“…It has been suggested that proliferation, as measured by Ki67 staining, found in cells in the SG 2 M phase of the cell cycle, is similar to measurements of activation using CD38 and DR expression [27]. Hence, the better long-term outcome in those with less apoptosis might be due to less inherent activation of cells from these patients [28,29]. In the one IL-2 long-term non-responder patient studied by Kovacs, et al [4], the DNA turnover of both CD4 + and CD8 + T cells remained high, even after 22 cycles of scIL-2, indicating that chronic activation in some people is not relieved by IL-2 therapy.…”