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Signs of immune activation and local inflammation are present in the bronchial tissue of patients with untreated early rheumatoid arthritis
  1. Gudrun Reynisdottir1,
  2. Helga Olsen2,
  3. Vijay Joshua1,
  4. Marianne Engström1,
  5. Helena Forsslund2,
  6. Reza Karimi2,
  7. C Magnus Sköld2,
  8. Sven Nyren3,
  9. Anders Eklund2,
  10. Johan Grunewald2,
  11. Anca I Catrina1
  1. 1Rheumatology Unit, Department of Medicine, Solna, Karolinska University Hospital and Institutet, Stockholm, Sweden
  2. 2Division of Respiratory Medicine, Department of Medicine, Solna, Center for Molecular Medicine, Karolinska University Hospital, Solna, Karolinska Institutet, Stockholm, Sweden
  3. 3Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden
  1. Correspondence to Dr Anca I Catrina, Rheumatology Unit, Department of Medicine, Karolinska Institutet/Karolinska University Hospital, Stockholm 171 76, Sweden; anca.catrina{at}ki.se

Abstract

Objectives Events in the lungs might contribute to generation of anticitrullinated protein antibodies (ACPA) in rheumatoid arthritis (RA). We investigated if signs of immune activation are present in bronchial biopsies and bronchoalveolar lavage (BAL) of patients with early-untreated RA without clinical signs of lung involvement.

Methods Twenty-four patients with RA with symptom duration <1 year and naïve to disease-modifying antirheumatic drugs were subjected to bronchoscopy where BAL and mucosal bronchial biopsies were retrieved. For comparison, 15 bronchial biopsies and 79 BAL samples from healthy volunteers were available. Histological examination was performed to evaluate lymphocyte infiltration, presence of immune cells (T and B cells, plasma cells, dendritic cells and macrophages) and immune activation markers. Cell composition of BAL samples was analysed by differential counting and T cell subsets by flow cytometry.

Results Lymphocyte infiltration was more frequently found in ACPA-positive patients (50%) as compared with ACPA-negative patients (17%) and controls (13%). Germinal centres, B cells and plasma cells were only found in ACPA-positive patients. The frequency of T cells in bronchial biopsies of patients with ACPA-positive RA was positively associated with expression of immune activation markers. BAL samples of patients with ACPA-positive, but not ACPA-negative, RA had significantly higher relative numbers of lymphocytes and expressed higher levels of activation markers compared with controls.

Conclusions Signs of immune cell accumulation and activation are present both in the bronchial tissue and in BAL of untreated patients with early RA without concomitant lung disease, strengthening the role of the lung compartment as an important player in ACPA-positive RA.

  • Rheumatoid Arthritis
  • Ant-CCP
  • T Cells

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