CD28 and periodontitis: Conversely, an increase in CD24 on IgD- CD38- B cells (OR = 1.05 [1.01,1.08], P = 0.011), CD25 on IgD + CD24 + B cells (OR = 1.03 [1.00,1.06], P = 0.036), CD25 on IgD + CD38- B cells (OR = 1.05 [1.02,1.08], P = 0.003), CD25 on Unswitched Memory B cells (OR = 1.04 [1.00,1.07], P = 0.041), CD28 on CD45RA- CD4 non-regulatory T cells (OR = 1.10 [1.01,1.19], P = 0.025), and CD45 on CD8 + T cells (OR = 1.02 [1.01,1.04], P = 0.004) was associated with an increased incidence of chronic periodontitis.