Fig. 4

Urine S100A4 levels from all patients with active lupus nephritis (LN) in longitudinal urine and cross-sectional urine cohorts compared according to (a) LN activity as defined by Systemic Lupus Erythematosus Disease Activity Index 2000 renal domain (SLEDAI-R) score and (b) International Society of Nephrology/Renal Pathology Society (ISN/RPS) class of LN. a The median and IQR S100A4 levels are depicted. The median urine S100A4 level for a SLEDAI-R score of 4 was 1.62 ng/ml (IQR 0.95–13.2), increasing to 5.68 ng/ml (IQR 1.97–14.6) for a SLEDAI-R score of 8 and 14.08 ng/ml (IQR 6.9–23.97) for a SLEDAI-R score ≥ 12. A statistically significant difference was present between patients with LN with a SLEDAI-R score of 4 and those with a SLEDAI-R score ≥ 12 (p = 0.032). b The median is represented by the horizontal line on each plot. Differences between urine S1004 values in class III/IV versus class V LN were assessed using the Mann-Whitney U test