Steroid therapy in children with IgA nephropathy

A lack of KDIGO guidelines for adolescents and young adults with IgA nephropathy

BACKGROUND

IgA nephropathy (IgAN) is one of the most prevalent primary glomerular diseases in children and adolescents. In 2021, The Kidney Disease: Improving Global Outcomes (KDIGO) released Clinical Practice Guidelines for the Management of Glomerular Diseases as an update to the 2012 guidelines. However, the lack of available evidence for the treatment of IgAN in children has led to an absence of treatment recommendations.

CLINICAL CASE

We present the case of a 19-year-old male with IgAN who was lost to follow-up after an appointment at a children's hospital 3 years prior. He presents for care at an adult hospital after running out of his medications for many months. He is found to have an elevated blood pressure of 152/97 and an elevated creatinine at 0.8 mg/dL.

DISCUSSION

There is not only a need for treatment guidelines for IgAN in pediatric patients, but also a need for guidelines for adolescent patients with IgAN as they transition from pediatric to adult care. Therefore, we review the KDIGO treatment guidelines for adults with IgAN and the treatment evidence for children with IgAN and discuss the management dilemma that exists for adolescents and young adults (AYA) with IgAN. Specifically, we propose renin-angiotensin-aldosterone blockade (RASB) treatment, irrespective of blood pressure, for AYA with proteinuria >0.5 g/day. We also propose treatment with corticosteroids for patients with proteinuria >1 g/day and/or mesangial hypercellularity.

CONCLUSION

The formation of treatment guidelines for patients transitioning from pediatric to adult nephrology care is paramount.

Corticosteroids in the treatment of IgA nephropathy: lessons from the TESTING trial

IgA nephropathy (IgAN), the most common form of primary glomerulonephritis, is mainly observed in young adults and children. Clinical and basic studies indicate the role of immunity in IgAN pathogenesis; however, corticosteroid therapy has been controversial in past decades. The TESTING study, initiated in 2012, is an international, multicenter, double-blinded, randomized, placebo-controlled trial that aimed to evaluate oral methylprednisolone's safety and long-term efficacy under conditions of optimized supportive treatment in patients with IgAN whose risk of progression is high. After a decade of effort, the successful completion of the TESTING study showed that a 6- to 9-month course of oral methylprednisolone is an effective regimen to protect kidney function in high-risk patients with IgAN, but also demonstrated safety concerns. Compared with the full-dose regimen, the reduced-dose regimen was reported to be beneficial, with successfully increased safety. Overall, the TESTING trial provided more data regarding the treatment dosage and safety of corticosteroids, a cost-effective therapy, in IgAN, which have important implications for pediatric patients with IgAN. With a deeper understanding of the disease pathogenesis of IgAN, ongoing studies of novel therapeutic regimens would help further optimize the benefit-risk ratio.

Glomerulonephritis

Glomerulonephritis (GN) encompasses several disorders that cause glomerular inflammation and injury through an interplay of immune-mediated mechanisms, host characteristics, and environmental triggers, such as infections. GN can manifest solely in the kidney or in the setting of a systemic illness, and presentation can range from chronic and relatively asymptomatic hematuria to fulminant renal failure. Classic acute GN is characterized by hematuria, edema, and hypertension, the latter 2 of which are the consequence of sodium and water retention in the setting of renal impairment. Although presenting signs and symptoms and a compatible clinical history can suggest GN, serologic and urinary testing can further refine the differential diagnosis, and renal biopsy can be used for definitive diagnosis. Treatment of GN can include supportive care, renin-angiotensin-aldosterone system blockade, immunomodulatory therapy, and renal transplant. Prognosis is largely dependent on the underlying cause of GN and can vary from a self-limited course to chronic kidney disease. This review focuses on lupus nephritis, IgA nephropathy, IgA vasculitis, and postinfectious GN.

Effects and mechanisms of Chinese herbal medicine on IgA nephropathy

BACKGROUND

Immunoglobulin A nephropathy (IgAN), is the main cause of end-stage renal disease, that causes serious physical and psychological burden to patients worldwide. Some traditional treatment measures, such as blocking the renin-angiotensin-aldosterone system, controlling blood pressure, and following a low-protein diet, may not achieve satisfactory results. Therefore, more effective and safe therapies for IgAN are urgently needed.

PURPOSE

The aim of this review is to summarize the clinical efficacy of Chinese herbal medicines (CHMs) and their active ingredients in the treatment and management of IgAN based on the results of clinical trials, systematic reviews, and meta-analyses, to fully understand the advantages and perspectives of CHMs in the treatment of IgAN.

STUDY DESIGN AND METHODS

For this review, the following electronic databases were consulted: PubMed, ResearchGate, Science Direct, Web of Science, Chinese National Knowledge Infrastructure and Wanfang Data, "IgA nephropathy," "traditional Chinese medicine," "Chinese herbal medicine," "herb," "mechanism," "Meta-analysis," "systematic review," "RCT" and their combinations were the keywords to search the relevant literature. Data were collected from 1990 to 2022.

RESULTS

This review found that the active ingredients of CHMs commonly act on multiple signaling pathways in the clinical treatment of IgAN, mainly with antioxidant, anti-inflammatory and anti-fibrosis effects, and regulation of autophagy.

CONCLUSION

Compared with the single-target therapy of modern medicine, CHMs can regulate the corresponding pathways from the aspects of anti-inflammation, anti-oxidation, anti-fibrosis and autophagy to play a multi-target treatment of IgAN through syndrome differentiation and treatment, which has good clinical efficacy and can be used as the first choice or alternative therapy for IgAN treatment. This review provides evidence and research direction for a comprehensive clinical understanding of the protective effect of Chinese herbal medicine on IgAN.

Association between glomerular C4d deposition, proteinuria, and disease severity in children with IgA nephropathy

BACKGROUND

C4d may be used as a marker to evaluate the condition and prognosis of adults with IgA nephropathy, but there have been few studies of children with IgA nephropathy.

METHODS

C4d immunohistochemical staining was performed on samples from children with IgA nephropathy with C1q-negative immunofluorescence. The clinical and pathological treatment and prognostic characteristics of children in the C4d-positive and -negative groups were compared.

RESULTS

A total of sixty-five children with IgA nephropathy were included in the study and were followed up for an average of 37 months. C4d was mainly deposited along the capillary loops. The urinary protein-to-creatinine ratio (UPCR) in the C4d-positive group was significantly higher than that in the C4d-negative group (3.97 vs. 0.81, P < 0.001), and the average integrated optical density value of each child was positively correlated with the UPCR (r = 0.441, P < 0.001). There was a significant difference in the proportions of children with mesangial hypercellularity (M1) (68.97% vs. 44.44%, P = 0.048) and segmental glomerulosclerosis (S1) (65.52% vs. 33.33%, P = 0.010) between the C4d-positive group and the C4d-negative group. The proportion of children who received immunosuppressants in the C4d-positive group was higher than that in the C4d-negative group (86.21% vs. 36.11%, P < 0.001). There was no significant difference in the proportion of children developing kidney failure between the two groups.

CONCLUSION

C4d was found to be associated with proteinuria, segmental lesions, and immunosuppressant treatment. Activation of the lectin pathway may reflect the severity of clinical and pathological manifestations of IgA nephropathy in children. A higher resolution version of the Graphical abstract is available as Supplementary information.

Nephropathy in a Child with Severe Recessive Dystrophic Epidermolysis Bullosa Treated with Cyclophosphamide: A Case Report

Long-term inflammation and recurrent skin infection in recessive dystrophic epidermolysis bullosa (RDEB) are associated with the presence of immunoglobulin A (IgA)-containing immune complexes in the glomerulus. Only eight pediatric RDEB cases with IgA nephropathy (IgAN) have been documented in English-language literature. Most RDEB patients with IgAN progress to kidney failure within 5 years of diagnosis, indicating that these patients may require more intensive early treatment compared to those with primary IgAN. However, diagnosing IgAN in RDEB cases with severe cutaneous manifestations can be challenging. Herein, we report a rare case of nephropathy in an 11-year-old boy with severe RDEB and a frameshift mutation on the COL7A1 gene, which may manifest as kidney disorders. He presented with persistent hematuria and progressing proteinuria. A presumptive IgAN diagnosis was based on clinical features and increased IgA serum levels, as kidney biopsy was refused by his parents. Nephrotic-range proteinuria persisted despite initial steroid and lisinopril treatment. Monthly intravenous cyclophosphamide (IV CPA; 500 mg/m2) led to proteinuria remission and preservation of kidney function for 2 years posttreatment. We conclude that COL7A1 mutations may result in extracutaneous manifestations, including kidney disorders. The association between IgA-containing immune complex deposits in the glomerulus and recurrent skin infection in RDEB may indicate IgAN, particularly when kidney biopsy is infeasible due to severe skin manifestations. In our case, positive results with IV CPA suggest further investigation is needed to explore its potential role in non-rapidly progressing IgAN in children with RDEB.

Potential of soluble (pro)renin receptor in kidney disease: can it go beyond a biomarker?

(Pro)renin receptor (PRR), also termed ATPase H+-transporting accessory protein 2 (ATP6AP2), is a type I transmembrane receptor and is capable of binding and activating prorenin and renin. Apart from its association with the renin-angiotensin system, PRR has been implicated in diverse developmental, physiological, and pathophysiological processes. Within the kidney, PRR is predominantly expressed in the distal nephron, particularly the intercalated cells, and activation of renal PRR contributes to renal injury in various rodent models of chronic kidney disease. Moreover, recent evidence demonstrates that PRR is primarily cleaved by site-1 protease to produce 28-kDa soluble PRR (sPRR). sPRR seems to mediate most of the known pathophysiological functions of renal PRR through modulating the activity of the intrarenal renin-angiotensin system and provoking proinflammatory and profibrotic responses. Not only does sPRR activate renin, but it also directly binds and activates the angiotensin II type 1 receptor. This review summarizes recent advances in understanding the roles and mechanisms of sPRR in the context of renal pathophysiology.

Management of IgA Nephropathy in Pediatric Patients

The onset of IgA nephritis in childhood and adolescence often develops into chronic glomerulonephritis with declining renal function. Although these long-term consequences are known, there is still a lack of evidence-based treatment recommendations in this age group. We report data from 22 pediatric patients who were biopsied to confirm the diagnosis of IgAN at our clinical center. 14 of them were treated with corticosteroids according to the recommendations for IgA nephritis vasculitis of the German Society of Pediatric Nephrology (GPN). Improvement was achieved in the majority of all cases, with a significant reduction in proteinuria five months after initiation of therapy. Our data suggest that treatment regimens for acute IgA nephritis and IgA vasculitis nephritis may be unified and are discussed in the context of current studies.

Efficacy and safety of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers for IgA nephropathy in children

BACKGROUND

IgA nephropathy (IgAN) is one of the most prevalent primary glomerulopathies in children. There are various studies investigating the efficacy of angiotensin-converting enzyme inhibitors (ACEI) and angiotensin II receptor blockers (ARB) in adults with IgAN. However, only few studies evaluated the efficacy of these medications in pediatric patients.

OBJECTIVE

To evaluate the efficacy and safety of ACEI/ARB in children with IgAN.

DATA SOURCES

Databases including PubMed, Web of Science, Cochrane, Scopus, and Google Scholar were searched between the 1st of April and 20th of July of 2021 using the keywords "IgA Nephropathy," "Berger's Disease," "Angiotensin-Converting Enzyme Inhibitors," "Angiotensin Receptor Antagonists," "Angiotensin II Type 1 Receptor Blockers," and similar entry terms collected from the Medical Subject Headings (MeSH).

STUDY ELIGIBILITY CRITERIA

Observational studies (case series, case-control, cohort, and cross-sectional) and clinical trials with descriptions of pediatric patients (under 19 years old) with histopathological diagnosis of IgA nephropathy and who received ACEI and/or ARB.

PARTICIPANTS AND INTERVENTIONS

Pediatric patients (under 19 years old) with histopathological diagnosis of IgA nephropathy and who received ACEI and/or ARB.

STUDY APPRAISAL

For quality assessment, the Risk of Bias 2 tool (RoB 2), the Risk Of Bias In Non-randomized Studies of Interventions tool (ROBINS-I), the National Institutes of Health (NIH) quality assessment tool, and the Newcastle-Ottawa Scale (NOS) were used.

RESULTS

After recovering 1,471 studies, only eight, published between 2003 and 2019, met the eligibility criteria and were included in this systematic review. Of the 737 included children in the studies, 202 (25.8%) used ACEI/ARB and were compared with placebo and other therapy regimens. Of the seven studies that evaluated proteinuria, six reported an efficacy of ACEI/ARB in reducing this marker. ACEI/ARB also showed a possible effect in reducing hematuria and oxidative stress. The most common side effect was dizziness.

LIMITATIONS

The number of studies about the treatment with ACEI/ARB in children with IgAN is scarce. In addition, the studies are very heterogeneous. There are few studies that compared ACEI/ARB with placebo.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

The use of ACEI and/or ARB appears to be safe and to reduce proteinuria in pediatric patients with IgAN. Nonetheless, further randomized controlled trials, with greater methodological rigor and longer follow-up time, are required to establish the efficacy and safety of this therapy in this population.

SYSTEMATIC REVIEW REGISTRATION NUMBER

The protocol of this systematic literature review was registered in PROSPERO under the number CRD42021245375, and in the OSF registries ( https://osf.io/qft4z/ ) with the registration https://doi.org/10.17605/OSF.IO/VADYR . A higher resolution version of the Graphical abstract is available as Supplementary information.

Clinicopathological significance of glomerular capillary IgA deposition in childhood IgA nephropathy

BACKGROUND

IgA nephropathy (IgAN) is characterized by predominant mesangial IgA deposition. Some patients with IgAN demonstrate IgA deposition in glomerular peripheral capillaries (cap-IgA). The clinicopathological significance of cap-IgA remains incompletely investigated in children.

METHODS

We retrospectively analyzed 503 consecutive cases of biopsy-proven childhood IgAN between July 1976 and June 2013 to compare clinical and pathological features between IgAN patients with and without cap-IgA.

RESULTS

Among the 503 patients, 30 (6.0%) had cap-IgA. We found significant differences in proteinuria (2.0 vs. 0.5 g/day/m², p < 0.0001), time from onset to kidney biopsy (2.2 vs. 8.3 months, p < 0.0001), and rate of proteinuria remission after treatment (23.3% vs. 48.0%, p = 0.007) between both groups. Pathological analysis revealed significant differences in M1 (83.3% vs. 56.0%, p = 0.002), ratio of subendothelial electron dense deposits (EDDs, 58.6% vs. 16.5%, p < 0.0001) and subepithelial EDDs (48.3% vs. 16.5%, p = 0.0001), and glomerular basement membrane (GBM) lysis (58.6% vs. 27.1%, p = 0.0006) between both groups. More than half of cap-IgA patients (17/30, 56.7%), whereas only 26.2% of non-cap-IgA patients (124/473), were treated with immunosuppressive treatments. Six of 30 cases (20%) with cap-IgA reached glomerular filtration rate (GFR) categories G3a-G5 (estimated GFR < 60 ml/min/1.73 m²) at most recent observation (mean observation period: 7.0 ± 4.0 years). According to Kaplan-Meier analysis, patients with cap-IgA had significantly lower kidney survival curves than non-cap-IgA patients (72.8% vs. 97.2% at 10 years, p < 0.0001).

CONCLUSIONS

Cap-IgA is associated with acute inflammation with GBM changes, resulting in refractory heavier proteinuria. Cap-IgA may represent a poor prognostic factor.

New therapeutic perspectives for IgA nephropathy in children

Childhood IgA nephropathy (cIgAN) differs from the adult by having an abrupt clinical onset, often presenting as an acute attack that can progress to a chronic phase. No treatment guidelines have been established for the treatment of cIgAN. Given the severity of acute attack in children, and the number of life-years at stake, pediatricians prescribe immunosuppression in addition to renin-angiotensin system blockade. Non-specific immunosuppressors, such as corticosteroids, have systemic toxic effects, and given recent therapeutic advances in adult glomerulonephritis, new tailored strategies should be expected for children. The mucosal immune system has been highlighted as a key player in IgAN pathogenesis, and several biomarkers have been identified with a direct role in pathogenesis. In this review, we discuss current studies of conventional and novel therapeutic approaches for cIgAN.

Updating the International IgA Nephropathy Prediction Tool for use in children

Although IgA nephropathy (IgAN) is a common cause of glomerulonephritis in children, the absence of a method to predict disease progression limits personalized risk-based treatment decisions. The adult International IgAN Prediction Tool comprises two validated Cox survival models that predict a 50% decline in estimated glomerular filtration rate (eGFR) or end stage kidney disease (ESKD) using clinical risk factors and Oxford MEST histology scores. Here, we updated the Prediction Tool for use in children using a multiethnic international cohort of 1,060 children with IgAN followed into adulthood. The updated pediatric Prediction Tool had better model fit than the original adult tool with lower Akaike Information Criterion, higher R²_D and similar C-statistics. However, calibration showed very poor agreement between predicted and observed risks likely due to the observed disease trajectory in children. Therefore, the Tool was updated using a secondary outcome of a 30% reduction in eGFR or ESKD, resulting in better R²_D (30.3%/22.2%) and similar C-statistics (0.74/0.68) compared to the adult tool but with good calibration. The trajectory of eGFR over time in children differed from adults being highly non-linear with an increase until 18 years old followed by a linear decline similar to that of adults. A higher predicted risk was associated with a smaller increase in eGFR followed by a more rapid decline, suggesting that children at risk of a 30% decrease in eGFR will eventually experience a larger 50% decrease in eGFR when followed into adulthood. As such, these two outcomes are analogous between pediatric and adult Prediction Tools. Thus, our pediatric Prediction Tool can accurately predict the risk of a 30% decline in eGFR or ESKD in children with IgAN.

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.

Crescentic IgA nephropathy in children

OBJECTIVES

Crescentic IgA nephropathy (C-IgAN) is defined as IgAN with more than 50% of glomeruli showing crescents. C-IgAN in children is rare; we investigate in detail for the first time.

METHODS

We retrospectively analyzed the 515 consecutive children who were newly diagnosed with biopsy-proven IgAN between June 1976 and May 2010. We compared clinical and pathological findings between C-IgAN and non-C-IgAN.

RESULTS

Among 515 cases of childhood IgAN, 25 children (4.9%) had C-IgAN. Of these 25, 16 children (64%) were referred to hospitals by annual school screening. Clinical findings showed significant differences in gross hematuria (76 vs. 50%, p = .03), excretion of proteinuria (1.9 vs. 0.5 g/day/m², p < .0001), eGFR (102 vs. 108 ml/min/1.73 m², p = .03), and duration from onset to renal biopsy (4.0 vs. 8.0 months, p = .04) between groups. Pathological findings showed significant differences in M1 (88 vs. 55%, p = .02), E1 (83 vs. 53%, p = .008), and presence of tubular atrophy/interstitial fibrosis (88 vs. 53%, p < .0001) between groups. The 16 children with C-IgAN were treated with prednisolone and immunosuppressant. Four cases (16%) reached chronic renal failure (eGFR < 60) at the latest observation (mean observation period: 6.0 ± 3.6 years). Patients with C-IgAN had significantly lower renal survival curve than non-C-IgAN patients according to Kaplan-Meier analysis (77.1% vs. 92.6% at 13 years, p < .0001). Compared with previous reports, however, they had better renal outcome.

CONCLUSIONS

We confirmed the importance of school screening to find C-IgAN. Although most crescents (mean: 98.1%) of C-IgAN were cellular/fibrocellular, and acute lesions were well modified with combination therapy, the presence of tubular atrophy in C-IgAN may be the reason for poorer prognosis.

Clinical and Pathophysiological Insights Into Immunological Mediated Glomerular Diseases in Childhood

The kidney is often the target of immune system dysregulation in the context of primary or systemic disease. In particular, the glomerulus represents the anatomical entity most frequently involved, generally as the expression of inflammatory cell invasion or circulant or in situ immune-complex deposition. Glomerulonephritis is the most common clinical and pathological manifestation of this involvement. There are no universally accepted classifications for glomerulonephritis. However, recent advances in our understanding of the pathophysiological mechanisms suggest the assessment of immunological features, biomarkers, and genetic analysis. At the same time, more accurate and targeted therapies have been developed. Data on pediatric glomerulonephritis are scarce and often derived from adult studies. In this review, we update the current understanding of the etiologic events and genetic factors involved in the pathogenesis of pediatric immunologically mediated primitive forms of glomerulonephritis, together with the clinical spectrum and prognosis. Possible new therapeutic targets are also briefly discussed.