Lung Cd4+T-Cells In Patients With Lung Fibrosis Produce Pro-Fibrotic Interleukin-13 Together With Interferon-Gamma

Progressive fibrosing interstitial lung diseases (PF-ILD) have poor prognosis and survival, and their pathogenesis is not well understood [1]. Mechanistically, lung fibrosis is thought to result from distorted wound-healing following tissue insults and inflammation, leading to scar formation by excess deposition of extracellular matrix proteins and destruction of lung architecture [2]. The fibrotic process is complex, and CD4+ T cells are likely involved by their production of a wide range of cytokines and growth factors that promote fibroblast proliferation and differentiation, collagen production, and stimulate production of pro-fibrotic mediators by tissue macrophages [3]. However, CD4+ T cells in PF-ILD are poorly characterised. To this end, we performed a detailed analysis of phenotype, cytokine production and clonality of T cells from the lungs [bronchoalveolar lavage (BAL)] of PF-ILD patients. We found that BAL from PF-ILD lungs contained high numbers of clonally expanded CD4+ T cells that produced an unusual combination of interferon (IFN) γ and pro-fibrotic interleukin (IL)-13. Such cells were not found in patient blood or in control BAL samples.\n\nFootnotes \n\nThis manuscript has recently been accepted for publication in the European Respiratory Journal . It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJ online. Please open or download the PDF to view this article.\n\nConflict of interest: Dr. Sikkeland reports grants from Norwegian Respiratory Society sponsored by Boehringer Ingelheim, during the conduct of the study;.\n\nConflict of interest: Dr. Qiao has nothing to disclose.\n\nConflict of interest: Dr. Ueland has nothing to disclose.\n\nConflict of interest: Dr. Myrdal has nothing to disclose.\n\nConflict of interest: Dr. Wyrozemski has nothing to disclose.\n\nConflict of interest: Dr. Aukrust has nothing to disclose.\n\nConflict of interest: Dr. Jahnsen has nothing to disclose.\n\nConflict of interest: Dr. Sjaheim reports personal fees from Boehringer Ingelheim and Roche, outside the submitted work;.\n\nConflict of interest: Dr. Kongerud has nothing to disclose.\n\nConflict of interest: Dr. Molberg has nothing to disclose.\n\nConflict of interest: Dr. Lund has nothing to disclose.\n\nConflict of interest: Dr. Baekkevold has nothing to disclose.