Phenotypic heterogeneity of circulating CD158k⁺T cells. (A) Among 47 patients, 28 display SCs of only 1 phenotype, mostly TCM, whereas 19 present a mix of several subsets, comprising naïve, TSCM, TCM, TTM, TEM, or TEMRA. (B) Example of 2 Sézary patients: CERA45, with 87% of SCs displaying a TSCM phenotype (CD45RA⁺CCR7⁺CD27⁺CD95⁺), stable over time; ARGP38, with SCs being exclusively naïve (85%) (CD45RA⁺CCR7⁺CD27⁺CD95⁻) in March 2014, presented a mix of naïve (66%) and TCM (30%) (CD45RA⁻CCR7⁺CD27⁺) in July 2016, along with an increase of blood tumoral burden and large-size lymphocytes (from 0.02 G/L CD158k⁺ T cells in November 2015 to 2.5 G/L in July 2016). (C) Vβ⁺CD158k⁺ T cells versus Vβ⁻CD158k⁻CD4⁺ T cells naïve/memory phenotype distribution within 17 patients. Ranges in 18 HDs are indicated by the blue backgrounds (mean ± 2 SD). Results were obtained after immunostaining on thawed PBMCs. Statistical analyses are paired among patients (Wilcoxon test), and a Mann-Whitney test was used for comparisons with HDs. Results are expressed as medians ± interquartile ranges. (D) Heat map resulting from supervised hierarchical clustering of differentially expressed genes among the TN, TSCM, and TCM phenotypes of CD4⁺ T cells from HDs and CD158k⁺CD4⁺ T cells from Sézary patients (P = .00001 | log2 fold change | > 1). ns, not statistically significant. *P < .05. **P < .01. ***P < .001.