Hydroxychloroquine alleviates persistent proteinuria in IgA nephropathy

Early reduction in total cholesterol to high-density lipoprotein cholesterol ratio predicts hydroxychloroquine efficacy in treating IgA nephropathy

BACKGROUND

Hydroxychloroquine (HCQ) effectively improves lipid levels in patients with autoimmune diseases. This study aimed to examine the effect of HCQ on lipid profiles in patients with immunoglobulin A (IgA) nephropathy (IgAN) and determine whether alterations in lipid profiles can predict the efficacy of HCQ.

METHODS

This study retrospectively analyzed 77 patients, and the total cholesterol to high-density lipoprotein cholesterol (TC/HDL-C) decline rate after 3 months of HCQ treatment was selected as a predictor based on receiver operating curve analysis. Patients were then divided into low and high TC/HDL-C decline rate groups based on the optimal cutoff value. The Cox proportional hazard model and Kaplan-Meier curve were used to evaluate the value of the TC/HDL-C decline rate in predicting the efficacy of HCQ in patients with IgAN.

RESULTS

Patients in the high TC/HDL-C decline rate group with ≥50% decrease in proteinuria from baseline experienced a significant improvement during the follow-up. Kaplan-Meier analysis revealed that a high TC/HDL-C decline rate was strongly associated with a higher proteinuria reduction rate in patients with IgAN. Furthermore, multivariate Cox analysis indicated that a higher reduction in the TC/HDL-C ratio (hazard ratio: 2.314; 95% confidence interval: 1.234-4.340; p = 0.009) was an independent predictive indicator for achieving ≥50% reduction in proteinuria with HCQ therapy in IgAN.

CONCLUSION

HCQ effectively improves lipid profiles in patients with IgAN, and an early decrease in the TC/HDL-C ratio serves as a predictor of better outcomes in patients treated with HCQ.

Drugs in Development to Treat IgA Nephropathy

IgA nephropathy is a common glomerulonephritis consequent to the autoimmune response to aberrant glycosylated immunoglobulin (Ig) A antibodies. Although it has historically been considered a benign disease, it has since become clear that a substantial percentage of patients reach end-stage kidney failure over the years. Several therapeutic attempts have been proposed, with systemic steroids being the most prevalent, albeit burdened by possible serious adverse events. Thanks to the more in-depth knowledge of the pathogenesis of IgA nephropathy, new treatment targets have been identified and new drugs developed. In this narrative review, we summarise the molecules under clinical development for the treatment of IgA nephropathy. As a search strategy, we used PubMed, Google, ClinicalTrials.gov and abstracts from recent international congresses. TRF budesonide and sparsentan are the two molecules at a more advanced stage, just entering the market. Other promising agents are undergoing phase III clinical development. These include anti-APRIL and anti-BLyS/BAFF antibodies and some complement inhibitors. Other new possible strategies include spleen tyrosine kinase inhibitors, anti-CD40 ligands and anti-CD38 antibodies. In an era increasingly characterised by 'personalised medicine' and 'precision therapy' approaches and considering that the potential therapeutic armamentarium for IgA nephropathy will be very broad in the near future, the identification of biomarkers capable of helping the nephrologist to select the right drug for the right patient should be the focus of future studies.

Influence of IgA nephropathy on the progression of pulpitis and apical periodontitis in HIGA mice

OBJECTIVES

Immunoglobulin (Ig)A nephropathy has been associated with oral infections such as periodontitis, but its pathogenesis is not fully understood; no treatments exist. This study analyzes the influence of IgA nephropathy, an autoimmune disease, on the pathogenesis of pulpitis and apical periodontitis.

METHODS

Two groups of mice were used in pulp infection experiments: high serum IgA nephropathy model mice (HIGA) and control mice (BALB/c). Histologic analyses of the pulp and apical periodontal tissues were performed on days 3, 5, 7, 14, and 28 following oral bacterial infection. The dynamics of odontoblasts, apoptotic cells, and IgA expression were analyzed using anti-Nestin, TUNEL, and anti-IgA staining, respectively.

RESULTS

Inflammatory cells infiltrated the exposed pulp at day three in both groups and by 14 days, these cells had infiltrated from the pulp to the apical periodontal tissue. The area of necrotic pulp tissue increased significantly in the control group at seven days. Odontoblasts decreased from day three onwards and disappeared by 28 days in both groups. The number of apoptotic cells in the pulp and apical periodontal tissues was significantly higher in the experimental group at day 28. The experimental group exhibited a significant increase in IgA production in the pulp after 14 days. Bone resorption in the apical periodontal tissue was significantly decreased in the experimental group at day 28.

CONCLUSIONS

The results of this study suggest that IgA nephropathy may modulate the inflammatory response and sustain long-term biological defense responses in pulpitis and apical periodontitis in HIGA mice.

Hydroxychloroquine Induces Remission for IgA Nephropathy With Mild to Moderate Proteinuria: A Single-Centered Retrospective Analysis

BACKGROUND

Hydroxychloroquine (HCQ) influences both toll-like receptor (TLR) signaling and leukocyte activation, which are speculated to play a role in the pathogenesis of IgA nephropathy (IgAN).

METHODS

This is a single-centered retrospective study involving 426 IgAN patients diagnosed from May 2016 to August 2020. All patients were matched according to a propensity score matching (PSM) to produce three groups: renin-angiotensin-aldosterone system inhibitors (RAASi) group (RAASi only), corticosteroids group (corticosteroids only or combined with RAASi), and HCQ group (HCQ only or combined with RAASi), consisting of 63 patients for each group.

RESULTS

After PSM, the median urine protein/creatinine ratio (UPCR) of overall patients was 0.91 g/g, while their median serum creatinine was 87.00 μmol/L. After the median follow-up period of 11.03 months, the total remission rates of the RAASi group, corticosteroids group, and HCQ groups were 49.21% (n = 31), 74.60% (n = 47), and 52.38% (n = 33), respectively (p = 0.017). Thirteen (6.88%) patients experienced a decline in estimated glomerular filtration rate (eGFR) of more than 25% from baseline, including six (9.52%) patients in the RAASi group, three (4.76%) patients in the corticosteroids group, and four (6.35%) patients in HCQ group (p = 0.677). One (1.59%) patient in the HCQ group had blurred vision and continued to use HCQ after ruling out retinal lesions by ophthalmic examination.

CONCLUSION

HCQ is effective in inducing remission and well-tolerated in IgAN patients with mild to moderate proteinuria.

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.

The role of toll-like receptors (TLRs) and their therapeutic applications in glomerulonephritis

One of the most important features of innate immunity is the presence of a special group of pattern recognition receptors (PRRs) called toll-like receptors (TLRs), which recognize pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs), resulting in a quick and effective immune response to them. Glomerulonephritis (GN) is one of the most important categories of renal disorders characterized by destructive responses of the immune system to the glomerulus. To date, the association of TLRs as important innate immune system members with GN has been one of the topics that attracted the attention of researchers in this field. However, the exact role of these receptors in the immunopathogenesis of GN has not yet been fully discussed. Therefore, this study aims to overview the role of TLRs in GN and the possibility of using them as a potential therapeutic target.

Hydroxychloroquine in nephrology: current status and future directions

Hydroxychloroquine is one of the oldest disease-modifying anti-rheumatic drugs in clinical use. The drug interferes with lysosomal activity and antigen presentation, inhibits autophagy, and decreases transcription of pro-inflammatory cytokines. Owing to its immunomodulatory, anti-inflammatory, anti-thrombotic effect, hydroxychloroquine has been an integral part of therapy for systemic lupus erythematosus and lupus nephritis for several decades. The therapeutic versatility of hydroxychloroquine has led to repurposing it for other clinical conditions, with recent studies showing reduction in proteinuria in IgA nephropathy. Research is also underway to investigate the efficacy of hydroxychloroquine in primary membranous nephropathy, Alport's syndrome, systemic vasculitis, anti-GBM disease, acute kidney injury and for cardiovascular risk reduction in chronic kidney disease. Hydroxychloroquine is well-tolerated, inexpensive, and widely available and therefore, should its indications expand in the future, it would certainly be welcomed. However, clinicians should be aware of the risk of irreversible and progressive retinal toxicity and rarely, cardiomyopathy. Monitoring hydroxychloroquine levels in blood appears to be a promising tool to evaluate compliance, individualize the dose and reduce the risk of retinal toxicity, although this is not yet standard clinical practice. In this review, we discuss the existing knowledge regarding the mechanism of action of hydroxychloroquine, its utility in lupus nephritis and other kidney diseases, the main adverse effects and the evidence gaps that need to be addressed in future research. Created with Biorender.com. HCQ, hydroxychloroquine; GBM, glomerular basement membrane; mDC, myeloid dendritic cell; MHC, major histocompatibility complex; TLR, toll-like receptor.

IgA Nephropathy: Current Understanding and Perspectives on Pathogenesis and Targeted Treatment

Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis worldwide, with varied clinical and histopathological features between individuals, particularly across races. As an autoimmune disease, IgAN arises from consequences of increased circulating levels of galactose-deficient IgA1 and mesangial deposition of IgA-containing immune complexes, which are recognized as key events in the widely accepted "multi-hit" pathogenesis of IgAN. The emerging evidence further provides insights into the role of genes, environment, mucosal immunity and complement system. These developments are paralleled by the increasing availability of diagnostic tools, potential biomarkers and therapeutic agents. In this review, we summarize current evidence and outline novel findings in the prognosis, clinical trials and translational research from the updated perspectives of IgAN pathogenesis.

The Effect of Hydroxychloroquine on Residual Proteinuria in Patients With Immunoglobulin A Nephropathy: A Retrospective Study Based on Propensity Score Matching

Background

There is insufficient evidence to support the use of hydroxychloroquine (HCQ) in Immunoglobulin A nephropathy (IgAN) patients with high residual proteinuria in spite of 6-month supportive treatment combined with corticosteroids (P) and/or immunosuppressives (IM). This study aims to explore the effect of HCQ on residual proteinuria in IgAN.

Materials and Methods

This is a retrospective study. IgAN patients who had residual proteinuria ≥0.3 g/24 h after 6-month treatment by renin-angiotensin system inhibitors (RASI) + P ± IM were included. Groups were divided based on the different regimens and then matched by the propensity score matching method. The primary outcome was defined as the cumulative frequency of residual proteinuria reduction ≥30%.

Results

RASI (n = 183), HCQ + RASI (n = 59), RASI + P ± IM (n = 145), and HCQ + RASI + P ± IM (n = 38) groups were included. HCQ + RASI group had a higher level of residual proteinuria and a worse renal function than those in the RASI group. The renal function was worse in the HCQ + RASI + P ± IM group than that in the control group, but residual proteinuria levels were similar. After matching, there were 40 patients in the first two groups and 29 patients in the latter two groups, respectively. The cumulative frequency of residual proteinuria reduction ≥30% in HCQ + RASI + P ± IM group was higher than that in control group (86.2% vs. 62.1%, χ2 = 6.397, p = 0.011). HCQ combination treatment was one of independent factors.

Conclusion

The addition of HCQ treatment can effectively reduce the residual proteinuria in IgAN patients previously treated with supportive treatment combined with P and IM treatment and the cumulative frequency of effective reduction of residual proteinuria can reach 86.2%.

Quantitative Comparison of the Clinical Efficacy of 6 Classes Drugs for IgA Nephropathy: A Model-Based Meta-Analysis of Drugs for Clinical Treatments

Introduction

There is a wide variety of drugs for the clinical treatment of immunoglobulin A (IgA) nephropathy; however, previous studies have failed to clarify the quantitative differences in the efficacy of various drugs. In this study, we aimed to quantitatively compare the clinical efficacy of 6 classes of drugs with different pharmacological mechanisms for the treatment of IgA nephropathy and to identify relevant influencing factors.

Methods

Clinical trials of drugs for the treatment of IgA nephropathy were obtained from public databases. The change in daily urinary protein excretion from baseline was used as the efficacy index, and the time–effect model was established using a model-based meta-analysis method. Based on the final model, the typical efficacy was simulated, and the differences in efficacy were compared.

Results

A total of 40 studies with 2288 subjects were included in this study. The results showed that the time–effect relationship of the placebo and 6 classes of drugs was consistent with the E_max model. The placebo reduced urinary protein excretion by up to 0.44 g/day, and it took more than 27 months to reach half of its maximum effect. The onset of the 6 classes of drugs were the same; they all reached half of their maximum effect after 5.59 months. More importantly, we found a significant influence of urinary protein baseline on drug efficacy, as indicated by an increase of 0.63 g/day in the theoretical maximum effect of drugs for every 1 g/day increase in urinary protein baseline. After correcting for the urinary protein baseline, the order of efficacy of the 6 classes of drugs was as follows: corticosteroids > immunosuppressants > other drugs > renin–angiotensin system blockers > antiplatelet agents > N-3 fatty acids.

Conclusion

This study provides the first comprehensive quantitative analysis of the differences in the efficacy of 6 classes of drugs with different pharmacological mechanisms for treating IgA nephropathy. The results of this study provide an important reference for the rational clinical use of drugs for IgA nephropathy, and also provide a reliable efficacy standard for the development of new drugs for IgA nephropathy.

Mechanism of Action and Efficacy of Immunosupressors in Lupus Nephritis

Approximately 70% of the patients with systemic lupus erythematosus will have clinical evidence of kidney damage during their evolution. Patients with impaired renal function at onset and those with recurrent flares have a poor prognosis. Understanding the mechanism of action of immunosuppressants is essential for proper prescription. Steroids inhibit the DNA sequence that promotes the release of inflammatory cytokines. Phosphoramide mustard, metabolite of cyclophosphamide, cross-link with the DNA, causing the aggregation of an alkyl group, causing cell death. Mycophenolate inhibits inosine monophosphate dehydrogenase, prevents de novo synthesis of guanine, inducing cell arrest in S phase. Azathioprine blocks the synthesis of purines and induces apoptosis. Calcineurin inhibitors prevent the dephosphorylation of NFAT and reduce the production of interleukin 2. Antimalarials alter the enzymatic release of lysosomes by increasing intravesicular pH. The mechanism of action of rituximab is related to complement-dependent cytotoxicity and the elimination of anti-CD20-labeled B cells. Progress in the knowledge and management of low doses of steroids may change the current paradigm and reduce the frequency of related adverse events. Mycophenolate seems to be a better choice than cyclophosphamide for induction, it is also preferred over azathioprine as a maintenance immunosuppressive agent, although azathioprine is preferred in women with a desire for conception, those pregnant, or with low resources. For treatment-resistant cases, tacrolimus, rituximab or belimumab may be effective. Ongoing clinical trials with new drugs offer promising results.

Effects of hydroxychloroquine on proteinuria in membranous nephropathy

BACKGROUND

Many patients with primary membranous nephropathy have severe proteinuria unresponsive to optimized renin-angiotensin-aldosterone system inhibitors (RAASi). We evaluated the efficacy and safety of hydroxychloroquine as an adjunctive agent in membranous nephropathy (MN) treatments.

METHODS

We prospectively recruited 126 patients with biopsy-proven primary membranous nephropathy and urinary protein 1-8 g/day while receiving optimized RAASi treatment for ≥ 3 months and well-controlled blood pressure. Forty-three patients received hydroxychloroquine and RAASi (hydroxychloroquine-RAASi group), and 83 patients received RAASi alone (RAASi group). Treatment responses, including proteinuria reduction, complete and partial remission rates, and autoantibody against phospholipase A2 receptor (anti-PLA2R) levels, were compared between the two groups at 6 months and over the long term.

RESULTS

At 6 months, the effective response rate (proteinuria reduction > 30%) (57.5% vs. 28.9%, P = 0.002), clinical remission rate (35.0% vs. 15.7%, P = 0.015), and percentage change in proteinuria (- 51.7% vs. - 21.9%, P < 0.001) were higher, and the rate of switching to immunosuppressants (25.0% vs. 45.8%, P = 0.027) was lower in the hydroxychloroquine-RAASi group than in the RAASi group. Hydroxychloroquine administration was an independent protective factor with an effective response (OR 0.37, P = 0.021). In the long term, the clinical remission rate was higher in the HCQ-RAASi group (62.5% vs. 38.6%, P = 0.013). Hydroxychloroquine therapy was associated with a higher rate of anti-PLA2R reduction (< 20 U/ml) (HR 0.28, P = 0.031). We observed no serious adverse events associated with hydroxychloroquine.

CONCLUSIONS

Hydroxychloroquine could be an option for patients with membranous nephropathy seeking to achieve proteinuria reduction and anti-PLA2R antibody reduction in addition to optimized RAASi. Randomized controlled trials are needed to confirm these findings.

TRIAL REGISTRATION

ChiCTR2100045947, 20210430, retrospectively registered.

Hydroxychloroquine in IgA nephropathy: a systematic review

Background

Hydroxychloroquine (HCQ) has recently been reported to be a promising and safe anti-proteinuric agent for IgA nephropathy (IgAN) patients. In the present systematic review, we aimed to summarize the evidence concerning the benefits and risks of HCQ therapy in IgAN.

Methods

Electronic databases were searched for randomized, cohort, or case-control studies with IgAN biopsy-proven patients comparing the effects of HCQ with angiotensin-converting enzyme inhibitors/angiotensin receptor blockers or immunosuppression on proteinuria reduction.

Results

Five studies, one randomized and three observational, involving a total of 504 patients, were eligible for inclusion. Overall, there was a tendency of HCQ treatment to reduce proteinuria. In the studies where the control arm was supportive therapy, HCQ significantly reduced proteinuria at 6 months. However, in the studies that compared HCQ to immunosuppressive therapy, we found no difference in proteinuria reduction. HCQ had no impact on eGFR.

Conclusion

HCQ seems to be an efficient alternative therapy for patients with IgAN who insufficiently respond to conventional therapy. However, ethnically diverse randomized controlled studies with long-term follow-up are needed.

The efficacy and safety of hydroxychloroquine in pregnant patients with IgA nephropathy: A retrospective cohort study

AIM

Hydroxychloroquine (HCQ) is used to control proteinuria in IgA Nephropathy (IgAN) However, its efficacy and safety in pregnant IgAN patients remains unknown. This study aimed to verify the safety of HCQ in pregnant IgAN patients and compare renal function and pregnancy outcomes with those of patients not treated with HCQ.

METHODS

We retrospectively reviewed medical records of all pregnant IgAN patients and singleton gestations at Peking University First Hospital from 2003-2021. Patients who did and did not receive HCQ treatment during pregnancy were compared.

RESULTS

We found no significant pre- or post-pregnancy differences in proteinuria or renal function between the two groups. However, the HCQ (+) group had higher proteinuria at the time of kidney biopsy (2.04 [1.26, 2.56] g/d vs. 0.80 [0.44, 1.11] g/d, P < .001); the proteinuria level at HCQ therapy initiation was also higher than that at the beginning of pregnancy (1.87 [1.30, 2.59] g/d vs. 1.08 [0.75, 1.50] g/d, P = .001). Despite no difference in preterm birth, birth weight, preeclampsia or postpartum haemorrhage, the proportion of patients with a previous history of spontaneous abortion was higher in the HCQ (+) group than in the HCQ (-) group (48.0% vs. 20.6%, P = .010). The eGFR (regression coefficient, 0.981; 95%CI 0.964-0.998) was a predictive factor for obstetrical complications.

CONCLUSION

HCQ is safe for IgAN treatment during pregnancy with effective reduction of proteinuria. HCQ might also be helpful in patients with a history of spontaneous abortion.

An Update on Targeted Treatment of IgA Nephropathy: An Autoimmune Perspective

Immunoglobulin (Ig) A nephropathy (IgAN) is the commonest form of primary glomerulonephritis worldwide and is, considered a significant cause of end-stage renal disease in young adults. The precise pathogenesis of IgAN is unclear. The clinical and pathological features vary significantly between individuals and races, which makes treating IgAN difficult. Currently, the therapeutic strategies in IgAN are still optimal blood pressure control and proteinuria remission to improve the renal function in most cases. Immunosuppressive drugs such as corticosteroids can be considered in patients with persistent proteinuria and a high risk of renal function decline; however, they include a high toxicity profile. Therefore, the safety and selectivity of medications are critical concerns in the treatment of IgAN. Various pharmacological therapeutic targets have emerged based on the evolving understanding of the autoimmune pathogenesis of IgAN, which involves the immune response, mucosal immunity, renal inflammation, complement activation, and autophagy; treatments based on these mechanisms have been explored in preclinical and clinical studies. This review summarizes the progress concerning targeted therapeutic strategies and the relevant autoimmune pathogenesis in IgAN.

Current treatment of IgA nephropathy

IgA nephropathy (IgAN) is the most common type of glomerulonephritis in Asia and the Western world. In most patients, it follows an asymptomatic to oligosymptomatic course and GFR loss, if any, is slow. The mainstay of therapy therefore is optimized supportive care, i.e., measures that lower blood pressure, reduce proteinuria, minimize lifestyle risk factors, and otherwise help to reduce non-specific insults to the kidneys. The value of immunosuppression has become controversial and if at all, systemic high-dose corticosteroid therapy should be considered for a few months taking into account patient characteristics that would caution against or preclude such therapy. In addition, adverse events related to corticosteroid therapy markedly increase as GFR declines. Beyond corticosteroids, there is little evidence that any additional immunosuppression is helpful, with the exception of mycophenolate mofetil in patients of Asian descent. A considerable number of clinical trials ranging from enteric coated budesonide to blockade of B-cell function to complement inhibitors are currently ongoing and will hopefully allow a more targeted therapy of high-risk patients with progressive IgAN in the future.

Increasing prescription of renin-angiotensin-aldosterone system blockers associated with improved kidney prognosis in Korean IgA nephropathy patients

BACKGROUND

We aimed to describe the characteristics of immunoglobulin A nephropathy (IgAN) in Korea with assessment for time trends.

METHODS

We performed a multicenter retrospective observational cohort study including biopsy-confirmed native IgAN cases from four tertiary hospitals in Korea. Time eras of diagnosis were stratified into 1979-2003, 2004-9 and 2010-17. The prognostic variable was progression to end-stage kidney disease (ESKD) analyzed by multivariable Cox regression analysis.

RESULTS

We included 1366 (from 1979 to 2003), 1636 (from 2004 to 2009) and 1442 (from 2010 to 2017) IgAN patients in this study. In the recent periods, IgAN had relatively better clinical characteristics, as patients had higher estimated glomerular filtration rates and lower baseline blood pressures than before. The use of renin-angiotensin-aldosterone system (RAAS) blockers increased from 57.7% in 1979-2003 to 80.0% in 2010-17. During a median follow-up duration of 11.3 years, 722 patients progressed to ESKD with an incidence rate of 12.5 per 1000 person-years. The 10-year risk of progression to ESKD was lower in 2010-17 compared with that of 1979-2003 [adjusted hazard ratio 0.692 (95% confidence interval 0.523-0.915)], even after adjustment for multiple clinicopathologic characteristics. The use of RAAS blockers was a significant mediator (P < 0.001) for the association between time trends and lower 10-year ESKD risk.

CONCLUSIONS

Clinicopathologic characteristics of IgAN in Korea have changed over time. Although the limitation of a retrospective observational study remains, the result showed that the prognosis of IgAN has improved over the study period, possibly related to increased prescription of RAAS blockers.

Serum TNF-α Level Is Associated with Disease Severity in Adult Patients with Immunoglobulin A Vasculitis Nephritis

Background

Tumor necrosis factor-α (TNF-α) is a proinflammatory factor involved in the pathogenesis of immunoglobulin A vasculitis (IgAV). The association between serum TNF-α and disease severity in adult patients with IgAV nephritis (IgAV-N) has been inadequately evaluated.

Methods

Serum TNF-α was measured by chemiluminescence immunoassay in 53 renal biopsy-proved IgAV-N patients, 53 healthy controls, and 53 IgA nephropathy (IgAN) patients. The correlations of clinicopathologic parameters of IgAV-N patients with serum TNF-α were analyzed.

Results

In this cross-sectional study, the median age of IgAV-N patients was 29 (25-37) years, and 67.9% were female. Serum TNF-α was significantly higher in the IgAV-N group than in the healthy group [7.4 (5.7-9.4) pg/mL vs. 5.9 (5.0, 7.1) pg/mL, P = 0.001], but comparable with sex, age, and estimated glomerular filtration rate (eGFR) grade-matched IgAN patients. Serum creatinine (P = 0.006) and serum cystatin C (P = 0.001) were positively correlated with serum TNF-α level, while albumin (P = 0.014) and eGFR (P = 0.021) were negatively correlated with serum TNF-α level. Multivariate linear regression analysis revealed that eGFR (P = 0.007) was an independent clinical predictor of serum TNF-α. Patients with higher pathological classification grade also had higher serum TNF-α.

Conclusions

Serum TNF-α is associated with renal function and the pathological classification of adult patients with IgAV-N. TNF-α is a potential biomarker for the assessment of IgAV-N severity.

Effect of hydroxychloroquine in patients with IgA nephropathy with insufficient responses to immunosuppressive therapy: a retrospective case-control study

Background

Hydroxychloroquine (HCQ) is a well-known immunomodulator that was recently used in immunoglobulin A (IgA) nephropathy (IgAN) due to its antiproteinuric effects. We investigated the effects of HCQ in patients with IgAN whose proteinuria remained above 1 g/d after conventional immunosuppressive (IS) therapy.

Methods

This study was a retrospective case-control study. Twenty-six patients with IgAN who received HCQ and had insufficient responses to IS therapy (corticosteroid (CS) therapy with/without IS agents) were included. Twenty-six matched historical controls who received conventional IS therapy were selected using propensity score matching. The clinical data from 6 months were compared.

Results

Proteinuria at baseline was comparable between the “IS therapy plus HCQ” and “conventional IS therapy” groups (2.35 [interquartile range (IQR), 1.47, 2.98] vs. 2.35 [IQR, 1.54, 2.98] g/d, p = 0.920). A significant reduction in proteinuria was noted in IgAN patients with HCQ treatment (2.35 [IQR, 1.47, 2.98] vs. 1.10 [IQR, 0.85, 1.61] g/d, p = 0.002). The percent reduction in proteinuria at 6 months was similar between the two groups (− 39.81% [− 66.26, − 12.37] vs. -31.99% [− 67.08, − 9.14], p = 0.968). The cumulative frequency of patients with a 50% reduction in proteinuria during the study was also comparable between the two groups (53.8% vs. 57.7%, p = 0.780). No serious adverse events (SAEs) were observed during the study.

Conclusions

Use of HCQ achieved has similar reduction in proteinuria compared to conventional IS therapy in patients with IgAN who had insufficient responses to IS therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-020-02141-9.

Toll-Like Receptor as a Potential Biomarker in Renal Diseases

One of the major challenges faced by modern nephrology is the identification of biomarkers associated with histopathological patterns or defined pathogenic mechanisms that may assist in the non-invasive diagnosis of kidney disease, particularly glomerulopathy. The identification of such molecules may allow prognostic subgroups to be established based on the type of disease, thereby predicting response to treatment or disease relapse. Advances in understanding the pathogenesis of diseases, such as membranous nephropathy, minimal change disease, focal segmental glomerulosclerosis, IgA (immunoglobulin A) nephropathy, and diabetic nephropathy, along with the progressive development and standardization of plasma and urine proteomics techniques, have facilitated the identification of an increasing number of molecules that may be useful for these purposes. The growing number of studies on the role of TLR (toll-like receptor) receptors in the pathogenesis of kidney disease forces contemporary researchers to reflect on these molecules, which may soon join the group of renal biomarkers and become a helpful tool in the diagnosis of glomerulopathy. In this article, we conducted a thorough review of the literature on the role of TLRs in the pathogenesis of glomerulopathy. The role of TLR receptors as potential marker molecules for the development of neoplastic diseases is emphasized more and more often, as prognostic factors in diseases on several epidemiological backgrounds.

A Personalized Update on IgA Nephropathy: A New Vision and New Future Challenges

IgA nephropathy (IgAN) is the most common primary glomerulonephritis in the world among patients undergoing renal biopsy. Approximately 30% of patients with IgAN develop end-stage kidney disease 20 years after renal biopsy. It is a glomerulopathy with a very broad clinical presentation, making it difficult to stratify and treat. IgAN is characterized by dysregulation of the immune system, which causes an abnormal synthesis of IgA1 that is deglycosylated causing its mesangial deposition. IgAN pathogenesis is incompletely understood; the current multi-hit hypothesis of IgAN pathogenesis does not explain the range of glomerular inflammation and renal injury associated with mesangial IgA deposition. Although associations between IgAN and glomerular and circulating markers of complement activation are established, the mechanism of complement activation and contribution to glomerular inflammation and injury are not defined. On the other hand, the renal-gut connection can also play an important role in the pathogenesis of IgAN with possible therapeutic implications. In order to standardize the histological findings, the Oxford Classification has allowed clarifying renal lesions that confer potential risk of progression. Currently, except for the blockade of the renin-angiotensin-aldosterone system, no other therapies are available in clinical setting for the treatment of IgAN, although the range of new drugs under investigation is extensive. The incorporation in the next trials of clinical parameters such as the amount of hematuria and histological lesions may allow more personalized therapeutic approaches. To summarize, in recent years, several important efforts have taken place in the understanding of IgAN, but still, further studies are warranted to elucidate the best therapeutic strategies according to the risk to improve the prognosis of this entity.

The TLR4-MyD88-NF-κB pathway is involved in sIgA-mediated IgA nephropathy

Previous studies have shown that secretory IgA (sIgA) was critically involved in IgA nephropathy (IgAN) immune responses. Toll-like receptors (TLRs), especially TLR4 which participates in mucosal immunity, may be involved in the pathogenesis of IgAN. The purpose of this study was to investigate whether sIgA and TLR4 interact to mediate kidney damage in IgAN patients. IgAN patients with positive sIgA deposition in renal tissues were screened by immunofluorescence assay. Patient salivary sIgA (P-sIgA) was collected and purified by jacalin affinity chromatography. Salivary sIgA from healthy volunteers was used as a control (N-sIgA). Expression of TLR4, MyD88, NF-κB, TNF-α, IL-6, and MCP-1 were detected in the mesangial area of IgAN patients by immunohistochemistry, the expression levels in patients with positive sIgA deposition were higher than that with negative sIgA deposition. Human renal mesangial cells (HRMCs) were cultured in vitro, flow cytometry showed that P-sIgA bound HRMCs significantly better than N-sIgA. HRMCs were cultured in the presence of sIgA (400 μg/mL) for 24 h, compared with cells cultured with N-sIgA, HRMCs cultured in vitro with P-sIgA showed enhanced expression of TLR4, increased secretion of TNF-α, IL-6, and MCP-1, and increased expression of MyD88/NF-κB. TLR4 shRNA silencing and NF-κB inhibition both reduced the ability of HRMCs to synthesize TNF-α, IL-6, and MCP-1. Our results indicate that sIgA may induce high expression of TLR4 in HRMCs and further activate downstream signalling pathways, prompting HRMCs to secrete multiple cytokines and thereby mediating kidney damage in IgAN patients.

Expanding horizons for clinical applications of chloroquine, hydroxychloroquine, and related structural analogues

Several experimental and clinical studies have transformed the traditional antimalarial role of chloroquine (CHQ) and related structural analogues to potent therapeutic agents for a host of nonmalarial indications. The expanding clinical applicability for these drugs includes rheumatological and cardiovascular disorders (CVD), chronic kidney disease (CKD), oncology, and a variety of nonmalarial infections. These clinical advancements are primarily related to pleiotropic pharmacological actions of these drugs, including immunomodulation, anti-inflammatory properties, and capabilities of inducing autophagy and apoptosis at a cellular level. Historically, many clinical benefits in nonmalarial indications were first recognized through serendipitous observations; however, with numerous ongoing systematic clinical studies, the clinical horizons of these drugs have a promising future.

Comparison of the effects of hydroxychloroquine and corticosteroid treatment on proteinuria in IgA nephropathy: a case-control study

Background

Hydroxychloroquine (HCQ), a well-known immunomodulator, has recently been found to be a promising and safe anti-proteinuric agent for treating IgA nephropathy (IgAN). We aimed to compare the efficacy and safety of HCQ and corticosteroid treatment in patients with IgAN.

Methods

This is a case-control study. Ninety-two patients with IgAN who received HCQ in addition to routine renin-angiotensin-aldosterone system inhibitors (RAASi) therapy were included. Ninety-two matched historical controls who received corticosteroids were selected by propensity score matching. The clinical data over 6 months were compared.

Results

Baseline proteinuria levels were comparable between the HCQ and corticosteroid groups (1.7 [1.2, 2.3] vs. 1.8 [1.3, 2.5] g/d, p = 0.96). The percentage reduction in proteinuria at 6 months was smaller in the HCQ group than in the corticosteroid group (− 48.5% [− 62.6, − 31.4] vs. -62.9% [− 81.1, − 34.9], p = 0.006). The time averaged proteinuria within the 6 months of observation was comparable for the HCQ and corticosteroid groups (1.1 [0.8, 1.5] vs. 1.1 [0.5, 1.8] g/d, p = 0.48). The cumulative frequency of patients with a 50% reduction in proteinuria during the study was also comparable between the two groups (52.2% vs. 62.0%, p = 0.25). However, six of the 92 (6.5%) patients suffered from severe adverse events (SAEs) in the corticosteroid group, while no SAEs were observed in the HCQ group (6.5% vs. 0%, p = 0.03).

Conclusions

The antiproteinuric effect of HCQ might be slightly inferior to that of corticosteroids over 6 months in patients with IgAN who were deemed to be candidates for HCQ and not corticosteroids treatment. However, HCQ treatment was safer than corticosteroid treatment.

Treatment of IgA Nephropathy: Evolution Over Half a Century

Fifty years into the original description of IgA nephropathy, there is still no specific therapy for this condition and general measures including blood pressure control with blockers of the renin-angiotensin-aldosterone system and salt restriction remain the cornerstone to slow disease progression. Although the paucity in treatment advances could be related to the disease's complex pathogenesis, which requires multiple hits, heterogeneity as reflected by diverse ethnic differences, and genetic predisposition and histopathologic variations, many nonspecific and immunomodulatory agents have been tested with variable degrees of success and tribulations. Here, we review the evolution of these different therapeutic approaches over time that culminated in the 2012 Kidney Disease: Improving Global Outcomes Clinical Practice Guideline for Glomerulonephritis that presently is being updated, and provide an appraisal of recent data on various forms of immunosuppressive agents. Finally, we discuss the theoretical basis of ongoing and upcoming clinical trials that are more pathway- or cell-type-specific as knowledge in disease mechanisms advances.

Effects of Hydroxychloroquine on Proteinuria in IgA Nephropathy: A Randomized Controlled Trial

RATIONALE & OBJECTIVE

Despite optimization of renin-angiotensin-aldosterone system (RAAS) inhibition, patients with immunoglobulin A nephropathy (IgAN) and persistent proteinuria remain at risk for kidney failure. We evaluated the efficacy and safety of hydroxychloroquine (HCQ), an immunomodulator, when added to the treatment regimen of patients with IgAN.

STUDY DESIGN

Double-blind, randomized, placebo-controlled, phase 2 clinical trial.

SETTING & PARTICIPANTS

Participants had IgAN (proteinuria with protein excretion of 0.75-3.5g/d and estimated glomerular filtration rate>30mL/min/1.73m²) and were receiving optimized RAAS inhibitor therapy.

INTERVENTIONS

Patients were randomly assigned 1:1 to receive daily oral HCQ or a placebo for 6 months.

OUTCOMES

The primary outcome was percentage change in proteinuria between baseline and 6 months.

RESULTS

60 participants (mean estimated glomerular filtration rate, 53.8mL/min/1.73m²; median urine protein excretion, 1.7g/d) were recruited and randomly assigned to receive HCQ (n=30) or placebo (n=30). Percentage change in proteinuria at 6 months was significantly different between the HCQ group and the placebo group (-48.4% [IQR, -64.2%, -30.5%] vs 10.0% [IQR, -38.7%, 30.6%]; P<0.001, respectively). At 6 months, median proteinuria level was significantly lower in the HCQ group than in the placebo group (0.9 [IQR, 0.6, 1.0] g/d vs 1.9 [IQR, 0.9, 2.6] g/d; P=0.002, respectively). No serious adverse events were recorded during the study in either study group.

LIMITATIONS

The short treatment period and lack of postwithdrawal observations limit conclusions about long-term renoprotective efficacy and safety.

CONCLUSIONS

HCQ in addition to optimized RAAS inhibition significantly reduced proteinuria in patients with IgAN over 6 months without evidence of adverse events. These findings require confirmation in larger treatment trials.

FUNDING

This study was supported by grants from a government entity, the Capital of Clinical Characteristics, and the Applied Research Fund.

TRIAL REGISTRATION

Registered at ClinicalTrials.gov with study number NCT02942381.

Serum levels of tumor necrosis factor alpha in patients with IgA nephropathy are closely associated with disease severity

Background

Tumor necrosis factor alpha (TNF-α) is considered to play an important role in the pathogenesis in IgA nephropathy (IgAN). The correlations between serum TNF-α and disease severity in patients with IgAN remain controversial.

Methods

Concentrations of serum TNF-α of 147 patients with IgAN and 126 healthy subjects were measured by chemiluminescence immunoassay. Correlations with clinicopathological features of patients with IgAN were evaluated.

Results

Serum levels of TNF-α [9.20 (7.70–10.60) pg/mL vs. 6.04 (5.11–7.23) pg/mL, P < 0.0001] were higher in patients with IgAN than that in healthy subjects. Receiver operating characteristic curve analysis revealed that TNF-α had better discrimination between patients with IgAN and healthy controls than estimated glomerular filtration rate [TNF-α: (AUC, 0.87; 95% CI, 0.83–0.91; P < 0.0001) vs. estimated glomerular filtration rate: (AUC, 0.76; 95% CI, 0.71–0.82; P < 0.0001), P = 0.007]. Multivariate linear regression analyses showed that serum levels of TNF-α were positively correlated with 24-h urine protein excretion (r = 0.33, P = 0.04), urinary protein to serum creatinine ratio (r = 0.33, P = 0.03), serum creatinine (r = 0.46, P < 0.0001) and Cystatin C (r = 0.59, P < 0.0001) in IgAN and negatively correlated with estimated glomerular filtration rate (r = − 0.49, P < 0.0001) after adjustment for sex, systolic blood pressure and diastolic blood pressure. Patients with higher mesangial hypercellularity or tubular atrophy/interstitial fibrosis score according to Oxford classification showed higher serum levels of TNF-α.

Conclusions

Our data showed that serum levels of TNF-α detected by chemiluminescence immunoassay was a potential biomarker for evaluating the disease severity in IgAN.

Electronic supplementary material

The online version of this article (10.1186/s12882-018-1069-0) contains supplementary material, which is available to authorized users.

Hydroxychloroquine Use and Risk of CKD in Patients with Rheumatoid Arthritis

BACKGROUND AND OBJECTIVES

Hydroxychloroquine is widely used in patients with rheumatoid arthritis. However, large-scale studies examining the long-term effects of hydroxychloroquine on the development of kidney disease in patients with rheumatoid arthritis are lacking. We aimed to assess the long-term association of hydroxychloroquine use with the risk of developing CKD in this population.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted an observational cohort study for patients with newly diagnosed rheumatoid arthritis who were enrolled prospectively in Taiwan's National Health Insurance Research Database between January 1, 2000 and December 31, 2013. We used multivariable Cox proportional hazard regression to analyze the association of hydroxychloroquine use with incident CKD.

RESULTS

A total of 2619 patients, including 1212 hydroxychloroquine users and 1407 hydroxychloroquine nonusers, were analyzed. Incident CKD was reported in 48 of 1212 hydroxychloroquine users and 121 of 1407 hydroxychloroquine nonusers. The incidence rate of CKD was lower in hydroxychloroquine users than in hydroxychloroquine nonusers (10.3 versus 13.8 per 1000 person-years). After multivariable adjustment, hydroxychloroquine users still had a lower risk of incident CKD (adjusted hazard ratio, 0.64; 95% confidence interval, 0.45 to 0.90; P=0.01) than hydroxychloroquine nonusers. The lower risk of subsequent CKD development was dose dependent and consistent across subgroup analyses.

CONCLUSIONS

Hydroxychloroquine use in patients with newly diagnosed rheumatoid arthritis is associated with a significantly lower risk of incident CKD compared with in nonusers.

New insights into the pathogenesis of IgA nephropathy

IgA nephropathy is the most common form of glomerulonephritis in many parts of the world and remains an important cause of end-stage renal disease. Current evidence suggests that IgA nephropathy is not due to a single pathogenic insult, but rather the result of multiple sequential pathogenic "hits". An abnormally increased level of circulating poorly O-galactosylated IgA1 and the production of O-glycan-specific antibodies leads to the formation of IgA1-containing immune complexes, and their subsequent mesangial deposition results in inflammation and glomerular injury. While this general framework has formed the foundation of our current understanding of the pathogenesis of IgA nephropathy, much work is ongoing to try to precisely define the genetic, epigenetic, immunological, and molecular basis of IgA nephropathy. In particular, the precise origin of poorly O-galactosylated IgA1 and the inciting factors for the production of O-glycan-specific antibodies continue to be intensely evaluated. The mechanisms responsible for mesangial IgA1 deposition and subsequent renal injury also remain incompletely understood. In this review, we summarize the current understanding of the key steps involved in the pathogenesis of IgA nephropathy. It is hoped that further advances in our understanding of this common glomerulonephritis will lead to novel diagnostic and prognostic biomarkers, and targeted therapies to ameliorate disease progression.

Effects of Hydroxychloroquine on Proteinuria in Immunoglobulin A Nephropathy

BACKGROUND

Hydroxychloroquine (HCQ) is a well-known immunomodulator that is useful as in the treatment for lupus because of its inhibitory effect on toll-like receptors and cytokines, which are speculated to play a role in the pathogenesis of Immunoglobulin A (IgA) nephropathy (IgAN). However, there was only one study that investigated the effect of HCQ on proteinuria in patients with IgAN.

METHODS

Ninety patients with IgAN who received HCQ in addition to optimized dosage of renin-angiotensin-aldosterone system inhibitors (RAASi) were recruited for this study, and 90 matched historical controls who received RAASi alone were selected from our registry by the propensity score matching method. Their clinical data were compared at baseline and during follow-up till the termination of HCQ or addition of immunosuppressive agents.

RESULTS

The median baseline proteinuria level of the 90 patients who received HCQ was comparable with the RAASi-alone group (1.5 [1.2, 2.1] vs. 1.5 [1.2, 1.9] g/day, p = 0.74). At 6 months post-study initiation, the median proteinuria level in the HCQ group was lower than that in the RAASi-alone group (0.8 [0.7, 1.2] vs. 1.2 [0.8, 1.8] g/day, p = 0.02). The percentage by which proteinuria was reduced in the HCQ group was significantly higher than that in the RAASi-alone group (-43% [-57, -12] vs. -19% [-46, 17], p = 0.01). No serious adverse effects were documented during treatment with HCQ.

CONCLUSION

The addition of HCQ to RAASi resulted in a significant and safe reduction in proteinuria in patients with IgAN.