It was found that there was a significant inverse association between plasma cells and most of the other immune cells, that is, plasma cells versus memory B cells (γ = − 0.84), plasma cells versus resting dendritic cells (γ = − 0.64), plasma cells versus resting CD4 memory T cells (γ = 0.50), plasma cells versus activated dendritic cells (γ = − 0.46), plasma cells vs. TFH (γ = − 0.46), plasma cells versus macrophage M2 cells (γ = − 0.43), or plasma cells vs. macrophage M1 cells (γ = − 0.40), in periodontitis tissues (Fig. 6). Here, CD4 is linked to periodontitis.