IRF6 and periodontitis: A secondary search on the listed abstracts by using the keyword “inflammation” further yielded keywords like “cytokines,” “tnf,” “lps” (Supplementary Figure 25), which are indicators of some mechanisms of Porphyromonas gingivalis infection in periodontitis (Jiang et al., 2018; Kajiura et al., 2018; Zhou et al., 2018).