NRP1 and systemic lupus erythematosus: In line with mRNA expression levels, patients with active LN had significantly higher urinary NRP-1 levels, as measured by ELISA, than lupus patients with active non-renal disease (1807 ± 2180 ng/mg Cr versus 95.26 ± 160.3 ng/mg Cr, p < 0.0001), patients with other glomerular diseases (1807 ± 2180 ng/mg Cr versus 13.11 ± 17.77 ng/mg Cr, p < 0.0001) and healthy controls (1807 ± 2180 ng/mg Cr versus 59.14 ± 26.39 ng/mg Cr, p < 0.0001) (Figure 1B).