Causal relationship between Helicobacter pylori infection and IgA nephropathy: a bidirectional two-sample mendelian randomization study.

IgA nephropathy (IgAN) is one of the most common primary glomerulonephritis, and serum Helicobacter pylori (H. pylori) antibody levels are increased in patients with IgA N, but the role of H. pylori infection in the pathogenesis of IgAN is unclear. In this study, we investigated whether there is a causal relationship and reverse causality between IgAN and H. pylori infection by using a bidirectional two-sample Mendelian randomization (MR) analysis. This study was estimated using inverse variance weighted (IVW), MR-Egger and weighted median methods, with the IVW method having the strongest statistical efficacy. Seven common serum H. pylori antibodies were selected as exposure factors for positive MR analysis. The results showed that there was no evidence of a causal relationship between H. pylori infection and IgAN. Reverse MR analysis showed that there was also no evidence that the occurrence of IgAN leads to an increased risk of H. pylori infection.

Role of serum complement C3 and C4 on kidney outcomes in IgA nephropathy.

IgA Nephropathy (IgAN) is the most prevalent glomerular disease worldwide. Complement system activation is crucial in its pathogenesis. Few studies correlated serum C3 and C4 with disease activity and prognosis. This retrospective study investigated the prognostic value of serum complement at the time of diagnosis in patients with IgAN. Specifically we evaluated whether adding serum C3 and C4 levels to established predictive models-one based on variables related to chronic kidney disease (CKD) progression and another incorporating variables from the International IgA Prediction Tool (IntIgAPT)-enhances the accuracy of outcome prediction. A composite renal outcome was defined as 50% decline in eGFR or onset of kidney failure. 101 patients were stratified according to baseline C3 levels in three groups (Low, Medium and High). During a median follow-up of 54 months, the Low group exhibited higher incidence of primary outcome (16.3 events vs 2.9 and 1.7 events × 100 pts/year, p = 0.0026). Model-1 (M1), consisting of CKD progression variables, and Model-3 (M3), comprising IntIgANPT variables, were implemented with baseline C3 and C4 to create Model-2 (M2) and Model-4 (M4), respectively. M2 demonstrated better predictive performance over M1, showing higher discrimination (lower AIC and BIC, higher C-index and NR2). Similarly, M4 outperformed M3, showing enhanced outcome prediction when C3 and C4 levels were added. Implementation of serum C3 and C4 can enhance prediction accuracy of already-validated prognostic models in IgAN. Lower C3 and higher C4 levels were associated with poorer prognosis, highlighting a more 'Complement-Pathic' subset of patients.

Correlation of Serum Bilirubin with Clinical and Pathological Characteristics of Patients with IgA Nephropathy.

OBJECTIVE: To investigate the correlations of total bilirubin (TBIL), direct bilirubin (DBIL), and indirect bilirubin (IBIL) with various clinical indicators and pathological features of patients with IgA nephropathy (IgAN). METHODS: Patients diagnosed with IgAN were included and divided into low and high TBIL/DBIL/IBIL groups. Correlation analysis was performed to assess the relationships between the bilirubin indices and other clinical and pathological variables. Logistic regression was applied to identify the independent risk factors of mesangial cell proliferation (corresponding to M1 in the Oxford classification of IgAN). RESULTS: Totally 192 patients with IgAN were included, and the patient clinical indicators were compared between the different bilirubin subgroups. Compared to the groups with higher TBIL, DBIL, and IBIL levels, groups with lower values of these bilirubin indices exhibited a higher 24-hour urine protein (24hUP) concentration but a lower proportion of males as well as reduced total protein, albumin, haemoglobin, and glutamic-pyruvic transaminase levels (p < 0.05). Moreover, the low-DBIL group displayed higher total cholesterol, triglyceride, and low-density lipoprotein (LDL) concentrations (p < 0.05) than those in the high DBIL group. Spearman analysis further revealed that TBIL, DBIL, and IBIL were negatively correlated with 24hUP and positively correlated with haemoglobin, total protein, and albumin (p < 0.05). Additionally, DBIL exhibited negative correlations with total cholesterol, triglyceride, and LDL (p < 0.05). From a pathological perspective, M1 incidence was higher in the low TBIL and IBIL groups (both p < 0.05). Furthermore, the high IBIL group showed a lower occurrence of cellular/fibrocellular crescents (C1 (in at least one glomerulus) and C2 (in >25% of glomeruli) in the Oxford classification, p < 0.05). Lastly, the multivariate regression model suggested that IBIL was an independent protective factor for M1 (odds ratio = 0.563, 95% confidence interval = 0.344-0.921, p = 0.022). CONCLUSIONS: Patients with IgAN accompanied by low values of bilirubin indices exhibit worsened disease-related clinical indicators (24hUP, total protein, albumin, and haemoglobin levels). Reduced TBIL and IBIL concentrations are indicative of severe renal pathology, with IBIL being a protective factor against M1.

Mendelian Randomization Analysis of Systemic Iron Status and Risk of Different Types of Kidney Disease.

With rapid increases in incidence, diverse subtypes, and complicated etiologies, kidney disease remains a global public health problem. Iron, as an essential trace element, has pleiotropic effects on renal function and the progression of kidney diseases. A two-sample Mendelian randomization (MR) analysis was implemented to determine the potential causal effects between systemic iron status on different kidney diseases. Systemic iron status was represented by four iron-related biomarkers: serum iron, ferritin, transferrin saturation (TfSat), and total iron binding capacity (TIBC). For systemic iron status, 163,511, 246,139, 131,471, and 135,430 individuals were included in the genome-wide association study (GWAS) of serum iron, ferritin, TfSat, and TIBC, respectively. For kidney diseases, 653,143 individuals (15,658 cases and 637,485 controls), 657,076 individuals (8160 cases and 648,916 controls), and 659,320 individuals (10,404 cases and 648,916 controls) were included for immunoglobulin A nephropathy (IgAN), acute kidney disease (AKD), and chronic kidney disease (CKD), respectively. Our MR results showed that increased serum iron [odds ratio (OR): 1.10; 95% confidence interval (95% CI): 1.04, 1.16; p < 0.0042], ferritin (OR: 1.30; 95% CI: 1.14, 1.48; p < 0.0042), and TfSat (OR: 1.07; 95% CI: 1.04, 1.11; p < 0.0042)] and decreased TIBC (OR: 0.92; 95% CI: 0.88, 0.97; p < 0.0042) were associated with elevated IgAN risk. However, no significant associations were found between systemic iron status and AKD or CKD. In our MR study, the genetic evidence supports elevated systemic iron status as a causal effect on IgAN, which suggests a potential protective effect of iron chelation on IgAN patients.

Differentiated metabolomic profiling reveals plasma amino acid signatures for primary glomerular disease.

Primary glomerular disease (PGD) is an idiopathic cause of renal glomerular lesions that is characterized by proteinuria or hematuria and is the leading cause of chronic kidney disease (CKD). The identification of circulating biomarkers for the diagnosis of PGD requires a thorough understanding of the metabolic defects involved. In this study, ultra-high performance liquid chromatography-tandem mass spectrometry was performed to characterize the amino acid (AA) profiles of patients with pathologically diagnosed PGD, including minimal change disease (MCD), focal segmental glomerular sclerosis (FSGS), membranous nephropathy, and immunoglobulin A nephropathy. The plasma concentrations of asparagine and ornithine were low, and that of aspartic acid was high, in patients with all the pathologic types of PGD, compared to healthy controls. Two distinct diagnostic models were generated using the differential plasma AA profiles using logistic regression and receiver operating characteristic analyses, with areas under the curves of 1.000 and accuracies up to 100.0% in patients with MCD and FSGS. In conclusion, the progression of PGD is associated with alterations in AA profiles, The present findings provide a theoretical basis for the use of AAs as a non-invasive, real-time, rapid, and simple biomarker for the diagnosis of various pathologic types of PGD.

The prognostic value of the systemic immune inflammation index in patients with IgA nephropathy.

BACKGROUND: Immune and inflammatory factors are considered the basic underlying mechanisms of IgA nephropathy (IgAN). The systemic immune inflammation index (SII) is a new inflammatory biomarker and has been identified as a prognostic indicator for various diseases. However, limited studies have been conducted on the prognostic value of the SII in patients with IgAN, and we aimed to address this gap. METHODS: A total of 374 patients with IgAN confirmed by renal biopsy performed from 1 January 2015 to 1 April 2019, were retrospectively included. The follow-up period of all patients was at least 12 months after diagnosis, and the endpoint was defined as end-stage kidney disease (ESKD). Patients were further divided into a high-risk group (SII ≥ 456.21) and a low-risk group (SII < 456.21) based on the optimal cutoff value of the SII determined by receiver operating characteristic (ROC) curve analysis. Baseline clinicopathological parameters were compared between the groups, and Cox proportional hazards analyses and Kaplan-Meier analysis were performed to assess renal survival in IgAN patients. RESULTS: After a median follow-up period of 32.5 months, a total of 53 patients eventually reached ESKD. Patients in the high-SII group tended to have a lower hemoglobin level (p = 0.032) and eGFR (p < 0.001), a higher serum creatinine level (p = 0.023) and 24-hour total protein level (p = 0.004), more severe tubular atrophy and interstitial fibrosis (p = 0.002) and more crescents (p = 0.030) than did those in the low-SII group. Univariate and multivariate Cox regression analyses demonstrated that an SII ≥456.21 was an independent risk factor for poor renal survival in IgAN patients (HR 3.028; 95% CI 1.486-6.170; p = 0.002). Kaplan-Meier analysis revealed that a high SII was significantly associated with poor renal prognosis (p < 0.001) and consistently exhibited remarkable discriminatory ability across different subgroups in terms of renal survival. CONCLUSION: A high SII was associated with more severe baseline clinical and pathological features, and an SII ≥456.21 was an independent risk factor for progression to ESKD in IgAN patients.

Haemoglobin, albumin, lymphocyte, and platelet score as an independent predictor for renal prognosis in IgA nephropathy.

Objective: The haemoglobin, albumin, lymphocyte, and platelet (HALP) score, a convenient and composite laboratory biomarker, can reflect inflammation and systemic nutritional status. This study was performed to investigate the effect of the HALP score on the prognosis of patients with IgA nephropathy (IgAN). Methods: This is a retrospective single centre study that enrolled 895 biopsy-confirmed IgAN patients from June 2019 to June 2022 who were followed for more than 1 year. Kaplan-Meier curves and Cox regression analyses were performed to determine the relationship between HALP and adverse outcomes. The restricted cubic splines was used to identify the possible associations. The optimal cut-off value of HALP for renal poor outcome was identified by the area under the receiver operating characteristic curve (AUC). Results: A total of 895 patients finally participated in the study and were divided into three groups (tertial 1-3) according to the baseline HALP score. More severe clinicopathologic features were observed in the lower HALP group, and Kaplan-Meier analysis showed patients in tertial 1 had a higher risk of kidney failure than the other groups (log-rank=11.02, P= 0.004). Multivariate Cox regression revealed that HALP score was an independent risk factor for renal prognosis in IgAN (adjusted HR: 0.967, 95% CI: 0.945-0.990, P = 0.006). The results of subgroup analysis suggested that HALP was more important in patients under the age of 50, BMI ≤ 23.9 and eGFR ≤ 90 mL/min/1.73 m2. The best cut-off HALP for renal survival was 38.83, sensitivity 72.1%, and specificity 55.9% (AUC: 0.662). Patients were further grouped according to HALP cut-off values and propensity matched. Multivariate Cox regression analysis revealed that HALP remained an independent predictor of IgAN in the matched cohort (HR 0.222, CI: 0.084-0.588, P=0.002). Conclusion: HALP is a novel and potent composite parameter to predict kidney outcome in patients with IgAN.

Machine learning-based diagnostic prediction of IgA nephropathy: model development and validation study.

IgA nephropathy progresses to kidney failure, making early detection important. However, definitive diagnosis depends on invasive kidney biopsy. This study aimed to develop non-invasive prediction models for IgA nephropathy using machine learning. We collected retrospective data on demographic characteristics, blood tests, and urine tests of the patients who underwent kidney biopsy. The dataset was divided into derivation and validation cohorts, with temporal validation. We employed five machine learning models-eXtreme Gradient Boosting (XGBoost), LightGBM, Random Forest, Artificial Neural Networks, and 1 Dimentional-Convolutional Neural Network (1D-CNN)-and logistic regression, evaluating performance via the area under the receiver operating characteristic curve (AUROC) and explored variable importance through SHapley Additive exPlanations method. The study included 1268 participants, with 353 (28%) diagnosed with IgA nephropathy. In the derivation cohort, LightGBM achieved the highest AUROC of 0.913 (95% CI 0.906-0.919), significantly higher than logistic regression, Artificial Neural Network, and 1D-CNN, not significantly different from XGBoost and Random Forest. In the validation cohort, XGBoost demonstrated the highest AUROC of 0.894 (95% CI 0.850-0.935), maintaining its robust performance. Key predictors identified were age, serum albumin, IgA/C3, and urine red blood cells, aligning with existing clinical insights. Machine learning can be a valuable non-invasive tool for IgA nephropathy.

The predictive value of free thyroxine combined with tubular atrophy/interstitial fibrosis for poor prognosis in patients with IgA nephropathy.

Background: IgA nephropathy (IgAN), the most common type of glomerulonephritis, has great individual differences in prognosis. Many studies showed the relationship between thyroid hormones and chronic kidney disease. However, the relationship between free thyroxine (FT4), as a thyroid hormone, and IgAN is still unclear. This study aimed to evaluate the impact of FT4 on IgAN prognosis. Methods: This retrospective study involved 223 patients with biopsy-proven IgAN. The renal composite outcomes were defined as: (1) ESRD, defined as eGFR < 15 ml/(min·1.73 m2) or initiation of renal replacement therapy (hemodialysis, peritoneal dialysis, renal transplantation); (2) serum creatinine doubled from baseline; (3) eGFR decreased by more than 50% from baseline. The predictive value was determined by the area under the curve (AUC). Kaplan-Meier and Cox proportional hazards analyses assessed renal progression and prognosis. Results: After 38 (26-54) months of follow-up, 23 patients (10.3%) experienced renal composite outcomes. Kaplan-Meier survival curve analysis showed that the renal survival rate of the IgAN patients with FT4<15.18pmol/L was lower than that with FT4≥15.18pmol/L (P < 0. 001). Multivariate Cox regression model analysis showed that FT4 was a protective factor for poor prognosis of IgAN patients, whether as a continuous variable or a categorical variable (HR 0.68, 95%CI 0.51-0.90, P =0.007; HR 0.04, 95%CI 0.01-0.20, P <0.001). ROC curve analysis showed that FT4 combined with t score had a high predictive value for poor prognosis of IgAN patients (AUC=0.881, P<0.001). Conclusion: FT4 was a protective factor for IgAN. In addition, FT4 combined with tubular atrophy/interstitial fibrosis had a high predictive value for poor prognosis of IgAN.

Complement system is overactivated in patients with IgA nephropathy after COVID-19.

IgA nephropathy (IgAN), which has been confirmed as a complement mediated autoimmune disease, is also one form of glomerulonephritis associated with COVID-19. Here, we aim to investigate the clinical and immunological characteristics of patients with IgAN after COVID-19. The level of plasma level of C5a (p < 0.001), soluble C5b-9 (p = 0.018), FHR5 (p < 0.001) were all significantly higher in Group CoV (33 patients with renal biopsy-proven IgAN experienced COVID-19) compared with Group non-CoV (44 patients with IgAN without COVID-19), respectively. Compared with Group non-CoV, the intensity of glomerular C4d (p = 0.017) and MAC deposition (p < 0.001) and Gd-IgA1 deposition (p = 0.005) were much stronger in Group CoV. Our finding revealed that for IgAN after COVID-19, mucosal immune responses to SARS-CoV-2 infection may result in the overactivation of systemic and renal local complement system, and increased glomerular deposition of Gd-IgA1, which may lead to renal dysfunction and promote renal progression in IgAN patients.

Association of time-averaged serum uric acid level with clinicopathological information and long-term outcomes in patients with IgA nephropathy.

Objective: Whether serum uric acid (SUA) at baseline could been identiûed as a risk factor for progression in IgA nephropathy (IgAN) patients remains unclear, therefore, long- term SUA control levels must be monitored. We aimed to investigate the relevant factors affecting time-averaged SUA (TA-SUA) and to assess the prognostic value of TA-SUA in IgAN. Methods: This retrospective study included 152 patients with IgAN. The relationships between TA-SUA and clinicopathological features and renal outcomes (defined as the doubling of the baseline serum creatinine level or end-stage renal disease) were analyzed in groups divided by quartiles of TA-SUA levels, the presence of hyperuricemia, and sex. Results: Patients with high TA-SUA levels had higher levels of baseline SUA, blood urea nitrogen (BUN), triglycerides, serum C3 and serum C4 and were more likely to be male and have hypertension, proteinuria, poor renal function, and pathological injuries including high grades of tubular atrophy/interstitial fibrosis (T1-T2). These patients had a poorer prognosis compared with patients with low TA-SUA levels. The TA-SUA level was positively correlated with baseline age and BUN, triglycerides, serum C3, and serum C4 levels, and negatively correlated with baseline eGFR. Survival curve analysis indicated that persistent hyperuricemia was associated with significantly poorer renal outcomes than normo-uricemia in both men and women. The TA-SUA level also was an independent predictor of renal outcome in patients with IgAN, with optimal cutoû values of 451.38 µmol/L (area under the curve (AUC) = 0.934) for men and 492.83 µmol/L (AUC = 0.768) for women. Conclusions: The TA-SUA level is associated with triglyceride level, complement component levels, renal function, and pathological severity of IgAN, and it may be a prognostic indicator in male and female patients with IgAN.

Differences of clinicopathological characteristics and outcomes of IgA nephropathy patients with and without nephrotic syndrome.

PURPOSE: To evaluate the differences in clinicopathological features and outcomes of IgA nephropathy (IgAN) patients with and without nephrotic syndrome. METHODS: In this retrospective cohort study, IgAN patients from January 2006 to December 2011 in the First Affiliated Hospital of Sun Yat-sen University were enrolled and followed up to Dec 31, 2013. Logistic and Cox regression were conducted to evaluate the associated factors of nephrotic syndrome (NS) and its relation with outcomes of creatinine doubling and progression to end-stage kidney disease (ESKD). RESULTS: A total of 1413 patients with IgAN were enrolled in this study, 57 (4.0%) of whom exhibited NS. Meanwhile, 13 (22.8%) of NS IgAN patients had minimal change disease (MCD). Logistic regression showed that more presence of hypertension, less glomerular sclerosis, less tubular atrophy/interstitial fibrosis, and lower density of IgA deposition in mesangial region were significantly associated with NS IgAN that were independent of age and gender. In addition, a total of 921 patients (890 with non-NS IgAN and 31 with NS IgAN) were followed up to Dec 31, 2013. After adjusting for age, sex, baseline estimated glomerular rate, hypertension and hemoglobin, no significant difference was observed in outcomes of serum creatinine doubling and ESKD between patients with or without NS IgAN. CONCLUSIONS: Prevalence of NS IgAN patients was 4.0%, and 22.8% of them had MCD. Patients with NS IgAN had more severe clinical but less severe pathological features. However, outcomes of serum creatinine doubling and ESKD were not significantly different between patients with or without NS IgAN.

Non-diabetic nephropathy in diabetic patients: incidence, HbA1c variability and other predictive factors, and implications.

PURPOSE: Diabetes mellitus (DM) is the leading cause of chronic kidney disease (CKD) in the population. In patients with diabetes mellitus, the incidence of non-diabetic nephropathy (NDNP) has been estimated to range from 3% to 69.5%. Personal judgment is frequently employed while deciding whether or not to do a kidney biopsy (KB) on diabetic patients. NDNP alters the prognosis and course of treatment for people with DM. In our study, we examined the incidence of NDNP concurrent with the progression of diabetes mellitus, as well as the laboratory and clinical indicators that could be utilized to forecast it. METHODS: A retrospective analysis of 76 diabetic patients who underwent KB was conducted. Based on the pathological diagnoses of these patients, they were categorized as DNP (diabetic nephropathy) or NDNP. The definition of HbA1c variability was determined by calculating the mean HbA1c and the average value of the HbA1c measurements, as well as the standard deviation (SD) for each participant. RESULTS: NDNP was detected in 50% of 76 patients. Among patients with NDNP, 36.8% had focal segmental glomerulosclerosis (FSGS), 23.6% had membranous glomerulonephritis, and 7.8% had IgA nephritis. The NDNP group exhibited significantly higher rates of female gender, absence of diabetic retinopathy, shorter time to diagnosis of diabetes mellitus, chronic kidney disease, and proteinuria, less intensive medication for diabetes mellitus, presence of hematuria and leukociduria, immunological serological marker positivity, and non-HbA1C variability. Risk factors for predicting non-diabetic nephropathy, as determined by multivariate analysis, included female gender, the absence of diabetic retinopathy, non-HbA1c variability and a positive immunological serological test. CONCLUSION: In this study, a significant number of diabetic patients with chronic kidney disease were diagnosed with NDNP. Identifying these patients allows for treatment of the specific underlying disease. Factors such as the absence of DR, non-HbA1c variability, female gender, and immunological serological test positivity can predict NDNP and guide the clinician's decision on kidney biopsy. Further prospective studies are warranted to validate the efficacy of potential predictive factors like HbA1c variability.

Unveiling biomarkers and therapeutic targets in IgA nephropathy through large-scale blood transcriptome analysis.

INTRODUCTION: IgA nephropathy (IgAN) is the most prevalent form of glomerulonephritis. Unfortunately, molecular biomarkers for IgAN derived from omics studies are still lacking. This research aims to identify critical genes associated with IgAN through large-scale blood transcriptome analysis. METHODS: We constructed novel blood transcriptome profiles from peripheral blood mononuclear cells (PBMCs) of 53 Chinese IgAN patients and 28 healthy individuals. Our analysis included GO, KEGG, and GSEA for biological pathways. We analyzed immune cell profiles with CIBERSORT and constructed PPI networks with STRING, visualized in Cytoscape. Key differentially expressed genes (DEGs) were identified using CytoHubba and MCODE. We assessed the correlation between gene expressions and clinical data to evaluate clinical significance and identified hub genes through machine learning, validated with an open-access dataset. Potential drugs were explored using the CMap database. RESULTS: We identified 333 DEGs between IgAN patients and healthy controls, mainly related to immune response and inflammation. Key pathways included NK cell mediated cytotoxicity, complement and coagulation cascades, antigen processing, and B cell receptor signaling. Cytoscape revealed 16 clinically significant genes (including KIR2DL1, KIR2DL3, VISIG4, C1QB, and C1QC, associated with sub-phenotype and prognosis). Machine learning identified two hub genes (KLRC1 and C1QB) for a diagnostic model of IgAN with 0.92 accuracy, validated at 1.00 against the GSE125818 dataset. Sirolimus, calcifediol, and efaproxiral were suggested as potential therapeutic agents. CONCLUSION: Key DEGs, particularly VISIG4, KLRC1, and C1QB, emerge as potential specific markers for IgAN, paving the way for future targeted personalized treatment options.

Combined Effects of the Serum IgA/C3 Ratio and Glomerular C3 Staining on the Renal Outcome in Adult Immunoglobulin A Nephropathy.

INTRODUCTION: The aim of this study was to evaluate the predictive value of the serum IgA/C3 ratio and glomerular C3 deposits in kidney biopsy in adult IgA nephropathy. METHODS: The study included 718 adult IgAN patients diagnosed based on kidney biopsy. Patients without corticosteroids or immunosuppressive drugs >1 month were regularly followed up for at least 1 year or until the study endpoint. The optimum serum IgA/C3 ratio was calculated by the AUROC-based cutoff ratio. Proteinuria, creatinine, eGFR, serum IgA, and serum C3 were evaluated at baseline. Kidney biopsy was categorized using the Oxford classification, with a calculation of the MEST-C score. The degree of glomerular C3 staining was semiquantitatively determined (grade 0, no or trace; grade 1, mild; grade 2, moderate; grade 3, marked) by immunofluorescence microscopy. The patients were divided into four groups by the serum IgA/C3 ratio and glomerular C3 staining. RESULTS: The baseline data suggested that when the serum IgA/C3 ratio was at the same level, patients with a high glomerular C3 staining score (≥2) always had mesangial proliferation, segmental glomerulosclerosis, and tubular atrophy/interstitial fibrosis (group 1 vs. group 2; group 3 vs. group 4). When glomerular C3 staining was at the same level, proteinuria was significantly higher in patients with serum IgA/C3<2.806 (group 1 vs. group 3; group 2 vs. group 4), which was contrary to previous studies that have suggested that the serum level of IgA/C3 was associated with disease severity. Hence, this study set out to investigate the combined effects of the serum IgA/C3 ratio and glomerular C3 staining on the renal outcome in adult IgA nephropathy. Renal survival analysis indicated that serum IgA/C3 ≥2.806 and glomerular C3 staining ≥2 (group 1) may be correlated with a poorer prognosis, especially in different clinicopathological characteristics of IgAN patients based on the subgroup analysis. Multivariate Cox analysis demonstrated that hypertension, serum creatinine, CKD stage, T1/2 and C3 staining were independent predictive factors of renal survival. CONCLUSIONS: The combination of serum IgA/C3 and C3 staining may contribute to improved optimization of the prognostic model in IgAN patients, especially patients with different sexes and degrees of disease. However, further study is required for validation in the future.

Treatment and outcome of IgA nephropathy in children from one single center experience.

BACKGROUND: There is no standard recommendation for IgA nephropathy treatment in children. METHODS: This is a retrospective study. From 2012 to 2020, newly diagnosed primary IgAN followed up for at least 1 year were enrolled. The correlation of MESTC scores and clinical index including proteinuria, gross hematuria and renal dysfunction was analyzed. Treatment and clinical response of 6 month, 1year and 3 year at follow up were also analyzed. Complete renal remission was calculated with Kaplan-Meier analysis. RESULTS: The median follow up was 36 months, from 12 months to 87months in 40 IgAN children. Angiotensin-converting enzyme inhibitor (ACEI) was applied to all patients. 30% received ACEI alone; 15% received glucocorticoids; 37.5% received glucocorticoids plus cyclophosphamide, 17.5% received glucocorticoids plus mycophenolate mofetil. Individuals with diffuse mesangial hypercellularity (M1) were more likely to have nephrotic range proteinuria compared to patients with M0 (80% vs. 20%, P < 0.01). Complete renal remission at 6-month, 1-year and 3-year follow up is 50.25%, 70% and 87.5% respectively. Five-year complete renal remission calculated by Kaplan-Meier analysis is 58.4%. Although without significant difference, there is trend of better survival with complete renal remission in group of nephrotic range proteinuria onset. There is no severe adverse effect. CONCLUSION: This study supports the use of glucocorticoids plus immunosuppressive in addition to ACEI in IgA nephrology pediatric patients with proteinuria. We suggest proactive immunosuppressive treatment in IgA nephropathy in children. This is from a single center in China as may not same results in other population.

IgA nephropathy in adults with epidermolysis bullosa.

Epidermolysis bullosa (EB) is a devastating genetic condition caused by mutations in genes that give rise to aberrant proteins. There are 16 different such proteins implicated in EB that are important in maintaining the integrity of the dermoepidermal junction. It is classified into four major subtypes: (i) EB simplex; (ii) junctional EB (JEB); (iii) dystrophic EB (DEB); and (iv) Kindler EB. Renal disease is a recognized complication of EB and the aetiology is complex. We describe our experience of managing five patients with EB and IgA nephropathy. We recommend that patients with recessive DEB and JEB routinely have the following monitored: renal function, urinary albumin/creatinine ratio, urine analysis, serum albumin levels and immunoglobulins; specifically serum IgA. Management of IgA nephropathy in the context of EB should be tailored to the individual and be carried out within a specialist multidisciplinary team. Our case series provides important insights into the treatment of IgA nephropathy in patients with EB and will help inform treatment in this rare genetic disease. Case series and reports like ours are key in gaining real-life data to quantify the actual risk of morbidity and mortality from each of the treatment modalities discussed.

Serum homocysteine is associated with tubular interstitial lesions at the early stage of IgA nephropathy.

BACKGROUND: The association between homocysteine (Hcy) and IgA nephropathy (IgAN) is not well understood. We aimed to investigate the relationship between Hcy and clinicopathologic features in IgAN patients. METHODS: A total of 337 IgAN patients and 150 sex- and age- matched healthy controls were enrolled in this single-center retrospective study. According to Hcy ≤ 10 µmol/L or > 10 µmol/L, patients were divided into low and high Hcy groups. Multivariate logistic regression was performed to explore the risk factors for elevated Hcy. RESULTS: Serum Hcy was higher in IgAN patients than in healthy controls [11.6 (9.1,15.3) vs. 8.8 (7.5,10.6) µmol/L, P < 0.001], unanimously in the subgroup of 156 patients with a normal estimated glomerular filtration rate (eGFR) (≥ 90 ml/min/1.73 m2) [9.9 (7.6,12.4) vs. 8.8 (7.5,10.6) µmol/L, P < 0.001]. Compared to the low Hcy group, serum creatinine (Scr), blood urine nitrogen (BUN), uric acid (UA), endocapillary hypercellularity (E) and tubular atrophy/interstitial fibrosis lesion (T) were higher in the high Hcy group. Hcy levels were positively correlated with Scr, BUN, UA, 24-h urine protein, and E and T lesions, but negatively correlated with eGFR and superoxide dismutase (SOD). In the subgroup with normal eGFR, patients with higher Hcy were persistent with higher Scr, BUN and T lesions. A multivariate logistic regression model showed that the risk of elevated Hcy in patients with pathological T increased by 2.87-fold. T lesions could better predict high Hcy, with an odds ratio (OR) of 14.20 in the subgroup with normal eGFR. CONCLUSIONS: Pathologic T was an independent risk factor associated with elevated Hcy, especially at the early stage of IgAN.

Is hyperuricemia an independent prognostic factor for IgA nephropathy: a systematic review and meta-analysis of observational cohort studies.

BACKGROUND: Hyperuricemia has been reported to be correlated with IgA nephropathy (IgAN). However, whether hyperuricemia or elevated serum uric acid (SUA) is an independent prognostic factor of IgAN remains unknown. Therefore, this systematic review and meta-analysis evaluated the prognostic value of hyperuricemia and elevated SUA in IgAN. METHODS: Databases including PubMed, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), and Open Gray were reviewed systematically. The kidney failure events of IgAN were defined as a doubling of serum creatinine, halving of eGFR, end-stage renal disease (ESRD), or death. The risk ratio (RR) between hyperuricemia and IgAN-caused kidney failure was evaluated before and after adjustment for relevant covariates. The RR between elevated SUA and IgAN-caused kidney failure was evaluated after adjustment for relevant covariates. RESULTS: A total of 11 548 patients from 14 studies were included in this meta-analysis. Hyperuricemia was found to be an independent prognostic factor of IgAN (unadjusted RR = 2.79, 95% CI = 1.93-4.03, p for heterogeneity <0.00001, I2 = 91%; adjusted RR = 2.12, 95% CI = 1.64-2.73, p for heterogeneity = 0.86, I2 = 0%). Subgroup and sensitivity analyses confirmed the stability of these results. Similarly, elevated SUA was positively correlated with kidney failure events of IgAN (adjusted RR = 1.25, 95% CI = 1.19-1.31, p for heterogeneity = 0.6, I2 = 0%). CONCLUSION: Our meta-analysis showed that hyperuricemia and elevated SUA were both independently associated with an increased incidence of kidney failure events in IgAN patients.