Single-cell transcriptome reveals immunopathological cell composition of skin lesions in subacute cutaneous lupus erythematosus.

Subacute cutaneous lupus erythematosus (SCLE) is a clinical subtype of cutaneous lupus erythematosus with psoriatic-like or annular papules with scaly erythemas, the pathological mechanism of which is poorly understood. To investigate the immune pathogenesis of SCLE, we performed single-cell RNA sequencing (scRNA-seq) of SCLE skin lesions and integrated the scRNA-seq data from skin tissues of healthy controls (HCs). Our results identified expanded fibroblasts and keratinocytes subtypes, abnormally activated lymphocyte and inflammatory M1 macrophages in SCLE. In SCLE, stromal cells, such as keratinocytes and fibroblasts, showed enhanced chemotactic functions for recruiting immune cells. Importantly, interferon-related genes were identified as key intermediate genes in the potential trajectory of fibroblasts, keratinocytes, and B cells from HCs to SCLE. Our investigation provides a comprehensive description of cell composition in SCLE and highlights several important clues for understanding the pathogenesis of SCLE.