Currently, only PD-L1 has been reported in DP-MSCs [50]; this could be because dental tissues are exposed to constant immunological challenge, and thus, tolerance mechanisms increase, as in periodontitis—the most common oral pathology caused by bacterial infections—which can be resolved by PD-L1 negatively regulating inflammation and maintaining periodontal tissue under constant immunological tolerance [17]. The gene discussed is CD274; the disease is periodontitis.