PDCD1 and autoimmune disease: As a matter of fact, after reaching the osteogenic commitment, the differentiated DPSCs co-cultured with aPBMCs lose the capability to express PD-L1, hinting that this feature is strictly correlated with the stemness status of DPSCs. In conclusion, since PD1/PD-L1 pathway plays a pivotal role in immune tolerance whose failure is characteristic in the establishment and development of autoimmune diseases such as rheumatoid arthritis it would be interesting to evaluate the efficacy of PD-L1-mediated anti-inflammatory potential of DPSCs when exposed to a chronic inflammatory microenvironment [9].