Noninvasive diagnostic value of urinary mir-663a in pediatric lupus nephritis

Lupus nephritis (LN) is a severe clinical manifestation seen in individuals with systemic lupus erythematous (SLE). It has a poor long-term prognosis in pediatric patients with high morbidity and mortality rates. MicroRNAs (miRNAs) are noncoding small RNAs that act as epigenetic modulators, regulating gene expression, and modulating the understanding of mechanisms and pathogenesis of human diseases. Depending on bioinformatics analysis, we aimed to investigate urinary expression of miR-663a in LN among SLE children and discriminate between proteinuria of LN versus chronic renal disease without SLE.

The urinary miR-663a expression levels were estimated in cellular pellets from 15 SLE patients, 15 SLE and biopsy-proven active LN patients, 15 chronic kidney disease (CKD) patients rather than LN and 15 healthy controls.

LN patients had significantly higher urinary miR-663a expression levels compared to other groups (p < 0.0001). Urinary miR-663a at a cutoff of 8.61 had a diagnostic value of 93.3% for LN among pediatric SLE with 100% specificity (p < 0.0001). Moreover, miR-663a was upregulated in advanced grades and LN classes V, IV, and III compared to class II. Furthermore, miR-663a was positively correlated with the duration of SLE, activity index, chronicity index, urinary protein, anti-dsDNA, and SLEDAI score, and negatively correlated with serum complement C3 (p < 0.05).

miR-663a could be related to the pathogenesis of kidney damage in LN; that could provide a specific noninvasive diagnostic and follow -up tool for LN patients.