For example, absence of the dsRNA sensor toll-like receptor 3 (TLR3) worsens bleomycin induced pulmonary fibrosis in mice and humans possessing the Leu412 Phe polymorphism in the TLR3 gene develop a rapidly progressive form of IPF (O’Dwyer et al., 2013). Here, TLR3 is linked to pulmonary fibrosis.