Furthermore, IL-33 increases bacterial loads and lethality through induction of type 2 cytokines in Legionella pneumophila-induced pneumonia [37], while IL-33 improves local immunity during Klebsiella pneumoniae-induced pneumonia by a combined effect on neutrophils and inflammatory monocytes but not on B, T, NK and ILC2 cells [38]. This evidence concerns the gene IL33 and pneumonia.