Validation of the Lupus Nephritis Clinical Indices in Childhood-Onset Systemic Lupus Erythematosus

[NETosis in lupus nephritis]

AIM

To evaluate the levels of MPO-DNA complex in patients with systemic lupus erythematosus (SLE) and its association with the presence of lupus nephritis (LN).

MATERIALS AND METHODS

The study included 77 patients with SLE, of whom 30 had SLE without anti phospholipid syndrome (APS), 47 had SLE with APS, and 20 were healthy individuals serving as the control group. The MPO-DNA complex in the serum was investigated using ELISA.

RESULTS

The levels of MPO-DNA complex in serum were significantly higher in patients with SLE compared to healthy controls (p=0.001). Among the patients with SLE, 30 (39%) had elevated levels of MPO-DNA complex. The presence of elevated MPO-DNA complex was significantly associated with the presence of a history of LN (p=0.009). Moreover, among the patients included in the study, 20 had active LN, and patients with elevated MPO-DNA complex levels were more likely to have active LN than patients without elevated MPO-DNA complex concentrations [12 (40%) of 30 vs 8 (17%) of 47, χ2=5.029; p=0.034]. An association was found between elevated levels of MPO-DNA complex and the presence of proteinuria, hematuria, cellular hematic/granular casts and aseptic leukocyturia. A direct correlation of MPO-DNA complex with SLEDAI-R was found in patients with active LN (rs=0.497; p=0.026).

CONCLUSION

Elevated levels of MPO-DNA complex were detected in 39% of patients with SLE. These patients had a higher prevalence of LN in their medical history and at the time of inclusion in the study. The correlation between MPO-DNA complex levels and the activity of LN according to SLEDAI-R indicates the potential role of MPO-DNA complex as a biomarker for assessing the activity of renal damage in SLE.

Potential involvement of circulating exosomal miRNA-146a in disease activity and TRAF6 gene expression in juvenile proliferative lupus nephritis

BACKGROUND

Juvenile SLE (JSLE) is a complex autoimmune disorder that predominantly affects children and adolescents with several unique challenges, and microRNA-146a (miRNA-146a) might be an interesting anti-inflammatory molecule. Because exosomes in the blood might protect miRNAs, the association between circulating exosomal miRNA-146a and lupus proinflammatory genes, such as IRAK1 and TRAF6, was studied in peripheral blood mononuclear cells from people with JSLE.

METHODS

Blood samples from 12 patients were collected every 3 months until 1 year with the recorded disease activity, and quantitative real-time PCR was used to determine the circulating exosomal miRNA-146a and the gene expression (IRAK1 and TRAF6).

RESULTS

The mean age was 12.60±0.43 years at diagnosis and all patients had a complete response at 12 months. According to the nanoparticle tracking analysis, the abundance of exosomes was significantly lower at 3, 6 and 12 months compared with 0 months, while the level of circulating exosomal miRNA-146a was significantly higher at 12 months than at diagnosis (p<0.001). There was a negative correlation between the level of circulating exosomal miRNA-146a expression and the level of TRAF6 mRNA (r=-0.30, p=0.049). Moreover, there were correlations between circulating exosomal miRNA-146a and disease severity such as SLE Disease Activity Index 2000 score, anti-double-stranded DNA antibody and proteinuria (urine protein-creatinine ratio), respectively. Therefore, increasing the level of circulating exosomal miRNA-146a, which might control TRAF6 mRNA expression, could have an effect on the production of inflammatory cytokines.

CONCLUSION

This suggests that miRNA-146a might serve as a non-invasive biomarker to evaluate the response to treatment in patients with juvenile lupus nephritis.

Usefulness of the lupus low disease activity state as a treatment target in childhood-onset SLE

OBJECTIVE

Treat-to-target (T2T) strategies are advocated to improve prognosis in childhood-onset SLE (cSLE). Proposed T2T states include SLEDAI score of <4 (SLEDAI-LD), limited corticosteroid use (low-CS), and lupus low disease activity state (LLDAS). We sought to compare T2T states for their association with cSLE prognosis under consideration of relevant disease characteristics such as pre-existing damage, race and lupus nephritis (LN).

METHODS

Longitudinal data from 165 patients enrolled in the Cincinnati Lupus Registry were included. LN presence was based on renal biopsy, and patients were followed up until 18 years of age.

RESULTS

The 165 patients (LN: 45, white: 95) entered the registry within a median of 0 (IQR: 0-1) year post diagnosis and were followed up for a median of 4 (IQR: 2-5) years during which 80%, 92% and 94% achieved LLDAS, low-CS and SLEDAI-LD. Patients with LN were significantly less likely to achieve any T2T state (all p<0.03) and required a significantly longer time to reach them (all p<0.0001). Over the study period, patients maintained low-CS, SLEDAI-LD or LLDAS for a median of 76% (IQR: 48%-100%), 86% (IQR: 55%-100%) or 39% (IQR: 13%-64%) of their follow-up. Significant predictors of failure to maintain LLDAS included LN (p≤0.0062), pre-existing damage (p≤0.0271) and non-white race (p≤0.0013). There were 22%, 20% and 13% of patients who reached SLEDAI-LD, CS-low and LLDAS and nonetheless acquired new damage. Patients with LN had a higher risk of new damage than patients without LN even if achieving low-CS (p=0.009) or LLDAS (p=0.04).

CONCLUSIONS

Patients with LN and pre-existing damage are at higher risk of increased future damage acquisition, even if achieving a T2T state such as LLDAS. Among proposed common T2T states, the LLDAS is the hardest to achieve and maintain. The LLDAS may be considered the preferred T2T measure as it conveys the highest protection from acquiring additional disease damage.

Lupus low disease activity state as a treatment target for pediatric patients with lupus nephritis

BACKGROUND

Lupus low disease activity state (LLDAS) is a treatment target for patients with SLE and is associated with decreased risk for severe flare and new damage. We investigated the utility of the achievement of LLDAS in children with lupus nephritis and whether attainment of LLDAS is associated with more favorable outcomes.

METHODS

Data of children, diagnosed with biopsy-proven lupus nephritis between January 2012 and December 2020, were retrospectively analyzed.

RESULTS

For patients who did not achieve LLDAS after initial treatment (first 6 months), presence of autoimmune hemolytic anemia (62% vs. 18%, p = 0.047), anti-Sm (85% vs. 18%, p = 0.003) and anti-dsDNA (77% vs. 27%, p = 0.038) antibodies, proliferative lupus nephritis (77% vs. 27%, p = 0.038), and hypertension (69% vs. 9%, p = 0.005) at onset were more frequently encountered. Also, a lower rate of complete kidney response (43% vs. 100%, p = 0.005) and a higher rate of hypertension (86% vs. 13%, p = 0.002) were observed in patients who did not achieve LLDAS-50, defined as being in LLDAS at least 50% of the observation time. Attainment of both LLDAS after initial treatment and LLDAS-50 were associated with lower rates of kidney flare (p = 0.001 and p = 0.002, respectively) and damage accrual (p = 0.007 and p = 0.02, respectively) through the observation period.

CONCLUSIONS

LLDAS is an attainable treatment target for children with lupus nephritis and associated with lower rates of kidney flare and damage. Presence of hematologic involvement, hypertension, and proliferative lupus nephritis at onset adversely influenced the early achievement of LLDAS. A higher resolution version of the Graphical abstract is available as Supplementary information.

Low serum uromodulin levels and their association with lupus flares

BACKGROUND

Only two previous studies in systemic lupus erythematosus (SLE) patients have identified that the blood concentrations of uromodulin are lower in nephritis. However, none of them had evaluated whether a low serum uromodulin adjusted by the glomerular filtration rate (sUromod/eGFR index) contributed to identify patients in risk of lupus nephritis (LN) using multivariable models.

AIM

Therefore, this study aimed two objectives to evaluate the association between low serum uromodulin levels and low sUromod adjusted by eGFR with renal flares in SLE excluding effects of potential confounders in multivariable analyses; and to identify the value of low sUmod and low sUmod/eGFR index as a potential diagnostic marker of LN.

PATIENTS AND METHODS

Design: Cross-sectional study. SLE patients (n = 114) were investigated for lupus flare with renal SLEDAI. Two groups: a) SLE with renal flare (renal-SLEDAI≥4, n = 41) and b) SLE non-renal flare (renal SLEDAI<4, n = 73). SLE patients were evaluated by other indices including a global disease activity index (SLEDAI) and SLICC renal disease activity score. Serum uromodulin levels (ng/mL) were quantified by ELISA. Serum uromodulin was adjusted by eGFR (sUromod/eGFR index). Cutt-offs of low sUromodulin and low sUromod/eGFR index were computed, ROC curves were performed and values of diagnostic tests were obtained. Multivariable logistic regression models were performed to identify if low sUromod/eGFR index is associated to renal flares.

RESULTS

Low serum uromodulin and low sUromod/eGFR index correlated to high scores of renal-SLEDAI, SLICC-renal and proteinuria. SLE patients with a renal flare had lower uromodulin levels compared to SLE patients without renal flare (p = 0.004). After adjusting by potential confounders, the low sUromod/eGFR index (<0.80 ng/mL) increased the risk of a renal flare (OR, 2.91; 95%CI, 1.21 to 6.98; p = 0.02).

CONCLUSIONS

We propose the low sUromod/eGFR index as a potential new marker of renal disease activity in SLE.

Urinary HER2, TWEAK and VCAM-1 levels are associated with new-onset proteinuria in paediatric lupus nephritis

Objective

Lupus nephritis is a key driver of morbidity and mortality in SLE. Detecting active nephritis on a background of pre-existing renal damage is difficult, leading to potential undertreatment and accumulating injury. An unmet need is a biomarker that distinguishes active lupus nephritis, particularly important in paediatrics where minimising invasive procedures is desirable.

Methods

This was a multicentre, prospective study of 113 paediatric patients with biopsy-proven lupus nephritis. Clinical data and urine were obtained every 3–4 months and patients averaged 2 years on study with seven time points. Urine was analysed for human epidermal growth factor receptor 2 (HER2), tumour necrosis factor-like weak inducer of apoptosis and vascular cell adhesion molecule-1 (VCAM-1) by ELISA. We defined active disease as either a rise in serum creatinine ≥0.3 mg/dL from baseline or a rise in renal Systemic Lupus Erythematosus Disease Activity Index score from the previous visit. These markers were also studied in patients with acute kidney injury, juvenile idiopathic arthritis (JIA), amplified pain syndrome and healthy controls.

Results

The rate of active disease was 56% over an average of 2 years of follow-up. HER2 and VCAM-1 were significantly elevated at time points with active disease defined by increased serum creatinine compared with time points with inactive disease or patients who never flared. All three biomarkers were associated with new-onset proteinuria and VCAM-1 was elevated at time points preceding new-onset proteinuria. These biomarkers were not increased in acute kidney injury or JIA.

Conclusion

All three biomarkers were associated with new onset proteinuria and increased VCAM-1 may predict impending proteinuria. These biomarkers provide potential non-invasive measures for monitoring that may be more sensitive to impending flare than conventional measures.

Stability of novel urinary biomarkers used for lupus nephritis

Background

The Renal Activity Index for Lupus (RAIL) is a composite score of six urinary biomarkers (neutrophil gelatinase-associated lipocalin (NGAL), monocyte chemoattractant protein-1 (MCP-1), kidney injury molecule-1 (KIM-1), ceruloplasmin, adiponectin, and hemopexin) used to monitor lupus nephritis activity in children. We tested stability of RAIL biomarkers prior to meaningful clinical use.

Methods

Urine samples were tested by ELISA under shipping conditions, freeze/thaw, ambient and longer-term storage. Statistical analysis was performed via Deming Regression, Bland-Altman and Spearman Correlation Coefficient.

Results

Biomarker concentration were comparable to freshly collected urine following storage at -80 °C for up to 3 months, and at 4 or 25 °C up to 48 h followed by -80 °C. Neither shipping on dry or wet ice exposure nor addition of two freeze-thaw cycles led to loss of signal, with excellent Spearman Correlation coefficients under all conditions.

Conclusions

RAIL biomarkers are stable following short-term storage at clinically relevant conditions.

Clinical measurement of lupus nephritis activity is inferior to biomarker-based activity assessment using the renal activity index for lupus nephritis in childhood-onset systemic lupus erythematosus

OBJECTIVES

The renal activity index for lupus (RAIL) measures lupus nephritis (LN) activity considering urine levels of 6 biomarkers (neutrophil gelatinase-associated lipocalin, monocyte chemoattractant protein-1, kidney injury molecule-1, adiponectin, haemopexin, ceruloplasmin). We aimed to compare the accuracy of the RAIL and the renal domain-score of the SLE disease activity index (rSLEDAI) in detecting LN activity.

METHODS

Random urine samples of patients with childhood-onset SLE with and without LN were assayed and scores of the RAIL, and RAIL standardised for urine creatinine (RAIL-Cr) were calculated. Clinical LN activity was measured by the rSLEDAI, and histological activity of LN was categorised as inactive/low-moderate/high for National Institute of Health-activity index scores of <2/2-10/>10, respectively.

RESULTS

115 patients were included in the analysis (47 patients without and 68 with LN). RAIL, RAIL-Cr and rSLEDAI scores at the time (±3 months) of kidney biopsy were available for 32 patients. Median rSLEDAI, RAIL and RAIL-Cr values were 4, -0.04, 0.02 for inactive LN, 12, 0.7 and 0.9 for low-moderate LN activity and 12, 2 and 1.8 for high LN activity, respectively. The area under the receiver operating characteristic curve (AUC) to capture high LN activity was the lowest for the rSLEDAI (AUC=0.62), followed by the RAIL-Cr (AUC=0.73) and RAIL (AUC=0.79). Notably, when testing urine samples collected during routine clinic visits remote (>3 months) from a kidney biopsy, 50% patients with rSLEDAI scores of 0 had RAIL scores reflecting low-moderate LN activity.

CONCLUSION

Monitoring of renal inflammation in children and adolescents with SLE can be improved by the measurement of urine biomarkers. The RAIL may constitute important auxiliary tool for the surveillance of LN in a clinical setting and assist with the decision to obtain a kidney biopsy.

Biomarkers in Childhood-Onset Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a complex, multisystem chronic autoimmune disease. Because of its diverse phenotypes, diagnosis of SLE can be challenging, and current biomarkers are insufficient. Childhood-onset SLE (cSLE), although less prevalent, has higher morbidity and mortality, and early diagnosis is critical for improving outcomes. Many studies have focused on discovering new biomarkers to better diagnose and monitor SLE and cSLE. Herein, the authors aim to review the most investigated biomarkers in development for cSLE, focusing on those that can be measured in the blood or urine.

High Systemic Type I Interferon Activity is Associated with Active Class III/IV Lupus Nephritis

OBJECTIVE

Previous studies suggest a link between high serum type I interferon (IFN) and lupus nephritis (LN). We determined whether serum IFN activity is associated with subtypes of LN and studied renal tissues and cells to understand the impact of IFN in LN.

METHODS

221 systemic lupus erythematosus (SLE) patients were studied. Serum IFN activity was measured by WISH bioassay. mRNA in-situ hybridization was used in renal tissue to measure expression of the representative IFN-induced gene, interferon-induced protein with tetratricopeptide repeats-1 (IFIT1), and the plasmacytoid dendritic cell (pDC) marker gene C-type lectin domain family-4 member C (CLEC4C or BDCA2). Podocyte cell line gene expression was measured by real-time PCR.

RESULTS

Class III/IV LN prevalence was significantly increased in patients with high serum IFN compared with those with low IFN (OR=5.48, p=4.0x10-7). In multivariate regression models, type I IFN was a stronger predictor of class III/IV LN than complement C3 or anti-dsDNA antibody, and could account for the association of these variables with LN. IFIT1 expression was increased in all classes of LN, but most in the glomerular areas of active class III/IV LN kidneys. IFIT1 expression was not closely co-localized with pDCs. IFN directly activated podocyte cell lines to induce chemokines and proapoptotic molecules.

CONCLUSION

Systemic high IFN is involved in the pathogenesis of severe LN. We do not find co-localization of pDCs with IFN signature in renal tissue, and instead observe the greatest intensity of IFN signature in glomerular areas, which could suggest a blood source of IFN.

Outcome Measures in Pediatric Rheumatic Disease

Reliable and responsive outcome measures that accurately detect changes in disease state, activity, and damage are crucial to conducting observational and interventional trials that can directly transform care for children with rheumatic disease. A combination of consensus-based and direct measurement approaches has led to the development of several validated, composite outcome measures in juvenile idiopathic arthritis, juvenile dermatomyositis, childhood-onset systemic lupus erythematosus, and pediatric vasculitis. This review outlines clinician-reported, disease-specific outcome measures developed for these conditions.

Clinical practice guidance for childhood-onset systemic lupus erythematosus-secondary publication

Childhood-onset systemic lupus erythematosus (cSLE) has been recognised as a more acute and severe autoimmune disease than adult-onset SLE. With the development of medications for the disease and supportive therapy, the mortality rate associated with cSLE has drastically improved; the 10-year survival rate among patients with cSLE between 1995 and 2006 in Japan was 98.3%. However, the 10-year survival rate without any permanent functional impairment remained low at 66.1%. Therefore, the current treatment goal for cSLE is to ensure that they can perform normal daily activities throughout their lives by preventing the occurrence and/or progression of organ damage. For this purpose, appropriate treatments and evaluations are required according to the severity and risk of organ damage; however, there are no established guidelines for cSLE. Therefore, the Pediatric Rheumatology Association of Japan and the Pediatric Rheumatology Subcommittee in the Japan College of Rheumatology developed a comprehensive guidance for clinical practice based on cSLE-related data collected from Japanese national surveys and relevant articles from both domestic and international sources. However, due to the lack of indications for defined and objective evidence quality levels, this guidance should be used on the basis of the judgement of the attending physicians for individual patients.

Successful Urine Multiplex Bead Assay to Measure Lupus Nephritis Activity

Introduction

Lupus nephritis (LN) confers a poor prognosis, mainly from lack of effective laboratory tests to diagnose and to evaluate therapies. We have previously shown that a set of 6 urinary biomarkers (NGAL, KIM-1, MCP-1, adiponectin, hemopexin, and ceruloplasmin) are highly sensitive and specific to identify adult and pediatric patients with active LN using renal biopsy as reference standard. Using these combinatorial urinary biomarkers, the Renal Activity Score for Lupus (RAIL) score was established, with biomarkers measured by enzyme-linked immunosorbent assay (ELISA). To enhance clinical utility of the biomarkers and RAIL, we tested the performance of RAIL with biomarkers measured by ELISA to that of biomarkers measured by the bead multiplex method, hypothesizing that the multiplex bead method would be comparable.

Methods

Spot urine samples (n = 341) of 46 patients aged 20 to 73 years with or without LN were used. Samples were assayed both by ELISA and multiplex using LUMINEX. RAIL scores and biomarker quantities were assessed for agreement with intraassay correlation coefficients and compared using Bland−Altman and regression.

Results

Biomarker measurement by LUMINEX was successful for NGAL, KIM-1, MCP-1, and adiponectin, but not for ceruloplasmin and hemopexin. There was good agreement of the RAIL obtained from these 4 biomarkers, irrespective of assay method (intraclass correlation coefficient [ICC] = 0.78, 95% confidence interval [CI] = 0.78−0.82). The RAIL scores from 4 biomarkers further correlated with those when considering all 6 biomarkers (ICC = 0.97, 95% CI = 0.96−0.98).

Conclusion

The LUMINEX platform allows for the convenient and simultaneous measurement of 4 RAIL biomarkers. RAIL scores considering only these 4 biomarkers may be sufficient to accurately capture LN activity.

Retrospective analysis of clinical and pathomorphological features of lupus nephritis in children

PURPOSE

The aim of the study was to evaluate the clinical course and pathomorphological correlations in Polish children with the diagnosis of lupus nephritis (LN).

METHODS

We retrospectively analyzed the medical records of 39 children hospitalized due to LN in 7 pediatric nephrology units in Poland between 2010 and 2019. Demographic data, clinical symptoms at the onset of LN and laboratory parameters were reviewed. We analyzed Systemic Lupus Erythematosus Disease Activity Index (SLEDAI), histological LN findings with the activity (IA) and chronicity index (IC).

RESULTS

We examined 32 girls and 7 boys, median age at LN onset was 14.75 (IQR 13.0-16.0) years, SLEDAI of 22.0 (IQR 18.0-27.0) points; LN histological class: IV (59.4%), III (18.9%), III/V (10.8%), IV/V (8.1%), VI (2.7%); IA 8.0 (IQR 6.0-11.0) points, IC 1.05 (IQR 0-2.0) points. Children with nephrotic (n ​= ​22) and non-nephrotic (n ​= ​17) proteinuria differed in median Hb level (9.55, IQR 8.3-11.2 vs 10.9, IQR 10.1-11.6 ​g/L; P ​< ​0.05), albumin level (2.5, IQR 2.1-3.19 vs 3.6, IQR 3.4-4.1 ​g/dL; P ​< ​0.001), proteinuria (5.76, IQR 3.0-7.5 vs 1.08, IQR 0.53-1.50 ​g/day; P ​< ​0.0001), eGFR (53.9, IQR 27.0-68.8 vs 96.7, IQR 73.8-106.2 ​mL/min/1.73 ​m²; P ​< ​0.01) and occurrence of hypertension (77% vs 23%; P ​< ​0.01). In multivariate analysis Hb level (β ​= ​8.0; 95%CI, 1.90-14.11) was the significant predictor of eGFR<90 ​mL/min/1.73 ​m².

CONCLUSIONS

Proliferative forms of LN in children may have a varying clinical presentation. Children with LN with nephrotic range proteinuria have lower Hb level, lower eGFR and higher occurrence of hypertension. Hb level is the significant predictor of eGFR<90 ​mL/min/1.73 ​m² in children with LN.

Serum uric acid as a predictor for nephritis in Egyptian patients with systemic lupus erythematosus

OBJECTIVE

Lupus nephritis (LN) is closely associated with hyperuricemia, and uric acid is considered a risk factor for renal involvement in systemic lupus erythematosus (SLE). This study aimed to examine the association between serum uric acid (SUA) level and LN development and progression in SLE patients with normal renal function.

METHODS

A total of 60 SLE patients with normal renal function from Ain Shams University Hospital were selected and assigned to group 1 (30 patients with LN) and group 2 (30 patients without LN). All patients were subjected to history taking, clinical examination, disease activity assessment based on SLE disease activity index (SLEDAI) and renal SLEDAI (SLEDAI-R) scores, and laboratory investigations, including as SUA, complete blood count, blood urea nitrogen (BUN), serum creatinine, creatinine clearance, urine analysis, protein/creatinine ratio, 24-h urinary protein excretion, Antinuclear antibodies (ANA), anti-dsDNA antibody, and serum complement (C3, C4).

RESULTS

Disease duration, SLEDAI score, and SUA level were higher in group 1 than in group 2 (p < 0.001). SUA level was positively correlated with SLEDAI and SLEDAI-R scores, proteinuria, urinary casts, renal biopsy class, disease activity and chronicity indices, BUN level, and serum creatinine level but was negatively correlated with creatinine clearance (p < 0.05). SUA was a predictor of LN development in SLE patients (sensitivity, 83.3%; specificity, 70%).

CONCLUSION

SUA is associated with the development of lupus nephritis in patients with normal kidney function also SUA in-dependently correlated with disease activity and chronicity in LN.

Urine biomarkers of chronic kidney damage and renal functional decline in childhood-onset systemic lupus erythematosus

OBJECTIVES

To delineate urine biomarkers that reflect kidney structural damage and predict renal functional decline in pediatric lupus nephritis (LN).

METHODS

In this prospective study, we evaluated kidney biopsies and urine samples of 89 patients with pediatric LN. Urinary levels of 10 biomarkers [adiponectin, ceruloplasmin, kidney injury molecule-1, monocyte chemotactic protein-1, neutrophil gelatinase-associated lipocalin, osteopontin, transforming growth factor-ß (TGFß), vitamin-D binding protein, liver fatty acid binding protein (LFABP), and transferrin] were measured. Regression analysis was used to identify individual and combinations of biomarkers that determine LN damage status [NIH-chronicity index (NIH-CI) score ≤ 1 vs. ≥ 2] both individually and in combination, and biomarker levels were compared for patients with vs. without renal functional decline, i.e., a 20% reduction of the glomerular filtration rate (GFR) within 12 months of a kidney biopsy.

RESULTS

Adiponectin, LFABP, and osteopontin levels differed significantly with select histological damage features considered in the NIH-CI. The GFR was associated with NIH-CI scores [Pearson correlation coefficient (r) = - 0.49; p < 0.0001] but not proteinuria (r = 0.20; p > 0.05). Similar to the GFR [area under the ROC curve (AUC) = 0.72; p < 0.01], combinations of osteopontin and adiponectin levels showed moderate accuracy [AUC = 0.75; p = 0.003] in discriminating patients by LN damage status. Renal functional decline occurred more commonly with continuously higher levels of the biomarkers, especially of TGFß, transferrin, and LFABP.

CONCLUSION

In combination, urinary levels of adiponectin and osteopontin predict chronic LN damage with similar accuracy as the GFR. Ongoing LN activity as reflected by high levels of LN activity biomarkers heralds renal functional decline.

KEY MESSAGES

• Levels of osteopontin and adiponectin measured at the time of kidney biopsy are good predictors of histological damage with lupus nephritis. • Only about 20% of children with substantial kidney damage from lupus nephritis will have an abnormally low urine creatinine clearance. • Continuously high levels of biomarkers reflecting lupus nephritis activity are risk factors of declining renal function.

Clinical trials in children and adolescents with systemic lupus erythematosus: methodological aspects, regulatory landscape and future opportunities

Childhood-onset systemic lupus erythematosus (cSLE) is rare in many regions of the world, including Europe. Access to approved medications for cSLE is currently limited, among others, due to a lack of high-quality evidence from clinical trials. The objectives of the study were to evaluate the current regulatory framework regarding medication approvals, delineate barriers to clinical trial conduct, and strategies to improve access to new medications for cSLE. Relevant methodological and regulatory aspects, epidemiological data, study designs and outcome measures are reviewed, and the results of a survey among Paediatric Rheumatology International Trials Organisation/Pediatric Rheumatology Collaborative Study Group investigators are presented. Laws and regulations in the USA and Europe necessitate that novel medicines are studied in paediatric populations, if similar or the same diseases in adults have been found to benefit from them. Regulatory agencies consider cSLE the paediatric form of SLE in adults. For medicines that have been found safe and effective in adult SLE, paediatric extrapolation strategies can limit the number and complexity of studies needed to support the labelling of these medicines for use in cSLE. In this setting, specialised research networks, validated outcome measures, stakeholder input, study designs as well as statistical methods successfully used in other uncommon diseases will help improve study efficiency in an effort to enhance the speed with which new drugs for cSLE can be studied. Open-label pharmacokinetic-pharmacodynamic studies are preferred by paediatric rheumatologists over double-blind parallel designs for cSLE trials. Appropriate infrastructure, outcome measures and sufficient numbers of patients are available for the testing of new medicines for children with cSLE.

Glomerular Diseases in Children

Unique challenges exist in the diagnosis and treatment of glomerular diseases with their onset during childhood. Mounting evidence supports the notion that earlier onset cases occur due to larger numbers of genetic risk alleles. Nearly all causes of adult-onset glomerulonephritis, nephrotic syndrome, and thrombotic microangiopathy have also been described in children, although the prevalence of specific causes differs. Postinfectious glomerulonephritis, Henoch-Schönlein purpura nephritis, and minimal change disease remain the most common causes of glomerular disease in younger children in the United States and can be diagnosed clinically without need for biopsy. IgA nephropathy is the most common pediatric glomerular disease diagnosed by kidney biopsy and is considered the most common chronic glomerulopathy worldwide. In both developing and developed countries, there is a strong relationship between infectious diseases and nephritis onset or relapse. Although research has led to a better understanding of how to classify and manage glomerular diseases in children, the need for disease-specific biomarkers of activity and chronicity remains a hurdle. The strength of the immune system and the growth and maturation that occurs during adolescence are unique and require age-specific approaches to disease management.

Lupus glomerulonephritis in 788 Chinese children: a multi-centre clinical and histopathological analysis based on 549 renal biopsies

BACKGROUND

System lupus erythematosus (SLE) is a severe multisystem autoimmune disease.

OBJECTIVE

To describe the clinical and pathological features, treatment, and renal outcome in children under 18 years with lupus nephritis (LN).

METHODS

The study was undertaken by a questionnaire completed in 26 Grade 3A hospitals' paediatric renal units in China. The study comprised 788 children (619 girls, 169 boys) diagnosed with SLE by the American College of Rheumatology criteria (1997) during 2005-2010. Results of renal biopsies were classified according to the guidelines of The International Association of Nephrology and the Renal Pathology Society (2003). Guidelines by the Chinese Society of Paediatric Nephrology were applied for the diagnosis and treatment (for trial implementation) in 2010 to determine inclusion. The data included the prevalence of acute kidney injury (AKI), SLE disease activity index (SLEDAI), renal histopathology and the induction of therapy mode.

RESULTS

The mean (SD) age of onset of SLE was 10.9 (2.90) years (range 1-18) and at diagnosis was 11.3 (2.9) years. The mean (SD) SLEDAI score was 13.5 (5.53). The clinical classification was as follows: about 36 (4.6%) patients had isolated haematuria, 99 (12.6%) isolated proteinuria, 60 (7.6%) isolated haematuria and proteinuria, 157 (19.9%) acute glomerulonephritis, 392 (49.7%) nephrotic syndrome, 20 (2.5%) rapidly progressive glomerulonephritis, 15 (1.9%) chronic nephritis, 2 (0.3%) tubule-interstitial damage and 7 (0.9%) subclinical LN. A total of 549 children (69.7%) underwent renal biopsy. The most frequent renal histopathological findings of LN were Class IV, followed by Class II and Class V + IV. There were no significant differences between the age groups in either renal pathological types or prognosis. In 242 (30.7%) patients, LN was complicated by AKI. Those with AKI had an older mean (SD) age at onset than the non-AKI patients [11.5 (2.8) years vs 10.7 (2.9) years, respectively, p < 0.0001] and a higher SLEDAI score [14.3 (5.8) vs 13.1 (5.4), respectively, p = 0.003]. In the induction phase, cyclophosphamide (CTX) and mycophenolate mofetil (MMF) were equally effective in the patients with the same pathological type. Follow-up records were only available for 482 (61.2%) patients, with a mean (SD) follow-up time of 21.5 (18.4) months. Six of the 35 patients who deteriorated required dialysis and seven died.

CONCLUSION

In LN, AKI is a risk factor for poor outcome. Owing to different times of onset and remission, the pathological types of LN cannot be estimated by clinical manifestation alone, and therefore renal biopsy should be undertaken in all LN children with AKI. In the induction phase, there was no significant difference in efficacy between CTX and MMF. Follow-up of children with LN in China needs to be improved.

Urine S100 proteins as potential biomarkers of lupus nephritis activity

Background

Improved, noninvasive biomarkers are needed to accurately detect lupus nephritis (LN) activity. The purpose of this study was to evaluate five S100 proteins (S100A4, S100A6, S100A8/9, and S100A12) in both serum and urine as potential biomarkers of global and renal system-specific disease activity in childhood-onset systemic lupus erythematosus (cSLE).

Methods

In this multicenter study, S100 proteins were measured in the serum and urine of four cSLE cohorts and healthy control subjects using commercial enzyme-linked immunosorbent assays. Patients were divided into cohorts on the basis of biospecimen availability: (1) longitudinal serum, (2) longitudinal urine, (3) cross-sectional serum, and (4) cross-sectional urine. Global and renal disease activity were defined using the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) and the SLEDAI-2K renal domain score. Nonparametric testing was used for statistical analysis, including the Wilcoxon signed-rank test, Kruskal-Wallis test, Mann-Whitney U test, and Spearman’s rank correlation coefficient.

Results

All urine S100 proteins were elevated in patients with active LN compared with patients with active extrarenal disease and healthy control subjects. All urine S100 protein levels decreased with LN improvement, with S100A4 demonstrating the most significant decrease. Urine S100A4 levels were also higher with proliferative LN than with membranous LN. S100A4 staining in the kidney localized to mononuclear cells, podocytes, and distal tubular epithelial cells. Regardless of the S100 protein tested, serum levels did not change with cSLE improvement.

Conclusions

Higher urine S100 levels are associated with increased LN activity in cSLE, whereas serum S100 levels do not correlate with disease activity. Urine S100A4 shows the most promise as an LN activity biomarker, given its pronounced decrease with LN improvement, isolated elevation in urine, and positive staining in resident renal cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-017-1444-4) contains supplementary material, which is available to authorized users.

Urine Biomarkers to Predict Response to Lupus Nephritis Therapy in Children and Young Adults

OBJECTIVE

To delineate urine biomarkers that forecast response to therapy of lupus nephritis (LN).

METHODS

Starting from the time of kidney biopsy, patients with childhood-onset systemic lupus erythematosus who were diagnosed with LN were studied serially. Levels of 15 biomarkers were measured in random spot urine samples, including adiponectin, α-1-acid glycoprotein (AGP), ceruloplasmin, hemopexin, hepcidin, kidney injury molecule 1, monocyte chemotactic protein-1, lipocalin-like prostaglandin D synthase (LPGDS), transforming growth factor-β (TGF-β), transferrin, and vitamin D binding protein (VDBP).

RESULTS

Among 87 patients (mean age 15.6 yrs) with LN, there were 37 treatment responders and 50 nonresponders based on the American College of Rheumatology criteria. At the time of kidney biopsy, levels of TGF-β (p < 0.0001) and ceruloplasmin (p = 0.006) were significantly lower among responders than nonresponders; less pronounced differences were present for AGP, hepcidin, LPGDS, transferrin, and VDBP (all p < 0.05). By Month 3, responders experienced marked decreases of adiponectin, AGP, transferrin, and VDBP (all p < 0.01) and mean levels of these biomarkers were all outstanding (area under the receiver-operating characteristic curve ≥ 0.9) for discriminating responders from nonresponders. Patient demographics and extrarenal disease did not influence differences in biomarker levels between response groups.

CONCLUSION

Low urine levels of TGF-β and ceruloplasmin at baseline and marked reduction of AGP, LPGDS, transferrin, or VDBP and combinations of other select biomarkers by Month 3 are outstanding predictors for achieving remission of LN. If confirmed, these results can be used to help personalize LN therapy.

Prospective validation of a novel renal activity index of lupus nephritis

Objectives The renal activity index for lupus (RAIL) score was developed in children with lupus nephritis as a weighted sum of six urine biomarkers (UBMs) (neutrophil gelatinase-associated lipocalin, monocyte chemotactic protein 1, ceruloplasmin, adiponectin, hemopexin and kidney injury molecule 1) measured in a random urine sample. We aimed at prospectively validating the RAIL in adults with lupus nephritis. Methods Urine from 79 adults was collected at the time of kidney biopsy to assay the RAIL UBMs. Using receiver operating characteristic curve analysis, we evaluated the accuracy of the RAIL to discriminate high lupus nephritis activity status (National Institutes of Health activity index (NIH-AI) score >10), from low/moderate lupus nephritis activity status (NIH-AI score ≤10). Results In this mixed racial cohort, high lupus nephritis activity was present in 15 patients (19%), and 71% had proliferative lupus nephritis. Use of the identical RAIL algorithm developed in children resulted in only fair prediction of lupus nephritis activity status of adults (area under the receiver operating characteristic curve (AUC) 0.62). Alternative weightings of the six RAIL UBMs as suggested by logistic regression yielded excellent accuracy to predict lupus nephritis activity status (AUC 0.88). Accuracy of the model did not improve with adjustment of the UBMs for urine creatinine or albumin, and was little influenced by concurrent kidney damage. Conclusions The RAIL UBMs provide excellent prediction of lupus nephritis activity in adults. Age adaption of the RAIL is warranted to optimize its discriminative validity to predict high lupus nephritis activity status non-invasively.

Serum Cytokines Th1, Th2, and Th17 Expression Profiling in Active Lupus Nephritis-IV: From a Southern Chinese Han Population

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by aberrant T cell immune response. Diffuse proliferative lupus nephritis (LN-IV) is the most common, severe, and active form of lupus nephritis. In this study, we investigated the production of Th1, Th2, and Th17 cytokines in prediction of active form of LN-IV. ProcartaPlex multiplex immunoassays panels were used for detection of serum Th1, Th2, and Th17 cytokines profiling. Th1 and Th17 cytokines (IL-18, IFN-γ, IL-12p70, IL-6, and IL-17A) were considerably expressed in the serum of lupus nephritis IV patients in comparison to the healthy control. However, only IL18 and IL6 were higher in class IV versus class III lupus nephritis. Importantly, the ratios of Th1/Th2 (IL-18/IL-4) and Th17/Th2 (IL-17A/IL-4) were significantly elevated in LN-IV when compared with LN-III, LN-V, and healthy controls. Consistently, the serum cytokines IL-18, IL-17A, and IFN-γ were markedly expressed in LN-IV patient glomeruli and interstitial tissue compared to other classes of LN by IHC. ROC further suggests that IL-18 was a potential marker for LN-IV. The data from our study suggests that the early detection and quantification of these cytokines may help in prediction of active form of LN-IV.