CD69 and HLA-DR expression on young or aged CD4 + CXCR5 + Tfh cells, CD4 + T, CD3 + CD4-T and CD4 + CXCR5-T cells. CD69 (A) and HLA-DR (B) expression on CD4 + T, CD3 + CD4-T, CD4 + CXCR5 + Tfh and CD4 + CXCR5-T cells from representative results were shown as in histograms. Thin line: isotype control (iso), heavy line: young individual (young), filled area: elderly individual (aged). Statistical results of percentages of CD69 + (C) (young subjects: n = 13, aged subjects: n = 11), and HLA-DR + (D) (young subjects: n = 10, aged subjects: n = 10) among CD4 + T, CD3 + CD4-T, CD4 + CXCR5 + Tfh and CD4 + CXCR5-T cells were shown. Y: young individuals, A: aged individuals. n.s: no significant difference. All data were expressed with line at mean with SEM.