NAMPT is a cytokine involved in the regulation of inflammatory responses.9,32 In vitro studies demonstrated that NAMPT modulates the actions of enamel matrix derivative, and may compromise the regenerative capacity of periodontal ligament cells.20 Besides its pro-inflammatory function in gingival tissue, it was shown that NAMPT can upregulate the expression and the activities of MMP1, MMP3 and RANKL in human gingival fibroblasts, resulting in alveolar bone loss.22 These reports indicated that NAMPT is an adverse factor in periodontitis. Here, TNFSF11 is linked to periodontitis.