title: HLA-DRB1 alleles associated with rheumatoid arthritis in southern France. Absence of extraarticular disease despite expression of the shared epitope.
abstract: OBJECTIVE
  Extraarticular rheumatoid arthritis (RA) is almost unknown in Marseille in southern France. We investigated whether this was due to rare expression of the HLA-DRB1 shared epitope.
  
  
  METHODS
  HLA-DRB1 alleles were characterized in 73 patients with RA and 108 controls by polymerase chain reaction amplification and oligonucleotide hybridization.
  
  
  RESULTS
  In patients with RA, 76% expressed the shared epitope (46% DR1, 45% DR4). Four HLA-DRB1 alleles were positively associated with disease: DRB1*0101, DRB1*0401, DRB1*0404, DRB1*0405. Patients with double dose shared epitope had the most severe articular damage, but no extraarticular disease.
  
  
  CONCLUSIONS
  In Marseille, 76% of patients with RA are shared epitope positive. Still, most do not develop extraarticular RA. This may be caused by the low frequency of HLA-DRB1*0401 in this population.
authors.affiliation: Immuno Rheumatology Laboratory, Faculté de Médecine, Hôpital La Conception, Marseille, France.
authors.forename: J F
authors.initials: JF
authors.lastname: Benazet
authors.forename: D
authors.initials: D
authors.lastname: Reviron
authors.forename: P
authors.initials: P
authors.lastname: Mercier
authors.forename: H
authors.initials: H
authors.lastname: Roux
authors.forename: J
authors.initials: J
authors.lastname: Roudier
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D001172:Arthritis, Rheumatoid / Q000453:epidemiology / Q000235:genetics* / Q000276:immunology*; D000939:Epitopes; D005260:Female; D005602:France; D005838:Genotype; D006684:HLA-DR Antigens / Q000235:genetics*; D059811:HLA-DRB1 Chains; D006801:Humans; D008297:Male; D008522:Mediterranean Sea; D008875:Middle Aged; D012307:Risk Factors
chemical_list: D000939:Epitopes; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains; C553505:HLA-DRB1*04:01 antigen