Expression profiling of immune cells in systemic lupuserythematosus by single-cell RNA sequencing

Systemic lupus erythematosus(SLE)is a systemic autoimmune disease characterized by abnormal cellular and humoral immune responses and excessive autoantibody production.The precise pathologic mechanism of SLE remains elusive.The advent of single-cell RNA sequencing(scRNA-seq)enables unbiased analysis of the molecular differences of cell populations at the single-cell level.We used scRNA-seq to profile the transcriptomes of peripheral blood mononuclear cells from an SLE patient compared with a healthy control(HC).A total of 16,021 cells were analyzed and partitioned into 12 distinct clusters.The marker genes of each cluster and the four major immune cell types(B cells,CD4+T cells,CD8+T cells,myeloid cells,and NK cells)were determined.Moreover,several genes involved in antigen processing and presentation through MHCII were highly enriched.GO enrichment analyses revealed abnormal gene expression patterns and signaling pathways in SLE.Of note,pseudotime analysis revealed that there was a different lineage hierarchy in the peripheral blood mononuclear cells(PBMCs)of the SLE patient,indicating that the cell states were substantially altered under disease conditions.Our analysis provides a comprehensive map of the cell types and states of the PBMCs of SLE patients at the single-cell level for a better understanding of the pathogenesis,diagnosis,and treatment of SLE.