MicroRNAs as Biomarkers for Uveitis in Juvenile Idiopathic Arthritis

Uveitis associated with juvenile idiopathic arthritis (JIA-U) is a clinically silent vision-impairing disease. Early detection and aggressive treatment are crucial for optimal visual outcome. Alterations in levels of microRNAs (miRNAs) are characteristic of autoimmune diseases. The present clinical study sought to explore the expression of miRNAs in JIA-U and their potential role as a predictive biomarker.

MiRNA expression profiling was performed on peripheral blood mononuclear cells derived from pediatric patients with JIA, JIA-U, or other types of uveitis using the high-throughput small-RNA sequencing (on Next Generation Sequencing (NGS)). Patient- and disease-related data were retrieved from the medical files. Main outcome measure was the differential expression of miRNAs among the groups.

The cohort included 35 patients; 20 children with JIA-U (8 with active disease), 10 with JIA without ocular involvement, and 5 with other types of uveitis (4 with active disease). Mean age was 8.6 years; 83% were female. Nineteen patients (54%) received immunomodulatory treatment. The expression of miR-4485-3p was significantly increased in patients with JIA-U compared to patients with JIA alone (p < 0.05), with no difference between patients with active or inactive uveitis. The expression in patients with uveitis of other etiologies was similar to the expression in JIA-U patients.

This study demonstrates a differential expression profile of a specific miRNA in JIA patients with and without uveitis. If verified in larger studies, the findings may assist to identify JIA patients at risk to develop uveitis and to improve early detection of disease activity.