CCL2 and ventilator-associated pneumonia: A review indicated that IFN-γ and TNF-α were associated with the prognosis of disease [40], but our aim was to predict the occurrence of ARDS, which might be the reason why differences between IFN-γ and TNF-α were not remarkable between two groups, and it was proved that the concentration of MCP-1 in ventilator-associated pneumonia patients with ARDS was significantly higher than that in patients without ARDS (p=0.04), but the blood plasma samples in study we mentioned above were collected after the occurrence of ARDS, so the results were slightly different from ours [41].