Evaluation of the Oxford Classification of IgA nephropathy: a systematic review and meta-analysis

External Validation of the International Prognosis Prediction Model of IgA Nephropathy

BACKGROUND

The International IgA Nephropathy (IgAN) Network developed and validated two prognostic prediction models for IgAN, one incorporating a race parameter. These models could anticipate the risk of a 50% reduction in estimated glomerular filtration rate (eGFR) or progression to end-stage renal disease (ESRD) subsequent to an IgAN diagnosis via renal biopsy. This investigation aimed to validate the International IgA Nephropathy Prediction Tool (IIgANPT) within a contemporary Chinese cohort.

METHODS

Within this study,185 patients diagnosed with IgAN via renal biopsy at the Center for Kidney Disease, Second Affiliated Hospital of Nanjing Medical University, between January 2012 and December 2021, were encompassed. Each patient's risk of progression was assessed utilizing the IIgANPT formula. The primary outcome, a 50% decline in eGFR or progression to ESRD, was examined. Two predictive models, one inclusive and the other exclusive of a race parameter, underwent evaluation via receiver-operating characteristic (ROC) curves, subgroup survival analyses, calibration plots, and decision curve analyses.

RESULTS

The median follow-up duration within our cohort spanned 5.1 years, during which 18 patients encountered the primary outcome. The subgroup survival curves exhibited distinct separations, and the comparison of clinical and histological characteristics among the risk subgroups revealed significant differences. Both models demonstrated outstanding discrimination, evidenced by the areas under the ROC curve at five years: 0.882 and 0.878. Whether incorporating the race parameter or not, both prediction models exhibited acceptable calibration. Decision curve analysis affirmed the favorable clinical utility of both models.

CONCLUSIONS

Both prognostic risk evaluation models for IgAN exhibited remarkable discrimination, sound calibration, and acceptable clinical utility.

Validation of IgA nephropathy diagnosis in the Swedish Renal Registry

AIM

The Swedish Renal Registry (SRR) is a unique national quality registry that monitors the clinical trajectory of patients with chronic kidney disease (CKD). We have validated the biopsy data registered in the SRR for IgA Nephropathy (IgAN) diagnosis.

METHODS

In total 25% of all patients (n = 142), registered with IgAN in the SRR after having performed a kidney biopsy during 2015-2019, were randomly selected. We obtained original biopsy and medical records for 139 (98%) patients. We evaluated the IgAN diagnosis using a standardized template, calculated its positive predictive value (PPV) with 95% confidence interval (CI) and reported clinical features at the time of diagnosis.

RESULTS

A histological and clinical diagnosis of IgAN was confirmed in 132 of the 139 patients, yielding a PPV of 95% (95% CI 90-98%). Median age was 46 years (range: 18-85) and the male:female ratio was 2.1:1. The median creatinine level was 123 µmol/L, with a corresponding estimated glomerular filtration rate (eGFR) level of 51 mL/min/1.73m2. Histological features of IgA deposits were seen in all patients, hypercellularity in 102/132 (77.2%), C3 deposits in 98/132 (72.4%) and C1q deposits in 27/132 (20.5%) of the cases.

CONCLUSION

Validating data is not research per se, but continuous validation of medical registries is an important feature necessary to ensure reliable data and the foundation of good epidemiological data for future research. Our validation showed a high PPV (95%) for IgAN diagnosis registered in the SRR. Clinical characteristics were consistent with previous reports. The biopsy data in the SRR will be a valuable resource in future IgAN research.

Treatment of IgA Nephropathy: A Rapidly Evolving Field

The pivotal event in the pathophysiology of IgA nephropathy is the binding of circulating IgA-containing immune complexes to mesangial cells, with secondary glomerular and tubulointerstitial inflammation and fibrosis. The paramount difficulty in the management of IgA nephropathy is the heterogeneity in its clinical presentation and prognosis, requiring an individualized treatment approach. Goal-directed supportive care remains the bedrock of therapy for all patients, regardless of risk of progression. Sodium-glucose transporter 2 inhibitors and sparsentan should be integral to contemporary supportive care, particularly in patients with chronic kidney damage. Pending the development of reliable biomarkers, it remains a challenge to identify patients prone to progression due to active disease and most likely to derive a net benefit from immunosuppression. The use of clinical parameters, including the degree of proteinuria, the presence of persistent microscopic hematuria, and the rate of eGFR loss, combined with the mesangial hypercellularity, endocapillary hypercellularity, segmental glomerulosclerosis, tubular atrophy/interstitial fibrosis, crescents score, is currently the best approach. Systemic glucocorticoids are indicated in high-risk patients, but the beneficial effects wane after withdrawal and come at the price of substantial treatment-associated toxicity. Therapies with direct effect on disease pathogenesis are increasingly becoming available. While targeted-release budesonide has garnered the most attention, anti-B-cell strategies and selective complement inhibition will most likely prove their added value. We propose a comprehensive approach that tackles the different targets in the pathophysiology of IgA nephropathy according to their relevance in the individual patient.

Validating the association of Oxford classification and renal function deterioration among Taiwanese individuals with Immunoglobulin A nephropathy

Validation of the Oxford classification (MEST and MEST-C) for Immunoglobulin A nephropathy (IgAN) in the Taiwanese population is lacking. Our study aimed to validate this classification and assess individual lesion impact. We conducted a retrospective cohort study at Taichung Veterans General Hospital, Taiwan (Jan 2011-Jul 2023). Composite renal outcomes were evaluated using clinical conditions and estimated glomerular filtration rate (eGFR). We used Kaplan-Meier, univariable/multivariable logistic regression and ROC curves. Subgroup analysis considered eGFR < or ≥ 30.0 ml/min/1.73 m2. In 366 renal biopsies, serum creatinine was 1.34 mg/dl, eGFR 53.8 ml/min/1.73 m2, urine protein-creatinine ratio 1159 mg/g. T1/T2 lesions had lowest baseline eGFR (39.6/11.5 ml/min/1.73 m2), correlating with poorest renal survival (median survival 54.7/34.4 months). Univariable analysis linked all individual variables to worse renal outcomes. Multivariable analysis (MEST/MEST-C) showed only T1/T2 linked to worse outcomes. T score had highest predictive power (AUC 0.728, sensitivity 60.2%, specificity 83.6%), with MEST having high AUC (0.758). No extra predictive power was seen transitioning MEST to MEST-C. Subgroup analysis (eGFR < 30.0 ml/min/1.73 m2) associated C1 with improved renal outcomes (odds ratio 0.14, 95% CI 0.03-0.65). T lesion correlated with worse outcomes across subgroups. The T lesion consistently correlated with worse renal outcomes across all groups and baseline statuses. Integrating the C lesion into the transition from MEST to MEST-C did not enhance predictive power. Importantly, the C1 lesion was linked to improved renal outcomes in the eGFR < 30.0 ml/min/1.73 m2 subgroup, likely due to treatment effects.

The predictive value and response to immunosuppressive therapy of IgA nephropathy patients with crescents in a large retrospective Chinese cohort

Background

The prognostic value and response to immunosuppressive therapy (IST) of patients with crescents in the different backgrounds of pathological presentations in immunoglobulin A nephropathy (IgAN) is unclear.

Methods

A total of 1262 IgAN patients were enrolled. Crescents (C, 0/1/2), fibrinoid necrosis (FN, 0/1) and endocapillary hypercellularity (E, 0/1) were integrated into different degrees of glomerular activity (0-4 points): mild (0), moderate (1-2) and severe (≥3). The effect of IST on patients with different glomerular activity scores and chronic tubular and interstitial lesions (T, 0/1/2) were analysed using Cox regression analysis. The kidney outcome was defined as an estimated glomerular filtration rate decrease ≥30% or end-stage kidney disease.

Results

C2 was an independent risk factor for kidney outcomes {overall cohort: hazard ratio [HR] 1.85 [95% confidence interval (CI) 1.03-3.31], P = .040; T0 patients: HR 6.52 [95% CI 2.92-14.54], P < .001; reference to C0} in those without IST, while the HR decreased to 0.83 (95% CI 0.54-1.27; P = .396) in the overall cohort and 2.39 (95% CI 1.00-5.67; P = .049) in T0 patients with IST. For patients with severe glomerular activity, IST decreased the risk of kidney outcomes by 70% in the overall cohort [HR 0.30 (95% CI 0.12-0.74), P = .009; reference to those without IST] and 86% in T0 patients [HR 0.14 (95% CI 0.04-0.54), P = 0.005; reference to those without IST].

Conclusions

IST could reduce the risk for kidney outcomes in IgAN patients with C2 and T0 lesions together, as well as in those with crescents and at least one other active lesion, including FN and E1 lesions.

Evaluating Progression Risk in Patients With Immunoglobulin A Nephropathy

The highly variable rate of decline in kidney function in patients with immunoglobulin A nephropathy (IgAN) provides a major clinical challenge. Predicting which patients will progress to kidney failure, and how quickly, is difficult. Multiple novel therapies are likely to be approved in the short-term, but clinicians lack the tools to identify patients most likely to benefit from specific treatments at the right time. Noninvasive and validated markers for selecting at-risk patients and longitudinal monitoring are urgently needed. This review summarizes what is known about demographic, clinical, and histopathologic prognostic markers in the clinician's toolkit, including the International IgAN Prediction Tool. We also briefly review what is known on these topics in children and adolescents with IgAN. Although helpful, currently used markers leave clinicians heavily reliant on histologic features from the diagnostic kidney biopsy and standard clinical data to guide treatment choice, and very few noninvasive markers reflect treatment efficacy over time. Novel prognostic and predictive markers are under clinical investigation, with considerable progress being made in markers of complement activation. Other areas of research are the interplay between gut microbiota and galactose-deficient IgA1 expression; microRNAs; imaging; artificial intelligence; and markers of fibrosis. Given the rate of therapeutic advancement, the remaining gaps in biomarker research need to be addressed. We finish by describing our route to clinical utility of predictive and prognostic markers in IgAN. This route will provide us with the chance to improve IgAN prognosis by using robust, clinically practical markers to inform patient care.

Automated evaluation with deep learning of total interstitial inflammation and peritubular capillaritis on kidney biopsies

BACKGROUND

Interstitial inflammation and peritubular capillaritis are observed in many diseases on native and transplant kidney biopsies. A precise and automated evaluation of these histological criteria could help stratify patients' kidney prognoses and facilitate therapeutic management.

METHODS

We used a convolutional neural network to evaluate those criteria on kidney biopsies. A total of 423 kidney samples from various diseases were included; 83 kidney samples were used for the neural network training, 106 for comparing manual annotations on limited areas to automated predictions, and 234 to compare automated and visual gradings.

RESULTS

The precision, recall and F-score for leukocyte detection were, respectively, 81%, 71% and 76%. Regarding peritubular capillaries detection the precision, recall and F-score were, respectively, 82%, 83% and 82%. There was a strong correlation between the predicted and observed grading of total inflammation, as for the grading of capillaritis (r = 0.89 and r = 0.82, respectively, all P < .0001). The areas under the receiver operating characteristics curves for the prediction of pathologists' Banff total inflammation (ti) and peritubular capillaritis (ptc) scores were respectively all above 0.94 and 0.86. The kappa coefficients between the visual and the neural networks' scores were respectively 0.74, 0.78 and 0.68 for ti ≥1, ti ≥2 and ti ≥3, and 0.62, 0.64 and 0.79 for ptc ≥1, ptc ≥2 and ptc ≥3. In a subgroup of patients with immunoglobulin A nephropathy, the inflammation severity was highly correlated to kidney function at biopsy on univariate and multivariate analyses.

CONCLUSION

We developed a tool using deep learning that scores the total inflammation and capillaritis, demonstrating the potential of artificial intelligence in kidney pathology.

Histological classification of Japanese IgA nephropathy with a small number of glomeruli using Bayes' theorem

In Japan an original pathological classification of IgA nephropathy was used, while Oxford classification of IgA nephropathy was used globally. The Oxford classification requires ≥ 8 glomeruli while the Japanese classification requires ≥ 10. Ninety-nine patients diagnosed with IgA nephropathy were included. To determine the accuracy of histological staging, we calculated the posterior probability using Bayes' theorem and adopted three model of prior distribution. First, the actual staging distribution was reclassified using the beta distribution (reclassified distribution). Second a model with the same distribution (actual distribution) as the actual staging was used. Third, a model assuming that all cases are equally distributed (equal distribution) was used. The median number of collected glomeruli was 12 (8-19). There were 33 cases (33%) wherein the glomerular count was ≤ 9. When only cases with ≥ 10 glomeruli were included, the median posterior probability was 91% (74-99) (actual distribution, 90% [74-98]; equal distribution, 85% [73-96]). Even among the 33 cases with ≤ 9 glomeruli, there were approximately 7 cases in which the posterior probability was ≥ 90% for each model. Using Bayesian probabilistic analysis, it was possible to evaluate the histologic classification of IgA nephropathy, even when the number of obtained glomeruli was ≤ 9.

Machine learning in predicting T-score in the Oxford classification system of IgA nephropathy

Background

Immunoglobulin A nephropathy (IgAN) is one of the leading causes of end-stage kidney disease (ESKD). Many studies have shown the significance of pathological manifestations in predicting the outcome of patients with IgAN, especially T-score of Oxford classification. Evaluating prognosis may be hampered in patients without renal biopsy.

Methods

A baseline dataset of 690 patients with IgAN and an independent follow-up dataset of 1,168 patients were used as training and testing sets to develop the pathology T-score prediction (T pre) model based on the stacking algorithm, respectively. The 5-year ESKD prediction models using clinical variables (base model), clinical variables and real pathological T-score (base model plus T bio), and clinical variables and T pre (base model plus T pre) were developed separately in 1,168 patients with regular follow-up to evaluate whether T pre could assist in predicting ESKD. In addition, an external validation set consisting of 355 patients was used to evaluate the performance of the 5-year ESKD prediction model using T pre.

Results

The features selected by AUCRF for the T pre model included age, systolic arterial pressure, diastolic arterial pressure, proteinuria, eGFR, serum IgA, and uric acid. The AUC of the T pre was 0.82 (95% CI: 0.80-0.85) in an independent testing set. For the 5-year ESKD prediction model, the AUC of the base model was 0.86 (95% CI: 0.75-0.97). When the T bio was added to the base model, there was an increase in AUC [from 0.86 (95% CI: 0.75-0.97) to 0.92 (95% CI: 0.85-0.98); P = 0.03]. There was no difference in AUC between the base model plus T pre and the base model plus T bio [0.90 (95% CI: 0.82-0.99) vs. 0.92 (95% CI: 0.85-0.98), P = 0.52]. The AUC of the 5-year ESKD prediction model using T pre was 0.93 (95% CI: 0.87-0.99) in the external validation set.

Conclusion

A pathology T-score prediction (T pre) model using routine clinical characteristics was constructed, which could predict the pathological severity and assist clinicians to predict the prognosis of IgAN patients lacking kidney pathology scores.

Systematic Review of the Oxford Classification of IgA Nephropathy: Reproducibility and Prognostic Value

Key Points

The Oxford classification of IgA nephropathy defined five features scored subjectively in renal biopsies, identified by the initials MESTC. Two large studies with independent observers showed reproducibility was moderate for T, moderate or poor for M and S, and poor for E and C. In multivariate analyses including clinical features, T was related to 58% of outcomes, with no correlation of MESTC with 24% of outcomes.

Background

The Oxford classification of IgA nephropathy defined five prognostic features scored subjectively in renal biopsies: mesangial cellularity (M), endocapillary hypercellularity (E), segmental sclerosis (S), interstitial fibrosis/tubular atrophy (T), and (fibro)cellular crescents (C). Pathological scoring systems should be reproducible and have prognostic value independently of clinical features. Reproducibility of the classification was not previously investigated in a systematic review, and the most recent systematic reviews of prognostic value were in 2017.

Methods

This systematic review followed PRISMA 2020 guidelines. MEDLINE, PUBMED, and EMBASE databases were searched using the terms “IgA nephropathy” and “Oxford.” Eligible papers applied the classification and mentioned statistical analysis of interobserver reproducibility and/or included multivariate analysis of outcomes related to individual Oxford scores and clinical features, including treatment with corticosteroids or other immunosuppressive drugs.

Results

There were 99 suitable papers before September 23, 2022. Of 12 papers that mentioned reproducibility, only six reported statistics for MEST/MESTC scoring. Four of these were small studies and/or had observers at the same institution. These were considered less representative of application of the classification than two large studies with independent observers, in which agreement was moderate for T, either moderate or poor for M and S, and poor for E and C. In 92 papers with 125 multivariate analyses of various outcomes, the commonest Oxford element associated with outcomes was T (73 of 125, 58%), with no correlation of any element with outcomes in 30 analyses (24%). Treatment with immunosuppression was often related to scores, particularly C and E, without consistent relations between Oxford scores and outcomes in immunosuppressed patients.

Conclusions

This systematic review showed limitations of the Oxford classification in practice, particularly the moderate or poor reproducibility of scores. T was the Oxford score most often related to clinical outcomes, but even this was not consistently reliable as a prognostic indicator.

A Rare Presentation of IgA Nephropathy in a 62-Year-Old Hispanic Female

A case of immunoglobulin A (IgA) nephropathy is presented here that demonstrates an unusual clinical presentation in multiple ways and is vitally important for clinicians to consider. The patient is a Hispanic female in her 7th decade of life that presented with nephrotic-range proteinuria without hematuria ultimately leading to a diagnosis of IgA nephropathy. After diagnosis, her clinical course was complicated by continued poorly controlled type II diabetes mellitus and hypertension, and ultimately her kidney disease progressed to chronic kidney disease IV and then end-stage renal disease requiring hemodialysis. Though IgA nephropathy predominantly presents as nephritic syndrome, it can also present as nephrotic range proteinuria and even rapidly progressive glomerulonephritis which should be considered even when the patient's ethnicity and age group carry a smaller risk.

Corticosteroid Therapy in Immunoglobulin A Nephropathy: A Friend or Foe?

BACKGROUND

The administration of corticosteroids in addition to supportive care to delay progressive immunoglobulin A nephropathy (IgAN), the most common primary glomerulonephritis worldwide, remains controversial. This is partly due to the paucity of well-designed randomized controlled trials and well-known corticosteroid-related side effects. As a result, clinical equipoise in corticosteroid therapy exists depending on geographical regions and the clinician's preference.

SUMMARY

Better understanding around the pathogenesis of IgAN has prompted several clinical trials exploring the effects of immunosuppressive agents including corticosteroids. Earlier studies of corticosteroids were limited by suboptimal study designs, inadequate implementation of standard of care, and inconsistent adverse event data collection. Two well-designed, adequately powered, multi-centre randomized controlled trials, the STOP-IgAN and TESTING studies, have reported contrasting kidney outcomes that have further fuelled the clinical conundrum regarding the efficacy of corticosteroids. Both studies independently reported greater adverse events with corticosteroids. A novel targeted release formulation of budesonide, which has been hypothesized to reduce the adverse events associated with systemic corticosteroids, has shown promising results in the Phase 3 NefigaRD trial. Studies of treatments targeting B cells and the complement cascade are currently underway, and early data appear encouraging. This review provides an overview of the current literature around the understanding of the pathomechanisms and benefits and harm of corticosteroid use in IgAN.

KEY MESSAGES

Recent evidence suggests the use of corticosteroids in a selected cohort of people with IgAN at high risk of disease progression can improve kidney outcomes but comes with an associated risk of treatment-related adverse events, particularly with higher doses. Management decisions should therefore follow an informed patient-clinician discussion.

Blind Spot in the Radar of MEST-C Score: Type and Severity of Tubulointerstitial Nephritis in IgA Nephropathy

Background

The updated version of predictive classification for immunoglobulin A nephropathy (IgAN) prognosis "The Oxford Classification" identifies five histopathological features including mesangial hypercellularity (M), endocapillary proliferation (E), segmental glomerulosclerosis (S), tubular atrophy/interstitial fibrosis (T) and crescents (C), the MEST-C. However, few studies suggest that tubulointerstitial inflammation, which is not included in the MEST-C, is also linked to disease progression and is, consequently, a neglected determinant of prognosis among others. Therefore, there is a need to evaluate this histopathological parameter in patients with IgA nephropathy.

Materials and Methods

This cross-sectional descriptive study was conducted at Shaukat Khanum Memorial Cancer Hospital and Research Center, Lahore, Pakistan. Data of histopathological and immunofluorescence proven renal biopsies (300) of IgA nephropathy patients from January 2016 through May 2022 were extracted using a convenient sampling technique. Biopsies were histologically reviewed for type and severity of tubulointerstitial inflammation, in addition to the MEST-C score. Renal biopsies of patients who had a history of transplant, autolyzed tissue, no glomeruli on histological examination, and/or a tubular atrophy/interstitial fibrosis score of 2 (T2) in MEST-C scoring were excluded. Data were analyzed using SPSS 20. An association between the variables was analyzed using the chi-square and Fischer exact tests. A p value less than 0.05 was considered statistically significant.

Results

A total of 247/300 biopsies were eligible for inclusion. The mean age at the time of biopsy was 31.90 ± 12.48 with 63.6% in the age group between 21 and 40 years, and 69.6% were male. Tubulointerstitial inflammation was observed in 90.2% cases with 49.4% showing moderate while 4.5% showing severe degree of inflammation. A strong association of both the type and severity of tubulointerstitial inflammation was found with M, E, T, and C scores (p value < 0.05).

Conclusion

The high-frequency and strong statistical association of tubulointerstitial inflammation with the M, E, T, and C scores in our study elucidate its prognostic role in the progression and management of IgA nephropathy.

Clinicopathologic Manifestations of Immunoglobulin A Nephropathy in a Northern Indian Cohort: A Mute Assassin with Delayed Diagnosis

Introduction

Immunoglobulin A nephropathy (IgAN) is the most common glomerulonephritis worldwide, but there is a marked geographic difference in its prevalence and prognosis. IgAN is known to have an aggressive course in Asians. However, its exact prevalence and clinicopathologic spectrum in North India are not well documented.

Materials and Methods

The study included all patients aged above 12 years with primary IgAN on kidney biopsy from January 2007 to December 2018. Clinical and pathological parameters were noted. Two histopathologists independently reviewed all kidney biopsies, and MEST-C score was assigned as per the Oxford classification.

Results

IgAN was diagnosed in 681 (11.85%) out of 5751 native kidney biopsies. The mean age was 32 ± 12.3 years, and the male to female ratio was 2.5:1. At presentation, 69.8% had hypertension, 68% had an estimated glomerular filtration rate (eGFR) of less than 60 ml/min, 63.2% had microscopic hematuria, and 4.6% had gross hematuria. The mean proteinuria was 3.61 ± 2.26 g/day, with 46.8% showing nephrotic range proteinuria and 15.2% showing nephrotic syndrome manifestation. Histopathologically, 34.4% of patients had diffuse global glomerulosclerosis. Oxford MEST-C scoring revealed M1 in 67%, E1 in 23.9%, S1 in 46.9%, T1/T2 in 33%, and crescents in 19.6% of biopsies. The mean serum creatinine was significantly higher in cases with E1, T1/2, and C1/2 scores (P < 0.05). Hematuria and proteinuria were significantly higher (P < 0.05) with E1 and C1/2 scores. Coexisting C3 was associated with higher serum creatinine at presentation (P < 0.05).

Conclusion

IgAN patients with late presentation and advanced disease became less amenable to immunomodulation in our cohort. The implementation of point-of-care screening strategies, early diagnosis, and retarding disease progression should be prioritized in the Indian strategy.

Structural modeling for Oxford histological classifications of immunoglobulin A nephropathy

In immunoglobulin A nephropathy (IgAN), Cox regression analysis can select independent prognostic variables for renal functional decline (RFD). However, the correlation of the selected histological variables with clinical and/or treatment variables is unknown, thereby making histology-based treatment decisions unreliable. We prospectively followed 946 Japanese patients with IgAN for a median of 66 mo. and applied structural equation modeling (SEM) to identify direct and indirect effects of histological variables on RFD as a regression line of estimated glomerular filtration rate (eGFR) via clinical variables including amount of proteinuria, eGFR, mean arterial pressure (MAP) at biopsy, and treatment variables such as steroid therapy with/without tonsillectomy (ST) and renin–angiotensin system blocker (RASB). Multi-layered correlations between the variables and RFD were identified by multivariate linear regression analysis and the model’s goodness of fit was confirmed. Only tubular atrophy/interstitial fibrosis (T) had an accelerative direct effect on RFD, while endocapillary hypercellularity and active crescent (C) had an attenuating indirect effect via ST. Segmental sclerosis (S) had an attenuating indirect effect via eGFR and mesangial hypercellularity (M) had accelerative indirect effect for RFD via proteinuria. Moreover, M and C had accelerative indirect effect via proteinuria, which can be controlled by ST. However, both T and S had additional indirect accelerative effects via eGFR or MAP at biopsy, which cannot be controlled by ST. SEM identified a systemic path links between histological variables and RFD via dependent clinical and/or treatment variables. These findings lead to clinically applicable novel methodologies that can contribute to predict treatment outcomes using the Oxford classifications.

The Effect of Body Mass Index on the Degree of Renal Interstitial Fibrosis and Tubular Atrophy - A Retrospective Case-Control Study

Introduction

The degree of interstitial fibrosis and tubular atrophy (IFTA) seen on kidney biopsy has long been used to judge the chronicity of kidney disease to predict renal disease outcomes and prognosis. It is an essential component incorporated in many renal disease prognostic classification systems on the native and renal allograft. The impact of increased body mass index on the body metabolism, and the human vascular system, including the functional unit of the kidney, the nephron, is well-addressed in the literature. In this study, we focus on evaluating the degree of IFTA concerning the patient's body mass index (BMI).

Method

All the specimens of nephrectomies performed in King Abdulaziz University Hospital for adults from January 2010 to February 2021 were evaluated for this study. A total of 125 cases were selected for the study. The glass slides were pulled and assessed for the degree of IFTA. The demographic data, and the patient's BMI, were collected from the hospital records.

Results

Subjects with high BMI showed a 1.62 (OR: 1.62, 95% CI: 0.62, 4.22) and 1.52 (AOR: 1.52, 95% CI: 0.56, 4.13) increased risk of high IFTA score compared with those with normal BMI. This study has proved that only at a BMI of 25 or more will there be a measurable, independent effect on the degree of IFTA.

Conclusion

Although a small number of hospital-based populations limits this study, it could prove the increased severity of IFTA in patients with high BMI. Its result may act as a spark that will drive extensive population-based studies that more precisely delineate the relationship between BMI and the degree of IFTA on different levels.

Automated Prediction of Kidney Failure in IgA Nephropathy with Deep Learning from Biopsy Images

BACKGROUND AND OBJECTIVES

Digital pathology and artificial intelligence offer new opportunities for automatic histologic scoring. We applied a deep learning approach to IgA nephropathy biopsy images to develop an automatic histologic prognostic score, assessed against ground truth (kidney failure) among patients with IgA nephropathy who were treated over 39 years. We assessed noninferiority in comparison with the histologic component of currently validated predictive tools. We correlated additional histologic features with our deep learning predictive score to identify potential additional predictive features.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Training for deep learning was performed with randomly selected, digitalized, cortical Periodic acid-Schiff-stained sections images (363 kidney biopsy specimens) to develop our deep learning predictive score. We estimated noninferiority using the area under the receiver operating characteristic curve (AUC) in a randomly selected group (95 biopsy specimens) against the gold standard Oxford classification (MEST-C) scores used by the International IgA Nephropathy Prediction Tool and the clinical decision supporting system for estimating the risk of kidney failure in IgA nephropathy. We assessed additional potential predictive histologic features against a subset (20 kidney biopsy specimens) with the strongest and weakest deep learning predictive scores.

RESULTS

We enrolled 442 patients; the 10-year kidney survival was 78%, and the study median follow-up was 6.7 years. Manual MEST-C showed no prognostic relationship for the endocapillary parameter only. The deep learning predictive score was not inferior to MEST-C applied using the International IgA Nephropathy Prediction Tool and the clinical decision supporting system (AUC of 0.84 versus 0.77 and 0.74, respectively) and confirmed a good correlation with the tubolointerstitial score (r=0.41, P<0.01). We observed no correlations between the deep learning prognostic score and the mesangial, endocapillary, segmental sclerosis, and crescent parameters. Additional potential predictive histopathologic features incorporated by the deep learning predictive score included (1) inflammation within areas of interstitial fibrosis and tubular atrophy and (2) hyaline casts.

CONCLUSIONS

The deep learning approach was noninferior to manual histopathologic reporting and considered prognostic features not currently included in MEST-C assessment.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2022_07_26_CJN01760222.mp3.

Correlation between IgAC3 ratio and oxford score in IgA nephropathy

BACKGROUND

Complement activation has an important role in the pathogenesis of IgA nephropathy.

OBJECTIVE

To determine the correlation between IgAC3 ratio (IgA/C3) and total Oxford score and predictive value of IgA/C3 in IgA nephropathy. Methods Forty-three patients diagnosed with IgA nephropathy with > 10 glomerular + 1 arteries in biopsy were included in the study. Hematological and biochemical variables of the blood sample taken before the biopsy and total Oxford score were recorded. The study group was divided into two groups as proteinuria ≥ 1 g (PU ≥ 1) and proteinuria < 1 g (PU < 1). Statistics were carried out with SPSS 22.0 program. p < .05 considered as significant.

RESULTS

The mean age of 43 patients was 40.4 (± 11.9) years; 51.2% of them were women. Proteinuria as 1 g or more was in 27 of 43 patients, and less than 1 g in 16 patients. The serum C3 level was lower in the group with PU ≥ 1 and showed a significant positive correlation with the IgA/C3 total Oxford score.

CONCLUSION

A significant correlation was found between serum IgA/C3 and total Oxford score.

Clinicopathological characteristics, risk factors and renal outcome in IgA nephropathy with crescents

BACKGROUND/AIMS

The aim of the study was to investigate the clinicopathological characteristics, risk factors and renal outcome in IgA nephropathy (IgAN) patients with crescents.

METHODS

Four hundred and fifty-eight biopsy-proven primary IgAN patients included between January 2010 and October 2021 for a retrospective analysis were divided into three groups according to crescent score of the updated Oxford classification: C0 group (n = 255), C1 group (n = 187) and C2 group (n = 16). The clinicopathological features and renal outcomes were recorded. In univariate and multivariate models, the association between crescents and renal outcome and C2-associated clinical factors were analyzed.

RESULTS

Patients with a higher proportion of crescents presented worse clinical characteristics with regard to kidney function, proteinuria, hematuria, hemoglobin, uric acid, cholesterol, and serum albumin, while global glomerulosclerosis, segmental adhesion, tuft necrosis, segmental glomerulosclerosis (S1), tubular atrophy/interstitial fibrosis (T1/2), and lymphocyte and monocyte infiltration were more severe. By multivariate logistic regression analysis, eGFR (OR 0.981, 95% CI 0.964-0.999, P = 0.039), proteinuria (OR 1.655, 95% CI 1.180-2.321, P = 0.004), and hematuria (OR 4.752, 95% CI 1.426-15.835, P = 0.011) were significantly associated with C2. C2 was significantly associated with poorer renal survival even in patients receiving immunosuppressive therapy. Nevertheless, only eGFR at baseline, rather than crescents, was an independent predictor for renal survival in multivariate Cox analyses.

CONCLUSION

IgAN patients with crescents presented more severe clinical and pathological features. Renal function, proteinuria and hematuria contributed to identifying patients with crescents. Crescents were associated with poorer renal survival, even in patients receiving immunosuppressive therapy, but it was not an independent predictor.

Efficacy of Modified Huangqi Chifeng decoction in alleviating renal fibrosis in rats with IgA nephropathy by inhibiting the TGF-β1/Smad3 signaling pathway through exosome regulation

ETHNOPHARMACOLOGICAL RELEVANCE

IgA nephropathy is the most common form of primary glomerulonephritis and is a major cause of renal failure worldwide. Modified Huangqi Chifeng decoction (MHCD), a traditional Chinese herbal preparation, has clinical efficacy in reducing the 24-h urine protein levels in patients with IgA nephropathy. However, the molecular mechanism of MHCD needs further study.

AIM OF THE STUDY

This study aimed to investigate the mechanisms by which MHCD treatment alleviates renal fibrosis.

MATERIALS AND METHODS

An IgA nephropathy rat model was established using bovine serum albumin, carbon tetrachloride, and lipopolysaccharide. The rats were divided into control, model, telmisartan, low-dose MHCD, medium-dose MHCD, and high-dose MHCD groups. Treatments were administered to these groups for 8 weeks. Subsequently, the 24-h urine protein, serum creatinine, blood urea nitrogen, and blood albumin levels were measured. Pathological changes and degree of fibrosis in renal tissues were observed, and levels of the transforming growth factor-β1 (TGF-β1)/Smad3 signaling pathway components in renal tissues and TGF-β1 in urinary exosomes were measured.

RESULTS

Telmisartan and MHCD reduced 24-h urine protein levels, alleviated renal pathological injury, and decreased the renal expression of fibronectin, laminin, and collagen IV in rats with IgA nephropathy. Urinary exosomes were extracted and identified for further investigation of their role in renal fibrosis. MHCD reduced TGF-β1 expression in urinary exosomes and reduced TGF-β1 and p-Smad3 levels in renal tissues.

CONCLUSION

MHCD alleviated renal fibrosis in rats with IgA nephropathy by inhibiting the TGF-β1/Smad3 signaling pathway through the downregulation of TGF-β1 expression in exosomes.

Retrospective analysis of crescent score in clinical prognosis of IgA nephropathy

The scoring of crescents (Cs) was recently added to the Oxford classification for IgA nephropathy (IgAN). Because of the short-term use of the C score in clinical practice, its validity and applicability need to be verified. We, retrospectively, analyzed the clinicopathological data of 144 primary IgAN patients diagnosed at our hospital from March 2017 to March 2019 and with complete ≥6-month follow-up data. We found that the C score was positively correlated with the Lee’s classification in the assessment of renal pathological changes and significantly correlated with increased proteinuria and decreased estimated glomerular filtration rate. Univariate Cox regression analysis showed an association of C formation with IgAN prognosis, and multivariate Cox regression indicated Cs as an independent prognosis factor. The optimal proportion of Cs for prognosis prediction by the receiver operating characteristic curve was 11%. Kaplan–Meier survival curve revealed a significantly decreased renal survival rate in patients with C proportions ≥11%. Further multivariate Cox regression analysis confirmed that the C proportion ≥11% is an independent risk factor for poor prognosis of IgAN patients. Our findings demonstrate that Cs are independently related to the prognosis of patients with IgAN, and the proportion of Cs ≥11% is an independent risk factor for poor outcomes.

A Novel Scoring System Based on Oxford Classification Indicating Steroid Therapy Use for IgA Nephropathy

Introduction

The usefulness of the Oxford classification (MEST-C score) for deciding the management approach for IgA nephropathy (IgAN) remains unclear.

Methods

Effects of steroid therapy on the long-term prognosis for all 858 patients with IgAN and patients classified according to each MEST-C score were evaluated using Kaplan-Meier and Cox regression analyses. Steroid responder score (SRS) and steroid nonresponder score (SNRS) were determined using individual pathology scores when steroids were found to be independently associated, or not, with clinical benefits. In addition, the effects of steroid therapy according to the total SRS/SNRS were analyzed.

Results

Steroid therapy improved the 20-year renal survival rates of patients with IgAN after matching (steroids[+] vs. steroids[−]; estimated glomerular filtration rate [eGFR] [ml/min per 1.73 m²]: 79.4 vs. 77.0, not significant; proteinuria [g/d]: 0.80 vs. 0.62, not significant; renal survival rate: 75.5% vs. 61.7%; P = 0.025) and of patients with M1, E1, S1, C1+2, and T0 scores. Therefore, we considered the total of the M1, E1, S1, and C1+2 scores (point 0: low, 1–2: medium, and 3–4: high) as the SRS and the total of the T1+2 scores (0: low and 1: high) as the SNRS. Multivariate Cox regression analyses revealed that steroid therapy improved the renal prognosis of patients with IgAN with high SRS and any SNRS, unlike patients with IgAN with medium SRS and any SNRS.

Conclusion

Patients with M1, E1, S1, and C1+2 scores responded to steroid therapy; however, those with T1+2 scores did not. Although a high SRS was a useful indicator for steroid therapy, SNRS indicated resistance to steroid therapy.

Utilizing the MEST score for prognostic staging in IgA nephropathy

Background

The Oxford classification/MEST score is an established histopathologic scoring system for patients with IgA nephropathy (IgAN). The objective of this study was to derive a prognostic model for IgAN based on the MEST score and histopathologic features.

Methods

A total of 306 patients with biopsy-proven primary IgAN were included. Histopathologic samples were retrieved from the Norwegian Kidney Biopsy Registry and reclassified according to the Oxford classification. The study endpoint was end-stage renal disease (ESRD). Patients were subclassified into three risk models based on histologic features (Model A), a composite score calculated from the adjusted hazard ratio values (Model B), and on quartiles (Model C).

Results

The mean follow-up time was 16.5 years (range 0.2–28.1). In total, 61 (20%) patients reached ESRD during the study period. Univariate analysis of M, E, S, T and C lesions demonstrated that all types were associated with an increased risk of ESRD; however, a multivariate analysis revealed that only S, T and C lesions were associated with poor outcomes. Statistical analysis of 15-year data demonstrated that Models A and B were as predictive as the MEST score, with an area-under-the-curve at 0.85. The Harrel c index values were 0.81 and 0.80 for the MEST score and Models A and B, respectively. In the present cohort, adding C lesions to the MEST score did not improve the models prognostic value.

Conclusions

Patients can be divided into risk classes based on their MEST scores. Histopathologic data provide valuable prognostic information at the time of diagnosis. Model B was the most suitable for clinical practice because it was the most user-friendly.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02653-y.

Glomerular C4d Deposition and Kidney Disease Progression in IgA Nephropathy: A Systematic Review and Meta-analysis

Background

Glomerular deposition of C4d is a widely used biomarker for activation of the lectin pathway in the complement system and is reported to be associated with kidney progression in immunoglobulin A nephropathy (IgAN). The aim of this study was to evaluate whether glomerular C4d deposition, as a new biomarker, improves the prediction of kidney prognosis in IgAN.

Study Design

Systematic review and meta-analysis.

Setting & Population

Patients with biopsy-proven primary IgAN without age limitations.

Selection Criteria for Studies: Cross-sectional or cohort studies reporting the prevalence of glomerular C4d deposition or evaluating its association with IgAN progression.

Predictor

Glomerular C4d deposition.

Outcome

Composite progression event of a >30% decline in estimated glomerular filtration rate or end-stage kidney disease.

Results

12 studies with 1,251 patients were included. The prevalence of glomerular C4d deposition was 34% (95% CI, 27%-41%), with large heterogeneity (I² = 86%; P < 0.001). Patients with C4d deposition had lower estimated glomerular filtration rates (mean difference [MD], −11.48; 95% CI, −18.27 to −4.70; P < 0.001) as well as higher urinary protein-creatinine ratios (MD, 0.87; 95% CI, 0.53-1.21; P < 0.001) or 24-hour urinary protein excretion (MD, 0.99; 95% CI, 0.50-1.47; P < 0.001) and higher risk for hypertension (relative risk [RR], 1.45; 95% CI, 1.06-1.99; P = 0.02) than patients without C4d deposition. Glomerular C4d deposition was associated with a high Oxford classification score, including M1, E1, S1, and T1/2 lesions (all P ≤ 0.006). Patients with C4d deposition had higher rates of use of renin-angiotensin system blockers and immunosuppressants. Glomerular C4d was found to be a risk factor for the composite kidney event (RR, 3.17; 95% CI, 2.29-4.40; P < 0.001; adjusted HR, 2.05; 95% CI, 1.53-2.76; P < 0.001) and end-stage kidney disease (RR, 4.37; 95% CI, 3.15-6.07; P < 0.001) without evidence of heterogeneity.

Limitations

The definition of positive C4d was not uniform and not all studies provided data about kidney outcomes.

Conclusions

Glomerular C4d deposition is associated with an adverse prognosis and may be a useful biomarker of disease prediction in IgAN.

Arterial-Arteriolar Sclerosis Is Independently Associated With Poor Renal Outcome in IgA Nephropathy Patients

Aim: This study aimed to investigate the clinicopathological features and prognosis of immunoglobulin A nephropathy (IgAN) with arterial-arteriolar sclerosis (AS).

Methods: Patients with biopsy-proven IgAN from the West China Hospital of Sichuan University were retrospectively enrolled. Clinicopathological features were collected. Patients were categorized based on the presence and the severity of the AS. All the patients were regularly followed-up until a composite end point. The correlation between AS and prognosis of IgAN was assessed.

Results: A total of 1,424 patients were recruited and followed for 60.0 ± 28.7 months. Patients with AS tended to have older age, higher blood pressure, heavier proteinuria, higher serum creatinine, uric acid, and total triglyceride (TG). Meanwhile, they were more likely to have a lower estimated glomerular filtration rate (eGFR), hemoglobin, and albumin. At the end of follow-up, 126 patients in the AS group and 47 patients in the non-AS group had reached the composite end point (p < 0.001). AS was associated with the renal outcome (log-rank p < 0.001) and was an independent risk factor for the progression of IgAN (p = 0.049). The severity of AS was associated with renal outcomes (log-rank p < 0.001) and there was a trend that it might serve as an independent risk marker for progression of IgAN. In the subgroup analysis, patients presenting with AS and lower eGFR, albumin, and hemoglobin or higher proteinuria, uric acid, and TG had a significant trend for a shorter time to reach the end point (log-rank p < 0.001).

Conclusion: AS was commonly seen in patients with IgAN and was independently associated with the poor prognosis.

A high value of fibrinogen in immunoglobulin A nephropathy patients is associated with a worse renal tubular atrophy/interstitial fibrosis score

Purpose

The purpose of our study was to investigate the relationship between serum fibrinogen value and renal tubular atrophy/interstitial fibrosis in immunoglobulin A nephropathy patients with eGFR ≥90 ml/min/1.73 m².

Patients and Methods

Of 359 patients diagnosed with immunoglobulin A nephropathy after renal biopsy were enrolled in this retrospective study. Demographic, histopathological features, and clinical data were collected. The relationships among these factors were analyzed by using Student's t test, Mann‐Whitney U test, Kruskal‐Wallis test, Chi‐square test, or Fisher's exact test, where appropriate. The logistic regression analysis was performed to examine the independent risk factors.

Results

Of 176 immunoglobulin A nephropathy patients with eGFR ≥90 ml/min/1.73 m² were included in this study, and patients were classified into low fibrinogen (fibrinogen <304.6 mg/dl) and high fibrinogen (fibrinogen ≥304.6 mg/dl) groups, respectively. High fibrinogen groups had advanced age, a higher classification of renal tubular atrophy/interstitial fibrosis, and higher levels of systolic pressure, D‐dimer, 24 h urine protein quantitation, nag enzyme. Multivariate logistic analysis showed that fibrinogen (OR = 1.018) was significantly associated with tubular atrophy/interstitial fibrosis.

Conclusion

Among patients with immunoglobulin A nephropathy, the higher levels of fibrinogen and uric acid may mean a higher score of tubular atrophy/interstitial fibrosis, which suggests the renal biopsy should be performed for these patients as early as possible to defined pathological classification, even though there is no obvious abnormal change in the test of renal function.

Epidemiology and risk factors for progression in Chinese patients with IgA nephropathy

BACKGROUND

IgA nephropathy (IgAN) is one of the main causes of primary glomerulonephritis worldwide, and it is also the main primary disease leading to chronic kidney disease. The purpose of this study is to evaluate the epidemiology and risk factors for progression in Chinese patients with IgAN.

METHODS

In this retrospective study, 246 patients with renal biopsy-proven IgAN were enrolled from January 2012 to June 2018. The patients' data were divided into two groups according to eGFR at the end of follow-up: a high-eGFR group (eGFR≥60ml/min) and a low-eGFR group (eGFR<60ml/min).

RESULTS

At the end of the study, we identified 49 (19.92%) patients with low-eGFR from 246 IgAN patients. Renal function, represented by serum creatinine, urea nitrogen and cystatin-C, was significantly decreased in the low-eGFR group (P<0.001 for all) at the time of renal biopsy. Compared with the high-eGFR group, the age, mean arterial blood pressure (MAP), proteinuria, cholesterol, triglycerides and serum uric acid were significantly higher (P<0.05 for all). According to the Oxford evaluation, the proportion of S1-2 (59.2%) and T1-2 (65.3%) was significantly increased (P<0.001 for both) and the proportion that had a MEST-C score ≥3 was statistically increased in the low-eGFR group (83.7%, P=0.001).

CONCLUSIONS

Male, MAP, haematuria, Scr, cholesterol, hemoglobin, Lee classification more than 3 and C1-2 are independent risk factors for low-eGFR in Chinese IgAN patients.

Severity of arterial and/or arteriolar sclerosis in IgA nephropathy and the effects of renin-angiotensin system inhibitors on its prognosis

IgA nephropathy (IgAN) patients often suffer from arterial and/or arteriolar sclerosis (AAS); however, it is unclear whether these features are associated with a poor prognosis. This retrospective cohort study aimed to analyse the prognosis of IgAN patients with AAS and assess whether treatment with renin–angiotensin system inhibitors (RASI) improved their survival. The study included 678 IgAN patients, who were grouped into AAS0 (n = 340; AAS absent) and AAS1 (n = 338; AAS present) groups. Each patient's clinical, laboratory, and histological backgrounds and 20‐year renal prognosis were analysed. In the AAS1 group, the impact of RASI initiated during the follow‐up period on the renal prognosis was also evaluated after adjustments for background characteristics. IgAN patients with AAS had significantly higher age, blood pressure, body mass index, total cholesterol, uric acid levels, and proteinuria than patients without AAS; they also had more severe histological findings, decreased renal function, and lower survival rates than those without AAS (64.0 versus 84.7%, p < 0.001). Multivariate Cox regression analysis incorporating clinical and histological findings and treatments revealed AAS as an independent factor for disease progression (hazard ratio: 2.23, p = 0.010). Participants in the AAS1 group treated with RASI during follow‐up had a significantly higher renal survival rate than those who were not (75.5 versus 44.3%, p = 0.013). In conclusion, AAS was found to be associated with serious clinical, laboratory, and histological findings and poor prognosis. RASI initiated during the follow‐up period was found to improve renal prognosis.

IgA vasculitis

IgA vasculitis (IgAV) is an inflammation of small vessels caused by perivascular deposition of IgA and activation of neutrophils. It may present as systemic vasculitis (IgAV - Henoch-Schönlein purpura) or as a variant restricted to the skin (skin-limited IgAV), while IgA nephropathy presents a variant restricted to the kidneys. Systemic IgAV affects children more frequently than adults (150 to 200 for 1; incidence 1 in 1 million/year). In the latter, disease more often leads to chronic renal disease. The dominant clinical features include round or oval and retiform palpable purpura predominantly on the lower legs, arthralgia or arthritis, gastrointestinal bleeding or pain and glomerulonephritis with mesangial IgA deposits (IgAVN). Pulmonary, cardiac, genital and neurological involvement occurs, but is rare. Immune complexes containing galactose-deficient IgA1 play a pivotal role in the pathophysiology of IgAV; via the Fc alpha receptor (CD89), they induce neutrophilic inflammation around cutaneous vessels and mesangial proliferation and inflammation in the glomerulus. In case of self-limited disease, only symptomatic treatment is recommended. Treatment of severe IgAV, nephritis or gastrointestinal manifestations, is not established, but some studies reported a benefit of corticosteroids, combined with immunosuppressive drugs. Short-term outcome depends on the severity of gastrointestinal manifestations, while long-term prognosis depends on the severity of nephritis.

Pre-treatment hematuria and crescents predict estimated glomerular filtration rate trajectory after methylprednisolone pulse therapy with tonsillectomy for IgA nephropathy

BACKGROUND

Glomerular hematuria and proteinuria are typical manifestations of IgA nephropathy (IgAN). However, hematuria severity is not considered a useful marker of the potential benefits of corticosteroid administration as proteinuria severity only is included in the current guidelines.

METHODS

In this retrospective cohort study, we enrolled 133 patients diagnosed with IgAN through biopsy. We calculated the 2-year estimated glomerular filtration rate (eGFR) slope (mL/min/1.73m²/year) and eGFR trajectory after methylprednisolone pulse therapy using mixed effects models stratified by the Oxford classification and three categories of pre-treatment hematuria: mild [urinary red blood cells (URBCs) < 10/high-power field (HPF)], moderate (URBCs 10-30/HPF), and severe (URBCs ≥ 30/HPF).

RESULTS

The severe pre-treatment hematuria group showed a significantly higher likelihood of having crescents (odds ratio (OR), 4.3; 95% confidence interval (CI), 1.7-10.9). In the longitudinal analysis of 103 patients, most of whom underwent tonsillectomy, the severe pre-treatment hematuria group had a significantly higher 2-year eGFR slope after methylprednisolone pulse therapy than the mild and moderate hematuria groups (mild, -0.52 ± 1.97; moderate, -0.32 ± 1.99; severe, 1.44 ± 3.20 mL/min/1.73m²/year). Patients with C2 scores showed a significantly higher 2-year eGFR slope after methylprednisolone pulse therapy than those with C0 and C1 scores (C0, -0.38 ± 1.74; C1, 0.81 ± 3.02; C2, 3.29 ± 3.68 mL/min/1.73m²/year). Analyses of eGFR trajectory after methylprednisolone pulse therapy revealed that the eGFR improved only in patients with severe pre-treatment hematuria or C2 score (P_interaction with time < 0.001).

CONCLUSIONS

The eGFR is likely to improve after methylprednisolone pulse therapy with tonsillectomy in IgAN patients with severe pre-treatment hematuria or a high percentage of crescents.

Predictability of the Oxford classification of IgA nephropathy in Henoch-Schonlein purpura nephritis

BACKGROUND

Whether the Oxford classification of immunoglobulin A nephropathy can be utilized to predict the adverse renal outcome of Henoch-Schonlein purpura nephritis (HSPN) has been long-debated. We, therefore, performed a meta-analysis to evaluate the prognostic value of Oxford classification lesions in HSPN.

METHODS

We systematically searched Medline, EMBASE, Web of Science, and the Cochrane Library for articles published from January 1970 to August 2020. Cohort and case-control studies investigating the correlation between the Oxford classification and renal outcome were included, the quality of which was assessed by the Newcastle-Ottawa scale criteria. The pooled odds ratios (ORs) with their 95% confidence intervals (CIs) were calculated with a random-effects model or a fixed-effects model depending on the heterogeneity.

RESULTS

A total of 485 papers were reviewed and eventually 9 comparisons were included, providing data of 1688 patients with HSPN. ORs for adverse renal events were 2.83 (95% CI 1.84-4.35; P < 0.001), 1.96 (95% CI 1.28-2.98; P < 0.05), and 5.45 (95% CI, 3.15-9.45; P < 0.001) for patients with lesions of endocapillary hypercellularity (E), segmental sclerosis (S), and tubular atrophy /interstitial fibrosis (T), respectively, without significant heterogeneity (E: I² = 0.0%; P = 0.498; S: I² = 22.4%; P = 0.258; T: I² = 33.6%; P = 0.171). Subgroup analysis adjusted for age also supported the results that E, S, and T lesions could serve as poor predictors (P < 0.05). Additionally, crescents (C) were strongly associated with renal outcome (OR 2.22; 95% CI 1.62-3.04; P < 0.001), with moderate heterogeneity (I² = 49.3%; P = 0.066). However, it should be noted that it is not the presence but the proportions of crescent lesions that were related to the high risk of progression to adverse renal events, because the predictability of lower rates of crescent (C1, with crescents > 0 and ≤ 25%) was uncertain (OR 2.21; 95% CI 0.75-6.51; P > 0.05). Although the pooled OR revealed that lesions of mesangial hypercellularity (M) were correlated with poor renal prognosis (OR 2.41; 95% CI 1.07-5.43; P < 0.05), subgroup analysis separating children from adults indicated that there seemed to be no significant difference.

CONCLUSIONS

Oxford classification, especially for E, S, T, and C, might be recommended for patients with HSPN, regardless of children and adults.

Role of Human Mesangial-Tubular Crosstalk in Secretory IgA-Induced IgA Nephropathy

BACKGROUND

IgA nephropathy (IgAN) is characterized by the mesangial deposition of pathogenic IgA. We previously detected the deposition of pathogenic secretory IgA (SIgA) in the mesangium of about one-third of IgAN patients. Tubulointerstitial injury has an important role in the development of IgAN. However, the relationship between SIgA and tubulointerstitial damage is currently unclear. In this work, the role of the mesangial-tubular crosstalk was explored in the tubulointerstitial damage in SIgA-induced IgAN.

METHODS

SIgA deposition in renal tissues of IgAN patients was detected by immunofluorescence. Flow cytometry was used to assess the binding of SIgA to human renal mesangial cells (HRMC) and human proximal tubule epithelial (HK-2) cells. HK-2 was co-cultured with HRMC added with SIgA isolated from patients or normal volunteers. Protein synthesis and gene expressions of TNF-α, TGF-β1, and MCP-1 were determined by ELISA and PCR, respectively. The expressions of the above cytokines in renal tissues of patients and normal controls were detected by immunohistochemistry.

RESULTS

Twenty-nine of 96 patients had SIgA deposition in the mesangium, but SIgA was rarely detected in the tubulointerstitium. The binding rate of SIgA to HK-2 (2.79%) was significantly lower than that of HRMC (81.6%) (p < 0.001). The expressions of TNF-α, TGF-β1, and MCP-1 in HRMC were significantly higher than in SIgA-stimulated HK-2 (p < 0.05), and their expressions were significantly higher in the SIgA-stimulated co-culture group compared with SIgA-stimulated HRMC (p < 0.05). The expressions of the above cytokines were mainly detected in tubulointerstitium of IgAN patients with positive and negative SIgA deposition, without significant difference between the 2 groups, but to a significantly higher level than that in normal controls, and their expressions positively correlated with tubulointerstitial injury.

CONCLUSION

Inflammatory factors released from the mesangium after SIgA deposition might mediate tubulointerstitial damage via mesangial-tubular crosstalk in IgAN.

CD71 mesangial IgA1 receptor and the progression of IgA nephropathy

The transferrin receptor (CD71) is known as a receptor for IgA1 on mesangial cells, but the role of CD71 in IgA nephropathy (IgAN) is unknown. We studied clinical implication of mesangial CD71 in 282 patients with biopsy-proven IgAN (2005-2018). The transcript and protein expression of glomerular CD71 was determined by real-time polymerase chain reaction and immunohistochemistry. Ten subjects with microscopic hematuria only and no evidence of histologic abnormalities on kidney biopsy were considered as controls. Human mesangial cells (HMCs) were treated with sera from IgAN patients and expression levels of CD71 and inflammatory cytokine markers were compared according to disease status. Disease progression was defined as a ≥30% decline in estimated glomerular filtration rate from the baseline value. During a mean follow up of 53.5 (18.3-75.9) months, 80 (28.4%) patients developed disease progression. The mRNA expression of CD71 was significantly higher in progressors than in nonprogressors (P = 0.001). Among the Oxford classification scores, patients with M1 had significantly higher CD71 expression levels than those with M0. In a multivariable Cox model, elevated transcript levels of CD71 were significantly associated with 4.32-fold higher risk of disease progression (P = 0.009). Furthermore, CD71 expression levels independently predicted the increase in proteinuria of ≥50% from the baseline (P = 0.03). Finally, HMCs treated with sera from IgAN patients with the higher Oxford score (M1E1S1T0) more increased the mRNA expression of CD71 and inflammatory markers than those with sera from negative score (M0E0S0T0). However, silencing CD71 significantly reduced expression levels of the inflammatory cytokine genes. Our results show that mesangial CD71 is significantly associated with disease progression and may play a biologic role in IgAN.

A Functional Variant rs3093023 in CCR6 Is Associated With IgA Nephropathy by Regulating Th17 Cells in a North Han Chinese Population

C-C chemokine receptor 6 (CCR6) is a susceptibility gene of various immune-related diseases, which was suggested to be shared with immunoglobulin A nephropathy (IgAN). In this study, we aimed to identify the functional variants. First, we analyzed the associations of CCR6 common and rare variants detected by multi-platform chips with IgAN susceptibility using imputation and identified 68 significantly associated common variants located in the regulatory region. Among them, rs3093023 showed both statistical significance (rs3093023-A, odds ratio [OR] = 1.15, P = 2.00 × 10⁻²) and the expression quantitative trait loci (eQTL) effect (P = 1.45 × 10⁻³). It was independently replicated (rs3093023-A, OR = 1.18, P = 5.56 × 10⁻³) and the association was reinforced in the meta-analysis (rs3093023-A, OR = 1.17, P = 6.14 × 10⁻⁷). Although rs3093023 was in a strong linkage disequilibrium with the reported CCR6 functional variant dinucleotide polymorphism, CCR6DNP, the alleles of rs3093023 (G>A) rather than of CCR6DNP were shown differential nuclear protein binding effect by electrophoretic mobility shift assay. The RegulomeDB and JASPAR databases predicted Pou2f1 as the potential transcription factor, which was negatively associated with CCR6 mRNA (r = −0.60, P = 3.94 × 10⁻⁹). At the mRNA level, the eQTL effect of CCR6 was validated (P = 4.39 × 10⁻²), and CCR6 was positively associated with the expression of CCR4 and IL-17A rather than that of CXCR3 and IFNG. At the protein level, a higher CCR6⁺ cell ratio was observed in a risk allele dose-dependent manner in lymphocytes (P = 3.57 × 10⁻²), CD3⁺ T cells (P = 4.54 × 10⁻²), and CD4⁺ T cells (P = 1.32 × 10⁻²), but not in CD8⁺ T cells. Clinical-pathological analysis showed that rs3093023 risk allele was significantly associated with diastolic blood pressure, serum creatinine, and high ratio of tubular atrophy/interstitial fibrosis. Overall, the rs3093023 was prioritized as the function variant in CCR6, which may contribute to IgAN susceptibility by regulating Th17 cells.

Novel urinary glycan profiling by lectin array serves as the biomarkers for predicting renal prognosis in patients with IgA nephropathy

In IgA nephropathy (IgAN), IgA1 molecules are characterized by galactose deficiency in O-glycans. Here, we investigated the association between urinary glycosylation profile measured by 45 lectins at baseline and renal prognosis in 142 patients with IgAN. The primary outcome was estimated glomerular filtration rate (eGFR) decline (> 4 mL/min/1.73 m²/year), or eGFR ≥ 30% decline from baseline, or initiation of renal replacement therapies within 3 years. During follow-up (3.4 years, median), 26 patients reached the renal outcome (Group P), while 116 patients were with good renal outcome (Group G). Multivariate logistic regression analyses revealed that lectin binding signals of Erythrina cristagalli lectin (ECA) (odds ratio [OR] 2.84, 95% confidence interval [CI] 1.11–7.28) and Narcissus pseudonarcissus lectin (NPA) (OR 2.32, 95% CI 1.11–4.85) adjusted by age, sex, eGFR, and urinary protein were significantly associated with the outcome, and they recognize Gal(β1-4)GlcNAc and high-mannose including Man(α1-6)Man, respectively. The addition of two lectin-binding glycan signals to the interstitial fibrosis/tubular atrophy score further improved the model fitness (Akaike’s information criterion) and incremental predictive abilities (c-index, net reclassification improvement, and integrated discrimination improvement). Urinary N-glycan profiling by lectin array is useful in the prediction of IgAN prognosis, since ECA and NPA recognize the intermediate glycans during N-glycosylation of various glycoproteins.

Efficacy and Safety of Immunosuppressive Monotherapy Agents for IgA Nephropathy: A Network Meta-Analysis

Background: The efficacy and safety of immunosuppressive monotherapy agents were evaluated for immunoglobulin A nephropathy (IgAN) using a network meta-analysis approach. Methods: Randomized controlled trials (RCTs) published prior to October 1, 2019, using immunosuppressive agents for treating IgAN, were systematically searched in PubMed, Embase, Cochrane Library, and Web of Science databases. Relative risks (RRs) or standard mean differences with 95% confidence intervals (CIs) were estimated using the random-effects model. The primary outcomes were clinical remission, end-stage renal disease (ESRD), and serious adverse events (SAEs). The secondary outcomes were urinary protein excretion and serum creatinine. Results: Twenty-five RCTs with 2,005 participants were deemed eligible. Six medications were evaluated: corticosteroids, mycophenolate mofetil (MMF), tacrolimus (TAC), cyclosporine, leflunomide, and hydroxychloroquine (HCQ). Steroids (RR 1.50, 95% CI 1.17-1.93), MMF (RR 2.05, 95% CI 1.15-3.65), TAC (RR 3.67, 95% CI 1.06-12.63), and HCQ (RR 3.25, 95% CI 1.05-10.09) significantly improved clinical remission rates compared to supportive care alone. Only steroids reduced the risk of ESRD (RR 0.35, 95% CI 0.12-0.98); however, there were significantly more SAEs than in the control group (RR 2.90, 95% CI 1.37-6.13). No significantly different effects in serum creatinine levels were found among the therapies. MMF showed no significant improvement in remission when excluding studies with a follow-up of fewer than 2 years in the sensitivity analysis (RR 1.41, 95% CI 0.40-4.92). The effect of TAC in the decrease of proteinuria was reversed after discontinuing medication for 3 months; the long-term effects of HCQ could not be evaluated due to the short follow-up duration. Conclusion: Corticosteroids might induce remission and increase renal survival in IgAN; however, adverse reactions should be taken into consideration. MMF, TAC, and HCQ might improve the remission of proteinuria when treating IgAN, but showed no superiority compared to steroids, and the long-term effects require further study.

Combining clinical features and MEST-C score in IgA nephropathy may be a better determinant of kidney survival

Introduction. IgA nephropathy (IgAN) is a heterogeneous disease with highly variable clinical and histopathological features. We investigated the effects of Oxford classification and clinical features on renal survival in patients with IgAN.Methods. This retrospective observational study conducted from 2013 to 2017. Ninety-seven patients who were followed up more than six months were examined.Results. A total of 97 patients (68% male and median age 40 years) were enrolled in this study. 13% of patients developed end stage renal disease (ESRD) within the median of 37 months of follow-up. Need for renal replacement therapy at the time of diagnosis, serum creatinine level of higher than 1.97 mg/dl, serum albumin level less than 3.5 gr/dl, 24-hour urine protein level of higher than > 3.5 g/day, the percentage of glomerulosclerosis higher than 53%, T2 score and total MEST-C score higher than two were found to be significant predictors of development of ESRD. None of the clinical or histopathological features were found to be significant predictor of steroid treatment sensitivity except T1-2 scores.Conclusion. We think that IgA nephropathy is a heterogeneous disease that requires clinical and histopathological features to be evaluated together, but not individually, to determine renal survival.What is new. Iga nephropathy is a heterogeneous disease and modern pathologic classification systems is not enough to predict to prognosis. Histopathological features to be evaluated with clinical features, but not individually, to determine renal survival. Also glucocorticoid treatment response seems to be independent from clinical and histopathological features except T1-2 score.

Repeat renal biopsy improves the Oxford classification-based prediction of immunoglobulin A nephropathy outcome

BACKGROUND

The prognosis of IgA nephropathy (IgAN) is very heterogeneous. Predicting the nature and the rate of the disease progression is crucial for refining patient treatment. The aim of this study was to evaluate the prognostic impact of an Oxford classification-based repeat kidney tissue evaluation to predict end-stage renal disease (ESRD).

METHODS

Patients with biopsy-proven primary IgAN who underwent two renal biopsies at our centre were analyzed retrospectively. Renal biopsies were scored by two pathologists blinded to the clinical data and according to the updated Oxford classification. Cox models were generated to evaluate the prognostic impact considering the Oxford classification elementary lesions from the first (Model 1) or the second (Model 2) biopsy, adjusted on clinical data at time of reevaluation. The prognostic impacts of the dynamic evolution of each elementary lesion between biopsies were also assessed through univariate and multivariate evaluation.

RESULTS

A total of 168 adult patients were included, with a median follow-up duration of 18 (range 11-24) years. The second biopsy was performed either systematically (n = 112) of for-cause (n = 56), after a median time of 5.4 years. The prognostic performances of Model 2 (second biopsy) were significantly better than Model 1 (first biopsy, analysis of deviance P < 0.0001). The dynamic changes of C and T lesions were significantly associated with the progression toward ESRD after adjustment on variables from Model 2.

CONCLUSION

Both static and dynamic Oxford-based histological evaluation offered by a repeat biopsy improves the prediction of ESRD in patients with IgAN.

Serum uric acid level is correlated with the clinical, pathological progression and prognosis of IgA nephropathy: an observational retrospective pilot-study

Objectives

This study was aimed to assess the relationship between serum uric acid (SUA) level and the clinical, pathological phenotype of IgA nephropathy (IgAN), and to determine the role of SUA level in the progression and prognosis of IgAN.

Methods

A total of 208 patients with IgAN were included in this study, and were classified into the normo-uricemia group and hyperuricemia group according to the SUA level. The clinical data at baseline, IgAN Oxford classification scores (MEST-C scoring system), and other pathological features were collected and further analyzed. All patients were followed up and the prognosis was assessed using Kaplan-Meier survival curves. GraphPad Prism 7.0 and SPSS 23.0 were used for statistical analyses.

Results

In clinical indicators, patients with hyperuricemia had the significantly higher proportion of males to females, mean arterial pressure, the levels of total cholesterol, triglyceride, Scr, BUN, 24 hour-urine protein, C3, and C4, the lower levels of high-density lipoprotein cholesterol and eGFR than those without (p < 0.05). In terms of pathological characteristics, the tubular atrophy/interstitial fibrosis scores, vascular injury scores, and glomerular sclerosis percentage were significantly higher in patients with hyperuricemia compared with those without (p < 0.01). There was no significant difference in the scores of mesangial hypercellularity, endocapillary hypercellularity, focal segmental glomerulosclerosis, as well as crescents between the two groups (p > 0.05). As for the depositions of immune complexes deposition in IgAN, the hyperuricemia group had less deposition of immunoglobulin G and FRA than the normo-uricemia group (p < 0.05), while the deposition of immunoglobulin A, immunoglobulin M, and complement C3 in the two groups showed no statistical difference. The survival curve suggested that patients in the hyperuricemia group have significantly poorer renal outcome than those in the normo-uricemia group (p = 0.0147). Results also revealed that the SUA level is a valuable predictor of renal outcome in patients with IgAN. The optimal cutoff value was 361.1 µmol/L (AUC = 0.76 ± 0.08167) and 614 µmol/L (AUC = 0.5728 ± 0.2029) for female and male, respectively.

Conclusions

The level of SUA is associated with renal function level and pathological severity of IgAN, and maybe a prognostic indicator of IgAN.

Corticosteroids Improve Renal Survival: A Retrospective Analysis From Chinese Patients With Early-Stage IgA Nephropathy

Background: The efficacy and safety of corticosteroids and immunosuppressive therapy remain controversial for the treatment of immunoglobulin A nephropathy (IgAN). This study aimed to evaluate the effects of corticosteroid and immunosuppressant therapy in Chinese patients with early-stage IgAN whose estimated glomerular filtration rate (eGFR) was ≥45 ml/min/1.73 m² and proteinuria was ≥1 g/24 h at biopsy.

Methods: Patients with biopsy-proven IgAN were retrospectively enrolled from four study centers between 2007 and 2016. Patients were regularly followed up for at least 1 year or until the study end point. Patients were categorized into three treatment groups: supportive care (SC), steroids alone (CS), and steroids plus immunosuppressants (IT). The observed responses to therapy included complete remission (CR), partial remission (PR), no response (NR), and end-stage renal disease (ESRD). The primary end point of the current study was defined as a 50% decline in eGFR and/or ESRD.

Results: A total of 715 patients (male 47% and female 53%) were recruited and followed up for 44.69 ± 24.13 months. The observed CR rate was 81.8% with corticosteroids alone (CS), 62.7% with corticosteroids + immunosuppresants (IT), and 37% with supportive care alone (SC). Renal outcomes were remarkably better in the CS group compared with the SC and IT groups (the percentage of patients reaching the end point in each group was 4.6 vs. 14.4 vs. 11.5%, respectively; p = 0.001). Moreover, 36 and 80-month renal survival were significantly better for the CS group (98.3 and 86.4%) than for the IT (94.2 and 82.4%) and SC (94.0 and 51.6%) groups. Early CKD stage also presented with better kidney survival (p < 0.001). Renal survival of CKD stage 1 patients was relatively good regardless of the specific treatment regimen. CS and IT treatment significantly improved renal survival for CKD stage 2 patients when compared with the SC group (p < 0.001 and 0.007, respectively). However, renal survival of CKD stage 3a patients was not impacted by any of the three treatment regimens. Subgroup analysis also showed that renal survival of patients with proteinuria >3.5 g, M1, E0, S1, T0, and C0 was significantly better in the CS group than in the SC and IT groups. A multivariate model showed that hypertension, serum creatinine, E1 lesion, and T1/T2 lesion remained independent predictors of poor renal survival.

Conclusions: Immunosuppressive therapy does not have further benefit beyond that provided by steroids. Corticosteroids plus optimal supportive care may further be beneficial in treating early-stage IgAN patients in that it could significantly improve the short-term renal outcome.

Evaluation of the Oxford classification in immunoglobulin A vasculitis with nephritis: a cohort study and meta-analysis

Background

Similarities in clinicopathological presentations in immunoglobulin A (IgA) nephropathy and IgA vasculitis with nephritis (IgAVN) raise the question of the utility of the Oxford classification in the latter. The aim of this study was to evaluate the Oxford classification in IgAVN.

Methods

We conducted a retrospective cohort study and meta-analysis following systematic searching of the MEDLINE and Excerpta Medica Database (EMBASE) databases between January 2009 and September 2019. We modeled the association of 30 and 50% decline in estimated glomerular filtration rate or end-stage renal disease with pathologic lesions of the Oxford classification including mesangial hypercellularity (M), endocapillary hypercellularity (E), segmental glomerulosclerosis (S), interstitial fibrosis/tubular atrophy (T) and crescents (C). Results were pooled using random-effects meta-analysis.

Results

The cohort study included 132 patients, and only T lesion was an independently risk factor in IgAVN. The meta-analysis yielded six retrospective studies with 721 patients and 139 endpoints. In multivariate model, T lesion was significantly associated with renal outcome (hazard ratio = 2.45, P = 0.007). M and C lesions could not predict renal outcome without evidence of heterogeneity. E and S lesions could not predict renal outcome with evidence of heterogeneity (I ² = 66.6%; P = 0.01, and I ² = 65.8%; P = 0.03, respectively). Subgroup analysis showed that the possible reasons to the heterogeneity were from usage of immunosuppressant, sample size and follow-up time.

Conclusions

The study suggests that the Oxford classification could not be fully validated in IgAVN. Higher portion of immunosuppressant especially before renal biopsy might be the main confounder for the predictive value of Oxford classification in IgAVN.

Validation of the revised Oxford classification for IgA nephropathy considering treatment with corticosteroids/immunosuppressors

The Oxford classification for IgA nephropathy (IgAN) was updated in 2017. We have validated the revised Oxford classification considering treatment with corticosteroids/immunosuppressors. In this retrospective analysis, 871 IgAN patients were enrolled. Patients were divided into two groups, those treated with or without corticosteroids/immunosuppressors. The 20-year renal prognosis up to end-stage renal disease was assessed using the Oxford classification. In all patients, the renal survival rate was 87.5% at 10 years and 72.6% at 20 years. The T score alone was significantly related to renal prognosis in the Kaplan–Meier analysis and multivariate Cox regression analysis. In the non-treatment group (n = 445), E, S, T, and C scores were significantly related to renal survival rates, however, in the treatment group (n = 426), T score alone was significantly related to renal prognosis on Kaplan–Meier analysis, indicating that corticosteroids/immunosuppressors improved renal prognosis in E1, S1, and C1. In patients with E1, S1, or C1, the treatment group showed significantly better renal prognosis than the non-treatment group in univariate and multivariate analysis. The Oxford classification and T score were used to determine renal prognosis in IgAN patients. Corticosteroids/immunosuppressors improved renal prognosis, especially E1, S1, and C1 scores.

Clinical course of Immunoglobulin A nephropathy with crescents in a multi-ethnic Southeast Asian cohort

AIM

Clinical presentation and course of Immunoglobulin A nephropathy vary by ethnicity and geography and significance of extracapillary proliferation or crescents (IgAN-C) in Southeast Asia is not well described. We aimed to describe the clinical course of IgAN-C in Singapore.

METHODS

Retrospective cohort study of adult biopsy-proven IgAN diagnosed between February 2011 and October 2016 in 2 hospital-based nephrology units. Outcome was chronic kidney disease (CKD) progression, defined as reduction in eGFR ≥50% or end stage renal failure (ESRF).

RESULTS

One hundred and forty-five patients were studied. Among individuals with IgAN-C (n = 44, 30%), 38 patients had cellular or fibrocellular crescents in 1 to 25% of the glomeruli and 6 had crescents in >25%. Median eGFR was 54 (33, 83) mL/min/1.73 m² . Compared to IgAN without crescents, IgAN-C had greater proteinuria (median 2.9 [1.4, 5.4] g/g vs 1.9 [1.1, 3.6] g/g, P = .03) and more had endocapillary hypercellularity (96% vs 39%, P < .001). IgAN-C were also more likely to receive immunosuppressants (66% vs 43%, P = .01) such as prednisolone (63% vs 38%, P = .006) and cyclophosphamide (12% vs 2%, P = .03). Median follow up was 27 (12, 46) months. IgAN-C were more likely to achieve proteinuria reduction ≥50% at 6 months (66% vs 44%, P = .03). CKD progression within 12 months was not different among those with and without crescents (13% vs 10% respectively, P = .73). However, immunosuppressant treatment of IgAN-C was associated with reduced ESRF (0 vs 20%, P = .03).

CONCLUSION

Immunosuppressants may attenuate the risk of ESRF in IgAN-C.

Efficacy and safety of Abelmoschus manihot for IgA nephropathy: A multicenter randomized clinical trial

RATIONALE AND OBJECTIVE

IgA nephropathy (IgAN) is an important cause for end-stage renal disease worldwide. The treatment for IgAN remains challenging, and few randomized and controlled clinical trials have been conducted to evaluate new therapies. The present study assesses the efficacy and safety of Abelmoschus manihot (AM) in IgAN patients.

STUDY DESIGN

Randomized, non-inferiority, double-blind, double-dummy multicenter trial.

SETTING AND PARTICIPANTS

This trial was designed to recruit 1,600 biopsy-proven IgAN patients (proteinuria between 0.5-3.0 g/d and estimated glomerular filtration rate [eGFR] of ≥ 45 ml/min/1.73 m2) across China.

INTERVENTIONS

The participants were randomized at 1:1 to AM (2.5 g for three times per day) or losartan potassium (100 mg per day) for 48 weeks.

OUTCOMES

The primary outcome was the change in 24-hour proteinuria from baseline to week 48. The secondary outcomes were the change in eGFR from baseline to week 48, and the incidents of endpoint events (proteinuria ≥ 3.5 g/24 h, doubling of serum creatinine, or receiving renal replacement treatment).

RESULTS

Among 1,470 randomized patients (mean age, 37.4 [SD, 10.6] years old; 777 [52.9%] were female; mean eGFR, 95.0 [SD, 24.3] mL/min/1.73 m2; mean 24-hour proteinuria, 1.2 [SD, 0.7] g/d), the mean decline in 24-h proteinuria at week 48 was 230 mg and 253 mg in the AM and losartan potassium groups, respectively (P = 0.676). The mean difference in the change in 24-h proteinuria between these two groups was -23.32 mg (95% confident interval: -123.2 to 76.6, p = 0.647). The mean decline in eGFR was 0.41 ml/min/1.73 m2 and 0.76 ml/min/1.73 m2 in the AM and losartan potassium groups, respectively (p = 0.661). The mean difference in the change in eGFR between these two groups was -0.43 ml/min/1.73 m2 (95% confident interval: -1.99 to 1.13, p = 0.589). The incidence of endpoint events was 8.6% in the AM group and 8.2% in the losartan group (p = 0.851).

LIMITATIONS

The results of the trial may not be generalized to IgAN patients with a proteinuria of > 3.0 g/d and an eGFR of < 45 ml/min/1.73 m2. The long-term benefits of AM in reducing the risk of progressive renal dysfunction remains unclear, based on this 48-week observation.

CONCLUSION

AM can be recommended as a promising treatment for IgAN patients.

Clinical relevance of membrane attack complex deposition in children with IgA nephropathy and Henoch-Schönlein purpura

BACKGROUND

IgA nephropathy (IgAN) and Henoch-Schönlein purpura are common glomerular disorders in children sharing the same histopathologic pattern of IgA deposits within the mesangium, even if their physiopathology may be different. Repeated exposure to pathogens induces the production of abnormal IgA1. The immune complex deposition in the renal mesangium in IgAN or potentially in small vessels in Henoch-Schönlein purpura induces complement activation via the alternative and lectin pathways. Recent studies suggest that levels of membrane attack complex (MAC) in the urine might be a useful indicator of renal injury. Because of the emerging availability of therapies that selectively block complement activation, the aim of the present study is to investigate whether MAC immunostaining might be a useful marker of IgA-mediated renal injury.

METHODS

We conducted immunohistochemistry analysis of the MAC on renal biopsies from 67 pediatric patients with IgAN and Henoch-Schönlein purpura. We classified their renal biopsies according to the Oxford classification, retrieved symptoms, biological parameters, treatment, and follow-up.

RESULTS

We found MAC expression was significantly related to impaired renal function and patients whose clinical course required therapy. MAC deposits tend to be more abundant in patients with decreased glomerular filtration rate (p = 0.02), patients with proteinuria > 0.750 g/day/1.73 m², and with nephrotic syndrome. No correlation with histological alterations was observed.

CONCLUSIONS

We conclude that MAC deposition could be a useful additional indicator of renal injury in patients with IgAN and Henoch-Schönlein purpura, independent of other indicators.

IgA nephropathy: A brief review

IgA nephropathy is a lifelong disease that is the most common primary glomerulopathy worldwide. It has a complicated and incompletely understood pathogenesis that is theorized as a four 'hit' process involving an improperly produced IgA. While it has a variety of histologic appearances, it is diagnosed by the presence of bright IgA deposits within the mesangium as seen on immunofluorescence and mesangial hypercellularity by light microscopy. This brief review explains the varied histologic features that are important in the diagnosis of IgA nephropathy and the calculation of the MEST-C score that was first introduced by the 2009 Oxford Classification working group.

Diffusion Weighted Magnetic Resonance Imaging in the Assessment of Renal Function and Parenchymal Changes in Chronic Kidney Disease: A Preliminary Study

Background

The aim of this study was to evaluate the feasibility of using intravoxel incoherent motion (IVIM) imaging for noninvasive assessment of pathologic changes in chronic kidney disease (CKD).

Material/Methods

Thirty-four patients with CKD and 20 healthy volunteers were examined on a 1.5 T magnetic resonance imaging (MRI) unit. The examination consisted of morphologic sequences and diffusion-weighted echo-planar sequence with 10 b values. Diffusion parameters were calculated with the use of mono- (apparent diffusion coefficient, ADC) and bi-exponential model: pure diffusion coefficient (D) and perfusion fraction (Fp). Blood samples to assess the serum creatinine level were taken immediately before examination. Ultrasound guided biopsies were performed in less than 30 days from MRI and were scored by an experienced nephropathologist. Parametrical unpaired t-test and ROC curve analysis were used to investigate differences in diffusion parameters in relation to estimated glomerular filtration rate (eGFR). Pearson’s correlation coefficients were calculated to assess relationship between diffusion parameters and laboratory and histopathological markers of renal damage. P-value <0.05 indicated statistical significance.

Results

Both ADC and D correlated positively with eGFR (respective r 0.74 and 0.72), however D showed a more significant correlation with histopathology: while D correlated negatively with parameters reflecting chronic glomerular (r −0.48) and tubulo-interstitial changes (r −0.47), ADC correlated only with interstitial infiltrations (r −0.44). Flow-related diffusion parameters showed high standard deviation.

Conclusions

IVIM imaging is sensitive to functional and morphologic changes in CKD. The separation of influence of Fp from true diffusion improves the assessment of chronic changes in renal parenchyma.

Treatment effects of Chinese medicine (Yi-Qi-Qing-Jie herbal compound) combined with immunosuppression therapies in IgA nephropathy patients with high-risk of end-stage renal disease (TCM-WINE): study protocol for a randomized controlled trial

Background

IgA nephropathy (IgAN) is the most common glomerular disease worldwide. It has a high incidence in Asians and is more likely to progress to end-stage renal disease (ESRD). For high-risk IgAN, which is clinically characterized by massive proteinuria and renal dysfunction, however, there has been no international consensus on treatment options. Compared with other developed countries, IgAN patients in China are often found to have severe kidney function loss at initial diagnosis. Yi-Qi-Qing-Jie formula (YQF; a compound recipe of Chinese medicinal herbs) has shown potential renal protection in our previous clinical studies. To further confirm the efficacy and safety of YQF in the treatment of high-risk IgAN, we have designed a prospective double-blind randomized placebo-controlled trial.

Methods/design

The TCM-WINE study is a single-center, prospective, double-blind randomized placebo-controlled trial. We plan to randomize 60 participants with biopsy-proven IgAN to a YQF combined group (YQF compound combined with prednisolone, and cyclophosphamide if necessary) or an immunosuppression group (placebo-YQF combined with prednisolone, and cyclophosphamide if necessary). The two groups will enter a 48-week in-trial treatment phase and receive post-trial follow-up until study completion (3 years). All patients will receive optimal supportive care. The primary composite outcome is defined as the first occurrence of a 40% decrease in estimated glomerular filtration rate (eGFR) from the baseline lasting for 3 months, initiating continuous renal replacement treatment, or death due to chronic kidney disease (CKD) during the 3-year study phase. The secondary endpoint events are defined as the mean annual eGFR decline rate (eGFR slope, ml/min per 1.73 m² per year), which is calculated by the eGFR regression curve for each eligible patient, and proteinuria remission (prescribed as proteinuria < 0.5 g/day) at weeks 24, 36, and 48 during the in-trial phase. The remission rate of symptoms and inflammation status will be evaluated at week 48. Safety monitoring and assessment will be undertaken during the study.

Discussion

The TCM-WINE study will evaluate the effects and safety of YQF combined therapy compared with immunosuppression monotherapy on the basis of the optimal supportive treatment in high-risk IgAN. The evidence from this study will provide a novel, effective, and safe Chinese characteristic therapy for high-risk IgAN patients.

Trial registration

ClinicalTrials.gov, NCT03418779. Registered on 18 June 2018.

Minor Glomerular Abnormalities are Associated with Deterioration of Long-Term Kidney Function and Mitochondrial Injury

Minor glomerular abnormalities (MGAs) are unclassified glomerular lesions indicated by the presence of minor structural abnormalities that are insufficient for a specific pathological diagnosis. The long-term clinical outcomes and pathogenesis have not been examined. We hypothesized that MGAs would be associated with the deterioration of long-term kidney function and increased urinary mitochondrial DNA (mtDNA) copy numbers. We retrospectively enrolled patients with MGAs, age-/sex-/estimated glomerular filtration rate (eGFR)-matched patients with immunoglobulin A nephropathy (IgAN), and similarly matched healthy controls (MHCs; n = 49 each). We analyzed the time × group interaction effects of the eGFR and compared mean annual eGFR decline rates between the groups. We prospectively enrolled patients with MGAs, age- and sex-matched patients with IgAN, and MHCs (n = 15 each) and compared their urinary mtDNA copy numbers. Compared to the MHC group, the MGA and IgAN groups displayed differences in the time × group effects of eGFR, higher mean annual rates of eGFR decline, and higher urinary mtDNA copy numbers; however, these groups did not significantly differ from each other. The results indicate that MGAs are associated with deteriorating long-term kidney function, and mitochondrial injury, despite few additional pathological changes. We suggest that clinicians conduct close long-term follow-up of patients with MGAs.