title: Usefulness of human leucocyte antigen-B27 subtypes in predicting ankylosing spondylitis: Taiwan experience.
abstract: BACKGROUND
  Genetic factors are clearly attributed to the susceptibility of ankylosing spondylitis (AS). The human leucocyte antigen (HLA)-B27 proved to be the very useful marker for diagnosing AS. The aim of this study was to determine the prevalence of HLA-B27 subtypes in Taiwan and to investigate whether these subtypes may be of help in predicting the diagnosis of AS.
  
  
  METHODS
  A total of 314 patients with AS and a control group of 71 subjects positive for HLA-B27 detected by flow cytometry analysis were recruited for the study. HLA-B27 subtypes were confirmed by the polymerase chain reaction-sequence-specific primers and sequence-specific oligonucleotide probing.
  
  
  RESULTS
  Four B27 alleles were identified: B*2704, B*2705, B*2706 and B*2707. HLA-B*2704 was the predominant allele. There were significant differences in the distribution of HLA-B27 subtypes between patients with AS and controls. Five of them who were homozygous for the B*2704 allele were solely found in AS group but not in controls. Statistical analysis showed that B*2704 was positively associated with AS, which suggested an increased possibility of having AS. Other HLA-B27 subtypes showed no strong correlation with AS.
  
  
  CONCLUSIONS
  In the Taiwanese population, susceptibility to AS was determined by the presence of HLA-B*2704. Although B*2706 was reported to have a negative association with AS in Taiwanese, Thai and Chinese Singaporean populations, we report, in our study, two AS patients with B*2706 (0.6%). Disease heterogeneity suggests that other than genetic background, many pathogenic factors could be associated with AS. This may need to be investigated with a larger group of patients with AS and controls.
authors: Division of Rheumatology/Immunology/Allergy, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
authors: T-Y
authors: TY
authors: Hou
authors: H-C
authors: HC
authors: Chen
authors: C-H
authors: CH
authors: Chen
authors: D-M
authors: DM
authors: Chang
authors: F-C
authors: FC
authors: Liu
authors: J-H
authors: JH
authors: Lai
mesh_terms: D015415:Biomarkers; D016022:Case-Control Studies; D005260:Female; D020022:Genetic Predisposition to Disease; D015796:HLA-B27 Antigen / Q000145:classification* / Q000235:genetics; D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction; D011237:Predictive Value of Tests; D015995:Prevalence; D013167:Spondylitis, Ankylosing / Q000175:diagnosis* / Q000235:genetics* / Q000276:immunology; D013624:Taiwan / Q000453:epidemiology
chemical_list: D015415:Biomarkers; D015796:HLA-B27 Antigen