Long-term outcome of IgA nephropathy patients with recurrent macroscopic hematuria

Overlap of Primary Membranous Nephropathy, IgA Nephropathy, and Diabetic Nephropathy: A Case Report

The coexistence of primary membranous nephropathy (PMN), immunoglobulin A nephropathy (IgAN), and diabetic nephropathy (DN) in the same patient has been a subject of clinical and pathological investigation, yielding inconclusive results. The limited availability of cases and resource materials has hindered a comprehensive understanding of this phenomenon. We present the case of a 70-year-old Saudi Arabian man diagnosed with type 2 diabetes mellitus and nephrotic syndrome. A kidney biopsy revealed the coexistence of PMN, IgAN, and DN. The patient presented with an unusual and rare combination of PMN, IgAN, and DN. To address his condition, the patient consented to rituximab therapy and planned follow-up with the kidney transplant team. However, before the first dose of rituximab could be administered, the patient experienced severe septic shock secondary to pneumonia, which tragically led to his demise. The simultaneous occurrence of PMN, IgAN, and DN represents a rare and scarcely documented condition. The purpose of this article is to report this exceptional case, emphasizing the significance of further research to deepen the understanding of the underlying pathology behind these concurrent renal disorders. This report aims to shed light on the complexities of managing such complex cases and advancing therapeutic approaches in the future.

Time-Averaged Hematuria as a Prognostic Indicator of Renal Outcome in Patients with IgA Nephropathy

We aim to investigate the association of time-averaged hematuria (TA-hematuria) with the progression of IgA nephropathy (IgAN). Based on TA-hematuria during follow-up, 152 patients with IgAN were divided into a hematuria remission group (≤28 red blood cells [RBCs]/μL) and a persistent hematuria group (>28 RBCs/μL). The persistent hematuria group had a higher percentage of patients with macroscopic hematuria, lower levels of hemoglobin and TA-serum albumin, and more severe renal pathologic lesions. The composite endpoint is defined as a doubling of the baseline SCr level (D-SCr), or the presence of ESRD. During the mean follow-up of 58.08 ± 23.51 months, 15 patients (9.9%) reached the primary outcome of ESRD and 19 patients (12.5%) reached the combined renal endpoint. Kaplan-Meier analysis showed that the persistent hematuria group had a lower renal survival rate. The persistent hematuria patients who were incorporated with proteinuria (≥1.0 g/day) and low TA-serum albumin (<40 g/L) had the worst renal outcomes. Multivariate Cox regression indicated that TA-hematuria (hazard ratio [HR] = 0.004, 95% CI: 0.001, 0.008; p = 0.010) was independently associated with the progression of IgAN. Receiver operating characteristic analysis indicated the optimal TA-hematuria cutoff value for predicting the progression of IgAN was 201.21 RBCs/μL in females and 37.25 RBCs/μL in males.

An evaluation of the roles of hematuria and uric acid in defining the prognosis of patients with IgA nephropathy

In recent years, many significant advances have been made in determining which clinical manifestations and pathologic lesions can provide prognostic information for patients with IgA nephropathy (IgAN). However, some important questions remain, including the long-term consequences of hematuria, both macroscopic (MH) and microscopic (mH), in patients with IgAN. The importance of distinguishing patients who have a single episode of MH of long duration from those with recurrent episodes of short duration and the prognostic importance of the episodes of acute kidney injury (AKI) that sometimes accompany episodic MH will be discussed. Studies that have evaluated the mechanisms that may be responsible for recurrent MH and the toxic effects of red blood cells (RBCs), or their constituents, on kidney tubules will also be addressed. In the last section, I will review the evidence that hyperuricemia (HU) may be a significant independent risk factor for progressive kidney disease in patients with IgAN.

The association of microhematuria with mesangial hypercellularity, endocapillary hypercellularity, crescent score and renal outcomes in immunoglobulin A nephropathy

BACKGROUND

Microhematuria is common in immunoglobulin A nephropathy (IgAN). However, current prognostication is based on proteinuria and mesangial hypercellularity, endocapillary hypercellularity, segmental sclerosis, tubulointerstitial fibrosis and crescent (MEST-C) scores.

METHODS

In this retrospective study, we evaluated whether MEST-C score components are associated with the presence of microhematuria at biopsy and whether the degree of microhematuria during follow-up is associated with change in estimated glomerular filtration rate (eGFR), after adjusting for clinical and histological parameters. We identified 125 patients with biopsy-proven IgAN and MEST-C scoring who were not on immunosuppressive therapy at biopsy. Microhematuria was defined as ≥3 red blood cells (RBCs)/high-power field (hpf).

RESULTS

Of the 125 patients, 97 had microhematuria at baseline and were more likely to have M1, E1 and C ≥ 1 lesions (P < 0.05 for all) compared with patients without microhematuria. Of the 125 patients, 72 had follow-up data available. An increase in the degree of microhematuria was significantly associated with an eGFR decline of -0.81 mL/min/1.73 m2 [95% confidence interval (CI) -1.44 to -0.19, P = 0.01], after adjusting for follow-up time, proteinuria and T score. Severe microhematuria (≥21 RBCs/hpf) was associated with an even larger decline in eGFR (-3.99 mL/min/1.73 m2; 95% CI -6.9411 to -1.0552, P = 0.008), after similar adjustments.

CONCLUSION

Degree of microhematuria during follow-up is an independent predictor of eGFR decline after adjusting for clinical and histological parameters. Therefore, monitoring the degree of microhematuria as well as proteinuria is important when evaluating patients with IgAN. Additional studies using improvement in microhematuria as a primary surrogate outcome are needed.

[Abnormal urine color assessment: The urine wheel]

Looking at the urine for diagnostic purposes, once performed by ancient Egyptians, can still provide some valuable clues in modern medicine. Several diseases have been named after their associated urine color and this underlines the clinical value of visual urine inspection: blue diaper disease, purple urine bag syndrome, black urine disease or porphyria. Abnormal urine color could be challenging for the clinician: it may reveal neoplastic disease (urologic cancer; melanoma), cell lysis (rhabdomyolysis; hemolysis), infection (lymphatic filariasis; malaria), enzyme deficiency (porphyria; alkaptonuria), medication or food intake. In this article, we present the diagnostic approach, the mechanisms involved and the main causes of abnormal urine color.

Hematuria was a high risk for renal progression and ESRD in immunoglobulin a nephropathy: a systematic review and meta-analysis

Background: The relationship between hematuria, a typical presentation of immunoglobulin A nephropathy (IgAN), and long-term adverse prognosis of these patients is still controversial. This meta-analysis aims to clarify the effect of hematuria on renal outcomes in IgAN.

Methods: Observational cohort studies reporting associations between various forms of hematuria and renal outcomes among IgAN patients were identified from the PubMed and Embase databases. The pooled adjusted risk ratios (RRs) were computed with random effects models.

Results: Thirteen studies encompassing 5660 patients with IgAN were included. Patients with initial hematuria did not have a significantly increased risk of developing end-stage renal disease (ESRD) compared with those without hematuria (RR, 1.32; 95% CI, 0.87–2.00; p = .19). However, initial microscopic hematuria was associated with an 87% increase in the risk of ESRD (RR, 1.87; 95% CI, 1.40–2.50; p < .001), while macroscopic hematuria was associated with a 32% decrease in the risk of ESRD (RR, 0.68; 95% CI, 0.58–0.79; p < .001). Additionally, persistent hematuria might be an independent risk factor for ESRD or a 50% decline in eGFR.

Conclusions: Among IgAN patients, hematuria, including initial microscopic hematuria and even persistent hematuria, was possibly associated with renal progression and ESRD. However, independent of other classical predictors, initial macroscopic hematuria might be a protective factor for IgAN.

Hyperuricosuria, hematuria, and novel bladder images with IgA nephropathy

Episodic (recurrent) macroscopic hematuria in patients with IgA nephropathy is usually associated with a benign prognosis, although some patients experience a transient fall in glomerular filtration rate during the episodes. We present a 15-year-old girl with mild IgA nephropathy who had multiple episodes of macroscopic hematuria associated with severe but transient decreases in estimated glomerular filtration rate, low levels of serum uric acid, and marked increases in fractional excretion of uric acid. Ultrasound studies showed marked inflammatory changes in the bladder, especially involving the trigone. Cystoscopic findings were consistent with these changes. We hypothesize that the macroscopic hematuria may have resulted, at least in part, from hyperuricosuria causing acute irritation of the bladder mucosa in the trigone area.

Remission of Proteinuria May Protect against Progression to Chronic Kidney Disease in Pediatric-Onset IgA Nephropathy

Immunoglobulin A nephropathy (IgAN) is one of the most common primary glomerulopathies diagnosed in children and adolescents. This study aimed to evaluate the clinical features in and outcomes of pediatric IgAN over the last 30 years. Patients who were diagnosed before age of 18 at 20 centers in Korea were evaluated retrospectively. Of the 1154 patients (768 males, 386 females) with a median follow-up of 5 years, 5.6% (n = 65) progressed to stage 3–5 chronic kidney disease (CKD). The 10- and 20-year CKD-free survival rates were 91.2% and 75.6%, respectively. Outcomes did not differ when comparing those in Korea who were diagnosed prior to versus after the year 2000. On multivariate analysis, combined asymptomatic hematuria and proteinuria as presenting symptoms and decreased renal function at the time of biopsy were associated with progression to CKD, while remission of proteinuria was negatively associated with this outcome. Patients who presented with gross hematuria or nephrotic syndrome tended toward positive outcomes, especially if they ultimately achieved remission. While remission of proteinuria might imply that the disease is inherently less aggressive, it also can be achieved by management. Therefore, more aggressive management might be required for pediatric-onset IgAN.

Relationship between serum C3/C4 ratio and prognosis of immunoglobulin A nephropathy based on propensity score matching

Background

Aberrant activation of the complement system plays an important role in the pathogenesis and development of immunoglobulin A nephropathy (IgAN). The relationship between serum complement and the clinical-histopathological features and outcomes of IgAN is controversial. This retrospective study aimed to examine the relationship between the complement 3/4 (C3/C4) ratio and the clinicopathologic changes and prognosis of patients with IgAN.

Methods

A total of 397 patients with primary IgAN from January 2007 to December 2012 at the Chinese People's Liberation Army General Hospital were included in this study. The correlation test and Chi-square test or one-way analysis of variance test were performed to evaluate the relationship between the C3/C4 ratio and other clinical-pathological factors. Propensity score matching and a multivariate Cox regression model were used to calculate the risk factors of renal outcome.

Results

The median follow-up period was 75 months. During the follow-up period, 62 patients (15.6%) developed into the end-stage renal disease (ESRD). The C3/C4 ratio at baseline was associated with the level of serum creatinine (SCr), 24 h urinary protein excretion (24 h Upre), global glomerular sclerosis, and tubulointerstitial lesion. The level of SCr and 24 h Upre and the degree of chronic kidney injury were statistically different among groups defined by different C3/C4 ratio levels. The survival rates of patients among groups with different C3/C4 ratio levels were different. After propensity score matching, eighty-eight pairs of patients were successfully matched, and the C3/C4 ratio was an influencing factor for the patients’ outcome (hazard ratio 0.587, 95% confidence interval 0.329–0.880). Patients with a C3/C4 ratio <3.6 had a poorer outcome compared with the others (P = 0.002).

Conclusions

IgAN patients with decreased C3/C4 ratio displayed significantly more severe clinical symptoms and chronic renal injury than patients with higher ratios. A low C3/C4 ratio could be a risk factor for patients developing to ESRD.

[Pathophysiology and treatment of IgA nephropathy]

The IgA nephropathy is the most frequent form of glomerulonephritis worldwide. In approximately 30% of patients a reduction in the glomerular filtration rate of approximately 50% is observed within 10 years. Patients with IgA nephropathy form IgG autoantibodies against galactose-deficient IgA1 antibodies. This results in deposition of these antibodies in the mesangium and activation of complement with mesangial hypercellularity, endocapillary hypercellularity, segmental glomerulosclerosis and atrophying interstitial fibrosis. The basic treatment for patients with IgA nephropathy consists of removing risk factors, in particular hypertension, with blockade of the renin-angiotensin-aldosterone system. Immunosuppressives were also investigated in various studies but a clear advantage was not observed.

A Patient with MPO-ANCA-positive IgA Nephropathy Diagnosed with the Clinical Onset of Macrohematuria

A 21-year-old woman presented with renal dysfunction during macrohematuria. A kidney biopsy revealed IgA nephropathy with a small percentage of crescent formation and macrohematuria-associated tubular injury. Macrohematuria-associated acute kidney injury could explain her renal dysfunction. However, she was seropositive for myeloperoxidase (MPO)-anti-neutrophil cytoplasmic antibody (ANCA) and showed fibrin deposition around one arteriole. Corticosteroids and mycophenolate mofetil were administered as for ANCA vasculitis, and the serum creatinine, abnormal urinalysis and MPO-ANCA titer all gradually ameliorated. The presence of extra-glomerular vasculitis, which was probably induced by ANCA, suggested that MPO-ANCA was an exacerbating factor for her prolonged renal dysfunction. This condition has so far only rarely been addressed in ANCA-positive IgA nephropathy.

Immunosuppression in IgA Nephropathy: Guideline Medicine Versus Personalized Medicine

The role of immunosuppression in IgAN remains controversial despite a growing evidence base of randomized controlled trials (RCTs). In IgAN with nephrotic syndrome the role for corticosteroids is limited to cases with minimal change on light microscopy. In crescentic IgAN, the use of immunosuppression is supported only by anecdotal data, and outcome may be poor especially when glomerular filtration rate is impaired severely at presentation or there are pathologic features of chronic injury. In slowly progressive IgAN, prediction of outcome now is based both on clinical and pathologic features. Most RCTs have studied patients with urine protein levels greater than 1 g/24 h and only a minority have enrolled patients with a glomerular filtration rate less than 60 mL/min. The Supportive versus immunosuppressive Therapy of Progressive IgA nephropathy (STOP) IgAN study emphasized the efficacy of supportive therapy (including blood pressure control and renin-angiotensin system blockade) in decreasing proteinuria to less than the usually accepted threshold for the use of corticosteroids. Earlier RCTs of corticosteroids usually did not deploy supportive therapy optimally. The recent Therapeutic Evaluation of STeroids in IgA Nephropathy Global (TESTING) study closed prematurely because of excess toxicity, but the high dose of corticosteroids seemed to provide benefit. Guidelines provide valuable information about the quality and limitations of available evidence that needs to be personalized in application to the individual patient's medical and nonmedical circumstances to ensure wise clinical decision making.

Renal outcomes in primary IgA nephropathy patients with segmental glomerular necrosis: a case-control study

The renal prognosis and treatment of primary IgA nephropathy (IgAN) patients with segmental glomerular necrosis (SGN) remain controversial. Patients with primary IgAN confirmed by renal biopsy were enrolled. Patients with SGN on renal biopsy were selected as the necrosis group, and a propensity score matching method was used to match a control group according to age, gender, weight, height and follow-up time. A total of 825 IgAN patients were enrolled in the present study. Seventy-three (8.8%) patients with SGN were selected as the necrosis group, and 292 patients without SGN were matched as the control group. Compared to the control group, a significantly increased serum fibrinogen level (3.97 g/L vs 3.54 g/L, P=.002) and proportion of patients with macroscopic hematuria (35.6% vs 14.7%, P<.001) was observed in the necrosis group. According to the new IgA pathological classification system, crescent formation was more pronounced in the necrosis group (P=.001). The average estimated glomerular filtration rate was obviously higher in the necrosis group and decreased more slowly during follow-up. However, the time-averaged urine protein-to-creatinine ratio remained low in the necrotic group, whereas it gradually increased in the control group. SGN suggests an active renal inflammatory state, but it was not an independent risk factor for a poor renal outcome in patients treated with immunosuppressive therapy. Furthermore, patients with SGN had a more stable renal function and low urinary protein excretion during follow-up, which may be attributable to aggressive immunotherapy.

Inhibition of STAT3 Signaling Reduces IgA1 Autoantigen Production in IgA Nephropathy

Introduction

IgA nephropathy is a chronic renal disease characterized by mesangial immunodeposits that contain autoantigen, which is aberrantly glycosylated IgA1 with some hinge-region O-glycans deficient in galactose. Macroscopic hematuria during an upper respiratory tract infection is common among patients with IgA nephropathy, which suggests a connection between inflammation and disease activity. Interleukin-6 (IL-6) is an inflammatory cytokine involved in IgA immune response. We previously showed that IL-6 selectively increases production of galactose-deficient IgA1 in IgA1-secreting cells from patients with IgA nephropathy.

Methods

We characterized IL-6 signaling pathways involved in the overproduction of galactose-deficient IgA1. To understand molecular mechanisms, IL-6 signaling was analyzed by kinomic activity profiling and Western blotting, followed by confirmation assays using siRNA knock-down and small-molecule inhibitors.

Results

STAT3 was differentially activated by IL-6 in IgA1-secreting cells from patients with IgA nephropathy compared with those from healthy control subjects. Specifically, IL-6 induced enhanced and prolonged phosphorylation of STAT3 in the cells from patients with IgA nephropathy, which resulted in overproduction of galactose-deficient IgA1. This IL-6−mediated overproduction of galactose-deficient IgA1 could be blocked by small molecule inhibitors of JAK/STAT signaling.

Discussion

Our results revealed that IL-6−induced aberrant activation of STAT3-mediated overproduction of galactose-deficient IgA1. STAT3 signaling pathway may thus represent a new target for disease-specific therapy of IgA nephropathy.

IgA Nephropathy

IgA nephropathy (IgAN) is a leading cause of CKD and renal failure. Recent international collaborative efforts have led to important discoveries that have improved our understanding of some of the key steps involved in the immunopathogenesis of IgAN. Furthermore, establishment of multicenter networks has contributed to rigorous design and execution of clinical trials that have provided important insights regarding immunotherapy in IgAN. In this article, we review emerging developments in clinical and translational IgAN research and describe how these novel findings will influence future strategies to improve the outcome of patients with IgAN.

The Origin and Activities of IgA1-Containing Immune Complexes in IgA Nephropathy

IgA nephropathy (IgAN) is the most common primary glomerulonephritis, frequently leading to end-stage renal disease, as there is no disease-specific therapy. IgAN is diagnosed from pathological assessment of a renal biopsy specimen based on predominant or codominant IgA-containing immunodeposits, usually with complement C3 co-deposits and with variable presence of IgG and/or IgM. The IgA in these renal deposits is galactose-deficient IgA1, with less than a full complement of galactose residues on the O-glycans in the hinge region of the heavy chains. Research from the past decade led to the definition of IgAN as an autoimmune disease with a multi-hit pathogenetic process with contributing genetic and environmental components. In this process, circulating galactose-deficient IgA1 (autoantigen) is bound by antiglycan IgG or IgA (autoantibodies) to form immune complexes. Some of these circulating complexes deposit in glomeruli, and thereby activate mesangial cells and induce renal injury through cellular proliferation and overproduction of extracellular matrix components and cytokines/chemokines. Glycosylation pathways associated with production of the autoantigen and the unique characteristics of the corresponding autoantibodies in patients with IgAN have been uncovered. Complement likely plays a significant role in the formation and the nephritogenic activities of these complexes. Complement activation is mediated through the alternative and lectin pathways and probably occurs systemically on IgA1-containing circulating immune complexes as well as locally in glomeruli. Incidence of IgAN varies greatly by geographical location; the disease is rare in central Africa but accounts for up to 40% of native-kidney biopsies in eastern Asia. Some of this variation may be explained by genetically determined influences on the pathogenesis of the disease. Genome-wide association studies to date have identified several loci associated with IgAN. Some of these loci are associated with the increased prevalence of IgAN, whereas others, such as deletion of complement factor H-related genes 1 and 3, are protective against the disease. Understanding the molecular mechanisms and genetic and biochemical factors involved in formation and activities of pathogenic IgA1-containing immune complexes will enable the development of future disease-specific therapies as well as identification of non-invasive disease-specific biomarkers.

Clinicopathological features and risk factors analysis of IgA nephropathy associated with acute kidney injury

OBJECTIVE

The aim of this work is to investigate the distinctive clinicopathological characteristics of AKI in Chinese IgAN population and possible risk factors for AKI.

METHODS

We performed a retrospective analysis of 1512 patients with biopsy-proven primary IgAN in the period 2006 through 2011 in The First Affiliated Hospital of Sun Yat-sen University. AKI was defined as 2012 KDIGO (Kidney Diseases: Improving Global Outcomes) criteria, and the patients were divided into AKI group (n = 145) and non-AKI group (n = 1367).

RESULTS

The prevalence of AKI of the IgAN patients in our center was 9.59% (145/1512). Most AKI patients were older age, male, with higher percentage of smoke, hypertension, hyperlipidemia and preexisting impaired kidney function (Scr > 133 μmol/L), and higher serum creatinine, proteinuria, uric acid, whilst less onset of macroscopic hematuria as well as lower serum albumin and hemoglobin (p < 0.05). The pathological features were much more severe in AKI group as well. Acute tubulointerstitial nephritis was found as the most predominant pathological change of intrinsic AKI in our IgAN population instead of macroscopic hematuria associated acute tubular injury/necrosis. In multivariate logistic regression analysis, we found that older age, male gender, malignant hypertension, proteinuria, cellular crescent, fibrocellular crescent, glomerular sclerosis ≥ 50% were possible risk factors for AKI.

CONCLUSIONS

AKI is commonly seen among IgAN population. The clinicopathological features are much more severe in IgAN patients with AKI. Useful clinicopathological predictors are recognized to improve the identification of IgAN patients who are at high risk for AKI.

IgA nephropathy

Globally, IgA nephropathy (IgAN) is the most common primary glomerulonephritis that can progress to renal failure. The exact pathogenesis of IgAN is not well defined, but current biochemical and genetic data implicate overproduction of aberrantly glycosylated IgA1. These aberrant immunoglobulins are characterized by galactose deficiency of some hinge-region O-linked glycans. However, aberrant glycosylation alone is insufficient to induce renal injury: the participation of glycan-specific IgA and IgG autoantibodies that recognize the undergalactosylated IgA1 molecule is required. Glomerular deposits of immune complexes containing undergalactosylated IgA1 activate mesangial cells, leading to the local overproduction of cytokines, chemokines and complement. Emerging data indicate that mesangial-derived mediators that are released following mesangial deposition of IgA1 lead to podocyte and tubulointerstitial injury via humoral crosstalk. Patients can present with a range of signs and symptoms, from asymptomatic microscopic haematuria to macroscopic haematuria. The clinical progression varies, with 30-40% of patients reaching end-stage renal disease 20-30 years after the first clinical presentation. Currently, no IgAN-specific therapies are available and patients are managed with the aim of controlling blood pressure and maintaining renal function. However, new therapeutic approaches are being developed, building upon our ever-improving understanding of disease pathogenesis.

Long-term outcome of IgA nephropathy with minimal change disease: a comparison between patients with and without minimal change disease

BACKGROUND

The clinicopathological characteristics, treatment response and long-term outcome of immunoglobulin (Ig)A nephropathy with minimal change disease (MCD-IgAN) are not well defined.

METHODS

Patients with biopsy-proven MCD-IgAN from the Jinling Hospital IgA nephropathy Registry were systematically reviewed and compared with those with IgA nephropathy without minimal change disease (Non-MCD-IgAN).

RESULTS

We compared data of 247 MCD-IgAN patients and 1,121 Non-MCD-IgAN patients. Compared to Non-MCD-IgAN, MCD-IgAN patients were younger,with male predominance, had higher levels of proteinuria, total cholesterol and estimated glomerular filtration rate (eGFR), lower incidence of hypertension and microhematuria, lower level of serum creatinine, and had less severe glomerular, tubulointerstitial and vascular lesions in renal pathology. In the Non-MCD-IgAN group, 157 patients (14.0 %) reached the renal endpoint and 103 patients (9.2 %) entered end-stage renal disease (ESRD). The 5-,10-, 15- and 20-year cumulative renal survival rates from ESRD, calculated by Kaplan-Meier method, were 95.0, 83.0, 72.9 and 65.4 %, respectively. In the MCD-IgAN group, no patients entered ESRD and only 4 (1.6 %) reached the renal endpoint. Patients with MCD-IgAN had a significantly better renal outcome than Non-MCD-IgAN (p < 0.01). At multivariate Cox analysis, proteinuria >1.0 g/day, hypertension, eGFR <60 ml/min/1.73 m(2), hypoproteinemia and hyperuricemia were independent risk factors of renal survival for Non-MCD-IgAN patients [hazard ratio (HR) 3.43, p < 0.001; HR 1.65, p < 0.05; HR 2.61, p < 0.001; HR 2.40, p < 0.001; HR 2.27, p < 0.001, respectively), but not for patients with MCD-IgAN.

CONCLUSIONS

The long-term outcome of patients with MCD-IgAN is significantly better than that of patients with Non-MCD-IgAN.