title: Association of the PD-1.3A allele of the PDCD1 gene in patients with rheumatoid arthritis negative for rheumatoid factor and the shared epitope.
abstract: OBJECTIVE
  To study the frequency of allele A of polymorphism PD-1.3 of the PDCD1 gene in patients with rheumatoid arthritis (RA) and its subsets, based on the presence of rheumatoid factor (RF) and the shared epitope (SE) alleles.
  
  
  METHODS
  A total of 1,175 patients with RA and 3,404 controls were genotyped for the PD-1.3 A/G polymorphism, which previously was identified as being involved in susceptibility to systemic lupus erythematosus (SLE) in patients of European descent.
  
  
  RESULTS
  We first detected a trend for association of allele A of the single-nucleotide polymorphism PD-1.3 with RA (P = 0.053, odds ratio [OR] 1.18, 95% confidence interval [95% CI] 0.99-1.41). To further clarify the nature of this association, patients with RA were divided into 4 groups according to the presence of RF and the SE alleles. Association was found only in the group of patients negative for both RF and the SE alleles (P = 0.0054 [corrected P = 0.015], OR 1.75, 95% CI 1.15-2.65).
  
  
  CONCLUSIONS
  Patients negative for both RF and the SE alleles showed association with the same allele that we previously identified as being involved in susceptibility to SLE. These results provide the first evidence of the involvement of the human PDCD1 gene in arthritis.
authors.affiliation: Uppsala University, Uppsala, Sweden.
authors.forename: Ludmila
authors.initials: L
authors.lastname: Prokunina
authors.forename: Leonid
authors.initials: L
authors.lastname: Padyukov
authors.forename: Anna
authors.initials: A
authors.lastname: Bennet
authors.forename: Ulf
authors.initials: U
authors.lastname: de Faire
authors.forename: Björn
authors.initials: B
authors.lastname: Wiman
authors.forename: Jonathan
authors.initials: J
authors.lastname: Prince
authors.forename: Lars
authors.initials: L
authors.lastname: Alfredsson
authors.forename: Lars
authors.initials: L
authors.lastname: Klareskog
authors.forename: Marta
authors.initials: M
authors.lastname: Alarcón-Riquelme
mesh_terms: D015703:Antigens, CD; D000954:Antigens, Surface / Q000235:genetics*; D051017:Apoptosis Regulatory Proteins; D001172:Arthritis, Rheumatoid / Q000235:genetics*; D000939:Epitopes / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D061026:Programmed Cell Death 1 Receptor; D012217:Rheumatoid Factor / Q000235:genetics*; D013548:Sweden
chemical_list: D015703:Antigens, CD; D000954:Antigens, Surface; D051017:Apoptosis Regulatory Proteins; D000939:Epitopes; C105992:PDCD1 protein, human; D061026:Programmed Cell Death 1 Receptor; D012217:Rheumatoid Factor