The TLR3 polymorphism Leu412Phe (rs3775291), previously linked to accelerated disease progression and increased mortality risk in idiopathic pulmonary fibrosis (IPF) (O’Dwyer et al., 2013), was examined in sarcoidosis patients and correlated with the progression of the disease to fibrosis (Cooke et al., 2018), in the mechanism of reduced apoptosis of fibroblasts and increased production of CCL-18, which also occurs in IPF. This evidence concerns the gene CCL18 and idiopathic pulmonary fibrosis.