TGFB1 and interstitial lung disease: Further studies are needed to confirm the underlying mechanisms of this association, but it can be hypothesized that pathological remodeling processes, as, for example, TGF-β signaling pathways or circulating fibroblasts, associated with ILD/IPF (34, 35) or COPD (36–39), may persist or be activated in some patients after LT and thus contribute to the higher risk of RAS.