TINAGL1 and rheumatoid arthritis: The fibrillar type XXVII collagen (COL27A1) and lipocalin-7 (also known as tubulointerstitial nephritis antigen-like 1; TINAGL1), which were identified as up-regulated molecules in RA-SFB in this study for the first time, are not intrinsic extracellular matrix molecules, but both exhibit differentiation potential.