Low-basal production of cytokines is an unexpectedfinding, since these two cytokines are considered to play a significant role inthe pathogenesis of joint inflammation in RA; TNFα and IL-6 may stimulatecollagenase production, increase bone resorption and inhibit cartilageregeneration targeting fibroblasts, osteoclasts, and chondrocytes [28, 29].Accordingly, previous studies demonstrated increased serum concentrations andenhanced generation of both cytokines by mononuclear cells from patients withRA [17–21]. This evidence concerns the gene TNF and rheumatoid arthritis.