Figure 4.

Interleukin-2/sirolimus/tacrolimus (IL-2/SIR/TAC) suppresses mTOR signal transduction but not STAT3 phosphorylation in CD4⁺ T cells. (A and B) Mean %pS6⁺ (mTOR signal transduction) and %pSTAT3⁺ CD4⁺ T cells [without (closed circle) or with (open circle) pulse of IL-6 for 15 minutes)] at pre-transplant, day +30, and day +90 after allogeneic hematopoietic stem cell transplantation (HCT) (ANOVA). (C) Mean amount of %pSTAT3⁺ CD4⁺ T cells on day +30 is significantly increased among patients who develop grade II-IV acute graft-versus-host disease (GvHD) by day +100 (Mann-Whitney test). (D) The previously identified cut-off point of 48% pSTAT3⁺ CD4⁺ T cells on day +30 significantly stratified acute GvHD incidence among those on IL-2/SIR/TAC (P<0.0001). The Gray method was used to evaluate the difference in incidence rates between the 2 groups. (E) Correlation between %pSTAT3⁺ CD4⁺ T cells versus %CD4⁺ CD25⁺ CD127⁺ conventional T cells. Log-Transformation was performed per the normality assumption test. Pearson correlation coefficient and P-value are shown. (F and G) Percentage of pS6⁺ and pSTAT5⁺ CD4⁺ T cells at day +30 was similar regardless of acute GvHD diagnosis by day +100. *P<0.05, **P=0.001–0.01, ***P=0.0001–0.001.