of onset and resolution of neutropenia were 9.8 months (median, 9.0 months; range, 4-28 months) and 22.5 months (median, 20.0 months; range, 13-44 months), respectively. The male-to-female ratio was 1.2:1. The mean absolute neutrophil count was 190 per microL (standard deviation, 213/microL). Most patients (74%) had antibodies against HNA-1a. Autoimmune neutropenia in children in Taiwan was significantly associated with HLA-DQB1*0503 (odds ratio, 6.48; p = 0.0002; p(c) = 0.003) allele.
  
  
  CONCLUSIONS
  In Taiwan, autoimmune neutropenia in children is associated with HLA-DQB1*0503. The autoantibody in autoimmune neutropenia is most commonly anti-HNA-1a.
authors.affiliation: Pediatric Hematology-Oncology, Mackay Memorial Hospital, Mackay Medicine, Nursing and Management College, Taipei, Taiwan.
authors.forename: Lin-Yen
authors.initials: LY
authors.lastname: Wang
authors.forename: Chang-Ling
authors.initials: CL
authors.lastname: Wang
authors.forename: Chen-Chung
authors.initials: CC
authors.lastname: Chu
authors.forename: Hui-Lin
authors.initials: HL
authors.lastname: Lee
authors.forename: Hsin-Tsung
authors.initials: HT
authors.lastname: Ho
authors.forename: Der-Cherng
authors.initials: DC
authors.lastname: Liang
authors.forename: Hsi-Che
authors.initials: HC
authors.lastname: Liu
authors.forename: Marie
authors.initials: M
authors.lastname: Lin
mesh_terms: D001323:Autoantibodies / Q000097:blood*; D001327:Autoimmune Diseases / Q000453:epidemiology; D016022:Case-Control Studies; D002675:Child, Preschool; D005260:Female; D006098:Granulocytes / Q000276:immunology; D006683:HLA-DQ Antigens / Q000235:genetics*; D059866:HLA-DQ beta-Chains; D006684:HLA-DR Antigens / Q000235:genetics; D006801:Humans; D007223:Infant; D007519:Isoantigens / Q000276:immunology; D008297:Male; D009503:Neutropenia / Q000175:diagnosis / Q000453:epidemiology / Q000276:immunology*; D013624:Taiwan / Q000453:epidemiology
chemical_list: D001323:Autoantibodies; D006683:HLA-DQ Antigens; D059866:HLA-DQ beta-Chains; C069051:HLA-DQB1 antigen; D006684:HLA-DR Antigens; D007519:Isoantigens; C067704:neutrophil-specific antigen NA1, human