We discovered that plasma MCP-1 levels were significantly increased in VAP patients who developed ARDS (1954.15 ± 294.81 ng/mL) when compared with patients without ARDS (1151.80 ± 269.73 ng/mL; p = 0.0417), healthy controls (176.02 ± 10.11 ng/mL; p < 0.0001), and non-VAP subjects (632.86 ± 349.91 ng/mL; p =0.0004). Here, CCL2 is linked to ventilator-associated pneumonia.