title: Shared-epitope HLA-DRB1 alleles and sex ratio in Italian patients with rheumatoid arthritis.
abstract: OBJECTIVE
  To investigate the association between the HLA-DRB1 alleles sharing the epitope (Q/R)(K/R)RAA and rheumatoid arthritis (RA) in a large sample of Italian patients (N = 264) recruited from a single centre over the last 5 years.
  
  
  METHODS
  Patients' classification according to the ACR criteria. DNA typing of HLA-DRB1 alleles by conventional polymerase chain reaction sequence specific oligonucleotide probing techniques.
  
  
  RESULTS
  Low-resolution DRB1 "generic" typing showed a significantly higher frequency of DR4+ RA patients as compared to normal controls. Both DR1 and DR10 specificities were over-represented in our patients, but neither reached the statistically significant P level of 0.05 after Bonferroni's correction. However, direct search of Q(K/R)RAA epitopes, which are present in most DR4+ and DRl+ samples, demonstrated that these motifs were found at increased frequencies in RA patients. Stratification according to gender did not show differences in the proportion of disease-associated HLA alleles.
  
  
  CONCLUSIONS
  Our study confirms the association of HLA-DR4, and -DR1 alleles, and more generally speaking of the shared epitopes Q(K/R)RAA, with disease susceptibility in Italian patients.
authors.affiliation: Rheumatology Unit, Department of Medical and Surgical Critical Care, Florence University, Florence, Italy.
authors.forename: S Maddali
authors.initials: SM
authors.lastname: Bongi
authors.forename: B
authors.initials: B
authors.lastname: Porfirio
authors.forename: G
authors.initials: G
authors.lastname: Rombolà
authors.forename: A
authors.initials: A
authors.lastname: Palasciano
authors.forename: E
authors.initials: E
authors.lastname: Beneforti
authors.forename: G
authors.initials: G
authors.lastname: Bianucci
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology; D000939:Epitopes; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D006684:HLA-DR Antigens / Q000235:genetics*; D059811:HLA-DRB1 Chains; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012744:Sex Ratio
chemical_list: D000939:Epitopes; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains