Expression and regulatory characteristics of peripheral blood immune cells in primary Sjögren’s syndrome patients using single-cell transcriptomic

Immune cell subgroups in peripheral blood mononuclear cells (PBMCs) in primary Sjogren’s syndrome (pSS) are thought to regulate immune responses, but the nature and functions of these subgroups remain unclear. Here we performed single-cell RNA sequencing (scRNA-seq) of about 68,500 PBMCs from three patients with pSS and three healthy controls (HCs). We found that CD14(+) monocytes from pSS patients expressed high levels of the transcription factor CEBPD, and the direct regulation of target genes expression by CEBPD tends to participate in the TNF-α signaling via NF-κB in monocytes. FOLR3 and IL1B were upregulated separately in CD14(+) monocyte subsets from different pSS patients. We proposed a system for classifying CD56(−)CD16(+) NK cells based on FCER1G expression. Compared with HCs, pSS patients showed a significantly higher ratio of CD56(−)CD16+FCER1G+ NK cells to CD56(−)CD16+FCER1G- NK cells. Our analysis provides a reference dataset and reveals its immune heterogeneity among PBMCs in pSS.