ACTB and rheumatoid arthritis: We compared the stability levels of nine of the most well-known RGs, namely GAPDH, ACTB, B2M, EEF1A1, TBP, RPLP0, PPIA, YWHAZ, and HPRT1, in SF-MSCs derived from healthy donors and RA patients to select the most stable RGs in both MSC types.