TNF and rheumatoid arthritis: In the RA 18-day and RA 28-day groups, numerous upregulated pathways were predominantly associated with inflammatory responses and immune activation, including cytokine–cytokine receptor interaction, chemokine signaling, NF-κB signaling, TNF signaling, Th1/Th2 and Th17 cell differentiation, as well as Toll-like and NOD-like receptor signaling.