TNF and legionellosis: KEGG pathway analysis showed that the hub genes were significantly enriched in rheumatoid arthritis, the IL-17 signaling pathway, Kaposi sarcoma-associated herpesvirus infection, cytokine-cytokine receptor interaction, viral protein interaction with cytokines and cytokine receptors, the NF-kappa B signaling pathway, the TNF signaling pathway, Salmonella infection, Legionellosis, and epithelial cell signaling in Helicobacter pylori infection (Fig. 4B, Table 4).