Figure 1

Characterization of T- and B-cell subsets. (a) Naïve lymphocytes were CD4+CD45RA+ and CD8+CD45RA+ cells, while central memory (CM) lymphocytes were cells with CD4+CD45RA-CCR7+ and CD8+CD45RA-CCR7+ phenotypes and effector memory (EM) lymphocytes were cells with CD4+CD45RA-CCR7- and CD8+CD45RA-CCR7- phenotypes. TEMRA were CD8+CD45RA+CCR7- cells. T-cell subtypes were given as absolute numbers (cells/µl) while TRECs (per ml) were reported after log transformation. (b) The B-cells were first gated for CD19 expression on lymphocytes, then analyzed for the expression of CD10 marker to identify CD19+CD10+ immature B cells and CD19+CD10- mature B cells. This last subset was examined for IgD and CD27 molecule expression in order to recognize IgD+CD27- naïve B cells, IgD+CD27+ unswitched memory B cells, and IgD-CD27+ switched memory B cells. B-cell subtypes were given as absolute numbers (cells/µl), while KRECs (per ml) were reported after log transformation. T- and B-cell subsets were analyzed at different time points in PML patients and MS controls (T0: samples prepared before natalizumab initiation; T1 and T2: at 6 and 12 months of therapy; and T3: at the time of PML. For details, see Table 2). For MS control patients, mean value for each immune parameter is reported. The color of the symbol is patient-specific. Light gray boxes represent the 99% confidence intervals of the means found in HC. Black symbol and bars indicate the values and the 99% confidence intervals for HIV+ patients. Values of PML patients outside these ranges are considered significant. With * are indicated the values statistically different from those of MS patients, in which are included MS#1 and MS#2, treated with natalizumab at the respective time point, as previously described¹⁴.