Transcriptomic Analysis of Classical Monocytes from African American Patients with Systemic Sclerosis

Systemic sclerosis is a multisystem autoimmune disorder that has an unclear etiology and disproportionately affects African Americans (AA). Additionally, monocytes show heightened activation in SSc, and in AA relative to European ancestry (EA) individuals. Monocytes are thus a good target tissue for elucidating disease mechanisms. In this study, we sought to identify differentially expressed genes in classical monocytes from AA SSc patients relative to unaffected AA controls. We performed RNAseq to profile the transcriptome on FACS-isolated classical monocytes (CD14++CD16-) from 16 female AA SSc cases and 18 female AA controls. We observed modest gene expression differences between cases and controls. The genes harboring the top differentially methylated cytosines are enriched for metabolic processes. The relatively modest differences in gene expression observed between patients and controls is consistent with prior evidence of stronger inflammatory signatures in AA. Overall design: RNAseq was was used to profile gene expression levels on FACS-isolated classical monocytes (CD14++CD16-) from 16 female AA SSc cases and 18 female AA controls.