Most African-American patients with rheumatoid arthritis do not have the rheumatoid antigenic determinant (epitope)

Ann Intern Med. 1995 Aug 1;123(3):181-7. doi: 10.7326/0003-4819-123-3-199508010-00004.

Abstract

Objective: To evaluate the relation between the presence of the "rheumatoid epitope," defined by a sequence motif in the HLA-DRB1 alleles, and disease severity in African-American patients with rheumatoid arthritis.

Design: Cross-sectional study.

Setting: Rheumatology outpatient clinics at two university medical centers.

Patients: 86 African-American patients with rheumatoid arthritis (66 seropositive and 20 seronegative for the rheumatoid factor) attending the clinics and 88 healthy African-American persons.

Measurements: HLA-DRB1 alleles were determined by restriction fragment length polymorphism and by allele-specific oligonucleotide typing of polymerase chain reaction-amplified HLA-DRB1 second exons.

Results: With the exception of an increased frequency of HLA-DRB1*04 alleles in seropositive patients with rheumatoid arthritis (27.3%) compared with controls (13.1%) (P = 0.02), the frequencies of HLA-DRB1 alleles were similar in patients and controls. Most seropositive (48 of 66) and seronegative (15 of 20) patients were HLA-DR4 negative, but some (7 of 48 seropositive patients and 3 of 15 seronegative persons) inherited the rheumatoid epitope on a non-DR4 allele. Disease features, including severity, were similar for patients without the epitope and for those with either a single or a double dose of an epitope-positive allele. Positivity for rheumatoid factor, but not for the rheumatoid epitope, was weakly associated with severity in these patients.

Conclusion: Most African-American patients with rheumatoid arthritis did not express the rheumatoid epitope. The predisposition to and severity of rheumatoid arthritis in African-Americans appears to be independent of the presence and dose of the shared rheumatoid epitope.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • African Continental Ancestry Group* / genetics
  • Aged
  • Alleles
  • Amino Acid Sequence
  • Arthritis, Rheumatoid / ethnology
  • Arthritis, Rheumatoid / immunology*
  • Cross-Sectional Studies
  • DNA Probes
  • Female
  • Genotype
  • HLA-DR Antigens / genetics
  • HLA-DR Antigens / immunology*
  • HLA-DRB1 Chains
  • Humans
  • Immunodominant Epitopes / blood*
  • Male
  • Middle Aged
  • Molecular Sequence Data
  • Nucleic Acid Hybridization
  • Polymorphism, Restriction Fragment Length
  • Prevalence
  • Severity of Illness Index

Substances

  • DNA Probes
  • HLA-DR Antigens
  • HLA-DRB1 Chains
  • Immunodominant Epitopes