Patients with L-CTCL exhibit a contracted T-cell repertoire and Th2 cytokine profile. (A) PBMCs from patients with stage 4 CTCL or healthy controls (n = 3/group) were analyzed by flow cytometry. Representative plots show cells analyzed for CD3 and CD4 expression. Arrow indicates contraction of the CD3⁺/CD4⁻ population. (B) Th cells from patients with stage 4 CTCL show increased expression of a single malignant TCR-Vβ clone. Representative plot is shown. (C) PBMCs from healthy controls or L-CTCL patients (n = 3/group) were stimulated ex vivo with PMA/ionomycin/brefeldin A, and intracellular levels of Th2 cytokines were analyzed by flow cytometry. Representative plot of L-CTCL patients is shown. (D) Graphical representation of data from all L-CTCL and health control donors depicting mean percentage of CD4⁺ cells expressing IL-4, IL-13, and IL-10. Statistically significant difference compared with healthy controls using Student paired t test: *P ≤ .05, **P ≤ .001. (E) PBMCs from healthy controls or L-CTCL patients were stimulated ex vivo with PMA/ionomycin/brefeldin A, and intracellular levels of IL-10 were analyzed in CD8⁺ T cells by flow cytometry. A representative plot is shown. (F) Graphical representation of undiluted plasma samples from patients with advanced-stage CTCL (triangles, n = 7) and healthy controls (squares, n = 5) were analyzed for Gal-1 expression by ELISA. Experiments were performed in triplicate. (G) PBMCs from L-CTCL patients or healthy controls were gated on CD3⁺/CD4⁺ and analyzed for specific TCR-Vβ expression and intracellular Gal-1. A representative plot is shown.