TNF and Epstein-Barr virus infection: KEGG pathway enrichment analysis indicated that the intersection of DEG pathways between the Nicotine group vs. the Control group and the Nicotine + Irisin group vs. the Nicotine group included the TNF signaling pathway (hsa04668), NOD-like receptor signaling pathway (hsa04621), P53 signaling pathway (hsa04115), Influenza A (hsa05164), Epstein-Barr virus infection (hsa05169) and Protein processing in endoplasmic reticulum (hsa04141, Figures 2E,F).