IgA Nephropathy Patient Research Articles

Prognosis of IgA nephropathy patient with proteinuria remission by supportive therapy: cohort from screening failed Chinese patients in TESTING study

Background During the run-in phase of the TESTING study, approximately half of patients with IgA nephropathy (IgAN) were excluded due to proteinuria below 1 g/24 h after intensive supportive therapy. The long-term prognosis of these patients needs further investigation. Methods 112 screening failed patients in the TESTING study from 10 centers in China were enrolled in this retrospective study. The prognosis of 88 patients, who were excluded because of proteinuria below 1 g/24 h, was analyzed by Landmark Kaplan-Meier analysis. The composite kidney endpoint was defined by a ≥ 50% reduction in eGFR, ESKD (eGFR <15 mL/min per 1.73 m2), chronic dialysis for at least 6 months, or renal transplantation. Results In total, 88 patients were excluded due to proteinuria less than 1 g/24 h. During the follow-up, 73/88 (83.0%) patients received renin-angiotensin system blocker. 72/88 (81.8%) had stable proteinuria remission and did not receive immunosuppressive therapy (IST), and 16/88 (18.2%) received IST because of a relapse of proteinuria. Landmark Kaplan–Meier analysis revealed that, the kidney survival from dialysis or composite kidney outcome of these excluded patients with IST was similar to those without IST during the early stages of follow-up (dialysis, before 60 months, p = 0.778; composite kidney outcome, before 48 months, p = 0.862); whereas the risk for dialysis of patients receiving IST was significantly higher than those without IST after 60 months (OR = 11.3, p = 0.03). Similarly, the risk for the composite kidney outcome of patients receiving IST was also significantly higher than those without IST after 48 months (OR = 5.92, p = 0.029). Conclusions IgAN patients who maintained a persistent remission of proteinuria after intensive supportive therapy had a much better long-term kidney outcome than those who experienced a relapse of proteinuria and needed IST.

#1261 A small-molecule inhibitor of Bruton's tyrosine kinase reduces production of galactose-deficient IgA1 in IgA nephropathy

Abstract Background and Aims IgA nephropathy (IgAN) is a chronic kidney disease characterized by glomerular immunodeposits that contain aberrantly glycosylated IgA1, i.e., IgA1 with some hinge-region O-glycans deficient in galactose (galactose-deficient IgA1; Gd-IgA1). These immunodeposits originate from circulating immune complexes that contain Gd-IgA1 bound by IgG autoantibodies. Consistent with this hypothesis, serum levels of Gd-IgA1 and IgG autoantibodies independently predict disease progression in IgAN patients. Biochemical studies using IgA1-secreting cell lines derived from peripheral blood of IgAN patients and healthy controls have revealed that Gd-IgA1 production is driven by altered biosynthetic pathways of IgA1 O-glycans. Specifically, cell lines from IgAN patients have altered expression and activity of several glycosyltransferases, C1GalT1 and ST6GalNAc2, and a C1GalT1-specific chaperone, C1GalT1C1. Genetic studies have shown that serum levels of Gd-IgA1 are genetically co-determined and genome-wide association studies (GWAS) identified genetic variations that impact the expression C1GALT1 and C1GALT1C1 genes. Moreover, macroscopic hematuria during an upper-respiratory-tract infection is common at the clinical onset of IgAN and during episodes of accentuated disease activity, indicating a connection between IgAN and mucosal inflammation. Notably, a pro-inflammatory cytokine interleukin-6 (IL-6), enhances production of Gd-IgA1 exclusively in the cell lines derived from IgAN patients. Leukemia inhibitory factor (LIF) has similar effects. LIF-induced effects are mediated by abnormal STAT1 signaling and pathways that include Lyn, a Src-family kinase. The corresponding gene, LYN, was recently identified in one of the 16 new IgAN-associated GWAS loci. Lyn, together with spleen tyrosine kinase (Syk) and Bruton's tyrosine kinase (Btk), is involved in B-cell-receptor (BCR)-signaling pathways that include activation and inhibitory signals. The aim of this study was to assess if Btk may be involved in Gd-IgA1 production in IgAN. Method IgA1-producing cell lines were cloned by limiting dilution of Epstein-Barr-virus-immortalized peripheral-blood B cells from patients with IgAN (n = 5) and healthy controls (n = 5). Cell signaling, induced by LIF or by BCR crosslinking with anti-IgA antibody, was assessed by flow cytometry or SDS-PAGE/immunoblotting using antibodies for specific phosphorylated sites of selected proteins. Data were normalized using antibodies for specific proteins. Total IgA and Gd-IgA1 were quantified in cell-culture medium using standard ELISA and lectin-ELISA, respectively. Gd-IgA1, normalized to IgA, was expressed in Units (U) of standard Gd-IgA1 protein. Results IgA1-producing cell lines from patients with IgAN and healthy controls secreted similar amounts of total IgA (17.2 ± 9.3 ug/ml vs. 14.6 ± 9.5 ug/ml), but the cells from IgAN patients secreted more Gd-IgA1 (24.2 ± 7.5 U vs. 15.5 ± 2.7 U; p &amp;lt; 0.05). Baseline phosphorylation of Btk (Y223), but not Syk (Y551), was higher in the cells from patients with IgAN than in those from healthy controls. We used an IgA1-secreting cell line from an IgAN patient to confirm that BCR crosslinking with F(ab’)2 anti-IgA antibody in IgA + CD19+ cells lines induced phosphorylation of Btk (Y223). Conversely, anti-IgM antibody, used as a negative control, did not activate Btk. LIF stimulation did not affect phosphorylation of Btk or Syk. A Btk inhibitor, PCI-32765 (ibrutinib), reduced Gd-IgA1 production in a dose-dependent fashion exclusively in the IgAN-derived cells. Notably, 1 uM PCI-32765 reduced Gd-IgA1 production to that for healthy controls (25.7 ± 1.2 U to 17.3 ± 1.8 U; p &amp;lt; 0.01). Conclusion Inhibition of Btk with a small-molecule inhibitor normalized Gd-IgA1 production in IgA1-secreting cells from patients with IgAN, revealing a previously unknown role of Btk in aberrant O-glycosylation of IgA1. Btk may thus represent a potential new target for disease-specific therapy of IgAN.

#1271 Risk of primary infections in patients with IgA nephropathy: a Swedish population-based cohort study

Abstract Background and Aims IgA nephropathy (IgAN) is the most common global kidney disease with a highly variable clinical presentation. Diagnosis IgAN requires a biopsy, and the immunohistologic examination is dominated by depositions of aberrant IgA1 antibodies. Since IgA antibodies are mainly produced by the mucosal associated lymphoid tissue the relationship between the mucosal immune system and IgAN has long been considered. The current theories on the origin of the disease involve genetic and environmental factors, with mucosal infections potentially playing a role. In some IgAN patients gastrointestinal and/or upper respiratory infections can aggravate the disease with episodic macrohematuria and/or increased proteinuria. Coincidently, these infections are also more common among patients with selective IgA deficiency. The aim of this study was to investigate whether the presence of IgAN confers an increased risk of infections in general to the IgAN patient. Method IgAN was defined by a computerized biopsy record from 1997 to 2011 in Sweden. Each IgAN patient was matched with up to five reference individuals based on age, sex, calendar year, and county of residence. Exclusions included those with organ transplants, HIV, immunodeficiency, or end-stage kidney disease before study entry, and follow-up data were censored for subsequent occurrences. Linear and Cox regressions, adjusted for age, sex, and education, were performed to analyze total infections and antimicrobial treatments in both patient and reference groups. Sibling analyses were also performed, adjusted for baseline age, sex and educational attainment. Results The linear regression analysis revealed a significant association between IgA nephropathy (IgAN) and the overall frequency of infections compared to the general population (β = 0.45; 95% CI: 0.37–0.54), women (β = 0.35; 95% CI: 0.19–0.50), men (β = 0.50; 95% CI: 0.40–0.60), and siblings (β = 0.37; 95% CI: 0.25–0.49) for women (β = 0.24; 95% CI: 0.06–0.41) and men (β = 0.43; 95% CI: 0.27–0.60). Similarly, a significant association was found for the frequency of prescribed antimicrobial agents compared to the general population (β = 0.66; 95% CI: 0.51–0.82), women (β = 0.92; 95% CI: 0.56–1.27), men (β = 0.55; 95% CI: 0.39–0.71), with similar estimates in the sibling analyses. The subtypes with the strongest association were urinary tract infections (β = 0.09; 95% CI: 0.07–0.11), ENT (ear, nose, and throat) infections (β = 0.08; 95% CI: 0.04–0.12), muscular infections (β = 0.08; 95% CI: 0.05–0.12), and infections in the GI (gastrointestinal) tract (β = 0.06; 95% CI: 0.04–0.09). Infections in the lower respiratory tract, skin and mycoses also had a significant positive association, however, no associations to infections in the central nervous system or infections caused by helminths and protozoans were identified. Cox regression showed an elevated risk of any infection with an adjusted hazard ratio (HR) of 2.05 (95% CI: 1.88–2.23), especially for sepsis (aHR = 3.13; 95% CI: 2.14–4.59), and time to the first prescription of antimicrobials with an aHR of 1.37 (95% CI: 1.30–1.45). Linear regression of prescribed antimicrobial treatments showed an overall β = 0.67; 95% CI: 0.51–0.82, and specifically for antibiotics (β = 0.64; 95% CI: 0.49–0.78). Conclusion Our study demonstrates an increased prevalence of infections and antibiotic prescriptions in IgAN patients compared to the general population and their siblings. Further studies on the potential impact of IgAN and its immunological aberrations on overall infection susceptibility is warranted.

Correlation between MEST-C score in kidney biopsy of IgA nephropathy patient and prognosis

Introduction: IgA nephropathy (IgAN) is the most common type of primary glomerulonephritis, and is the most common type of glomerulopathy which leading to end-stage renal disease (ESRD). Prompt diagnosis of high-risk patients is important to initiate specific treatment early and prevent progression to ESRD. Oxford pathological classification, known as MEST-C score, attempts to predict prognosis based on pathological factors. Objectives: In this study, we evaluated the value of pathological and clinical variables in estimating the prognosis of IgAN in Iranian patients. Patients and Methods: In this retrospective cohort study, 165 specimens were reviewed by a nephropathologist, who reported the MEST-C score after the definitive diagnosis of IgAN. Patient records were reviewed to gather clinical data, including serum creatinine, 24-hour urine protein levels, diagnosis of hypertension and/or diabetes, and any treatment received. The pre-specified endpoints were determined as progression to ESRD, a reduction in estimated glomerular filtration rate (eGFR) to less than 50% of its baseline, performance of renal transplant, or death. The variables were compared in patients who had reached the pre-specified endpoints and those who had not, to estimate their prognostic value. Results: Findings showed that the urinary protein level and T-score on biopsy were significant prognostic factors. Other pathological factors such as C, S, and M scores lost their significance on multivariate analysis. Further research is needed to validate the efficacy of the MEST- C score in different racial populations. Conclusion: In our study, urinary protein level at diagnosis and T-score on biopsy were validated as prognostic factors, while M, E, S and C scores were not deemed significant. Further research is necessary to validate the MEST-C scoring system in different populations before its use in routine clinical practice.

Efficacy and safety of sequential immunosuppressive treatment for severe IgA nephropathy: A retrospective study.

Background: This study compared the efficacy and safety of sequential immunosuppressive therapy in patients with non-end-stage IgA nephropathy (IgAN) with Lee's classification of IV ∼ V and provided evidence for the use of immunotherapy in patients with severe IgAN. Methods: We retrospectively analyzed the clinical data of patients with Lee's IV ∼ V non-end-stage IgA nephropathy. Results: 436 patients were diagnosed with IgAN, and 98 patients who met the inclusion criteria were included in this retrospective study. Of these, 17 were in the supportive care group, 20 in the P group (prednisone-only), 35 in P + CTX group (the prednisone combined with cyclophosphamide followed by mycophenolate mofetil), and 26 in the P + MMF group (prednisone combined with mycophenolate mofetil). The four groups showed differences in the segmental glomerulosclerosis score and the proportion of patients with Lee's grade IV (p < 0.05), but no differences in other indicators. Compared with the baseline values, urine protein-to-creatinine ratio (PCR) significantly decreased and serum albumin increased (p < 0.05), but there was no significant difference between the groups. The estimated Glomerular Filtration Rate (eGFR) of the P, P + MMF, and P + CTX groups were higher than that of the supportive care group at the 6th and 24th month after treatment (all p < 0.05). At the 24th month, the eGFR in the P + CTX group was higher than that in the P + MMF group (p < 0.05). The effective remission rate of the P + CTX group was higher than that of the supportive care group (p < 0.05). At 12months, the effective remission rate of the P group was higher than that of the supportive care group (p < 0.05). At the 24th month, there was no significant difference in the effective remission rates among the three groups (P, P + MMF, and P + CTX). Nine patients with severe IgA nephropathy reached the endpoint. Conclusion: This study showed that immunosuppressive therapy insevere IgAN patient scan effectively reduce urinary protein, increase albumin, and protect renal function in the early stages of IgAN. P + CTX is the most commonly used, which has a high effective remission rate of urine protein and a low incidence of end-point events.

Serum and Urine Biomarkers Related to Kidney Fibrosis Predict Kidney Outcome in Czech Patients with IgA Nephropathy.

We evaluated biomarkers related to kidney fibrosis for the outcome of patients with IgA nephropathy (IgAN). Clinical parameters (estimated glomerular filtration rate, hypertension, proteinuria) and histological findings were assessed in 134 patients with IgAN at the time of diagnosis and followed up prospectively (mean follow-up time, 56.5 months). We measured biomarkers of collagen and laminin turnover in serum and urine collected at the time of kidney biopsy using a novel enzyme-linked immunosorbent assay. Linear discriminant analysis and logistic regression models were used to predict the patient's kidney outcome. Five serum and urine biomarkers of laminin and collagen turnover (sLG1M, sPRO-C3, sPRO-C6, uPRO-C6/Cr, uC3M/Cr) could significantly differentiae IgAN patients with a worse prognosis. Clinical parameters (glomerular filtration rate (GFR), proteinuria) distinguished patients at risk of IgAN progression with a specificity of 87.3% and a sensitivity of 45.2% (area under the curve-AUC 0.751). The addition of the biomarkers significantly increased the prognostic ability with a specificity of 85.1% and a sensitivity of 73.3% (AUC 0.905). We have identified three serum (sLG1M, sPRO-C3, sPRO-C6) and two urinary markers (uPRO-C6/Cr, u-C3M /Cr) that significantly improve the prognostic ability of markers of kidney function to identify an IgAN patient's risk of progressing to ESKD.

Fecal Capsule as a Therapeutic Strategy in IgA Nephropathy: A Brief Report.

In this brief report, we reported an IgA nephropathy (IgAN) patient who presented in November 2020 with an acute exacerbation with massive proteinuria and diarrhea. He had the earliest onset in 2018 when his IgAN was diagnosed by renal biopsy. He has been treated with active ACEI/ARB drugs for more than 90 days, intermittent steroid therapy, combined with anti-infective therapy. Although his acute symptoms resolved with each episode, he became increasingly severe as the interval between episodes shortened. Accordingly, the immunosuppressive drugs were administered under the KDIGO guidelines and related guidelines. However, the patient and his family refused this treatment. We pondered over the possible pathogenesis of IgAN, and after a full discussion with the patient and his family, FMT was administered to him after obtaining his informed consent. During the FMT procedure, one healthy volunteer (the doctor himself) also took the FMT capsules. In the end, the patient’s urine protein dropped significantly and even turned negative after treatment. Neither the patient nor the healthy volunteer experienced any serious adverse effects during the use of the capsules and the subsequent 6-month follow-up period. We also used metagenomic sequencing to analyze the intestinal flora of patients before and after treatment, and a gradual increase stood out in the abundance of the patient’s intestinal flora after drug administration.

MO243: Intestinal Fatty-Acid Binding Protein: A Potential Biomarker of Enterocyte Damage in IGA Nephropathy?

Abstract BACKGROUND AND AIMS An abundance of inflammatory cells has been found in duodena of IgA nephropathy (IgAN) patients [1, 2]. The degree of intestinal inflammation was shown to correlate with the amount of proteinuria and haematuria in IgAN [3]. Serum intestinal fatty-acid-binding protein (I-FABP) has shown to correlate with the degree of enterocyte damage in untreated coeliac disease (CD) patients [4]. The median level of I-FABP in untreated CD patients was 785 pg/mL and 173 pg/mL in healthy controls [5]. We conducted this study hypothesizing that I-FABP would be elevated in IgAN as a potential biomarker for the presence of subclinical enterocyte damage and intestinal inflammation. CD was excluded with coeliac autoantibody tests. METHOD This study was carried out at the Tampere University Hospital and Tampere University, Finland. Altogether 85 IgAN patients participated (median age 55 years, 54% males). None of the patients had progressed to end-stage kidney disease, nor had they a diagnosed enteropathy. Fifteen healthy controls (median age 57 years, 47% males) were participants from our previous CD studies. Coeliac autoantibodies were determined from the serum samples by measuring IgA class endomysial antibodies (EmA) and transglutaminase antibodies (tTGAb). EmA was determined by an in-house indirect immunofluorescence method using human umbilical cord as substrate. A serum dilution of 1: ≥ 5 was considered positive. tTGAb levels were determined with EliA Celikey assay (ThermoFisher Scientific, Waltham, MA, USA, cut-off for positivity 7.0 U/mL). The serum levels of I-FABP were determined with a commercially available ELISA kit (Hycult Biotech, Uden, The Netherlands, detection limit 47 pg/mL). Current kidney function was available in 68 IgAN patients (80%), and eGFR &amp;gt;60 mL/min/1.73 m2 was regarded as preserved kidney function. RESULTS I-FABP levels among IgAN patients (median 830 pg/mL, IQR 475–1378) were higher (P &amp;lt; .001) compared with healthy controls (289 pg/mL, IQR 199–568). A total of 57% of the IgAN patients from whom the data on current kidney function were available had preserved kidney function. Also, I-FABP levels in IgAN patients with preserved kidney function (650 pg/mL, IQR 419–880) were higher compared with healthy controls (P .006). tTGAb levels in IgAN patients (1.3, 0.8–1.9 U/mL) were higher (P &amp;lt;.001) compared with healthy controls (0.6, 0.3–0.7 U/mL). One IgAN patient had a borderline elevated tTGAb of 7.1 U/mL. No one had an elevated EmA test result. I-FABP and tTGAb levels had no correlation (rS 0.182, P = .051). CONCLUSION The clear difference in the levels of I-FABP in IgAN patients with preserved kidney function compared with healthy controls was of utmost interest. Elevated I-FABP may represent enterocyte injury and intestinal inflammation present in IgAN. Even though CD was excluded serologically, also the tTGAb levels were higher among IgAN patients. These findings spur us in search for an intestinal process in the pathophysiology of IgAN.

The Role of Complement in Microangiopathic Lesions of IgA Nephropathy

IntroductionArteriolar microangiopathic (MA) lesions are independent risk factors for IgA nephropathy (IgAN) patient prognosis, and the underlying mechanism remains to be elucidated. The complement plays an important role in IgAN and thrombotic microangiopathy; however, its role in MA lesions in IgAN remains unclear.MethodsImmunohistochemistry was performed to detect arteriolar complement deposition. Enzyme-linked immunosorbent assay (ELISA) and whole-exome sequencing were performed to explore possible mechanism.ResultsIn this study, we found that patients with IgAN with MA lesions have more complement deposition, especially C4d, on renal arterioles than those in patients with arteriolosclerosis (AS) and patients with no vascular lesions (100% vs. 53% vs. 14%, P < 0.05). Furthermore, our large prospective cohort demonstrated that patients with IgAN with MA lesions had higher levels of Gd-IgA1 (median: 326.98 U/ml, interquartile range 303.46–370.5 vs. 319.22, 292.01–347.3 vs. 321.95, 291.68–350.68, P = 0.014) and C3a (122.57 ± 42.07 vs. 93.79 ± 29.49 vs. 93.51 ± 45.87 ng/ml, P = 0.01) than those in patients with AS and those with no vascular lesions. However, serum IgA1 and C3 levels were not significantly different. Finally, through whole-exome sequencing, we found that nearly half of the patients with MA lesions had rare genetic variations in complement-related genes.ConclusionOur results indicate that the complement is involved in the development of MA lesions in IgAN, which might be associated with the circulating complex containing Gd-IgA1.

POS-304 A TARGETED LITERATURE REVIEW OF PREVALENCE AND TREATMENT PATTERNS OF IgA NEPHROPATHY IN MAINLAND CHINA, TAIWAN, AND SOUTH KOREA

IgA nephropathy (IgAN) is the most common primary glomerulonephritis (GN) worldwide with higher rates in East and Pacific Asia compared to North America and Europe. Despite high reported prevalence of IgAN in these countries, the overall disease prevalence across Asia is not available. Treatment patterns of IgAN patients across Asian countries have also not been summarized. This literature review synthesized IgAN prevalence and treatment patterns among patients in Asian countries/regions, specifically Mainland China, Taiwan, and South Korea. A targeted literature review (TLR) was conducted in PubMed, Chinese (China National Knowledge Infrastructure, WANFANG) and Korean (Korean Medical Database, Korean Information Service System) databases for studies on IgAN prevalence and treatment patterns (e.g., percentage of patients using a given therapy, treatment adherence) from January 2010-May 2021. Grey literature searches using Google Scholar and Baidu (for China) were also conducted. This targeted review included 27 publications. IgAN prevalence is highly variable across Mainland China, Taiwan, and South Korea, with prevalence rates ranging from 6%-62%. In Mainland China, mean prevalence of IgAN is estimated at 25% among patients with renal biopsies (range: 6%-41%) and 38% (range: 30%-50%) among primary GN patients. In Taiwan, mean prevalence of IgAN is estimated at 12% (range: 11%-13%) among patients with renal biopsies and 26% among primary GN patients. In South Korea, mean prevalence of IgAN is estimated at 38% (range: 26%-62%) among patients with renal biopsies and 51.6% (range: 51.3%-51.9%) among primary GN patients. Country-specific treatment guidelines were identified for Mainland China only. Studies on real-world treatment patterns of IgAN were scarce in the study countries/regions. In Mainland China, only two pediatric and four adult IgAN patient studies were identified. No study reporting IgAN treatment patterns in Taiwan was identified. Three studies among adult IgAN patients in South Korea were identified. Among adult IgAN patients, angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers (ACEI/ARBs) were the most common treatment ranging from 27.7%-90% in Mainland China and South Korea, followed by immunosuppressants (1.6%-85.5%) and steroids (10%-36.1%). ACEI/ARB and steroid use was also high among Chinese pediatric IgAN patients, ranging from 1.6%-45% across included studies. Approximately 6% of Chinese pediatric IgAN patients reported mycophenolate mofetil (MMF) use and 50% of patients underwent a tonsillectomy in one study sample. One study reported less optimal adherence with steroid treatment among Chinese IgAN patients, particularly among younger and female patients, due to concerns over side effects of steroid use. This TLR suggests variable IgAN prevalence in Mainland China, Taiwan, and South Korea. IgAN treatment primarily consisted of ACEI/ARBs, and high steroid use was found despite mixed evidence on its benefits and safety. There are also limited data on IgAN treatment patterns from Taiwan. Further research into IgAN epidemiology and treatment patterns at national levels across multiple Asian countries/regions is warranted to address gaps in evidence.

Impact of the number of steroid pulses in tonsillectomy combined with steroid pulse therapy: a nationwide retrospective study in Japan.

Steroid pulse therapy with tonsillectomy is known as a major treatment for IgA nephropathy (IgAN). However, its protocol was different among institutions and the effects of varying the number of steroid pulses remain unclear. From a total of 1,174 IgAN patients in a multicenter retrospective cohort analysis in Japan, 195 patients were treated by tonsillectomy combined with corticosteroid. They were divided into four groups based on the number of administered steroid pulses from 0 to three (TSP0-3), and remission of urinary abnormalities and renal survival until 1.5-fold increase in serum creatinine level from baseline were analyzed among the four groups and between TSP1 and TSP3. Among the four groups, renal function was relatively good when the estimated glomerular filtration rate was approximately 80-90mL/min/1.73m2 and proteinuria was relatively mild (< 1.0g/gCre). The ratio of patients who developed renal dysfunction was < 5% in all groups, and the cumulative renal survival rate by Kaplan-Meier analysis was similar among groups (log-rank test, p = 0.37), despite varying clinical backgrounds and treatments. After adjustment of the background variables between TSP1 and TSP3, the remission rates of urinary abnormalities were similar and the renal survival rate also remained similar (66.8 vs. 85.4%, p = 0.45). In patients with mild proteinuria and good renal function, the number of steroid pulses did not affect the renal outcome in steroid pulse therapy with tonsillectomy. The adaptation and protocols, such as the number of steroid pulses, should be determined for each IgAN patient's background.

A case presentation of an IgA nephropathy patient with Vogt-Koyanagi-Harada syndrome

BackgroundVogt-Koyanagi-Harada syndrome is a rare disease characterized by skin and eyelash bleaching, chronic granulomatous iridocyclitis and exudative retinal detachment, and aseptic meningitis and encephalopathy. IgA nephropathy complicated by Vogt-Koyanagi-Harada syndrome is very rare, even though they might have similar pathogeneses. Ocular lesions often are not examined when patients are diagnosed with IgA nephropathy, which affects the prognosis.Case presentationWe describe a 55-year-old male IgA nephropathy patient who was admitted with high fever and hematuria. Physical examination revealed impaired binocular vision with blurred vision, impaired hearing, and a congestive rash on the chest and back. Renal ultrasound examination showed no abnormalities. Laboratory examination showed that glomerulonephritis was complicated by infection, and anti-infection therapy was ineffective. Bilateral fluorescein angiography showed Vogt-Koyanagi-Harada syndrome. Further renal biopsy confirmed IgA nephropathy. Hormone shock therapy and cyclophosphamide adjuvant therapy were administered, and the patient’s symptoms improved.ConclusionFor the first time, we reported the case of simultaneous onset of IgA nephropathy and Vogt-Koyanagi-Harada syndrome, which is very rare. The onset of Vogt-Koyanagi-Harada syndrome is rapid and serious, while that of IgA nephropathy is relatively milder, making it easy for specialized doctors to neglect this condition. Doctors should be highly alert to the clinical concomitant occurrence of the two diseases with similar mechanisms, especially in the case of neurological defects and ocular symptoms in IgA nephropathy patients, since timely immunosuppressive treatment may improve the outcome of ocular diseases.

P0371DENTAL CARIES INDUCED BY CNM-POSITIVE STREPTOCOCCUS MUTANS DERIVED FROM IGA NEPHROPATHY PATIETNS IN RATS INDUCED GLOPERULONEPHRITIS LIKE IGA NEPHROPATHY

Abstract Background and Aims IgA nephropathy (IgAN) is one of most common primary glomerulonephritis, whose pathogenesis had remained unclear. We had reported that Cnm-(+)Streptococcus mutans, a kinds of major dental caries bacteria. Cnm-(+)S. mutans had strong collagen binding ability, resulting in high pathogenicity. We reported that the prevalence of Cnm-(+)S. mutans in IgA nephropathy is significantly higher than that in control (Misaki-T et al, Clin Exp Nephrol 2015; 19:844-50), and that Cnm-(+)S. mutans in IgA nephropathy was associated with proteinuria (Misaki-T et al, Sci Rep 2016). We also reported C.rectus and S. mutans increased proteinuria synergistically (Misaki-T et al, Nephron, 2018). In this point, there is no direct evidence that Cnm-(+)S. mutans could induce IgA nephropathy. In this study, we evaluated the renal lesions in rats which had dental caries induced by Cnm-(+)S. mutans derived from IgA nephropathy patient to confirm the pathogenesis of IgA nephropathy like lesions induced by Cnm-(+)S mutans. Method Cmn-(+)S. mutans from saliva of IgA nephropathy patients was orally administrated into 4 weeks old male Sprague-Dawley rats. Addition of sugar to water had been kept during study period to develop dental carits. At week 34 after the infection, blood, urine, and kidney samples were evaluated. Kidney samples were stained by Periodic Acid-Schiff (PAS), IgA, C3. Historical evaluation by electron microscope analysis was also performed. Results At week 34, plaque score and dental caries score in infectious rats significantly elevated, compared with control rats (P&amp;lt;0.001) (Figure 1). These findings suggested Cmn-(+)S. mutans from IgA nephropathy patients induced dental caries in rats. PAS staining revealed the significant mesangial proliferation. At week 34, the prevalence of IgA deposition in infections rats was higher than that in control rats (52.4% vs 4%), and the prevalence of C3 deposition in infectious rats was also higher than that in control rats (42% vs 11%) (Figure 2). Incidence of hematuria was also significantly higher in dental caries group than control. Electron microscopy analysis revealed high dense deposit in mesangial areas. Conclusion Cmn-(+)S. mutans from saliva of IgA nephropathy patients could induce IgA-dominant infection-associated glomerulonephritis, or IgA nephropathy.

P0301FIT FOR PURPOSE VALIDATION OF A CLINICAL ASSAY FOR THE DETECTION OF SERUM LEVELS OF GALACTOSE-DEFICIENT IMMUNOGLOBULIN A1 (GD-IGA1) IN PATIENTS WITH IGA NEPHROPATHY (IGAN)

Abstract Background and Aims Analysis of serum or plasma from patients with IgA nephropathy (IgAN) has confirmed the presence of elevated levels of circulating immune complexes containing Gd-IgA1 (Czerkinsky 1986). New sensitive and reasonably specific noninvasive tests are emerging to guide the therapeutic strategy that is applicable to all stages of IgAN (Suzuki 2014). Here we are reporting the fit for purpose validation of an ELISA method for the quantitative determination of Gd-IgA1 in human serum samples to support biomarker investigations in clinical studies of Merck KGaA, Darmstadt. Method The assay was developed based on a commercially available immunoassay kit. The dynamic range of the calibration curve was determined from 1.56 ng/mL (LLOQ) to 100 ng/mL (ULOQ). With a minimum required dilution of 200-fold and standard assay volume of 50.0 μL, the range of the method in matrix was from 312 ng/mL to 20, 000 ng/mL. In assay validation phase, multiple validation parameters were evaluated, which included minimum required dilution (MRD), calibration curve, matrix effect, Intra- &amp; Inter run accuracy &amp; precision, selectivity, and parallelism. Additional validation parameters include sample stability (short/long term, freeze-thaw) and batch-to-batch comparison. Results All samples measured for intra &amp; Inter - assay precision, accuracy, fulfilled the specifications according to the acceptance criteria. The selectivity was assessed using blank serum matrix from 10 individuals: the result indicated that matrix components in serum did not interfere with the detection of Gd-IgA1. Parallelism assessment was performed successfully for both samples from healthy donors and IgAN patient samples up to dilution factor (DF) 3200 (serum samples from healthy donors were determined up to DF 1600). All DF-corrected results within the assay range were determined with %CV ≤ 30.0%. Batch to batch comparison was assessed successfully based on the known shelf life of the kit. Short term stability using QC samples were given for up to 24hrs at room temperature. Freeze-thaw stability was given for up to 3 cycles at -20°C±5°C and -75°C±15°C. The investigations were performed according to general guidelines for method validation and applicable regulations. The results of investigated validation parameters fulfilled the requirements and recommendations, generally accepted for bioanalytical projects. Conclusion The present validation qualified the method for the quantitative determination of Gd-IgA1 in human serum samples from clinical studies.

Type IV Collagen Mutations in Familial IgA Nephropathy

Type IV Collagen Mutations in Familial IgA Nephropathy

IgA1 deposition may induce NLRP3 expression and macrophage transdifferentiation of podocyte in IgA nephropathy

BackgroundThe NLRP3 inflammasome plays an important role in mediating podocyte injury in various kidney diseases. The aim of this study was to investigate whether NLRP3 expression associated with podocyte injury was involved in the pathogenesis of IgA nephropathy (IgAN).MethodsNLRP3 inflammasomes and macrophage marker (F4/80) were detected in the renal tissues of IgAN patients. Association between kidney NLRP3 levels and the clinical feature of IgAN patients was analyzed. Podocytes were incubated with serum containing dys-glycosylated IgA1 protein isolated from IgAN patients. Expression of NLRP3 inflammasomes, F4/80, inflammatory cytokine and renal fibrosis marker were measured using RT-PCR and Western blotting.ResultsRenal NLRP3 inflammasome expression was significantly increased in IgAN patients compared to normal control tissues. Moreover, co-expression of NLRP3 and F4/80 could be observed in the podocytes of IgAN patients. Patients with eGFR < 60 ml/min/1.73 m2 had remarkably higher tubular NLRP3 expression (P < 0.05), while patients with gross proteinuria (≥ 3.5 g/day) had a significantly higher glomerular NLRP3 expression (P < 0.05). Further analysis indicated that dys-glycosylated IgA1 isolated from IgAN patient serum could induce podocyte expression of NLRP3 and the macrophage marker F4/80, which could lead to induction of an inflammatory reaction (increased expression of ICAM-1) and fibrosis (increased expression of α-SMA).ConclusionDys-glycosylated IgA1 isolated from IgAN patient serum could induce NLRP3 expression in podocytes and initiate podocyte macrophage transdifferentiation (PMT). After PMT, podocytes secrete proinflammatory cytokines that can contribute to the inflammation cascade and renal fibrosis changes associated with IgAN.

Plasma CXCL16 May Predict Renal Inflammation and the Progression of Immunoglobulin a Nephropathy

Background. A recognized non-invasive biomarker to improve risk stratification of IgA nephropathy (IgAN) patients is scarce. CXCL16 has been shown to play a key role in inflammatory disease as chemoattractant, adhesion and even fibrosis factor. The current study assessed possibility of plasma CXCL16 as a novel biomarker in IgAN patient. Methods. Plasma CXCL16 was measured in 230 patients with renal biopsy consistent IgAN from 2012 to 2014, and clinical, pathological and prognostic relationships were analyzed. Results. The plasma CXCL16 levels in IgAN patients were significantly correlated with the uric acid and estimated glomerular filtration rate by both univariate and multivariate analysis. Tubular atrophy/interstitial fibrosis score was still significantly correlated with the plasma CXL16 levels even after adjustment for other potential predictor variables by multivariate analysis. In addition, the counts of CD4+ T cells, CD8+ T cells and CD20+ B cells in renal biopsies of IgAN patients were significantly correlated with the plasma CXCL16 levels, but not CD68+ macrophage. Finally, we concluded that patients with higher plasma CXCL16 levels had higher risk of poor renal outcome compared with those with lower plasma CXCL16 levels. No association was observed between the CXCL16 polymorphisms and clinical parameters including plasma CXCL16 levels and prognosis. Human kidney cells (HK2) expression of CXCL16 was up-regulated by interferon-γ (IFN-γ) via p65 pathway and recombinant CXCL16 promoted the chemotaxis of Jurkat T cells. Conclusions: Plasma CXCL16 levels were associated with creatinine level, 24-urine protein, tubular atrophy/interstitial fibrosis pathological damage, the CD4+ T cells, CD8+ T cells and CD20+ B cells infiltration in renal tissue and renal outcome in IgAN patients. Plasma CXCL16 might be a potential prognosis novel predictor in Chinese patients with IgAN. Funding: This work was financially supported by the Major Research Plan of the National Natural Science Foundation of China (Grant No. 91742204); International (regional) cooperation and exchange projects, (NSFC-DFG, Grant No. 81761138041), National Natural Science Foundation of China (Grants 81470948, 81670633, 81570667), National key research and development program (Grants 2016YFC0906103) and The National Key Technology R&D Program (Grant 2013BAI09B06, 2015BAI12B07). Declaration of Interest: We declare no competing interests. Ethical Approval: This study conformed with the Declaration of Helsinki and approved by the Huazhong University of Science and Technology, Tongji Hospital Ethics Committee on Human Experimentation. Written informed consent was obtained from each patient.

Targeting the tyrosine kinase signalling pathways for treatment of immune-mediated glomerulonephritis: from bench to bedside and beyond.

Glomerulonephritis (GN) affects patients of all ages and is an important cause of morbidity and mortality. Non-selective immunosuppressive drugs have been used in immune-mediated GN but often result in systemic side effects and occasionally fatal infective complications. There is increasing evidence from both preclinical and clinical studies that abnormal activation of receptor and non-receptor tyrosine kinase signalling pathways are implicated in the pathogenesis of immune-mediated GN. Activation of spleen tyrosine kinase (SYK), Bruton's tyrosine kinase (BTK), platelet-derived growth factor receptor (PDGFR), epidermal growth factor receptor (EGFR) and discoidin domain receptor 1 (DDR1) have been demonstrated in anti-GBM disease. SYK is implicated in the pathogenesis of ANCA-associated GN. SYK, BTK, PDGFR, EFGR, DDR1 and Janus kinase are implicated in the pathogenesis of lupus nephritis. A representative animal model of IgA nephropathy (IgAN) is lacking. Based on the results from in vitro and human renal biopsy study results, a phase II clinical trial is ongoing to evaluate the efficacy and safety of fostamatinib (an oral SYK inhibitor) in high-risk IgAN patient. Various tyrosine kinase inhibitors (TKIs) have been approved for cancer treatment. Clinical trials of TKIs in GN may be justified given their long-term safety data. In this review we will discuss the current unmet medical needs in GN treatment and research as well as the current stage of development of TKIs in GN treatment and propose an accelerated translational research approach to investigate whether selective inhibition of tyrosine kinase provides a safer and more efficacious option for GN treatment.

Soluble Urokinase Receptor Levels Are Correlated with Focal Segmental Glomerulosclerosis Lesions in IgA Nephropathy: A Cohort Study from China.

BackgroundSoluble urokinase receptor (suPAR) may be involved in the pathological mechanisms of focal segmental glomerulosclerosis (FSGS) changes. However, it remains unclear whether suPAR is correlated with the FSGS-like lesions in IgA nephropathy (IgAN).MethodsWe measured the plasma suPAR levels in 138 patients with IgAN, and then their clinical and pathological relationships were analyzed.ResultsWe found that the plasma suPAR levels were significantly correlated with age and renal function by both univariate and multivariate analysis in our IgAN patient cohort. Female had higher plasma suPAR levels and no significant correlation was observed between plasma suPAR levels and 24-h urine protein and highly sensitive C-reaction protein with multivariate analysis. In our cohort, sixty of these IgAN patients could be diagnosed with a type of FSGS lesions. The plasma suPAR levels were higher in the IgAN patients with FSGS lesions than in the IgAN patients without FSGS lesions by univariate (P < 0.0001) and multivariate (P < 0.001) analysis adjusting for other predictor variables, which might be helpful to differentiate the pathological changes with and without FSGS lesions. And the optimal cutoff value was 1806 pg/ml in this study. The plasma suPAR concentrations were also associated with the degree of tubular atrophy/interstitial fibrosis in both univariate and multivariate analysis. In multivariate analysis, the plasma suPAR levels were correlated with the percentage of crescents, not global sclerosis and arterial lesions.ConclusionsOur study suggested that the plasma suPAR levels were associated with age, gender, renal function, the degree of tubular atrophy/interstitial fibrosis and the percentage of crescent formation. The plasma suPAR might be a potential predictor for the presence of FSGS pathological lesions in Chinese patients with IgAN.

Current Status of Primary Glomerulonephritis

Recent change in major indication for renal biopsy from nephrotic syndrome to asymptomatic urinary abnormality (AU) in Korea makes IgA nephropathy the most common biopsy- confirmed glomerulonephritis (GN). Beside from the most common manifestation of AU, a significant portion (22%) of IgA nephropathy (IgAN) patient revealed the nephrotic-range proteinuria. About 1/3 of patients with minimal change disease (MCD), membranous nephropathy (MN) and focal segmental glomerulosclerosis (FSGS) presented with AU. In elderly patient (> 60 years), the proportion of cresentic glomerulonephritis, MN, and FSGS increased, while the prevalence of IgAN decreased compared to younger patients. MCD showed no change based on old age. GN was the third most common cause of ESRD constituting 11-15% of cases. ESRD patients from GN start dialysis younger and live longer on dialysis compared to diabetic and hypertensive patients in Korea. (Korean J Med 2013;84:1-5)