Activation of STAT3 gene targets in L-HES clones. (A) The mean fold-change of transcript levels (log2) in L-HES clones compared with CD4⁺ T-cell controls (control memory [CM]) as evaluated through RNA sequencing. L-HES clone 1 possesses the p.Y640F mutation. ***P = .0002; **P = .0007; *P = .008. (B) Gene set enrichment analysis of STAT3 gene signature in L-HES clones compared with CD4⁺ T-cell controls (P = .002). (C) Relative levels of messenger RNA (mRNA) transcripts of known STAT3 gene targets in unstimulated L-HES clones as compared with CD4⁺ T-cell controls. (D) Relative levels of cytokine expression in L-HES clones as compared with CD4⁺ T-cell controls. For panels C-D, closed symbols represent the L-HES clone containing the p.Y640F mutation. In panel D cytokine profiles, unstimulated L-HES clones were not annotated with closed symbols for the sake of clarity. Each T-cell sample was cultured with or without pharmacologic stimulation with phorbol 12-myristate 13-acetate and ionomycin. *P < .05, **P < .005, ***P < .0005. fpkm, fragments per kilobase per million reads.