Studies revealed that administration of MSCs and hemopoietic stem cells suppress the production of interleukin (IL)-6, tumor necrosis factor-alpha (TNF-α), transforming growth factor-beta (TGF-β), and IL-10, and inhibit the expression of nuclear factor-kappaB (NF-κB), toll-like receptor-2 (TLR-2), matrix metalloproteinase-3 (MMP-3) and cartilage oligomeric matrix protein-1 (COMP-1) genes in a rat model of rheumatoid arthritis [6]. The gene discussed is TNF; the disease is rheumatoid arthritis.