TBCE and fibrosis: A new pro-fibrogenic scar-associated TREM2+CD9+MNDA+ subpopulation of macrophages (scar-associated macrophages, SAMs) was identified, which expanded in the liver in the context of fibrosis, originated from differentiating circulating monocytes (Ramachandran et al., 2019) and was distinct from KCs (Ramachandran et al., 2020).