TNF and rheumatoid arthritis: After the LPS-and-IFN-γ stimulus, the monocytes from the PERIO group presented a statistically significantly higher expression of TNF-α (MFI) (median of 24,053.00) in comparison with the HEALTHY group (median of 5517.00) and the PERIO+RA group (median of 13,421.00) (p = 0.030 and p = 0.010, respectively) (Table 2).