T-cell transcriptomics from peripheral blood highlights differences between polymyositis and dermatomyositis...

Area of Science:

• Immunology
• Genomics
• Molecular Biology

Background:

• Polymyositis (PM) and dermatomyositis (DM) are idiopathic inflammatory myopathies characterized by muscle weakness and inflammatory infiltrates.
• Distinct immune cell profiles characterize PM (CD8+ T cells) and DM (CD4+ T cells, plasmacytoid dendritic cells, B cells).

Purpose of the Study:

• To differentiate the involvement of CD4+ and CD8+ T-cell subpopulations in PM and DM.
• To investigate transcriptomic profiles of T cells from peripheral blood in myositis patients.

Main Methods:

• RNA was extracted from isolated CD4+ and CD8+ T cells from PM and DM patients.
• Sequencing libraries were generated and sequenced using Illumina platforms.
• Differential gene expression analysis was performed using DESeq2.

Main Results:

• In CD4+ T cells, only two genes (ANKRD55, S100B) showed significant differential expression between PM and DM.
• In CD8+ T cells, 176 genes were differentially expressed between PM and DM patients.
• Differentially expressed genes in CD8+ T cells were associated with lymphocyte migration and T-cell differentiation regulation.

Conclusions:

• CD8+ T cells show major divergence between PM and DM patients compared to CD4+ T cells.
• Gene expression alterations in T cells suggest distinct immune mechanisms underlying PM and DM subphenotypes.