(A–F) Single-cell RNA-seq (scRNA-Seq) studies from lesions of adult morphea (n = 13) and healthy skin (HS) (n = 8) biopsies showing major skin cell populations (A), T cell counts and frequencies (B), T cell and NK cell subsets (C), cytotoxic gene expression across T cell subsets in morphea (D), endothelial cell (EC) subsets (E), and differentially expressed genes (F) in pooled vascular ECs from morphea versus HS. (G) CellChat analysis predicted TNF ligand-receptor interactions among all cell populations in morphea, with thicker lines indicating stronger interaction strength; only significant interactions are shown. (H) Postcapillary venule ECs are reduced in morphea, with a relative increase of other venular endothelial cells. (I) Multiplex immunofluorescence shows apoptotic (cleaved-caspase-3⁺) ECs (CD31⁺) adjacent to CD3⁺ T cells in morphea, with quantification per 200× high-power field (HPF) shown. (J and K) Representative morphea images show necroptotic (pMLKL⁺) ECs near CD3⁺CD8⁺ cytotoxic T cells (J) and CD3⁺CD69⁺ or CD3⁺CD103⁺ tissue-resident T cells (K), with corresponding quantification per 200× HPF versus HS. Insets: arrowheads indicate T cells; arrows indicate apoptotic (I) or necroptotic (J and K) ECs. Scale bars: 50 μm. Bars represent individual donors; data are shown as mean ± SEM of 3 independent measurements. Statistical significance for immunostaining was determined by nested 2-tailed t tests; for box plots, by 2-tailed unpaired t tests.