Single-cell transcriptomic atlas of adult dermatomyositis, cutaneous lupus erythematosus and healthy skin

Adult-onset dermatomyositis (DM) is a systemic autoimmune disease associated with an elevated risk of malignancy, yet the cellular and molecular features distinguishing cancer-associated DM from non-cancer DM remain poorly defined. Here, we conduct a comprehensive single-cell RNA sequencing analysis of adult-onset DM skin, including lesional and non-lesional samples, alongside cutaneous lupus erythematosus (CLE) and healthy control skin, to characterize immune and stromal cell states and disease-specific transcriptional programs. We identify distinct immune-stromal cell populations that differentiate cancer-associated DM from non-cancer-associated DM and CLE, including a vascular injury phenotype with hypoxia and metabolic reprogramming enriched in cancer-associated DM. These findings nominate cell-state-defining molecular features as potential biomarkers for cancer screening and therapeutic targeting in adult dermatomyositis.