CX3CR1 and Hepatic fibrosis: The production of ample amounts of chemokines by MSCs coordinates their immunosuppressive effects on immune cells.16 CCL2 is expressed in in vitro-expanded MSCs and further induced by inflammatory cytokines.43 An acute immune response characterized by the temporal induction of CCR2+ and CX3CR1+ macrophages underlies the benefit of cardiac stem cell therapy.10 Here, we provide direct in vivo evidence that MSC-induced rapid inflammatory macrophage recruitment is essential for the therapeutic effect of stem cells in liver fibrosis.