Urine biomarkers for monitoring juvenile lupus nephritis: a prospective longitudinal study

Background

In juvenile-onset systemic lupus erythematosus (JSLE), renal involvement (lupus nephritis) is frequently seen and can result in long-term morbidity. This prospective longitudinal study aimed to identify the utility of standard and/or novel biomarkers for monitoring and predicting lupus nephritis in a real world setting.

Methods

Using an unselected JSLE cohort, urine samples were collected during routine clinical review. Protein concentrations of urinary monocyte chemo-attractant protein 1 (uMCP1) and neutrophil gelatinase-associated lipocalin (uNGAL) were analysed along with standard disease activity markers, and were compared with current and subsequent disease activity.

Results

JSLE patients (n?=?64; median age 14.1 years) were seen at 3 (interquartile range: 2–5) clinical reviews over 364 (182–532) days. Multivariate analysis demonstrated uMCP1 and serum C3 as independent variables (p?p?=?0.013). uNGAL was a good predictor of worsened renal disease activity (AUC 0.76; p?=?0.04) over time.

Conclusion

Biomarkers (uMCP1, serum C3) can indicate current renal involvement in JSLE, whilst uMCP1 and uNGAL are able to predict subsequent renal disease activity changes. Moving towards biomarker-led monitoring may improve the renal outcome for our patients.