Considering the interactions between HLA-DMB and HLA-DMA in periodontitis, the ROC analysis was also conducted on HLA-DMA, which indicated that HLA-DMA displayed a good performance on distinguishing periodontitis from normal samples (Fig 5B, AUC=0.786; Fig 5D, AUC= 0.855). This evidence concerns the gene HLA-DMB and periodontitis.