As TRAIL could induce the signaling pathway of TRAIL-related apoptosis, both hUCMSCs and HFLS-RA with or without IL-1β stimulation were directly co-cultured for 24 h to determine which apoptotic pathway is involved in hUCMSCs induced apoptosis of HFLS-RA. The gene discussed is TNFSF10; the disease is rheumatoid arthritis.