Collectively, these results suggest that Nintedanib target pathways (PDGF-AA, PDGF-BB, FGF-2, VEGF and M-CSF) are augmented in all PF-ILD subsets and importantly their concentrations are similar across PF-ILD subsets suggesting that Nintedanib treatment should have similar efficacy in PF-ILD regardless of aetiology and should have a relative reduction in the annual rate of decline in FVC (mL/year) of approximately 45–50% for PF-ILD. Here, FGF2 is linked to pemphigus foliaceus.