Small RNA sequencing identifies T cell-derived tsRNAs as novel biomarkers for diagnosis and clinical assessment of rheumatoid arthritis.

OBJECTIVE: The functional role of tRNA-derived small RNAs (tsRNAs) in CD3+ T lymphocytes in rheumatoid arthritis (RA) remains unclear. This study aimed to characterize their expression profile and evaluate their biomarker potential in RA. METHODS: Small RNA sequencing of CD3+ T lymphocytes was performed to profile tsRNA expression. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were employed to explore associated pathways. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to verify the differentially expressed tsRNAs. Receiver operating characteristic curve analysis was conducted to assess diagnostic performance. RESULTS: We identified 316 tsRNAs in CD3+ T lymphocytes from RA patients and healthy controls, with 15 differentially expressed. Five of ten selected candidate tsRNAs were validated in CD3+ T cells. Their expression levels were associated with corticosteroid and non-steroidal anti-inflammatory drug use. Three tsRNAs (tRNA Arg ACG_3, tsRNA 3014a SerAGA/SerTGA, and tRNA Glu CTC_5) were further confirmed as differentially expressed in peripheral blood mononuclear cells (PBMCs). Their expression correlated with key clinical indicators, including erythrocyte sedimentation rate, anti-citrullinated protein antibody levels, and immunoglobulin levels. For diagnostic performance, a panel of the five dysregulated CD3+ T cell tsRNAs achieved an area under the curve (AUC) of 0.826, while the three-tsRNA panel yielded an AUC of 0.741. CONCLUSION: We identified three tsRNAs consistently dysregulated in both CD3+ T lymphocytes and PBMCs of RA patients. Their expression correlates with clinical parameters and demonstrates promising diagnostic accuracy, suggesting their potential as novel biomarkers for early RA detection and as therapeutic targets.