CXCL1 and infection: At 3 days post-infection, intravenous administration of hMSCs significantly decreased the concentrations of pro-inflammatory cytokines and chemokines, i.e. TNF-α, IL-1β, MCP-1, CXCL1 in lung homogenate and/or BAL fluid, respectively, as compared with mice treated with NHLFs group (Fig. 2a and b).