When M1 macrophages excessively accumulate in the lung, their secretion of pro‐inflammatory mediators such as tumour necrosis factor‐alpha (TNF‐α), interleukin (IL)‐6 (IL‐6), IL‐1 and inducible nitric oxide synthase (iNOS) amplifies the immune response, causing inflammatory storms leading to ALI [10]. This evidence concerns the gene NOS2 and acute respiratory distress syndrome.