MUC5AC and legionellosis: GSEA investigation suggested that these DEGs were mainly associated with fatty acid biosynthesis; graft‐versus‐host disease; intestinal immune network for IgA production; legionellosis; mucin‐type O‐glycan biosynthesis; nitrogen metabolism; pantothenate and CoA biosynthesis; PPAR signaling pathway; primary immunodeficiency; starch and sucrose metabolism; Th1, Th2, and Th17 cell differentiation; Type I diabetes mellitus; ubiquinone and other terpenoid‐quinone biosynthesis; and viral myocarditis (Figure 1c).