While fibroblast-specific deficiency of TLR4 has been shown to be protective against fibrosis, and TLR2 has shown to exacerbate bleomycin-induced pulmonary fibrosis by inducing an oxidative response [123–125], mice deficient in both TLR4 and TLR2 have been shown to have increased pulmonary fibrosis in response to radiation injury [126–128]. This evidence concerns the gene TLR4 and pulmonary fibrosis.