Variations in plasma IL-7 levels also correlated with changes in the proportions (D%Ki-67+ in CD4+RTEs; r = 0.806, p = 0.0002; Figure 5D , left panel) and numbers (DKi-67+RTEs; r = 0.706, p = 0.002; Figure 5E , left panel) of cycling RTEs in acute and chronic HCV infected patients and with D%Ki-67+RTE counts in co-infected patients (r = 0.709, p = 0.022; Figure 5E , right panel). Overall, IL-7 concentration was associated with reduced thymopoiesis and RTE proliferation, lower consequently leading to limited circulating RTE and naïve T-cell counts. These data strongly suggest that changes in IL-7 plasma levels during IFNa therapy directly impact the homeostasis of RTEs.