Fig. 2

a. B-cell subpopulations in pneumococcal vaccine naïve (n = 25) and previously immunized with 23-valent pneumococcal polysaccharide vaccine (PPV23) (n = 35) patients with severe chronic kidney disease on day 7 post-immunization with 13-valent pneumococcal conjugate vaccine. Isolated peripheral blood mononuclear cells were stained for CD19, CD27, and IgM and analyzed by flow cytometry. The geometric mean of each subpopulation proportion is displayed. No statistically significant difference was detected between the groups. b. Absolute numbers of B-cell subpopulations in pneumococcal vaccine naïve (n = 14) and previously immunized with 23-valent pneumococcal polysaccharide vaccine (PPV23) (n = 19) patients with severe chronic kidney disease 7 days post-immunization with 13-valent pneumococcal conjugate vaccine. Isolated peripheral blood mononuclear cells were stained for CD19, CD27, and IgM. Geometric mean absolute numbers of B-cell subpopulations were determined by multiplying the proportions of B-cell subpopulations by the absolute number of lymphocytes. Statistical significance *p < 0.05 (Student’s t-test for class switched B cells, Mann-Whitney U test for IgM memory and class switched memory B cells)