Multi-Modal Single-Cell Sequencing Identifies Cellular Immunophenotypes Associated With Juvenile Dermatomyositis...

Area of Science:

• Immunology
• Genomics
• Rare Diseases

Background:

• Juvenile dermatomyositis (JDM) is a rare autoimmune disease lacking sufficient biomarkers and effective treatments.
• Understanding the specific immune cells and genetic factors driving JDM is crucial for developing targeted therapies.

Purpose of the Study:

• To investigate the immunophenotypes and cell-specific gene expression patterns associated with JDM disease activity.
• To identify potential biomarkers and therapeutic targets by analyzing immune cells at single-cell resolution.

Main Methods:

• Multiplexed RNA and protein single-cell sequencing was performed on peripheral blood mononuclear cells (PBMCs) from treatment-naïve JDM (TN-JDM) patients and patients with inactive disease.
• Analysis included 55,564 cells, examining cell populations, differential gene expression, and protein markers.

Main Results:

• TN-JDM cells showed distinct clustering within monocyte, NK, CD8+ effector T, and naïve B cell populations.
• An interferon (IFN) gene signature was over-expressed across all cell types in TN-JDM, correlating with disease activity, particularly in cytotoxic cells.
• CD16+ monocytes in TN-JDM exhibited the highest IFN gene score and an inflammatory, antigen-presenting phenotype.
• Expanded transitional B cells in TN-JDM displayed a unique transcriptomic signature with altered CD24, CD5, and CD39 protein expression.

Conclusions:

• This study provides novel cellular and molecular insights into immune dysregulation in JDM.
• The identified IFN gene signature and specific immune cell alterations (e.g., CD16+ monocytes, transitional B cells) represent potential therapeutic targets for JDM.