title: The presence of the HLA-DRB1 shared epitope correlates with erosive disease in Chilean patients with rheumatoid arthritis.
abstract: OBJECTIVE
  To assess the contribution of the HLA-DRB1 shared epitope (SE) to the radiological outcome of rheumatoid arthritis (RA) after 6 yr of follow-up in a reported series of 129 Chilean patients with established disease.
  
  
  METHODS
  A prospective study was conducted between 1992 and 1998 using hand radiographs to assess disease outcome in a published series of patients in whom two doses of the SE were present in 20%, one dose was present in 34% and the SE was absent in 46%. At study entry, 29 of the 92 patients with hand radiographs were at Steinbrocker stages I or II (non-erosive), with a median disease duration of 2.8 yr (0.4-17).
  
  
  RESULTS
  In 1998, 113 (87%) of the patients were alive. One hundred and eight patients underwent complete clinical evaluation. Their median age was 57 yr (range 30-81) and the median disease duration was 15 yr (6-50). We were able to study 25 of the 29 patients who had non-erosive disease at study entry in 1992. We found that 10 of 11 patients having one or two doses of the SE developed erosive disease compared with three of 14 without the SE (Yates' corrected P=0.0023, relative risk 4.24, 95% confidence interval 1.53-11.77).
  
  
  CONCLUSIONS
  These observations support and extend the notion that the presence of the SE in one or two doses can predict the development of erosions even in RA populations in whom the SE is not as prevalent as in Caucasians.
authors.affiliation: Departamento de Inmunología Clínica y Reumatología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: L
authors.initials: L
authors.lastname: Massardo
authors.forename: N
authors.initials: N
authors.lastname: Gareca
authors.forename: M A
authors.initials: MA
authors.lastname: Cartes
authors.forename: V
authors.initials: V
authors.lastname: Cervilla
authors.forename: A
authors.initials: A
authors.lastname: González
authors.forename: S
authors.initials: S
authors.lastname: Jacobelli
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000235:genetics*; D002677:Chile; D000939:Epitopes / Q000235:genetics; D006684:HLA-DR Antigens / Q000235:genetics*; D059811:HLA-DRB1 Chains; D006801:Humans; D008875:Middle Aged; D015995:Prevalence; D011379:Prognosis; D011446:Prospective Studies; D011859:Radiography; D012307:Risk Factors
chemical_list: D000939:Epitopes; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains