Effects of IL-15 injections on additional IL-15–responsive lymphocyte subpopulation in participants with ATL and PTCL. (A-C) Average fold increases + standard deviation of CD4⁺ T, CD8⁺ T, and γδ⁺ T cells among PBMCs after IL-15 treatment are shown for each treatment group. (D-F) Total numbers of respective proliferating Ki67⁺ cells for each patient before and after treatment. ∗P < .01; ∗∗P < .001; NS, not significant.