CCL2 and infection: In order to study the state of the immune response at the local site of infection, we conducted multiplex enzyme-linked immunosorbent assays to measure the levels of a panel of 23 different cytokines (IL-1a, IL-1b, IL-2, IL-3, IL-4, IL-5, IL-6, IL-9, IL-10, IL-12(p40), IL-12(p70), IL-13, IL-17, Eotaxin, GCSF, GM-CSF, IFNγ, KC, MCP-1, MIP-1a, MIP-1b, RANTES and TNFα) on lung samples obtained throughout the study.