Single-Cell Sequencing Combined With Spatial Transcriptomics Reveals the Characteristics of Follicle-Targeted Inflammation Patterns in Primary Cicatricial Alopecia

This study examines the inflammatory patterns in primary cicatricial alopecia (PCA), focusing on lichen planopilaris (LPP), using single-cell RNA sequencing and spatial transcriptomics. Analyzing 55,957 cells from 7 patients with cicatricial alopecia and 2 controls, the research identifies 21 cell types, highlighting the roles of CD8+ effector memory T cells, macrophages, and bulge cells. It reveals significant upregulation of Tem cells in LPP and localized scleroderma (LS), with macrophages notably increased in LS. The study suggests that specific macrophage subpopulations and signaling pathways, such as the JAK-STAT pathway, contribute to hair follicle inflammation and hair loss, offering insights into potential therapeutic targets like Janus kinase inhibitors for treating LPP. Despite the small sample size, the findings are supported by spatial transcriptomics and immunofluorescence, providing a foundation for future research and drug development.