Study of the frequency of HLA-DRB1 alleles in Brazilian patients with rheumatoid arthritis

Rev Bras Reumatol. Sep-Oct 2011;51(5):474-83.
[Article in English, Portuguese]

Abstract

The HLA-DRB1 alleles encoding an amino acid sequence (QKRAA/QRRAA/RRRAA) at position 70 74 of the third hypervariable region of the β1 chain of the HLA-DRB1 gene, called shared epitope (SE), are associated with increased susceptibility to and severity of rheumatoid arthritis (RA) in different populations.

Objective: To determine the frequency of HLA-DRB1 alleles in Brazilian patients with RA and their association with rheumatoid factor (RF) and anti-citrullinated peptide antibodies (ACPA).

Methods: Four hundred and twelve patients with RA (ACR 1987) and 215 controls were included. HLA-DRB1 typing was performed by use of polymerase chain reaction (PCR) with specific primers and hybridization with sequence-specific oligonucleotide probe (SSOP). ACPA was measured by use of the ELISA technique and RF by nephelometry. The statistical analysis comprised the chi-square and Student t tests and logistic regression.

Results: HLA-DRB1*04:01, *04:04, *04:05 alleles were associated with RA (P < 0.05); despite the wide confidence interval, it is worth noting the association between the DRB1*09:01 allele and RA (P < 0.05). HLA-DRB1 SE+ alleles were observed in 62.8% of the patients and in 31.1% of controls (OR 3.62; P < 0.001) and were associated with ACPA (OR 2.03; P < 0.001). DRB1-DERAA alleles showed a protective effect against RA (OR 0.42; P < 0.001).

Conclusion: In a sample of Brazilian patients with RA, most of whom of mixed heritage, HLA-DRB1 SE+ alleles were associated with susceptibility to disease and presence of ACPA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Alleles
  • Arthritis, Rheumatoid / genetics*
  • Brazil
  • Case-Control Studies
  • Female
  • HLA-DRB1 Chains / genetics*
  • Humans
  • Male
  • Middle Aged
  • Young Adult

Substances

  • HLA-DRB1 Chains