Validation of naïve B-cell enrichment and LGALS9 expression in independent CHL cohorts. (A) Proportional analysis of total B-cell populations in early-relapse vs late-relapse CHL in the validation cohort 1. (B) UMAP plot of B-cell subclusters identified in the validation cohort 1. (C) LGALS9 expression in naïve B cells in the validation cohort 1. (D) Proportional analysis of naïve and memory B-cell populations in early-relapse vs late-relapse CHL in the validation cohort 1. Mann-Whitney U test was used for statistical analysis. (E) Quantification of IgD⁺ B cells across diagnostic, early-relapse, and late-relapse CHL samples based on IHC staining of validation cohort 2. Mann-Whitney U test was used for statistical analysis. (F) Paired statistical analysis (Wilcoxon signed-rank test) comparing IgD⁺ naïve B-cell proportions between diagnostic and early-relapse CHL samples based on IHC staining of validation cohort 2. ∗P < .05; ∗∗P < .01. GCB, germinal center B cell.