title: HLA-B27 predicts a more chronic disease course in an 8-year followup cohort of patients with juvenile idiopathic arthritis.
abstract: OBJECTIVE
  We investigated associations of HLA-B27 with clinical manifestations and longterm outcome in a near population-based setting among patients with juvenile idiopathic arthritis (JIA).
  
  
  METHODS
  We studied clinical and serological data from 410 patients with HLA-B27 results among 440 prospectively collected patients with JIA with 8-year followup data in a Nordic database. The study was structured to be as close to a population-based study as possible.
  
  
  RESULTS
  HLA-B27 was analyzed in 93% of patients, and was positive in 21% of the cohort, in 18.4% of the girls and in 25.9% of the boys. Boys who were HLA-B27-positive had significantly higher age at onset compared to HLA-B27-negative boys and compared to both HLA-B27-negative and positive girls. This difference in onset age in relation to HLA-B27 was not found in girls. HLA-B27 was associated with clinical signs of sacroiliitis, enthesitis, and tenosynovitis in boys, but not in girls. After 8 years of disease, 46 children (11.2%) were classified as having enthesitis-related arthritis (ERA). Boys with ERA had clinical signs of sacroiliitis more often than girls with ERA. HLA-B27-positive children, as well as children with clinical signs of sacroiliitis, enthesitis, and hip arthritis, had higher odds of not being in remission off medication after 8 years of disease.
  
  
  CONCLUSIONS
  In this near population-based Nordic JIA cohort we found significant differences between HLA-B27-positive boys and girls in age at disease onset, clinical signs of sacroiliitis, and ERA classification. HLA-B27 was negatively associated with longterm remission status, possibly because of its association with clinical disease characteristics, such as sacroiliitis, rather than being a general marker of persistent disease.
authors.affiliation: Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden. lillemor.berntson@kbh.uu.se
authors.forename: Lillemor
authors.initials: L
authors.lastname: Berntson
authors.forename: Ellen
authors.initials: E
authors.lastname: Nordal
authors.forename: Kristiina
authors.initials: K
authors.lastname: Aalto
authors.forename: Suvi
authors.initials: S
authors.lastname: Peltoniemi
authors.forename: Troels
authors.initials: T
authors.lastname: Herlin
authors.forename: Marek
authors.initials: M
authors.lastname: Zak
authors.forename: Susan
authors.initials: S
authors.lastname: Nielsen
authors.forename: Marite
authors.initials: M
authors.lastname: Rygg
mesh_terms: D017668:Age of Onset; D001171:Arthritis, Juvenile / Q000097:blood / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D005260:Female; D005387:Finland / Q000453:epidemiology; D020022:Genetic Predisposition to Disease; D015796:HLA-B27 Antigen / Q000097:blood / Q000235:genetics*; D006801:Humans; D007596:Joints / Q000473:pathology; D008297:Male; D011446:Prospective Studies; D012537:Scandinavian and Nordic Countries / Q000453:epidemiology; D012720:Severity of Illness Index; D012737:Sex Factors; D013997:Time Factors
chemical_list: D015796:HLA-B27 Antigen
keywords: CHILD; GENETICS; HLA-B27; JOINTS; JUVENILE RHEUMATOID ARTHRITIS