Although constitutively expressed in neutrophils [36], its expression in monocytes/macrophages is induced by early response molecules such as lipopolysaccharide (LPS) and TNFα.[37] Our observations are consistent with the previously published findings of increased S100A12 protein in both the BAL fluid and plasma of patients with ARDS [25-27]. This evidence concerns the gene S100A12 and acute respiratory distress syndrome.