Compared to the low HLA-DMB expression periodontitis samples, significantly higher proportions of B cells memory, plasma cells, monocytes and neutrophils were observed, but lower proportions of B cells naïve, T cells CD4 memory resting, Macrophages M2 and Mast cells activated were found in high HLA-DMB expression group (Fig 3C). The gene discussed is HLA-DMB; the disease is periodontitis.