IL6 and pulmonary fibrosis: In addition, studies have shown that c-reactive protein (CRP), interleukin-6(IL-6), D-dimer and hepatic cytokines (HGF) and C-X-C motif chemokine 13 (CXCL13) are associated with the occurrence of pulmonary fibrosis in patients with COVID-19 (Francone et al., 2020; Yu et al., 2020; Perreau et al., 2021).