Increase of TSG-6-encoding mRNA in lesional AD skin. (a) TSG-6 and PPIB (CTL+) mRNA detection using in situ hybridization and hemalun counterstaining of healthy and lesional AD skin. Bar = 20 μm. (b) TSG-6-encoding mRNA expression in normal and lesional AD skin assessed by RT-qPCR. The reference gene is RPLP0 (mean ± SD; n = 5 for normal skin and n = 10 for AD skin; unpaired t-test with Welch’s correction). (c) TSG-6-encoding mRNA expression in normal, nonlesional AD, and lesional AD skins analyzed from GEO Profiles database (accession GSE5667; GPL96; 206026_s_at) (mean ± SD; n = 5 or 6; one-way ANOVA). (d) UMAP visualization of undifferentiated and differentiated KC in healthy and lesional AD skins found in single-cell RNA-seq dataset (https://developmentcellatlas.ncl.ac.uk/datasets/ hca_skin_portal) (n = 5). Normalized gene expressions of K14, K10, CA2, NELL2, and TNFAIP6 are represented in green for a low expression and in red for a strong expression. AD, atopic dermatitis; CTL, control; GEO, Gene Expression Omnibus; K, keratin; KC, keratinocyte; RNA-seq, RNA sequencing; UMAP, Uniform Manifold Approximation and Projection.