Since High mobility group box 1 protein (HMGB1) is overexpressed in IPF lungs and its antibody mediated neutralization exacerbates BLM-induced fibrosis, role of HMGB1 has been also suggested in PF as a DAMP which eventually stimulates TLR2 and TLR4 in PF (150). Here, TLR4 is linked to idiopathic pulmonary fibrosis.