TNF and rheumatoid arthritis: In addition to the differential expression between RA and OA after BC for the 8 genes of interest from the top-ranked GO term at time point 0 hours (Table 4b), these genes also remained differentially expressed between RA and OA at all time points following stimulation with either TNF-α or TGF-β1 (Figure 5, Additional file8: Table S4).