319 Spatial transcriptomics and single-cell transcriptomics elucidates the intricate inflammatory cellular network in atopic dermatitis

Atopic dermatitis (AD) is the most common chronic inflammatory skin disease. We aimed to investigate complex spatial and neighboring characteristics of AD skin. performed Visium transcriptomics sequencing in biopsies from 6 healthy control (HC) donors 7 patients (lesion non lesion). For single-cell analysis, we analyzed previously published data suction blister material full-thickness (4 ADs 5 HCs). The multiple proximity extension assays were serum samples 36 28 HCs. analysis identified unique clusters fibroblasts, dendritic cells (DCs), macrophages lesional Spatial showed upregulation COL6A5, COL4A1, TNC, CCL19 COL18A1-expressing fibroblasts especially leukocyte-infiltrated areas Moreover, CCR7-expressing DCs CCL13- CCL18-expressing M2 a similar distribution this lesion. Furthermore, ligand–receptor interaction transcriptome infiltration between activated COL18A1+ CCL18+ macrophages, CCR7+ DCs, T cells. As observed lesions, levels TNC CCL18 significantly elevated AD, correlated with clinical disease severity. In study, demonstrate upper dermis as tertiary lymphoid structures-like cellular infiltrate. These molecular interactions may play central role lesion formation AD.