High definition longitudinal spatial atlas of psoriasis reveals SPRR2F+ keratinocytes and distinct tissue-resolution trajectories under IL-17 and IL-23 inhibition

How inflammation is established and resolved within tissues remains a fundamental question in human biology. Psoriasis is a chronic inflammatory skin disease driven by the IL-23/IL-17 pathway, with IL-17 pathway targeting biologics producing more rapid clinical improvement than IL-23 inhibitors. This difference raises the question of how IL-17 and IL-23 inhibition differentially remodel the cellular and transcriptional landscape of psoriatic skin during resolution. Here, we generated a longitudinal spatial atlas of plaque psoriasis using 2 micron high-definition spatial transcriptomics (HD-SPT), profiling 42 matched biopsies from 11 biologic treatment-naive patients before and during IL-17- or IL-23-targeted therapy. By integrating HD-SPT with a single-cell RNA-sequencing (sc-RNAseq) reference atlas, we resolved the cellular composition and spatial organization of psoriatic skin and mapped its remodeling during treatment. We identified a distinct cluster of SPRR2F+ keratinocytes (KCs) that was spatially restricted to the upper stratum granulosum at the transition to the stratum corneum and was strongly associated with inflamed psoriatic epidermis. SPRR2F+ KCs were enriched for antimicrobial and inflammatory barrier genes, including S100A8, S100A9, LCN2, IL36G, and PI3, and their abundance correlated with disease activity during treatment. In psoriasis patient-derived human epidermal KCs (P-HEK), SPRR2F knockdown attenuated inflammatory and antimicrobial transcriptional responses, supporting a functional role for SPRR2F in sustaining the inflammatory KC response in psoriasis. Longitudinal profiling further revealed distinct trajectories of tissue remodeling following IL-17 and IL-23 inhibition. Following IL-17 inhibition, SPRR2F+ KCs and their characteristic transcriptional signature resolved rapidly, whereas IL-23 inhibitors produced more gradual resolution of KC-centered transcriptional changes accompanied by broader immune and stromal remodeling. Together, these findings established the first HD-SPT atlas of a human skin disease and revealed distinct cellular and transcriptional trajectories of psoriatic skin during therapeutic resolution, identifying SPRR2F as a regulator of persistent KC inflammation.