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Fcγ receptor profile of monocytes and macrophages from rheumatoid arthritis patients and their response to immune complexes formed with autoantibodies to citrullinated proteins
  1. Lætitia Laurent1,
  2. Cyril Clavel1,2,
  3. Olivia Lemaire3,
  4. Florence Anquetil1,
  5. Martin Cornillet1,
  6. Laurent Zabraniecki3,
  7. Leonor Nogueira1,2,
  8. Bernard Fournié3,
  9. Guy Serre1,2†,
  10. Mireille Sebbag1†
  1. 1Laboratory of ‘Epidermis Differentiation and Rheumatoid Autoimmunity’, Unité Mixte de Recherche 5165, Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier (Toulouse III University), Unité 1056, Institut National de la Santé et de la Recherche Médicale (INSERM), Institut Fédératif de Biologie Médicale de Toulouse Recherche (IFR150, CNRS, INSERM, Toulouse III University, Centre Hospitalier Universitaire (CHU) de Toulouse), Toulouse, France
  2. 2Laboratory of Cell Biology and Cytology, Institut Fédératif de Biologie, Hôpital Purpan, CHU de Toulouse, Toulouse, France
  3. 3Clinical Rheumatology Department, Hôpital Purpan, CHU de Toulouse, France
  1. Correspondence to Dr Guy Serre, Unité ‘Différenciation Épidermique et Auto-immunité Rhumatoïde’, UMR 5165 CNRS - U1056 INSERM -, Université Paul Sabatier, Hôpital Purpan, Place du Dr Baylac, 31059 Toulouse Cedex 9, France; secretariat.cnrs-purpan{at}udear.cnrs.fr

Abstract

Objective To analyse Fcγ receptor (FcγR) expression on monocytes and macrophages from rheumatoid arthritis (RA) patients versus healthy controls (HC), and to compare their responses to immune complexes containing RA-specific anti-citrullinated proteins auto antibodies (ACPA).

Methods Monocytes and monocyte-derived macrophages were obtained from the peripheral blood of 34 RA patients and 69 HC. FcγR expression was studied by flow cytometry. Cells were stimulated with ACPA-containing immune complexes, and tumour necrosis factor alpha (TNFα) was assayed in culture supernatants.

Results Variations distinguished RA from HC monocytes, corresponding to a 5% and 6% decrease in the percentages of monocytes expressing FcγRI and FcγRII, respectively, and a 7% increase in the proportion of FcγRIII-positive monocytes. Although in both HC and RA patients macrophage differentiation was accompanied by a dramatic increase in the percentage of FcγRIII-expressing cells (72% vs 74.5%), the parallel decline in the proportion of FcγRI-positive cells was markedly smaller in RA (7% vs 43%). Monocytes and macrophages from patients were responsive to ACPA-containing immune complexes but TNFα production in both cell types neither differed from that observed with the corresponding cells from HC, nor correlated with FcγR expression or clinical or biological data. In RA as in HC, ACPA-containing immune complexes induced secretions of more TNFα in macrophages than in paired monocytes (ninefold). Finally, the proinflammatory potential of ACPA-containing immune complexes was confirmed in CD14-positive monocyte macrophages from the synovial fluid of four RA patients.

Conclusions ACPA-containing immune complexes induce TNFα secretion by blood and synovial fluid-derived macrophages from RA patients, fitting with their probable involvement in RA pathophysiology.

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Footnotes

  • LL and CC and GS and MS contributed equally to this work.

  • Funding This study was supported by grants from the Toulouse III University, the ‘CNRS’ and the ‘Fondation Arthritis’.

  • Competing interests None.

  • Patient consent Obtained.

  • Ethics approval The use of blood samples has been approved by the Local Committee for the Protection of Persons (Sud Ouest et Outre-Mer I) and has been declared to the Ministry of Higher Education and Research (file no. DC-2008-264).

  • Provenance and peer review Not commissioned; externally peer reviewed.

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