title: 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.
abstract: 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.
authors.affiliation: "Epidermis Differentiation and Rheumatoid Autoimmunity" Laboratory, UMR CNRS 5165, INSERM U1056, Toulouse III University, Toulouse, France; Laboratory of Cell Biology and Cytology, Toulouse University Hospital, Toulouse, France. Electronic address: Nogueira.l@chu-toulouse.fr.
authors.forename: Leonor
authors.initials: L
authors.lastname: Nogueira
authors.affiliation: "Epidermis Differentiation and Rheumatoid Autoimmunity" Laboratory, UMR CNRS 5165, INSERM U1056, Toulouse III University, Toulouse, France; Laboratory of Cell Biology and Cytology, Toulouse University Hospital, Toulouse, France.
authors.forename: Martin
authors.initials: M
authors.lastname: Cornillet
authors.affiliation: Unit of Rheumatology, School of Medicine, University of Yaounde I, Cameroon.
authors.forename: Madeleine
authors.initials: M
authors.lastname: Singwe-Ngandeu
authors.affiliation: Arthritis Research UK Center for Genetics and Genomics, Centre for Musculoskeletal Research, Manchester Academic Health Science Centre, The University of Manchester, UK.
authors.forename: Sebastien
authors.initials: S
authors.lastname: Viatte
authors.affiliation: Division of Rheumatology, University Hospitals of Geneva, Geneva, Switzerland; Department of Genetics and Laboratory Medicine, Geneva, Switzerland.
authors.forename: Sylvette
authors.initials: S
authors.lastname: Bas
authors.affiliation: Division of Rheumatology, University Hospitals of Geneva, Geneva, Switzerland; Department of Pathology & Immunology, University of Geneva, School of Medicine, Geneva, Switzerland.
authors.forename: Cem
authors.initials: C
authors.lastname: Gabay
authors.affiliation: "Epidermis Differentiation and Rheumatoid Autoimmunity" Laboratory, UMR CNRS 5165, INSERM U1056, Toulouse III University, Toulouse, France; Laboratory of Cell Biology and Cytology, Toulouse University Hospital, Toulouse, France.
authors.forename: Guy
authors.initials: G
authors.lastname: Serre
mesh_terms: D000349:Africa; D000595:Amino Acid Sequence; D001172:Arthritis, Rheumatoid / Q000175:diagnosis / Q000235:genetics / Q000276:immunology*; D001323:Autoantibodies / Q000276:immunology*; D015415:Biomarkers / Q000032:analysis; D044383:Black People; D002956:Citrulline / Q000276:immunology; D000939:Epitopes / Q000235:genetics / Q000276:immunology; D005340:Fibrinogen / Q000276:immunology; D059811:HLA-DRB1 Chains; D006801:Humans; D010455:Peptides / Q000235:genetics / Q000276:immunology*; D044465:White People
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; D000939:Epitopes; D059811:HLA-DRB1 Chains; D010455:Peptides; D002956:Citrulline; D005340:Fibrinogen
keywords: Anti-citrullinated protein autoantibodies (ACPA); B-cell epitopes; Black Africans; Citrullinated fibrin; Rheumatoid arthritis