Urinary Neuropilin-1: A Predictive Biomarker for Renal Outcome in Lupus Nephritis.

At present, Lupus Nephritis (LN) is still awaiting a biomarker to better monitor disease activity, guide clinical treatment, and predict a patient's long-term outcome. In the last decade, novel biomarkers have been identified to monitor the disease, but none have been incorporated into clinical practice. The transmembrane receptor neuropilin-1 (NRP-1) is highly expressed by mesangial cells and its genetic deletion results in proteinuric disease and glomerulosclerosis. NRP-1 is increased in kidney biopsies of LN. In this work we were interested in determining whether urinary NRP-1 levels could be a biomarker of clinical response in LN. Our results show that patients with active LN have increased levels of urinary NRP-1. When patients were divided according to clinical response, responders displayed higher urinary and tissue NRP-1 levels at the time of renal biopsy. Areas under the receiver operating characteristic curve, comparing baseline creatinine, proteinuria, urinary NRP-1, and VEGFA protein levels, showed NRP-1 to be an independent predictor for clinical response. In addition, in vitro studies suggest that NRP-1could promote renal recovery through endothelial proliferation and migration, mesangial migration and local T cell cytotoxicity. Based on these results, NRP-1 may be used as an early prognostic biomarker in LN.

Neutrophil gelatinase-associated lipocalin as a biomarker for lupus nephritis.

BACKGROUND: One of the challenges of treating patients with lupus nephritis (LN) is to accurately assess disease activity and predict its outcome. Since renal-biopsy cannot be performed routinely, new surrogate biomarkers are needed. METHODS: We evaluated neutrophil gelatinase-associated lipocalin (NGAL), to predict renal outcome in LN. Serum and urinary NGAL levels, measured by the enzyme-linked immunosorbent assay, and the fractional excretion (FE) of NGAL relative to the FE of proteins (FE NGAL/FE protein ratio) were determined in a cross-sectional (n = 199) and longitudinal (n = 45) cohort of systemic lupus erythematosus (SLE) patients. Global and renal disease activity was assessed by the SLE disease activity indices, SLEDAI and rSLEDAI, respectively. Correlations between traditional biomarkers were established. Sensitivity, specificity and predictive values of NGAL for renal flare, response to therapy and progression to chronic kidney disease were calculated. RESULTS: The FE NGAL/FE protein ratio exhibited the best sensitivity and specificity to discriminate patients with active LN from those with non-renal flare and inactive SLE. In the prospective study, this biomarker was found to be the best candidate to predict proteinuric flares with an 87% sensitivity and 62% specificity for ratios >14.56 and complete response with a 61% sensitivity and 78% specificity for ratios >26.54 in the presence of a simultaneous worsening or improving rSLEDAIs, respectively. In both conditions, the FE NGAL/FE protein ratio outperformed the anti-dsDNA antibody titres and C3 predictive value. Progression to chronic kidney disease was best predicted by estimated glomerular filtration rate levels, but persistently high levels of serum NGAL (>444.4 ng/mL, P = 0.0001 by Kaplan-Meier) predicted a faster progression. CONCLUSIONS: The FE NGAL/FE protein ratio is a reliable marker of disease activity in patients with SLE and could be used as an indicator of response to therapy, although further studies are required to confirm these results.

Enhanced transcript levels of CD48 in CD4⁺ T cells from systemic lupus erythematosus patients.

It is known that CD48 regulates T-cell activation. We evaluated the transcriptional expression of CD48 in CD4⁺ T cells from 30 SLE patients and 30 healthy controls. CD48 mRNA levels were considerably higher in the patients group: 1.80 ± 1.41 versus 1.10 ± 0.50 (p=0.023). An inverse correlation was obtained with respect to CD48 mRNA levels and age in the control group (r= -0.478, p=0.007). None association was found between CD48 mRNA expression and levels of anti-dsDNA, complement, or lymphocyte counts. Alternatively, a statistically significant positive correlation was observed between CD48 transcript levels and SLEDAI values (r=0.372, p=0.042). The higher CD48 mRNA levels observed in CD4⁺ T cells from SLE patients and the positive correlation found with SLEDAI lead us to infer that an overexpression of the protein coded by this gene may have important consequences on the development of SLE.

Long-term outcomes--mycophenolate mofetil treatment for lupus nephritis with addition of tacrolimus for resistant cases.

BACKGROUND: Although mycophenolate mofetil (MMF) is being increasingly used to manage lupus nephritis (LN), long-term experience is limited. Despite treatment, a significant proportion of patients will be refractory to this regime. METHODS: We report, in this observational study, our long-term experience treating 70 patients with biopsy-proven LN, with MMF as continuous induction-maintenance therapy, who were followed up prospectively over a 5-year period. As rescue therapy for MMF-resistant cases, tacrolimus (0.075 mg/kg/day) was added. The study primary end point was complete response (CR). Secondary end points included partial response (PR), treatment failure, relapse and side effects. Predictor factors associated to renal outcome were analysed by Cox regression analysis. RESULTS: Thirty-six MMF-treated patients (51%) remained in CR, and 23 (33%) failed treatment at last follow-up. Time to treatment failure was associated with persistent hypoalbuminaemia (hazard ratio (HR) = 0.87; 95%CI, 0.81-0.95; P = 0.001), higher proteinuria (HR = 1.29; 95%CI, 1.03-1.62; P = 0.030) and fewer early responses (HR 0.28; 95%CI, 0.10-0.77; P = 0.014). Renal relapse occurred in 24 (34%) patients. Time to flare was associated with persistent anti-dsDNA titres (HR = 1.001; 95%CI, 1.001-1.003; P = 0.005) and younger age at inclusion (HR = 0.36; 95%CI, 0.14-0.90; P = 0.029). Tacrolimus was added to 17 (24%) patients. A significant reduction of proteinuria was already observed at 3 months (P = 0.002). After 2 years follow-up, 12 (70%) of them achieved clinical response (six CR and six PR). Conclusions. MMF is an effective treatment for LN. Combination therapy with tacrolimus is an effective and safe alternative for MMF-resistant patients.