Fig. 5

Changes in the composition of the naive CD45RA⁺ regulatory T cell (Treg)/responder T cell (Tresp) pool and the CD31⁻ Treg/Tresp pool during the course of life in healthy volunteers (n = 94) and SLE patients (n = 78). The percentages of recent thymic emigrant (RTE) and mature naive (MN) Tregs/Tresps within the naive CD45RA⁺ Treg/Tresp pool, as well as those of MN Tregs/Tresps within the total CD31⁻ Treg/Tresp pool, were estimated in healthy volunteers (black diamonds) and SLE patients (red diamonds). The figures present the regression lines concerning the changes of the Treg/Tresp subsets with age (a–c and g–i) or with their Ki67-expression (d–f and j–l). Significant changes with age are marked by black p values (healthy volunteers) or red p values (SLE patients). In SLE patients, age-independent significantly decreased (red downward arrow) percentages of RTE Tregs within the naive CD45RA⁺ Treg pool (a) but increased (red upward arrow) percentages of MNs within the naive CD45RA⁺ Treg pool (b) (marked by red p* values) were detected, but not for RTE Tresps or for MN Tresps within the total CD45RA⁺ Tresp pool (g and h). A significant negative correlation between the percentage of RTE Tregs/Tresps and their Ki67 expression was found for both healthy volunteers and SLE patients (d and j). A significant correlation between the percentage of MN Tregs within total naive CD45RA⁺ Tregs and their Ki67 expression was not found for healthy volunteers or for SLE patients (e). A significant positive correlation was found between the percentage of MN Tresps within total naive CD45RA⁺ Tresps and their Ki67 expression which could not be assessed for SLE patients (k). The percentage of resting naive MN Tregs within total CD31⁻ Tregs decreased significantly with age (c), while that of resting naive MN Tresps increased slightly, but not significantly, within total CD31⁻ Tresps (i). A significant negative correlation between the percentage of resting naive MN Tregs within total CD31⁻ Tregs and their Ki67 expression was found for both study groups (f). In contrast, the percentage of MN Tresps within CD31⁻ Tresps did not correlate with their Ki67 expression in healthy controls but showed a nearly significant negative correlation for SLE patients (l)