MiR‑365b‑5p and MiR‑3614‑5p are elevated in PBMCs of systemic lupus erythematosus and exhibit potential as complementary diagnostic indicators.

INTRODUCTION: Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune disorder lacking ideal early diagnostic biomarkers. This study aimed to identify and validate novel microRNAs (miRNAs) in peripheral blood mononuclear cells (PBMCs) as diagnostic biomarkers for SLE. METHODS: This study comprised a screening stage and a validation stage. We performed high-throughput miRNA sequencing in 3 SLE patients and 3 healthy controls, then validated candidate miRNAs in 39 SLE patients and 40 healthy controls using quantitative real-time polymerase chain reaction (qPCR). Diagnostic performance was assessed using receiver operating characteristic (ROC) curves, and correlations with clinical indicators were analysed. RESULTS: Seventy-eight differentially expressed miRNAs were identified in SLE. Among them, miR-365b-5p and miR-3614-5p were significantly upregulated in SLE PBMCs (both P<0.001). ROC analysis showed area under the curve (AUC) values of 0.733 and 0.782 for the individual models and 0.805 for the combination. MiR-365b-5p was positively correlated with IgM, while miR-3614-5p was associated with immune cell counts, liver and kidney function, and metabolic parameters. Bioinformatics suggested involvement in immune regulation and the MAPK signaling pathway. CONCLUSIONS: miR-365b-5p and miR-3614-5p are significantly elevated in SLE and have favourable diagnostic value. These two miRNAs may serve as complementary diagnostic biomarkers that could facilitate early detection, differential diagnosis, and the elucidation of immune pathogenesis in SLE. Key Points • MiR‑365b‑5p and miR‑3614‑5p were significantly upregulated in SLE PBMCs. • MiR‑365b‑5p and miR‑3614‑5p may serve as novel diagnostic biomarkers for SLE and contribute to its pathogenesis via immune regulation and the MAPK signaling pathway.