TNF and rheumatoid arthritis: The results of qRT-PCR and Enzyme-linked immunosorbent assay (ELISA) (Figure 4A,B) displayed that the mRNA expression of IL-1β, IL-6, and tumor necrosis factor (TNF)-α in the synovial tissues and their contents in serum of the RA group were significantly increased, when compared with the normal group (all P<0.05).