Systemic sclerosis (SSc) is a multisystem rheumatic disease characterized by vascular dysfunction, autoimmune abnormalities, and progressive organ fibrosis. A series of studies in SSc patients and fibrotic models suggest that immune cells, fibroblasts, and endothelial cells participate in inflammation and aberrant tissue repair. Furthermore, the growing number of studies on single-cell RNA sequencing (scRNA-seq) technology in SSc elaborate on the transcriptomics and heterogeneities of these cell subsets significantly. In this review, we summarize the current knowledge regarding immune cells and stromal cells in SSc patients and discuss their potential roles in SSc pathogenesis, focusing on recent advances in the new subtypes by scRNA-seq.

Rheumatic diseases are a group of highly heterogeneous autoimmune and inflammatory disorders involving multiple systems. Dysfunction of immune and non-immune cells participates in the complex pathogenesis of rheumatic diseases. Therefore, studies on the abnormal activation of cell subtypes provided a specific basis for understanding the pathogenesis of rheumatic diseases, which promoted the accuracy of disease diagnosis and the effectiveness of various treatments. However, there was still a far way to achieve individualized precision medicine as the result of heterogeneity among cell subtypes. To obtain the biological information of cell subtypes, single-cell sequencing, a cutting-edge technology, is used for analyzing their genomes, transcriptomes, epigenetics, and proteomics. Novel results identified multiple cell subtypes in tissues of patients with rheumatic diseases by single-cell sequencing. Consequently, we provide an overview of recent applications of single-cell sequencing in rheumatic disease and cross-tissue to understand the cell subtypes and functions.

Objectives Identification of characteristics and risk factors of new-onset dermatomyositis patients with recurrent aggravation after regular treatment. Methods In this cohort study, clinical characteristics of 142 new-onset dermatomyositis patients were analyzed. We defined three different clinical outcomes after long-term follow-up: mild, aggravation, and death. The clinical presentation of patients with recurrent aggravations was primarily analyzed and discussed in this cohort. The decision tree algorithm was used to predict the outcomes. Results In this corhort, there were 72 in the mild group, 56 in the aggravation group (39 were single aggravation and 17 were multiple aggravations), 14 in the death group. The median time point for patients to experience their first aggravation was 40 weeks after initial treatment, the median interval between multiple aggravations was 32 weeks, and for anti-MDA5 positive patients, the median interval was 16 weeks. Symptoms of aggravation were generally manifested as progression of pulmonary interstitial lesions, or extended skin rashes. Baseline CRP and CK levels were higher in the multiple aggravations or death group. Conclusions DM patients tended to aggravate after glucocorticoid was regular reduced to approximately the lowest maintenance dose. Higher baseline CRP and CK levels have a certain predictive effect on adverse outcomes in DM.