ANGPTL4 and rheumatoid arthritis: In contrast, the negative effect of TNFα on ANGPTL-4 previously observed in RA FLS was absent in HSF, where a gradual increase in ANGPTL-4 mRNA was observed with stimulation time (see Additional file 2), suggesting that ANGPTL-4 inhibition by TNFα is a pathological feature of RA FLS.