title: Influence of human leucocyte antigen-DRB1 on the susceptibility to rheumatoid arthritis and on the production of anti-cyclic citrullinated peptide antibodies in a Portuguese population.
abstract: OBJECTIVE
  To clarify the influence of the HLA-DRB1 locus on the susceptibility to rheumatoid arthritis and the production of anti-cyclic citrullinated peptide antibodies (anti-CCP) in a Portuguese population.
  
  
  METHODS
  141 patients with rheumatoid arthritis fulfilling the American College of Rheumatology 1987 revised criteria for rheumatoid arthritis were compared with 150 healthy controls. Human leucocyte antigen (HLA)-DRB1 locus genotyping was assessed by polymerase chain reaction reverse probing assays and sequence-specific primers. Anti-CCP antibodies were quantified by ELISA in patients with rheumatoid arthritis. Frequencies between groups were compared by the two-sided Fisher's exact test and considered significant if p<0.05.
  
  
  RESULTS
  The HLA-DRB1*04 and HLA-DRB1*10 groups were highly associated with rheumatoid arthritis (p<0.001 and p = 0.031, respectively). High titres of anti-CCP antibodies were largely associated with the presence of HLA-DRB1*04/10.
  
  
  CONCLUSIONS
  The well-recognised susceptibility alleles to rheumatoid arthritis, HLA-DRB1*04, were associated with rheumatoid arthritis in Portuguese patients. The relatively rare DRB1*10 was also associated with rheumatoid arthritis, as was described previously in other southern European countries. Both groups were associated with high anti-CCP titres, reinforcing its relevance to disease onset.
authors.affiliation: Centro de Histocompatibilidade do Sul, Lisboa, Portugal.
authors.forename: D
authors.initials: D
authors.lastname: Ligeiro
authors.forename: J E
authors.initials: JE
authors.lastname: Fonseca
authors.forename: O
authors.initials: O
authors.lastname: Abade
authors.forename: I
authors.initials: I
authors.lastname: Abreu
authors.forename: M
authors.initials: M
authors.lastname: Cruz
authors.forename: P
authors.initials: P
authors.lastname: Nero
authors.forename: J
authors.initials: J
authors.lastname: Cavaleiro
authors.forename: J
authors.initials: J
authors.lastname: Teles
authors.forename: H
authors.initials: H
authors.lastname: Trindade
authors.forename: J M
authors.initials: JM
authors.lastname: Caetano
authors.forename: J
authors.initials: J
authors.lastname: Branco
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D001172:Arthritis, Rheumatoid / Q000235:genetics / Q000276:immunology*; D001323:Autoantibodies / Q000276:immunology*; D016022:Case-Control Studies; D004198:Disease Susceptibility; D000939:Epitopes / Q000276:immunology*; D005260:Female; D005838:Genotype; D006684:HLA-DR Antigens / Q000276:immunology*; D059811:HLA-DRB1 Chains; D006801:Humans; D016130:Immunophenotyping; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010456:Peptides, Cyclic / Q000276:immunology*; D011174:Portugal; D012306:Risk
chemical_list: D001323:Autoantibodies; D000939:Epitopes; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains; D010456:Peptides, Cyclic; C487763:cyclic citrullinated peptide