Spatial and single-cell transcriptomics reveal keratinocytes as key players in vulvar lichen sclerosus pathogenesis.

Vulvar diseases are a neglected area of women's health, profoundly affecting patients' quality of life. Lichen sclerosus (LS) is a chronic inflammatory vulvar skin disorder leading to severe itching, pain, scarring, and an increased risk of malignancy. Despite this burden, the molecular pathogenesis of vulvar LS (VLS) is not well understood, limiting treatment options. Here, we analyze lesional, non-lesional, and healthy vulvar skin using technologies including spatial and single-cell transcriptomics. Our findings identify unifying molecular changes across multiple cell types in lesional VLS skin, including keratinocyte stress response, necroptosis, and basal/stem cell depletion. Chronic T cell activation, enhanced cytotoxicity, aberrant cell-cell communication, and elevated IFN-γ/JAK/STAT signaling were also observed. Functional studies suggest keratinocytes' dual role as both targets of microenvironmental signaling (e.g., IFN-γ) and sources of inflammatory alarmins (e.g., S100A8/9). This work reveals keratinocytes as central players in VLS pathogenesis and identifies potential biomarkers and therapeutic targets for future research.