Fig. 2

CD43 + CD5+ B cells and CD21^low B cells in peripheral blood upon aging. Analysis of total cell numbers (a,c) and relative frequencies (b,d) of CD5 + CD43+ B cells and CD21^low B cells, respectively. Data were evaluated for four age categories: < 50 (n = 47), 50–60 (n = 31), 60–70 (n = 45), and > 70 (n = 32). Statistical significance between age groups was determined using the Mann-Whitney U test; *, p < 0.05; **, p < 0.01; ***, p < 0.001; ****, p < 0.0001