Fig. 4: Effect of therapy on immune cell subsets and association of Tregs with PFS.

PBMCs collected at pre-trial screening and after 8 weeks of trial treatment were assessed for different immune cell subsets by flow cytometry. All patients in the FAS for whom paired samples were available were included in the analysis (placebo-chemo n = 18, atezo-chemo n = 29). The gating strategy is shown in Supplementary Fig. 1. Cell counts were estimated by multiplying the percentage of each subset within the lymphocyte gate by the clinical lymphocyte differential cell count obtained for each patient at each timepoint. Fold changes from screening were calculated and log₂-transformed. The baseline level is indicated with a dotted line. Data are presented as box and whisker plots, with the center line showing the median and the hinges showing the IQR. Whiskers show minimum and maximum values. a, Immune cell absolute cell counts. Immune cell subsets are defined as follows: CD4 T cells (CD3⁺CD4⁺CD8⁻), CD8 T cells (CD3⁺CD4⁻CD8⁺), Tregs (CD3⁺CD4⁺Foxp3⁺CD25^Hi), B cells (CD3⁻CD19⁺), NK cells (CD3⁻CD56⁺), NKT cells (CD3⁺CD56⁺) and gd-T cells (CD3⁺gd-TCR⁺). b, Percentage of T cell subsets. CD4 and CD8 subsets are shown as a percentage of total lymphocytes, and Tregs are shown as a percentage of total CD4⁺ T cells. Two-tailed P values were calculated using the Wilcoxon matched-pairs signed-rank test. c,d, Kaplan–Meier analysis of PFS in the placebo-chemo group compared to the atezo-chemo group in patients with low (≤ median; c) and high (> median; d) levels of Tregs as percentage of total CD4⁺ T cells. Two-tailed P values were calculated using the log-rank test and HRs with CIs using the Cox proportional hazards method.