IL6 and pulmonary fibrosis: IL-6 isa proinflammatory cytokine secreted by immune cells whose presencein serum is a clear sign of infection.22 IL-6 is also expressed in blood during or after kidney disease23 and lung fibrosis,24 and even serious cases of SARS-CoV-2 have been recently correlatedwith high concentrations of IL-6 in serum samples.25,26