Regarding CD105, Jones et al. reported that “synovial fibroblastic/stromal cells”, which were negatively selected for CD45 and CD31, expressed CD105 at moderate levels and synovial MSCs, which were expanded by “synovial fibroblastic/stromal cells”, expressed CD105 at high levels in RA patients [19]. This evidence concerns the gene PECAM1 and rheumatoid arthritis.