The understanding of the mechanisms underlying the development and progression of ILD remains elusive [13, 14] . Indeed, for a long time, chronic ILD and pulmonary fibrosis were believed to result mainly from chronic inflammation following an initial injury to the alveolar epithelial lining [15, 16] . In cases of limited injury, it was thought that the reparative attempt could reverse the trend toward fibrosis. By contrast, in situations of continuing injury, the repair process driven by inflammatory molecules produced by the local cells will result in scarring and structural changes. Therefore, by targeting the inflammatory response, the belief was that fibrosis could be prevented or controlled. This theory explains the large use of anti-inflammatory therapy with, however, limited clinical efficacy.