MMP9 and infection: Here, it was demonstrated that administration of MSCs during established infection did not alter the potent earlier-phase proinflammatory cytokines TNF-α, IL-1β, and IFN-γ in the BAL, but there was a significant reduction in BAL MMP-9, IL-6, CINC1, MIP-3α, and MCP-1, which are considered to be functional later-phase cytokines with downstream effects on the innate and adaptive immune systems.