TNF and rheumatoid arthritis: Furthermore, similar to our observations with TREM1, DAP12 expression was also unregulated by culturing healthy PMNs with the inflammatory cytokines IL6, IL17 and TNFα (Fig. 4B) and blocking TNFα dose-dependently prevented the up-regulation of this adaptor (Fig. 4C) demonstrating a correlation between adaptor and receptor expression patterns in RA.