In this study, pPDGFRαβ-positive cells that proliferate specifically in the SL of RA exhibited low expression of TNF-receptor-1 (TNF-R1) and the cell-cycle suppressor p16, as well as high expression of B-cell lymphoma 2 (Bcl-2), which confers resistance to cell death. This evidence concerns the gene TNFRSF1A and rheumatoid arthritis.