title: Rheumatoid factor, HLA-DR4, and allelic variants of DRB1 in women with recent-onset rheumatoid arthritis.
abstract: OBJECTIVE
  To examine the relationship of rheumatoid factor (RF) to HLA-DR4 and alleles of DRB1 in women with recent-onset rheumatoid arthritis (RA).
  
  
  METHODS
  Incident cases of RA were identified as part of a prospective, population-based case-control study. HLA typing was completed for 246 cases meeting criteria for definite or classic RA.
  
  
  RESULTS
  One hundred thirty-six patients (55%) were positive for DR4, and 130 (53%) were RF positive. DR4 was found to be strongly associated with seropositivity (odds ratio 4.1, P < 0.0001). Patients with a shorter interval from RA onset to RF testing had a higher frequency of seropositivity than those with a longer interval (< or = 18 months 60%, > 18 months 33%). Further analysis of patients who had RF testing within 18 months of RA onset showed that the frequency of seropositivity was significantly greater among DR4-positive patients who had the shared sequence stretch of DR beta 1 associated with RA susceptibility (76% RF positive) than among DR1-positive patients who had this sequence (45% RF positive) (odds ratio 3.8, P = 0.01). Moreover, the frequency of seropositivity among DR1-positive patients with the sequence did not differ from that among all patients without the shared sequence (47%) (odds ratio 0.9, P = 0.8).
  
  
  CONCLUSIONS
  HLA-DR4 is strongly associated with seropositivity in women with recent-onset RA. The amino acid sequence of DR beta 1 that is associated with susceptibility to RA and is shared between DR4 and DR1 appears not to be the primary determinant of seropositivity in these women.
authors.affiliation: Division of Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA 98104.
authors.forename: J L
authors.initials: JL
authors.lastname: Nelson
authors.forename: C E
authors.initials: CE
authors.lastname: Dugowson
authors.forename: T D
authors.initials: TD
authors.lastname: Koepsell
authors.forename: L F
authors.initials: LF
authors.lastname: Voigt
authors.forename: A M
authors.initials: AM
authors.lastname: Branchaud
authors.forename: R A
authors.initials: RA
authors.lastname: Barrington
authors.forename: M H
authors.initials: MH
authors.lastname: Wener
authors.forename: J A
authors.initials: JA
authors.lastname: Hansen
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000175:diagnosis / Q000276:immunology*; D016022:Case-Control Studies; D005260:Female; D006684:HLA-DR Antigens / Q000235:genetics*; D015804:HLA-DR4 Antigen / Q000032:analysis*; D006801:Humans; D008875:Middle Aged; D016017:Odds Ratio; D011446:Prospective Studies; D012217:Rheumatoid Factor / Q000032:analysis*; D012307:Risk Factors; D012698:Serologic Tests
chemical_list: D006684:HLA-DR Antigens; D015804:HLA-DR4 Antigen; D012217:Rheumatoid Factor