Lenalidomide shifts T-cell populations toward effector subset. (A) List of canonical pathways related to immune system and metabolism upregulated in PD-1⁺ T cells. (B) Percentages of naive, CM, EM, and terminally differentiated effector T cells assessed by flow cytometry in circulating CD4 (upper row) and CD8 T cells (lower row) of first-line patients with FL. (C) Proliferation index of CD4 and CD8 T cells stimulated ex vivo by CD3 and CD28 cross-linking at the indicated time points. D0, first day of the first cycle of treatment (before lenalidomide intake); D7, seventh day of the first cycle (before obinutuzumab infusion); D28, first day of the second cycle (before lenalidomide intake). *P < .05, **P < .01, ***P < .001, multiple paired samples Wilcoxon tests.