title: Human leukocyte antigens in undifferentiated spondyloarthritis.
abstract: OBJECTIVE
  Undifferentiated spondyloarthritis (USpA) is a major member of the spondyloarthritis family. Ankylosing spondylitis (AS), the prototype of the family, is a largely genetic disease, with human leukocyte antigens (HLA)-B27 being the essential gene. Other genes in the HLA region have also been implicated. The purpose of this study was to identify the alleles of the HLA-A, -B, -C, -DR, and -DQ, which are present at higher frequencies in USpA patients compared with an ethnically matched control population.
  
  
  METHODS
  Sixty-three Taiwanese patients with USpA were compared with 75 matched healthy controls. HLA typing was performed by polymerase chain reaction-sequence specific oligo-nucleotide genotyping.
  
  
  RESULTS
  The frequencies of HLA-B27, -B60, -C3, and -DR12 were strikingly higher in USpA patients compared with healthy subjects, with odds ratios of 75.4, 14.0, 9.6, and 7.0, respectively. When USpA patients with axial involvement were compared with those with peripheral arthritis, the following were more marginally frequent in those with axial involvement: HLA-B27 and -DR12 (odds ratios, 4.0 and 4.0, respectively). There was no association of HLA typing with other variables, including enthesitis, uveitis, erythrocyte sedimentation rate, and serum C-reactive protein. Interestingly, in 12 HLA-B27-negative USpA patients, HLA-B60, -C3, and -DR12 were more frequent compared with controls (odds ratios, 35, 16.2, and 8.1, respectively).
  
  
  CONCLUSIONS
  Similar to AS, USpA is also linked to HLA-B27. A linkage to other HLA alleles observed here, even in our HLA-B27-negative USpA patients, strongly suggests that USpA in general is a genetic disease.
authors.affiliation: Taipei Medical University--Municipal Wan Fang Hospital, Taipei, Taiwan.
authors.forename: Hsien-Tzung
authors.initials: HT
authors.lastname: Liao
authors.forename: Kuan-Chia
authors.initials: KC
authors.lastname: Lin
authors.forename: Chun-Hsiung
authors.initials: CH
authors.lastname: Chen
authors.forename: Toong-Hua
authors.initials: TH
authors.lastname: Liang
authors.forename: Ming-Wei
authors.initials: MW
authors.lastname: Lin
authors.forename: Chang-Youh
authors.initials: CY
authors.lastname: Tsai
authors.forename: David
authors.initials: D
authors.lastname: Tak Yan Yu
authors.forename: Chung-Tei
authors.initials: CT
authors.lastname: Chou
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D008040:Genetic Linkage; D006680:HLA Antigens / Q000235:genetics*; D015235:HLA-B Antigens / Q000235:genetics; D015796:HLA-B27 Antigen / Q000235:genetics; D015236:HLA-C Antigens / Q000235:genetics; D006684:HLA-DR Antigens / Q000235:genetics; D059810:HLA-DR Serological Subtypes; D006801:Humans; D008297:Male; D010865:Pilot Projects; D012189:Retrospective Studies; D025241:Spondylarthritis / Q000235:genetics* / Q000276:immunology
chemical_list: D006680:HLA Antigens; D015235:HLA-B Antigens; D015796:HLA-B27 Antigen; C081918:HLA-B60 antigen; D015236:HLA-C Antigens; D006684:HLA-DR Antigens; D059810:HLA-DR Serological Subtypes; C082411:HLA-DR12 antigen