HGF and susceptibility to pneumonia measurement: The results showed that the levels of 11 cytokines were significantly higher in the pneumonia group than in the non-pneumonia group: interleukin 6 (IL-6), interleukin 18 (IL-18), interferon gamma (IFN-γ), interleukin 8 (IL-8), monocyte chemoattractant protein-1/3 (MCP-1/MCP-3), colony stimulating factor-granulocyte colony stimulating factor (G-CSF), macrophage-stimulating factor (M-CSF), hepatocyte growth factor (HGF), interleukin-2 receptor subunit alpha (IL-2Ra), and macrophage migration inhibitory factor (MIF).