CD27 and periodontitis: In terms of median fluorescence intensity, an increase in CD27 on Unswitched Memory B cells (0.95 [0.90,1.00], P = 0.045), CD38 on Plasma Blast-Plasma Cell (OR = 0.91 [0.84,0.98], P = 0.009), CD3 on Terminally Differentiated CD4 + T cells (OR = 0.95 [0.91,1.00], P = 0.040), HVEM on Terminally Differentiated CD8 + T cells (OR = 0.95 [0.92,0.99], P = 0.019), and CD45 on CD33 + HLA DR + CD14dim (0.95 [0.91,1.00], P = 0.043) was associated with a reduced incidence of chronic periodontitis.