Histological predictors of renal outcome in lupus nephritis: the importance of tubulointerstitial lesions and scoring of glomerular lesions

Characteristics and outcomes of biopsy-proven lupus nephritis in the Eastern Cape province of South Africa

OBJECTIVE

In Africa, the treatment outcomes of lupus nephritis (LN) are not well known. This is especially true in the current era where contemporary treatment options are more widely available. This retrospective study aimed to measure the outcomes of biopsy-proven LN treated at the Livingstone Tertiary Hospital (LTH) Renal Unit in Gqeberha (formerly Port Elizabeth), South Africa and to identify predictors of a poor outcome.

METHODS

A retrospective cohort study of 131 patients with biopsy-proven LN who had a kidney biopsy between 01 January 2012 to 31 December 2021 as identified from the biopsy register. A sub-analysis of 107 patients with proliferative and/or membranous LN was performed.

RESULTS

Mean age was 31.4 ± 12.7 years with a female predominance of 86.3%. At 6-month follow-up, 69.6% of patients had complete or partial response to treatment. This increased to 70.3% and 72.6% at 18 and 30 months, respectively. Twenty-seven patients were lost to follow-up, while 7 (5.3%) patients progressed to kidney failure (KF). There were 3 (2.3%) deaths. Predictors of poor response were an elevated baseline serum creatinine (OR = 2.53, 95% CI 0.99 - 6.52, p = .054), a decreased eGFR (OR = 2.92, 95% CI 0.94 - 9.09, p = .065) and an elevated blood pressure (OR = 6.06, 95% CI 1.11 - 33.33, p = .038) at the time of biopsy. Infections were the most common adverse event with 50 infections seen in 39 (29.8%) patients. Herpes viral infections were frequently noted (n = 12) accounting for 24.0% of all documented infections.

CONCLUSION

Response rates were similar in this cohort when compared to other contemporary studies. Predictors of poor response were an elevated baseline serum creatinine, a decreased eGFR and an elevated blood pressure at time of the biopsy. Infections were the most common occurring adverse event, although the mortality rate remained low at 2.3%.

Hypoxia Promotes the Expression of ADAM9 by Tubular Epithelial Cells, Which Enhances Transforming Growth Factor β1 Activation and Promotes Tissue Fibrosis in Patients With Lupus Nephritis

OBJECTIVE

Enhanced expression of transforming growth factor (TGF) β in the kidneys of patients with lupus nephritis (LN) can lead to progressive fibrosis, resulting in end-organ damage. ADAM9 activates TGFβ1 by cleaving the latency-associated peptide (LAP). We hypothesized that ADAM9 in the kidney may accelerate fibrogenesis by activating TGFβ1.

METHODS

We assessed the expression of ADAM9 in the kidneys of mice and humans who were lupus prone. In vitro experiments were conducted using tubular epithelial cells (TECs) isolated from mice and explored the mechanisms responsible for the up-regulation of ADAM9 and the subsequent activation of TGFβ1. To assess the role of ADAM9 in the development of tubular-intestinal fibrosis in individuals with LN, we generated MRL/lpr mice who were Adam9 deficient.

RESULTS

ADAM9 was highly expressed in tubules from MRL/lpr mice. The transcription factor hypoxia-inducible factor-1α was found to promote the transcription of ADAM9 in TECs. TECs from mice who were Adam9 deficient and exposed to the hypoxia mimetic agent dimethyloxalylglycine failed to cleave the LAP to produce bioactive TGFβ1 from latent TGFβ1. Coculture of TECs from mice who were Adam9 deficient with fibroblasts in the presence of dimethyloxalylglycine and latent TGFβ1 produced decreased amounts of type I collagen and α-smooth muscle actin (SMA) by fibroblasts. MRL/lpr mice who were Adam9 deficient showed reduced interstitial fibrosis. At the translational level, ADAM9 expression in tissues and urine of patients with LN was found to increase.

CONCLUSION

Hypoxia promotes the expression of ADAM9 by TECs, which is responsible for the development of interstitial fibrosis in patients with LN by enhancing the TGFβ1 activation, which promotes fibroblasts to produce collagen and α-SMA.

Validation of histopathological chronicity scores in native kidney biopsies using light microscopy and digital morphometry for predicting renal outcome

Quantitative assessment of chronicity changes in native kidney biopsies offer valuable insights in to disease prognosis, despite the strength of qualitative information. Yet, standardization and reproducibility remain challenging. The present study aims to assess and compare the prognostic utility and reproducibility of two chronicity scoring systems based on light microscopy and whole slide imaging with morphometry and also to evaluate the prognostic utility of structural measurements: cortical non-sclerotic glomerular (NSG) density and NSG area/volume. We designed a retrospective longitudinal study involving 101 adult and paediatric patients who underwent native kidney biopsies. Chronicity scoring was performed using two semi-quantitative methods: Method 1 (method proposed in PMID: 28314581) and Method 2 (method proposed in PMID: 32516862), under light microscopy as well as on whole-slide scanned images, and assessed for prognostic utility. Kidney-Failure-Risk-Equation (KFRE) was employed in combination with chronicity-scoring-methods and assessed for predictive capability. Interobserver reproducibility for the two chronicity methods was studied among three renal pathologists. Structural measurements were performed on whole-slide- scanned-images. Both the chronicity scoring methods significantly predicted decline in estimated glomerular filtration rate (eGFR) and persistent need for renal replacement therapy in follow-up. Method 1 combined with KFRE, outperformed Method 2 in predicting renal survival. Method 2 however showed higher interobserver reproducibility. Combined KFRE plus histopathological scoring methods showed better predictive accuracy. The study validates the precision of chronicity scoring using whole slide scanned images. The morphometric structural measurements showed significant correlations with follow-up eGFR, thereby providing supplementary prognostic information.

A nomogram to predict the risk of proliferative lupus nephritis in patients with systemic lupus erythematosus involving the kidneys

Proliferative lupus nephritis (PLN) is a serious organ-threatening manifestation of systemic lupus erythematosus (SLE) that is associated with high mortality and renal failure. Here, we analyzed data from 1287 SLE patients with renal manifestations, including 780 of which were confirmed as proliferative or non-proliferative LN patients by renal biopsy, divided into a training cohort (547 patients) and a validation cohort (233 patients). By applying a least absolute shrinkage and selection operator (LASSO) regression approach combined with multivariate logistic regression analysis to build a nomogram for prediction of PLN that was then assessed by receiver operating characteristic (ROC) curves, calibration curves, and clinical decision curves (DCA) in both the training and validation cohorts. The area under the ROC curve (AUC) of the model in the training cohort was 0.921 (95% confidence interval (CI): 0.895-0.946), the AUC of internal validation in the training cohort was 0.909 and the AUC of external validation was 0.848 (95% CI: 0.796-0.900). The nomogram showed good performance as evaluated using calibration and DCA curves. Taken together, our results indicate that our nomogram that comprises 12 significantly relevant variables could be clinically valuable to prognosticate on the risk of PLN in SLE, so as to improve patient prognoses.

Histological reappraisal of IgA nephropathy: the role of glomerular pattern of injury and mesangial complement deposition

BACKGROUND

There is a clear need to refine the histological assessment in IgA Nephropathy (IgAN). We sought to investigate the clinical significance of the light microscopy (LM) pattern of glomerular injury and of the intensity of mesangial C3 staining in IgAN.

METHODS

We conducted a retrospective, observational study that included all patients with biopsy-proven primary IgAN that had at least 12 months of follow-up. The LM pattern of glomerular injury was reevaluated based on a modified HAAS classification. Mesangial C3 deposition by immunofluorescence (IF) staining was scored semi-quantitatively. The study primary composite endpoint was defined as doubling of serum creatinine or ESRD (dialysis, renal transplant or eGFR < 15 ml/min). The secondary study endpoint was eGFR decline per year.

RESULTS

This cohort included 214 patients with IgAN (mean age, 41.4 ± 12.6 years), with a mean eGFR and median 24-h proteinuria of 55.2 ± 31.5 ml/min/1.73m2 and 1.5 g/day (IQR:0.8-3.25), respectively. The most frequent LM pattern was the mesangioproliferative (37.4%), followed by the sclerotic (22.5%) and proliferative/necrotizing patterns (21.4%). Regarding the IF findings, mild-moderate and intense mesangial C3 staining was present in 30.6% and 61.1% of patients, respectively. Those with sclerosing and crescentic patterns had the worst renal survival (5-year renal survival of 48.8% and 42.9%) and the highest rate of eGFR change/year (-2.32 ml/min/y and - 2.16 ml/min/y, respectively) compared to those with other glomerular patterns of injury. In addition, those with intense C3 staining reached the composite endpoint more frequently compared to those without intense C3 staining (35.5% vs. 21.4%, p = 0.04). After multivariate adjustment, patients with crescentic and sclerosing patterns had a 3.6-fold and 2.1-fold higher risk for the composite endpoint compared to those with mesangioproliferative pattern, while an intense mesangial C3 deposition being also associated with a worse renal outcome (HR, 3.33; 95%CI, 1.21-9.2).

CONCLUSIONS

We have shown that the LM pattern of glomerular injury and the intensity of mesangial C3 deposition might stratify more accurately the renal outcome in patients with IgAN.

Renal histopathological predictors of end-stage kidney disease in ANCA-associated vasculitis with glomerulonephritis: a single-centre study in Korea

This study investigated whether histopathological classification and histologic lesion scores could significantly and independently predict the progression to end-stage kidney disease (ESKD) in Korean patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis-glomerulonephritis (AAV-GN). This study included 113 patients with AAV-GN confirmed by kidney biopsy. The glomerular, tubulointerstitial, and vascular lesions were systematically assessed using a scoring system. The scoring system was adopted from the Banff scoring system but also the Oxford study and the revision of the ISN/RPS. For comparison, the scores were classified into two groups; the low, and the high, and the difference was investigated between ESKD and non-ESKD groups using Cox proportional analysis. At diagnosis, the median age was 59.0 years and 33.6% were males. Of 113 patients, 44.2% had ESKD progression during follow-up. There were significant differences in several kidney-, inflammation-, and AAV-pathogenesis-related variables between AAV-GN patients with ESKD and those without. The sclerotic class exhibited the worst renal prognosis among the four histopathological classes. Among histopathological features, high interstitial fibrosis, tubular atrophy and global glomerulitis scores were significantly associated with ESKD progression. Whereas multivariable Cox analysis revealed only a high global glomerulitis score which means global endocapillary hypercellularity in a larger number of glomeruli is an independent predictor of ESKD progression. Moreover, among clinical and histopathological features, a high global glomerulitis score could also predict ESKD progression in addition to serum blood urea nitrogen and creatinine. This study demonstrated the worst renal prognosis for the sclerotic class and first discovered that a high global glomerulitis score was an independent predictor of ESKD in patients with AAV-GN.

Pathogenic cellular and molecular mediators in lupus nephritis

Kidney involvement in patients with systemic lupus erythematosus - lupus nephritis (LN) - is one of the most important and common clinical manifestations of this disease and occurs in 40-60% of patients. Current treatment regimens achieve a complete kidney response in only a minority of affected individuals, and 10-15% of patients with LN develop kidney failure, with its attendant morbidity and considerable prognostic implications. Moreover, the medications most often used to treat LN - corticosteroids in combination with immunosuppressive or cytotoxic drugs - are associated with substantial side effects. Advances in proteomics, flow cytometry and RNA sequencing have led to important new insights into immune cells, molecules and mechanistic pathways that are instrumental in the pathogenesis of LN. These insights, together with a renewed focus on the study of human LN kidney tissue, suggest new therapeutic targets that are already being tested in lupus animal models and early-phase clinical trials and, as such, are hoped to eventually lead to meaningful improvements in the care of patients with systemic lupus erythematosus-associated kidney disease.

Use of Histologic Parameters to Predict Glomerular Disease Progression: Findings From the China Kidney Biopsy Cohort Study

RATIONALE & OBJECTIVE

Challenges in achieving valid risk prediction and stratification impede treatment decisions and clinical research design for patients with glomerular diseases. This study evaluated whether chronic histologic changes, when complementing other clinical data, improved the prediction of disease outcomes across a diverse group of glomerular diseases.

STUDY DESIGN

Multicenter retrospective cohort study.

SETTING & PARTICIPANTS

4,982 patients with biopsy-proven glomerular disease who underwent native biopsy at 8 tertiary care hospitals across China in 2004-2020.

NEW PREDICTORS & ESTABLISHED PREDICTORS

Chronicity scores depicted as 4 categories of histological chronic change, as well as baseline clinical and demographic variables.

OUTCOME

Progression of glomerular disease defined as a composite of kidney failure or a ≥40% decrease in estimated glomerular filtration rate from the measurement at the time of biopsy.

ANALYTICAL APPROACH

Multivariable Cox proportional hazard models. The performance of predictive models was evaluated by C statistic, time-dependent area under the receiver operating characteristic curve (AUROC), net reclassification index, integrated discrimination index, and calibration plots.

RESULTS

The derivation and validation cohorts included 3,488 and 1,494 patients, respectively. During a median of 31 months of follow-up, a total of 444 (8.9%) patients had disease progression in the 2 cohorts. For prediction of the 2-year risk of disease progression, the AUROC of the model combining chronicity score and the Kidney Failure Risk Equation (KFRE) in the validation cohort was 0.76 (95% CI, 0.65-0.87); in comparison with the KFRE model (AUROC, 0.68 [95% CI, 0.56-0.79]), the combined model was significantly better (P = 0.04). The combined model also had a better fit, with a lower Akaike information criterion and a significant improvement in reclassification as assessed by the integrated discrimination improvements and net reclassification improvements. Similar improvements in predictive performance were observed in subgroup and sensitivity analyses.

LIMITATIONS

Selection bias, relatively short follow-up, lack of external validation.

CONCLUSIONS

Adding histologic chronicity scores to the KFRE model improved the prediction of kidney disease progression at the time of kidney biopsy in patients with glomerular diseases.

PLAIN-LANGUAGE SUMMARY

Risk prediction and stratification remain big challenges for treatment decisions and clinical research design for patients with glomerular diseases. The extent of chronic changes is an important component of kidney biopsy evaluations in glomerular disease. In this large multicenter cohort including 4,982 Chinese adults undergoing native kidney biopsy, we evaluated whether histologic chronicity scores, when added to clinical data, could improve the prediction of disease prognosis for a diverse set of glomerular diseases. We observed that adding histologic chronicity scores to the kidney failure risk equation improved the prediction of kidney disease progression at the time of kidney biopsy in patients with glomerular diseases.

Predicting kidney outcomes among Latin American patients with lupus nephritis: The prognostic value of interstitial fibrosis and tubular atrophy and tubulointerstitial inflammation

OBJECTIVE

To assess the effect of tubulointerstitial inflammation (TII) and interstitial fibrosis and tubular atrophy (IFTA) on kidney survival in lupus nephritis (LN).

METHODS

Two hundred eighty five patients with biopsy-proven LN were retrospectively studied. Kidney survival was defined as the time from initial biopsy to end-stage kidney disease (ESKD), dialysis, or transplant. Kidney survival analysis was performed by the Kaplan-Meier method and the statistical difference between survival curves compared by the log-rank test. Cumulative incidence functions with competing risk of death for kidney survival were also graphed. Multivariable Cox proportional hazards regression and competing-risk analyses were performed to identify independent predictors of ESKD.

RESULTS

Fifty-seven patients (20%) progressed to ESKD during a median time of 4.2 (2.0-55.2) months after biopsy. TII was present in 206 (72.3%) biopsies, while IFTA in 99 (34.7%) biopsies. Patients with moderate-to-severe IFTA had worse kidney survival than those with none or mild IFTA in both the Kaplan-Meier (p = 0.018) and the competing-risk analyses (p = 0.017). Patients with class IV ± V LN had worse kidney survival than those with non-class IV LN by the Kaplan-Meier method (p = 0.050), but not in the competing-risk analysis (p = 0.154). Worse kidney survival was also found among those with fibrous crescents than those without, in both the Kaplan-Meier (p = 0.010) and the competing-risk (p = 0.011) analyses. By multivariable Cox regression analysis, older age (HR 1.04, 95% CI 1.01-1.07) and class IV ± V LN (HR 5.06, 95% CI 1.82-14.09) were associated with higher risk of ESKD after adjusting for sex, ethnicity, TII, and IFTA. By competing-risk analyses, class IV ± V LN (SHR 3.32, 95% CI 1.25-8.83) and no response to immunosuppressive therapy (SHR 4.55, 95% CI 1.54-13.41) were associated with a higher risk of ESKD, while eGFR >90 mL/min/1.73 m² (SHR 0.98 for each ml/min/1.73 m², 95% 0.97-0.99) with a lower risk.

CONCLUSIONS

Patients with moderate-to-severe IFTA had worse kidney survival than those with none or mild IFTA. Worse kidney survival was also found among those with class IV LN and fibrous crescents versus those without IV LN and fibrous crescents, respectively.

Searching for a prognostic index in lupus nephritis

BACKGROUND

Currently we do not have an ideal biomarker in lupus nephritis (LN) that should help us to identify those patients with SLE at risk of developing LN or to determine those patients at risk of renal progression. We aimed to evaluate the development of a prognostic index for LN, through the evaluation of clinical, analytical and histological factors used in a cohort of lupus. We have proposed to determine which factors, 6 months after the diagnosis of LN, could help us to define which patients will have a worse evolution of the disease and may be, more aggressive treatment and closer follow-up.

METHODS

A retrospective study to identify prognostic factors was carried out. We have included patients over 18 years of age with a clinical diagnosis of systemic lupus erythematosus (SLE) and kidney involvement confirmed by biopsy, who are followed up in our centre during the last 20 years. A multi-step statistical approach will be used in order to obtain a limited set of parameters, optimally selected and weighted, that show a satisfactory ability to discriminate between patients with different levels of prognosis.

RESULTS

We analysed 92 patients with LN, although only 73 have been able to be classified according to whether or not they have presented poor renal evolution. The age of onset (44 vs. 32; p = 0.024), the value of serum creatinine (1.41 vs. 1.04; p = 0.041), greater frequency of thrombocytopenia (30 vs. 7%; p = 0.038), higher score in the renal chronicity index (2.47 vs. 1.04; p = 0.015), proliferative histological type (100%) and higher frequency of interstitial fibrosis (67 vs. 32%; p = 0.017) and tubular atrophy (67 vs. 32%; p = 0.018) was observed between two groups. The multivariate analysis allowed us to select the best predictive model for poor outcome at 6 months based on different adjustment and discrimination parameters.

CONCLUSION

We have developed a prognostic index of poor renal evolution in patients with LN that combines demographic, clinical, analytical and histopathological factors, easy to use in routine clinical practice and that could be an effective tool in the early detection and management.

Utility of the 2018 revised ISN/RPS thresholds for glomerular crescents in childhood-onset lupus nephritis: a Pediatric Nephrology Research Consortium study

BACKGROUND

The revised 2018 ISN/RPS Classification System for lupus nephritis (LN) includes calculations for both activity index (A.I.) and chronicity index (C.I.). Unchanged were the thresholds of < 25%, 25-50%, and > 50% crescents to distinguish between mild, moderate, and severe activity/chronicity. We aimed to evaluate these thresholds for percent crescents in childhood-onset LN.

METHODS

Eighty-six subjects < 21 years of age were enrolled from the Pediatric Glomerulonephritis with Crescents Registry, a retrospective multi-center cohort sponsored by the Pediatric Nephrology Research Consortium. Thresholds of 10%, 25%, and 50% for both cellular/fibrocellular and fibrous crescents were interrogated for primary outcomes of kidney failure, eGFR, and eGFR slope.

RESULTS

Median age at time of initial biopsy was 14 years (range 1-21). Median follow-up time was 3 years (range 1-11). Cumulative incidence of kidney failure was 6% at 1 year and 10% at latest follow-up. Median eGFR slope was - 18 mL/1.73 m²/min (IQR - 51 to + 8) at 1 year and - 3 mL/min/1.73 m²/year (IQR - 19 to + 6) at latest follow-up. We found no difference in kidney failure at the proposed < 25% and 25-50% cellular crescents thresholds, and thus added a new provisional threshold of 10% that better predicted outcomes in children. Moreover, use of 10% and 25% thresholds for fibrous crescents showed a fourfold and sevenfold increase in risk of kidney failure.

CONCLUSIONS

In children with crescentic LN, use of 10% and 25% thresholds for cellular crescents better reflects disease activity, while these thresholds for fibrous crescents better discriminates kidney disease outcomes. A higher resolution version of the Graphical abstract is available as Supplementary information.

Renal Fibrosis in Lupus Nephritis

Fibrosis can be defined as a pathological process in which deposition of connective tissue replaces normal parenchyma. The kidney, like any organ or tissue, can be impacted by this maladaptive reaction, resulting in persistent inflammation or long-lasting injury. While glomerular injury has traditionally been regarded as the primary focus for classification and prognosis of lupus nephritis (LN), increasing attention has been placed on interstitial fibrosis and tubular atrophy as markers of injury severity, predictors of therapeutic response, and prognostic factors of renal outcome in recent years. This review will discuss the fibrogenesis in LN and known mechanisms of renal fibrosis. The importance of the chronicity index, which was recently added to the histological categorization of LN, and its role in predicting treatment response and renal prognosis for patients with LN, will be explored. A better understanding of cellular and molecular pathways involved in fibrosis in LN could enable the identification of individuals at higher risk of progression to chronic kidney disease and end-stage renal disease, and the development of new therapeutic strategies for lupus patients.

Characteristics of SARS-CoV-2 Infection in an Actively Monitored Cohort of Patients with Lupus Nephritis

(1) Background: We sought to investigate the impact of the COVID-19 pandemic in patients with lupus nephritis (LN); (2) Methods: A total of 95 patients with LN actively monitored in our department between 26 February 2020, when the first case of COVID-19 was diagnosed in Romania, and 1 May 2021, were included in the study. Multivariate logistic regression analysis was performed to identify the independent risk factors for SARS-CoV-2 infection; (3) Results: A total of 15 patients (15.8%) had a confirmed SARS-CoV-2 infection during a total follow-up time of 105.9 patient-years (unadjusted incidence rate: 14.28 SARS-CoV-2 infections per 100 patient-years). Median time to SARS-CoV-2 infection was 9.3 months (IQR: 7.2–11.3). The majority of patients had a mild form of SARS-CoV-2 infection (73.3%), while the remaining had moderate forms. None of the patients had a severe infection or a SARS-CoV-2-related death. The most frequent symptom was fatigue (73.3%), followed by loss of taste/smell (53.3%) and fever (46.7%). Forty percent of those with SARS-CoV-2 infection were hospitalized for a median 11.5 days (IQR:3.75–14). In the multivariate logistic regression analysis, a current oral corticosteroid dose ≥ 15 mg/day was associated with a 7.69-fold higher risk (OR, 7.69; 95%, 1.3–45.46), while the use of hydroxychloroquine was associated with a 91% lower risk for a SARS-CoV-2 infection (OR, 0.09; 95%CI, 0.01–0.59). (4) Conclusions: Our study confirms that the SARS-CoV-2 infection-associated morbidity might only be moderately increased in patients with LN. The current oral corticosteroid dose was the only independent predictor of infection occurrence, while use of hydroxychloroquine was associated with a protective effect.

Predictors of increase in chronicity index and of kidney function impairment at repeat biopsy in lupus nephritis

OBJECTIVES

Based on available data, the histological predictors of long-term outcome of lupus nephritis (LN) are not clearly defined. Aims of this retrospective study were: (i) to evaluate the change of chronicity index from the first to second kidney biopsy and to find the predictors of chronicity index increase and (ii) to detect the clinical/histological features at first and at second kidney biopsy associated with long-term kidney function impairment.

METHODS

Among 203 biopsy proven LN subjects, 61 repeated kidney biopsy 49 months after the first biopsy. The reasons for repeated biopsy were: nephritic flares in 25 (41%), proteinuric flares in 21 (36%) of patients and protocol biopsy in 14 (23%) of cases.

RESULTS

During 23-year follow-up, 25 patients presented a decrease in glomerular filtration rate (eGFR) ≥30%. At repeat biopsy, chronicity index increased in 44 participants (72%) and did not increase in 17 (28%). Nephritic syndrome and serum creatinine >1.6 mg/dL at presentation correlated with chronicity index increase (p=0.031, 0.027, respectively), cyclophosphamide therapy tended to protect against chronicity index increase (p=0.059). Kidney flares occurred in 53.6% of patients with vs 23.5% of those without chronicity index increase (p=0.035). Chronicity index increases of 3.5 points in patients with kidney flares vs 2 in those without flares (p=0.001). At second, but not at first kidney biopsy, two different models predicted eGFR decrease at multivariate analysis. The first included activity index >3 (OR: 3.230; p=0.013) and chronicity index >4 (OR: 2.905; p=0.010), and the second model included moderate/severe cellular/fibrocellular crescents (OR: 4.207; p=0.010) and interstitial fibrosis (OR: 2.525; p=0.025).

CONCLUSION

At second biopsy, chronicity index increased in 3/4 of participants. Its increase was predicted by kidney dysfunction at presentation and occurrence of LN flares. Kidney function impairment was predicted by both activity and chronicity index and by some of their components at repeated biopsy, but not at first biopsy.

A Histology-Guided Approach to the Management of Patients with Lupus Nephritis: Are We There Yet?

Renal involvement is a frequent complication of systemic lupus erythematosus (SLE). It occurs in up to two-thirds of patients, often early during the disease course, and is the most important predictor of the morbidity and mortality of SLE patients. Despite tremendous improvements in the approach of the lupus nephritis (LN) therapy, including the recent approval of two new disease-modifying therapies, up to 50% of patients do not obtain a renal response and up to 25% will eventually progress to end-stage renal disease (ESRD) within 10 years of diagnosis. Given the lack of correlation between clinical features and histological lesions, there is an increasing need for a histology-guided approach to the management of patients with LN. Apart from the initial diagnosis of type and severity of renal injury in SLE, the concept of a repeat kidney biopsy (either in a for-cause or a per-protocol scenario) has begun to gain increasing popularity in the nephrology community. Herein, we will provide a comprehensive overview of the most important areas of utility of the kidney biopsy in patients with LN.

Association of Bowman's capsule rupture with prognosis in patients with lupus nephritis

BACKGROUND AND OBJECTIVE

Lupus nephritis is one of the most severe manifestations of systemic lupus erythematosus. The clinical and prognostic significance of Bowman's capsule rupture in patients with lupus nephritis is unknown.

METHODS

One hundred eighty patients with lupus nephritis were enrolled in the study and the integrity of Bowman's capsule was assessed. Both inflammatory and proliferative cells were detected by immunochemistry staining. The primary events of interest were end-stage renal disease and death.

RESULTS

After retrospective analysis of the data, 52 (28.9%) patients were found to have Bowman's capsule rupture, which was accompanied by high levels of serum creatinine, 24 h urine protein, and Activity/Chronicity Index. Bowman's capsule rupture was correlated with the level of crescents, tubular atrophy, and interstitial fibrosis. The number of CD20⁺ cells was higher in the Bowman's capsule rupture ( +) group compared with the Bowman's capsule rupture (-) group, while no differences in other inflammatory cells were observed. In addition, the end stage renal disease-free survival in the Bowman's capsule rupture ( +) group was lower than in the Bowman's capsule rupture (-) group. Moreover, serum creatinine (HR 39.56, P < 0.001), Activity Index (HR 1.50, P < 0.05) as well as Bowman's capsule rupture (HR 1.09, P < 0.05) predicted end-stage renal disease progression. Notably, for patients with existing crescents, Bowman's capsule rupture increased the cumulative risk of end-stage renal disease.

CONCLUSIONS

Bowman's capsule rupture is an important renal pathological lesion, which correlates with severe clinical manifestations, pathological changes, and poor prognosis in patients with lupus nephritis.

Causes and predictors of mortality from lupus nephritis in Southern Hunan, China

OBJECTIVES

The objective of the study was to explore the causes and predictors of mortality in a cohort of LN with LN in southern Hunan, China.

METHODS

We analyzed 236 patients with biopsy-proven LN during 2010-2018. Demographic data, laboratory data, SLEDAI scores, treatment strategies, and comorbidity were collected. Cox regression analysis was carried out to determine the independent predictors of mortality.

RESULTS

The patients had mean disease duration of 67.9 ± 28.2 months. Class IV LN was the predominant biopsy class within the cohort (38.1%). After 1 year therapy, the majority of patients achieved complete remission (72.9%) and 44 (18.6%) patients achieved partial remission. The 5- and 10-years survival rates for our cohort were 94.4 and 85.2%, respectively. There were 18 deaths (7.6%), of which the main causes were infection (50%) alone and cardiovascular diseases (27.8%). Independent predictors of mortality in our cohort were: platelet-to-neutrophil ratio (PNR) [hazard ratio (HR) 5.910; confidence interval (CI) 1.253-27.875], onset age (HR 1.090; CI 1.035-1.147), and SLEDAI scores (HR 1.258; CI 1.068-1.482).

CONCLUSION

We firstly revealed that PNR might be a promising predictor of mortality and reported the causes and prognostic predictors of mortality in LN from southern Hunan, China.

Close Association between Altered Urine-Urothelium Barrier and Tertiary Lymphoid Structure Formation in the Renal Pelvis during Nephritis

BACKGROUND

Kidneys with chronic inflammation develop tertiary lymphoid structures (TLSs). Infectious pyelonephritis is characterized by renal pelvis (RP) inflammation. However, the pathologic features of TLSs, including their formation and association with non-infectious nephritis, are unclear.

METHODS

RPs from humans and mice that were healthy or had non-infectious chronic nephritis were analyzed for TLS development, and the mechanism of TLS formation investigated using urothelium or lymphoid structure cultures.

RESULTS

Regardless of infection, TLSs in the RP, termed urinary tract-associated lymphoid structures (UTALSs), formed in humans and mice with chronic nephritis. Moreover, urine played a unique role in UTALS formation. Specifically, we identified urinary IFN-γ as a candidate factor affecting urothelial barrier integrity because it alters occludin expression. In a nephritis mouse model, urine leaked from the lumen of the RP into the parenchyma. In addition, urine immunologically stimulated UTALS-forming cells via cytokine (IFN-γ, TNF-α) and chemokine (CXCL9, CXCL13) production. CXCL9 and CXCL13 were expressed in UTALS stromal cells and urine stimulation specifically induced CXCL13 in cultured fibroblasts. Characteristically, type XVII collagen (BP180), a candidate autoantigen of bullous pemphigoid, was ectopically localized in the urothelium covering UTALSs and associated with UTALS development by stimulating CXCL9 or IL-22 induction via the TNF-α/FOS/JUN pathway. Notably, UTALS development indices were positively correlated with chronic nephritis development.

CONCLUSIONS

TLS formation in the RP is possible and altered urine-urothelium barrier-based UTALS formation may represent a novel mechanism underlying the pathogenesis of chronic nephritis, regardless of urinary tract infection.

The relationship between the modified National Institute of Health activity and chronicity scoring system, and the long-term prognosis for lupus nephritis: A retrospective single-center study

BACKGROUND

The revision of International Society of Nephrology/Renal Pathology Society (ISN/RPS) classification guidelines for lupus nephritis (LN) was suggested by a working group, who recommended a modified National Institute of Health (NIH) activity and chronicity scoring system to evaluate active and chronic LN lesions. However, whether this approach was useful for estimating long-term prognosis for LN patients is unclear.

METHODS

We conducted a retrospective cohort study in Japanese subjects with biopsy-proven LN, between 1977 and 2018. Pathologic lesions were evaluated based on ISN/RPS 2003 classifications and the modified NIH scoring system. Patients were grouped by activity index (low, 0-5; moderate, 6-11; high, 12-24), and chronicity index (low, 0-2; moderate, 3-5; high, 6-12). The primary outcome was a composite of end-stage kidney disease (ESKD) or all-cause death, and the secondary outcome was ESKD alone.

RESULTS

Sixty-six subjects with a median age of 31 years were included. During median follow-up (11.5 years), 15 patients reached the primary outcome: 10 had ESKD, four had died, and one had ESKD and died. Kaplan-Meier analysis showed that the cumulative primary outcome incidence increased with a higher chronicity index (log-rank trend p < 0.001). From multivariable survival analysis, moderate (hazard ratio [HR] 6.17, 95% confidence interval [CI] 1.14 to 33.20; p = 0.034) and high chronicity indices (HR 20.20, 95% CI 1.13 to 359.82; p = 0.041) were risk factors for the primary outcome.

CONCLUSION

Moderate and high chronicity indices were associated with an increased ESKD risk for LN.

The Asia-Pacific League of Associations for Rheumatology consensus statements on the management of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is prevalent in Asia and carries a variable prognosis among patients across the Asia-Pacific region, which could relate to access to health care, tolerability of medications, and adherence to therapies. Because many aspects of SLE are unique among patients from this region, the Asia-Pacific League of Associations for Rheumatology developed the first set of consensus recommendations on the management of SLE. A core panel of 13 rheumatologists drafted a set of statements through face-to-face meeting and teleconferences. A literature review was done for each statement to grade the quality of evidence and strength of recommendation. 29 independent specialists and three patients with SLE were then recruited for a modified Delphi process to establish consensus on the statements through an online voting platform. A total of 34 consensus recommendations were developed. Panellists agreed that patients with SLE should be referred to a specialist for the formulation of a treatment plan through shared decision making between patients and physicians. Remission was agreed to be the goal of therapy, but when it cannot be achieved, a low disease activity state should be aimed for. Patients should be screened for renal disease, and hydroxychloroquine is recommended for all Asian people with SLE. Major organ manifestations of SLE should be treated with induction immunosuppression and subsequently maintenance; options include cyclophosphamide, mycophenolate mofetil, azathioprine, and calcineurin inhibitors, in combination with glucocorticoids. Biologics, combination regimens, plasma exchange, and intravenous immunoglobulins should be reserved for cases of refractory or life-threatening disease. Anticoagulation therapy with warfarin is preferred to the direct oral anticoagulants for thromboembolic SLE manifestations associated with a high-risk antiphospholipid antibody profile.

Life prognosis and renal relapse after induction therapy in Japanese patients with proliferative and pure membranous lupus nephritis

OBJECTIVE

We aimed to compare life prognosis and renal relapse after induction therapy in proliferative (PLN) and pure membranous LN (MLN).

METHODS

We retrospectively analysed the cases of 140 of 172 patients with LN who underwent a renal biopsy at our hospital or community hospitals from 1993 to 2016. We determined the complete response (CR) rate at 12 months after the patients had started induction therapy, and we evaluated the predictive factors for CR, life prognosis and renal relapse in PLN and pure MLN. We defined PLN as International Society of Neurology and the Renal Pathology Society (ISN/RPS) Class III or IV and MLN as ISN/RPS Class V.

RESULTS

The renal pathology of 99 (70.7%) patients was classified as PLN, and that of the other 41 (29.3%) patients as MLN. Fifty patients (50.5%) with PLN and 22 patients (53.7%) with MLN achieved a CR at 12 months. A multivariate analysis showed that a lower index of chronicity in PLN and a higher total haemolytic complement (CH50) level in MLN were predictive factors for achieving a CR at 12 months. A Kaplan-Meier analysis showed that the life prognosis (P = 0.93) and renal relapse (P = 0.52) were not significantly different between PLN and MLN.

CONCLUSIONS

The predictive factors for a CR at 12 months post-induction therapy were index of chronicity in PLN and CH50 level in MLN. There were no significant differences in life prognosis or renal relapse between PLN and MLN in the achievement of a CR at 12 months post-induction therapy.

Urinary Peptides as Potential Non-Invasive Biomarkers for Lupus Nephritis: Results of the Peptidu-LUP Study

Background: Lupus nephritis (LN) is a severe manifestation of Systemic Lupus Erythematosus (SLE). The therapeutic strategy relies on kidney biopsy (KB) results. We tested whether urinary peptidome analysis could non-invasively differentiate active from non-active LN. Design: Urinary samples were collected from 93 patients (55 with active LN and 38 with non-active LN), forming a discovery (n = 42) and an independent validation (n = 51) cohort. Clinical characteristics were collected at inclusion and prospectively for 24 months. The urinary peptidome was analyzed by capillary-electrophoresis coupled to mass-spectrometry, comparing active LN to non-active LN, and assessing chronic lesions and response to therapy. The value of previously validated prognostic (CKD273) and differential diagnostic (LN172) signatures was evaluated. Results: Urinary peptides could not discriminate between active and non-active LN or predict early response to therapy. Tubulo-interstitial fibrosis was correlated to the CKD273. The LN172 score identified 92.5% of samples as LN. Few patients developed new-onset CKD. Conclusions: We validated the CKD273 and LN172 classifiers but did not identify a robust signature that could predict active LN and replace KB. The value of urinary peptidome to predict long-term CKD, or renal flares in SLE, remains to be evaluated.

Advances in Lupus Nephritis Pathogenesis: From Bench to Bedside

Systemic lupus erythematosus (SLE) is the prototype of autoimmune disorders caused by a loss of tolerance to endogenous nuclear antigens triggering an aberrant autoimmune response targeting various tissues. Lupus nephritis (LN), a major cause of morbidity and mortality in patients with SLE, affects up to 60% of patients. The recent insights into the genetic and molecular basis of SLE and LN paved the way for newer therapies to be developed for these patients. Apart from the traditional B-cell-centered view of this disease pathogenesis, acknowledging that multiple extrarenal and intrarenal pathways contribute to kidney-specific autoimmunity and injury may help refine the individual therapeutic and prognostic characterization of such patients. Accordingly, the formerly induction-maintenance treatment strategy was recently challenged with the exciting results obtained from the trials that evaluated add-on therapy with voclosporin, belimumab, or Obinutuzumab. The scope of this review is to provide an insight into the current knowledge of LN pathogenesis and future therapeutic strategies.

Revised ISN/RPS 2018 classification of lupus renal pathology predict clinical remission

BACKGROUND

A precise description of renal histological lesions and an appropriate classification of lupus nephritis are both essential for nephrologists to guide treatment and predict prognosis among patients. The prognostic value of ISN/RPS 2003 classification is controversial. A new classification for lupus nephritis was recently proposed, namely, the revised ISN/RPS 2018 classification.

OBJECTIVE

The study aimed to evaluate the predictive value of the clinical and pathological factors according to ISN/RPS 2018 classification on renal remission among patients with proliferative lupus nephritis.

METHODS

A total number of 41 patients with proliferative lupus nephritis on adequate renal biopsy specimen between 2017 and 2018 were included. Clinical and histological variables were tested for their association with renal remission. Univariate and multivariate logistic regression analysis were performed to identify independent predictors of renal remission after 24 weeks of induction therapy.

RESULTS

After induction therapy, 56.1% of patients reached complete and partial remission and 43.9% reached no remission. In univariate analyses, baseline glomerular filtration rate (GFR), presence of anti-DNA titer, cellular crescents, interstitial inflammation, glomerulosclerosis, interstitial fibrosis, tubular atrophy and total chronicity index strongly impacted renal response. After multivariate logistic regression analysis, we identified aging, presence of cellular crescents, and high total renal chronicity index as independent predictors of renal remission. Receiver operating characteristic (ROC) analysis revealed that baseline estimated GFR (AUC = 0.708; 95% CI 0.527-0.888), anti-DNA titer (AUC = 0.674; 95% CI 0.491-0.858), cellular crescent (AUC = 0.750; 95% CI 0.585-0.915) and renal chronicity index (AUC = 0.765; 95% CI 0.585-0.915) predicted renal remission. Combining all factors achieved a perfect score predicting renal response (AUC 0.924; 95% CI 0.840-1.000).

CONCLUSION

The study identified baseline GFR, anti-DNA titer, cellular crescent, and high chronicity index according to revised ISN/RPS 2018 classification as important predictors of renal response after induction therapy in proliferative lupus nephritis.

Corticosteroids are the major contributors to the risk for serious infections in autoimmune disorders with severe renal involvement

INTRODUCTION

We sought to investigate the infection profile and associated risk factors in a compiled cohort of patients with autoimmune disorders with severe renal involvement treated with aggressive immunosuppressive (IS) regimens.

METHODS

A total of 162 patients with aggressive glomerulonephritis [101 with lupus nephritis (LN), 24 with cryoglobulinemic vasculitis (CryoVasc), and 37 with ANCA-associated vasculitis (AAV)] were retrospectively reviewed for any infection occurrence. Infection incidence, type, site, and grade (1-5) were recorded. Multivariate Cox proportional hazard regression analysis was performed to identify independent risk factors for infections.

RESULTS

A total of 179 infection episodes occurred during a follow-up of 468 patient-years. Eighty-two patients (50.6%) had at least one infection. The incidence rates of infections and severe infections were 38.2 and 14.3 events per 100 patient-years. Patients with AAV had more infections than those with CryoVasc and LN (100.6, 47.5, and 26.6 infections per 100-patient-years, respectively; p = 0.002). Most patients developed infections early during the initial induction therapy (62.1% in the first 6 months of follow-up). In multivariate Cox regression analysis, high-dose oral corticosteroids (≥ 0.5 mg/kg/day in the first month of induction therapy) was an independent predictor of any infection (HR 2.66; 95% CI, 1.5-4.73), severe infections (HR 2.45; 95% CI, 1.03-5.82), and pulmonary infections (HR 2.91; 95% CI, 1.05-8.01). Pulmonary involvement increased the risk for pulmonary infections (HR 3.67; 95% CI, 1.32-10.1) and severe infections (HR 2.45; 95% CI, 1.01-5.92).

CONCLUSION

Infections occur frequently with current IS regimens in aggressive glomerulonephritis. Pulmonary involvement and high-dose corticosteroid regimen were the most significant risk factors for infections. Key Points • Infections occur frequently with current immunosuppressive regimens in autoimmune aggressive glomerulonephritis. • High-dose corticosteroids are the major contributors to the risk for serious infections.

The ISN/RPS 2016 classification predicts renal prognosis in patients with first-onset class III/IV lupus nephritis

Lupus nephritis (LN) is a life-threatening complication of systemic lupus erythematosus. The 2003 pathological classification of LN was revised in 2016; it quantitatively evaluates the interstitium in addition to the glomeruli. We performed a retrospective multi-centre cohort study and investigated the utility of the 2016 classification—including the activity index (AI), chronicity index (CI), and each pathological component to predict complete remission or renal function decline, defined as 1.5-fold increase in serum creatinine levels—and compare with that of the 2003 classification. Ninety-one consecutive adult patients with first-onset class III/IV LN who were newly prescribed any immunosuppressants were enrolled and followed up for a median of 51 months from January 2004. Cox regression analysis demonstrated the subclasses based on the 2003 classification, which mainly evaluate glomerular lesions, were not associated with clinical outcomes. After adjustments for estimated glomerular filtration rate and urinary protein levels, higher CI and higher interstitial fibrosis and lower hyaline deposit scores were associated with renal functional decline. Similarly, higher CI and interstitial inflammation scores were associated with failure to achieve complete remission. Therefore, the 2016 classification can predict the clinical outcomes more precisely than the 2003 classification.

Outcome of biopsy-proven lupus nephritis with low glomerular filtration rate at presentation

OBJECTIVES

Currently, there is limited data regarding the outcomes of lupus nephritis (LN) with moderate to severe renal failure at presentation (defined by low glomerular filtration rate; GFR <30 mL/min).

METHODS

Sixty-four patients with biopsy-proven LN and estimated GFR (eGFR) <30 mL/min were prospectively analyzed. Outcome measure of persistently low eGFR, end-stage renal disease (ESRD) or death at 365 days were grouped as Major Adverse Kidney Events (MAKE365).

RESULTS

Diagnosis of lupus was simultaneous with onset of renal disease in 60% of cases. Histologically, 82.3% (n = 51) were class IV, the median serum creatinine was 4 mg/dL (interquartile range [IQR] 3.1-5.9 mg/dL), median eGFR was 13.75 mL/min (IQR 9.25-19 mL/min) and 42.2% (n = 27) required dialysis at presentation. Induction regimens included National Institute of Health (68.2%), Eurolupus protocol (10.9%) and mycophenolate mofetil (8%). Over 365 days, 23 (37.5%) subjects died, while 41 (62.5%) survived. The majority of deaths were due to infection and sepsis (14/23). Among the survivors, 70.7% had good renal outcome, 12.1% had persistently low GFR (<30 mL/min), while 17% developed ESRD. In this group, treatment response rate was 84.6% (complete response 25.6%, partial response 59%). Those with a better renal function at presentation had a good treatment response (100% vs. 40%). Altogether, n = 35 (54.6%) were included in the MAKE365 category. Between the renal survival group (n = 29) versus the MAKE365 group (n = 35) there was no difference in clinical or histological parameters.

CONCLUSION

The current treatment protocols had a good response rate in patients with LN even with severe kidney injury at presentation. However, the risk of serious infections and subsequent mortality was high.

An Update on the Diagnosis and Management of Lupus Nephritis

PURPOSE OF REVIEW

Update on the diagnosis, treatment, and monitoring of lupus nephritis.

RECENT FINDINGS

The recent criteria enable the earlier classification of lupus nephritis based on kidney biopsy and compatible serology. Treatment of active nephritis includes low-dose intravenous cyclophosphamide or mycophenolate, followed by maintenance immunosuppression. Recent trials have suggested superiority of regimens combining mycophenolate with either calcineurin inhibitor or belimumab, although their long-term benefit/risk ratio has not been determined. Encouraging results with novel anti-CD20 antibodies confirm the effectiveness of B cell depletion. Achievement of low-grade proteinuria (< 700-800 mg/24 h) at 12-month post-induction is linked to favorable long-term outcomes and could be considered in a treat-to-target strategy. Also, repeat kidney biopsy can guide the duration of maintenance immunosuppression. Lupus nephritis has increased cardiovascular disease burden necessitating risk-reduction strategies. An expanding spectrum of therapies coupled with ongoing basic/translational research can lead to individualized medical care and improved outcomes in lupus nephritis.

Association of explanatory histological findings and urinary protein and serum creatinine levels at renal biopsy in lupus nephritis: a cross-sectional study

Background

The aim of the present study was to evaluate the association between the histology of active and chronic lesions and urinary protein and serum creatinine (SCr) levels, as common clinical endpoints in clinical trials for lupus nephritis (LN).

Methods

In total, 119 patients diagnosed with LN class III, IV, and V, as defined by the International Society of Nephrology/Renal Pathology Society, between 1990 and 2015, were enrolled in the present study. Multiple regression analysis was performed to explore semi-quantitative histological variables associated with urinary protein and SCr levels.

Results

The mean age of the enrolled patients was 45 years, and 79% were female. The mean SCr and mean urinary protein levels at the time of renal biopsy were 0.87 mg/dl and 3.00 g/gCr, respectively. Class IV (71%) was the most common type of LN followed by class III (17%), and class V (13%). Multicollinearity was confirmed between monocellular infiltration (variance inflation factor [VIF] = 10.22) and interstitial fibrosis (VIF = 10.29), and between karyorrhexis (VIF = 4.14) and fibrinoid necrosis (VIF = 4.29). Fibrinoid necrosis and monocellular infiltration were subsequently excluded, and multiple regression analysis revealed that only the urinary protein level was correlated with wire loop lesions (β-coefficient [β]: 1.09 and confidence interval [CI]: 0.35 to 1.83), and that the SCr level was correlated with glomerular sclerosis (β: 1.08 and CI: 0.43 to 1.74).

Conclusion

As urinary protein and SCr levels were not quantitatively associated with active lesions, they may not accurately reflect the response to remission induction therapy in patients with LN.

Stellenwert der Nierenbiopsie bei Lupusnephritis

Bei systemischem Lupus erythematodes (SLE) findet sich häufig eine renale Mitbeteiligung, der verschiedene pathogenetische Mechanismen zugrunde liegen. Die Nierenbeteiligung hat einen negativen Einfluss auf die Prognose des SLE, insbesondere bei progredienter Niereninsuffizienz. Eine Nierenbiopsie ist aufgrund der Heterogenität der Nierenbeteiligung und der damit verbundenen therapeutischen Konsequenzen unabdingbar. Sie kann durch nicht-invasive Untersuchungen wie die Urindiagnostik oder Serologie nicht ersetzt werden, da das Ausmaß der Proteinurie oder der Mikrohämaturie keine sicheren Rückschlüsse auf den Schweregrad, die Pathogenese und die Prognose der Nierenbeteiligung erlauben. Die Nierenbiopsie gibt neben der korrekten Klassifikation der Lupusnephritis (LN) Informationen über die Mitbeteiligung des Niereninterstitium, der intrarenalen Gefäße und der Aktivität sowie Chronizität der Nephritis. Auch kann der Pathologe die Frage beantworten, inwieweit mit einer Besserung der Nierenfunktion unter Therapie gerechnet werden kann. Der folgende Beitrag gibt einen Überblick über den Stellenwert der Nierenbiopsie bei SLE, der revidierten Klassifikation der LN von 2018 einschließlich Sonderformen der LN und über die Implikationen des Biopsie-Ergebnisses für die Therapie.

The glomerular crescent: triggers, evolution, resolution, and implications for therapy

PURPOSE OF REVIEW

Crescents are classical histopathological lesions found in severe forms of rapidly progressive glomerulonephritis, also referred to as crescentic glomerulonephritis (CGN). Crescent formation is a consequence of diverse upstream pathomechanisms and unraveling these mechanisms is of great interest for improving the management of patients affected by CGN. Thus, in this review, we provide an update on the latest insight into the understanding on how crescents develop and how they resolve.

RECENT FINDINGS

Cellular crescents develop from activated parietal epithelial cells (PECs) residing along Bowman's capsule and their formation has as a consequence the decline in glomerular filtration rate (GFR). Cellular crescents can be reversible, but when multilevel growth of PECs associate with an epithelial--mesenchymal transition-like change in cell phenotype, fibrous crescents form, and crescents become irreversible also in terms of GFR recovery. Different molecular pathways trigger the activation of PECs and are a prime therapeutics target in CGN. First, crescent formation requires also vascular injury causing ruptures in the glomerular basement membrane that trigger plasmatic coagulation within Bowman's space. This vascular necrosis can be triggered by different upstream mechanisms, such as small vessel vasculitides, immune complex glomerulonephritis, anti-GBM disease, and C3 glomerulonephritis, that all share complement activation but involve diverse upstream immune mechanisms outside the kidney accessible for therapeutic intervention.

SUMMARY

Knowing the upstream mechanisms that triggered crescent formation provides a tool for the development of therapeutic interventions for CGN.

Association of Urine sCD163 With Proliferative Lupus Nephritis, Fibrinoid Necrosis, Cellular Crescents and Intrarenal M2 Macrophages

CD163 is a marker for alternatively activated macrophages, which have been implicated in the pathogenesis of lupus nephritis (LN). In our preliminary screening of urine proteins in LN, urine soluble CD163 (sCD163) was significantly elevated in patients with active LN. To evaluate the potential of sCD163 as a biomarker in LN, urine sCD163 was assayed in patients with active LN, active non-renal lupus patients (ANR), inactive SLE and healthy controls (HC), using ELISA and normalized to urine creatinine. The correlation of urine sCD163 with clinical parameters and renal pathological attributes was further investigated in LN patients with concurrent renal biopsies. A total of 228 SLE patients and 56 HC were included from three cohorts. Results demonstrated that urine sCD163 was significantly elevated in active LN when compared with HC, inactive SLE, or ANR in African-American, Caucasian and Asian subjects (all P < 0.001). In LN patients with concurrent renal biopsies, urine sCD163 was significantly increased in patients with proliferative LN when compared with non-proliferative LN (P < 0.001). Urine sCD163 strongly correlated with SLEDAI, rSLEDAI, activity index (AI) of renal pathology, fibrinoid necrosis, cellular crescents, and interstitial inflammation on biopsies (all P < 0.01). Macrophages, particularly M2 macrophages, the predominant cells expressing CD163 within LN kidneys, represented a potential source of elevated urine sCD163, based on single-cell RNA sequencing analysis. To conclude, urine sCD163 discriminated patients with active LN from other SLE patients and was significantly elevated in proliferative LN. It strongly correlated with concurrent AI and several specific pathological attributes, demonstrating its potential in predicting renal pathology.

2019 Update of the Joint European League Against Rheumatism and European Renal Association-European Dialysis and Transplant Association (EULAR/ERA-EDTA) recommendations for the management of lupus nephritis

OBJECTIVE

To update the 2012 EULAR/ERA-EDTA recommendations for the management of lupus nephritis (LN).

METHODS

Following the EULAR standardised operating procedures, a systematic literature review was performed. Members of a multidisciplinary Task Force voted independently on their level of agreeement with the formed statements.

RESULTS

The changes include recommendations for treatment targets, use of glucocorticoids and calcineurin inhibitors (CNIs) and management of end-stage kidney disease (ESKD). The target of therapy is complete response (proteinuria <0.5-0.7 g/24 hours with (near-)normal glomerular filtration rate) by 12 months, but this can be extended in patients with baseline nephrotic-range proteinuria. Hydroxychloroquine is recommended with regular ophthalmological monitoring. In active proliferative LN, initial (induction) treatment with mycophenolate mofetil (MMF 2-3 g/day or mycophenolic acid (MPA) at equivalent dose) or low-dose intravenous cyclophosphamide (CY; 500 mg × 6 biweekly doses), both combined with glucocorticoids (pulses of intravenous methylprednisolone, then oral prednisone 0.3-0.5 mg/kg/day) is recommended. MMF/CNI (especially tacrolimus) combination and high-dose CY are alternatives, for patients with nephrotic-range proteinuria and adverse prognostic factors. Subsequent long-term maintenance treatment with MMF or azathioprine should follow, with no or low-dose (<7.5 mg/day) glucocorticoids. The choice of agent depends on the initial regimen and plans for pregnancy. In non-responding disease, switch of induction regimens or rituximab are recommended. In pure membranous LN with nephrotic-range proteinuria or proteinuria >1 g/24 hours despite renin-angiotensin-aldosterone blockade, MMF in combination with glucocorticoids is preferred. Assessment for kidney and extra-renal disease activity, and management of comorbidities is lifelong with repeat kidney biopsy in cases of incomplete response or nephritic flares. In ESKD, transplantation is the preferred kidney replacement option with immunosuppression guided by transplant protocols and/or extra-renal manifestations. Treatment of LN in children follows the same principles as adult disease.

CONCLUSIONS

We have updated the EULAR recommendations for the management of LN to facilitate homogenization of patient care.

Wire-loop lesion is associated with serological immune abnormality, but not renal prognosis, in lupus nephritis

BACKGROUND

Wire-loop lesion (WL) is one of the active lesions of lupus nephritis (LN). However, few reports have focused on the clinicopathological relationships of WL to serological immune abnormality and renal prognosis.

METHODS

We enrolled 126 Japanese LN patients subjected to renal biopsy in 11 hospitals from 2000 to 2018. In patients with class III or IV of the International Society of Nephrology/Renal Pathology Society classification, we retrospectively compared clinicopathological findings between those with WL (WL+ group) and without WL (WL- group) to detect factors associated with WL. Chronic kidney disease (CKD) was defined as an estimated glomerular filtration rate of <60 mL/min/1.73m² for more than three months. We also compared these findings between those with CKD (CKD+ group) and without CKD (CKD- group) at the last visit to investigate factors associated with renal prognosis.

RESULTS

Of 126 patients, 100 (79.4%) were classified as class III or IV. WL was found in 36 (36.0%) of them. Although the renal function did not differ, the WL+ group had a higher titre of serum anti-dsDNA antibodies and lower serum complement 3 levels than the WL- group. Linear regression analysis revealed a significant association only between anti-dsDNA antibodies and WL (β = 0.27, 95% confidence interval (CI) 0.001-0.100, p = 0.01). Of these patients, 69 were tracked for 59.6 ± 55.1 months. Kaplan-Meier analysis showed no difference in renal prognosis between these groups. Next, the CKD+ group included 15 (22.1%) patients. They were older and had higher frequencies of hypertension and hyperuricaemia, serum creatinine (Cr) level, glomerulosclerosis, interstitial inflammation, interstitial fibrosis and tubular atrophy than the CKD- group at the time of renal biopsy. The frequency of WL was not significantly different. Cox regression analysis revealed significant associations of CKD with hypertension, hyperuricaemia, serum Cr level at the time of renal biopsy clinically and with tubular atrophy histologically.

CONCLUSIONS

WL was associated with serum anti-dsDNA antibodies but not with renal prognosis, suggesting that WL reflects immune abnormality but is not an independent factor predictive of renal prognosis in LN.

Initial renal histology and early response predict outcomes of Brazilian lupus nephritis patients

Objective

We analyzed baseline and follow-up characteristics related to poorer renal outcomes in a Brazilian cohort of admixture race patients with lupus nephritis.

Methods

Overall, 280 outpatients with a diagnosis of systemic lupus erythematosus and previous kidney biopsy of lupus nephritis were recruited from August 2015 to December 2018 and had baseline laboratory and histologic data retrospectively analyzed; patients were then followed-up and data were recorded. The main outcome measure was the estimated glomerular filtration rate at last follow-up. Secondary analyses assessed the impact of initial kidney histology and treatment in long-term kidney survival.

Results

Median duration of lupus nephritis was 60 months (interquartile range: 27–120); 40 (14.3%) patients presented progressive chronic kidney disease (estimated glomerular filtration rate <30 and ≥10 ml/min/1.73 m2) or end-stage kidney disease at last visit. Adjusted logistic regression analysis showed that class IV lupus nephritis (odds ratio 14.91; 95% confidence interval 1.77–125.99; p = 0.01) and interstitial fibrosis ≥25% at initial biopsy (odds ratio 5.87; 95% confidence interval 1.32–26.16; p = 0.02), lack of complete or partial response at 12 months (odds ratio 16.3; 95% confidence interval 3.74–71.43; p < 0.001), and a second renal flare (odds ratio 4.49; 95% confidence interval 1.10–18.44; p = 0.04) were predictors of progressive chronic kidney disease. In a Kaplan-Meier survival curve we found that class IV lupus nephritis and interstitial fibrosis ≥25% were significantly associated with end-stage kidney disease throughout follow-up (hazard ratio 2.96; 95% confidence interval 1.3–7.0; p = 0.036 and hazard ratio 4.96; 95% confidence interval 1.9–12.9; p < 0.0001, respectively).

Conclusion

In this large cohort of admixture race patients, class IV lupus nephritis and chronic interstitial damage at initial renal biopsy together with non-response after 1 year of therapy and relapse were associated with worse long-term renal outcomes.

Lupus nephritis: challenges and progress

PURPOSE OF REVIEW

The management of lupus nephritis remains unsatisfactory due to insufficiently effective treatment regimens and the dearth of reliable predictors of disease onset or progression to guide individualized therapeutic decisions. This review summarizes new findings related to lupus nephritis over the last 18 months and discusses clinical needs that should be considered to advance trials of mechanism-based therapeutic strategies.

RECENT FINDINGS

Collaborative teams are addressing how to improve disease definitions and are developing predictive models for disease onset, disease response and risk of flare in individual patients. More attention is being paid to clinical trial design. Advanced technologic approaches are allowing the analysis of small amounts of human tissue and urine in unprecedented detail so as to discover new pathogenic mechanisms and identify disease biomarkers. Novel therapies continue to be tested in disease models and include new strategies to protect renal tissue from cell damage and fibrosis.

SUMMARY

The collaborative efforts of patients, clinical and translational researchers, the pharmaceutical industry and funding sources are needed to advance therapies for lupus nephritis. Specialized clinical centers can then deliver optimal and more personalized patient care that will improve patient outcomes.

Has The Time Arrived to Refine The Indications of Immunosuppressive Therapy and Prognosis in IgA Nephropathy?

Immunoglobulin A nephropathy (IgAN) is the most frequent glomerular disease worldwide and a leading cause of end-stage renal disease. Particularly challenging to the clinician is the early identification of patients at high risk of progression, an estimation of the decline in renal function, and the selection of only those that would benefit from additional immunosuppressive therapies. Nevertheless, the pathway to a better prognostication and to the development of targeted therapies in IgAN has been paved by recent understanding of the genetic and molecular basis of this disease. Merging the data from the Oxford Classification validation studies and prospective treatment studies has suggested that a disease-stratifying algorithm would be appropriate for disease management, although it awaits validation in a prospective setting. The emergence of potential noninvasive biomarkers may assist traditional markers (proteinuria, hematuria) in monitoring disease activity and treatment response. The recent landmark trials of IgAN treatment (STOP-IgAN and TESTING trials) have suggested that the risks associated with immunosuppressive therapy outweigh the benefits, which may shift the treatment paradigm of this disease. While awaiting the approval of the first therapies for IgAN, more targeted and less toxic immunotherapies are warranted. Accordingly, the targeting of complement activation, the modulation of mucosal immunity, the antagonism of B-cell activating factors, and proteasomal inhibition are currently being evaluated in pilot studies for IgAN treatment.

microRNAs in chronic kidney disease

Chronic kidney disease (CKD) results in high morbidity and mortality worldwide causing a huge socioeconomic burden. MicroRNA (miRNA) exert critical regulatory functions by targeting downstream genes and have been associated with many pathophysiologic processes including CKD. In fact, many studies have shown that the expression of various miRNAs was significantly changed in CKD. Current investigations have focused on revealing the relationship between miRNAs and CKD states including diabetic nephropathy, lupus nephritis, focal segmental glomerulosclerosis and IgA nephropathy. In this review, we summarize the latest advances elucidating miRNA involvement in the progression of CKD and demonstrate that miRNAs have the potential to be effective biomarkers and therapeutic targets for subsequent treatment.