IL6 and pulmonary fibrosis: Lastly, several cytokines involved in TH2 cell recruitment and fibrosis (IL-6, eotaxin, PDGF-ββ, IL-10, IL-1β) were released from macrophages in vitro and correlated with in vivo BAL response, which aligns with KE4 (TH2 cell activation) in the lung fibrosis AOP.