Mirroring qRT-PCR gene expressions, following TGF-β + IL-6, the collagen I (p = 0.049) and α-SMA (p = 0.049) protein expressions were significantly increased in RA-FLSs more than UT-cells (Figure 2E and Supplementary Figure S2). Here, TGFB1 is linked to rheumatoid arthritis.