In Black Africans with rheumatoid arthritis, ACPA recognize citrullinated fibrinogen and the derived peptides α36-50Cit38,42 and β60-74Cit60,72,74, like in Caucasians

Clin Immunol. 2014 May-Jun;152(1-2):58-64. doi: 10.1016/j.clim.2014.02.011. Epub 2014 Mar 1.


Well documented in Caucasians and Asians, the diagnostic value of anti-CCP2 antibodies has been confirmed in Black African populations. However, autoantibodies to other citrullinated peptides/proteins and their fine specificities have not yet been studied. Here, we show that in Cameroonian patients, anti-citrullinated fibrinogen autoantibodies (AhFibA) are sensitive (73%) diagnostic markers for RA. We also determine that autoantibodies directed to α36-50Cit38,42 or β60-74Cit60,72,74 peptides which bear the immunodominant epitopes of citrullinated fibrin, are present in similar proportions in Black Africans and Caucasians with 25/56 (45%) and 41/56 (73%) positive RA-sera in Cameroonians, respectively. They also account for almost all the AhFibA reactivities since 38/41 (93%) AhFibA-positive sera contain anti-α36-50Cit38,42 and/or anti-β60-74Cit60,72,74 autoantibodies. Finally, HLA-DRB1 SE alleles were associated with higher titres of AhFibA and anti-β60-74Cit60,72,74 autoantibodies. In the genetic and environmental backgrounds of Black Africans, AhFibA are a hallmark of RA like in Caucasians, moreover they recognize the same fibrin epitopes.

Keywords: Anti-citrullinated protein autoantibodies (ACPA); B-cell epitopes; Black Africans; Citrullinated fibrin; Rheumatoid arthritis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Africa
  • Amino Acid Sequence
  • Arthritis, Rheumatoid / diagnosis
  • Arthritis, Rheumatoid / genetics
  • Arthritis, Rheumatoid / immunology*
  • Autoantibodies / immunology*
  • Biomarkers / analysis
  • Black People
  • Citrulline / immunology
  • Epitopes / genetics
  • Epitopes / immunology
  • Fibrinogen / immunology
  • HLA-DRB1 Chains
  • Humans
  • Peptides / genetics
  • Peptides / immunology*
  • White People


  • Autoantibodies
  • Biomarkers
  • Epitopes
  • HLA-DRB1 Chains
  • Peptides
  • Citrulline
  • Fibrinogen