Single-cell transcriptomics reveals an abnormal immune microenvironment in plasma cell mastitis.

INTRODUCTION: Plasma cell mastitis (PCM) is a non-bacterial inflammatory breast disorder affecting young and middle-aged nonpregnant and nonlactating women. However, a comprehensive and systematic analysis of PCM has not been conducted. METHODS AND RESULTS: Comprehensive cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq) analysis was performed on 10,185 cells derived from PCM tissue to generate a highly detailed transcriptomic atlas. Thirteen distinct clusters were identified, and eight cell types were successfully annotated, including endothelial cells, common myeloid progenitor cells and neutrophils. Additionally, the overall alterations in immune cell composition in PCM patients were evaluated. Furthermore, differentially expressed genes between normal and PCM samples were assessed, and functional enrichment analysis was conducted. Finally, cellular communication and interaction were analysed to determine cell-to-cell communications. CONCLUSION: This study significantly contributes to the field of PCM, presenting a systematic and valuable perspective that serves as a fundamental resource for further exploration of the cellular and molecular mechanisms, pathogenesis of associated diseases and potential interventions.