Spatial and single cell proteomic analysis reveal alterations in type2 inflammation in prurigo nodularis and atopic dermatitis

Summary: Abstract Body: Type 2 inflammation is a shared feature of prurigo nodularis (PN) and atopic dermatitis (AD), driven by Th2 cell activation and cytokines such as IL-4, IL-13, and IL-31. Despite recent advances, the spatial and single-cell resolution of immune cell localization in skin lesions remains limited. Imaging Mass Cytometry (IMC) integrates high-dimensional antibody-based detection with spatial tissue architecture, offering a novel approach to studying immune dysregulation in PN and AD. We prospectively analyzed lesional and non-lesional skin biopsies from 24 PN patients, 10 AD patients, and 10 healthy controls. Spectral analysis identified significant enrichment of Th2 cells and elevated expression of IL-4, IL-13, TSLP, and IL-31 in lesional PN skin and lesional AD skin compared to non-lesional (p < 0.05) and healthy control tissues (p < 0.01 for all). Co-localization of type 2 cytokines with dermal fibroblasts and keratinocytes suggested an immune-stromal interplay in chronic inflammation. Additionally, we observed enrichment of IFN-γ in subsets of keratinocytes and fibroblasts neighboring M2 macrophages in lesional PN (p < 0.05), indicating a complex inflammatory milieu involving both Th2 and Th17 pathways. IMC also revealed distinct more numerically dense clusters of macrophages and dendritic cells within the dermis neighboring VIM+ and SMA+ fibroblast clusters (p < 0.05) that may contribute to skin fibrosis in PN. This study demonstrates the power of IMC to map the spatial and cellular landscape of type 2 inflammation in PN and AD, laying the groundwork for targeted therapies that address key pathogenic interactions. Shahin Shahsavari¹, Kavita Vats¹, Louis J. Born¹, Yagiz M. Akiska¹, Davies Gage¹, Selina M. Yossef¹, Sarah Shin², Alexei Hernandez², Won jin Ho², Shawn Kwatra¹ 1. Dermatology, University of Maryland Baltimore School of Medicine, Baltimore, MD, United States. 2. Cancer Center, Johns Hopkins Medicine, Baltimore, MD, United States. Bioinformatics, Computational Biology, and Imaging