Granulomatosis With Polyangiitis With And Without Antineutrophil Cytoplasmic Antibodies: A Case-Control Study.

BACKGROUND: ANCA-negative GPA remains a diagnosis of exclusion. Clinical differences between patients with ANCA-negative vs ANCA-positive GPA have not been analyzed in sizable case-control studies, and the effects of ANCA-seroconversion from negative to positive are not well documented. METHODS: A single-center, sex, and age matched case-control study evaluated ANCA-negative vs ANCA-positive GPA from January 1, 1996, to December 31, 2015. Patients who experienced seroconversion were the subject of a case crossover study. Clinical data and outcomes were retrieved from electronic medical records. RESULTS: ANCA-negative GPA was identified in 110 patients; 65% were female; median age was 55 (IQR 39-65) years at time of diagnosis. Disease severity was milder in ANCA-negative GPA (BVAS/WG = 2 vs 6, p< 0.001). Mucous membranous/eye manifestations were more frequent in ANCA-negative GPA. General symptoms, pulmonary, and renal involvement were more frequent in ANCA-positive GPA. Patients with ANCA-positive GPA relapsed more over 60 months (21.8% vs.9.1%, p= 0.009) compared with ANCA-negative GPA and had shorter time to event (p= 0.043). Patients with general manifestations, BMI > 30kg/m2 and necrotizing granulomatous inflammation were more likely to relapse. The 16 patients who seroconverted into ANCA-positive during follow-up had higher mean BVAS/WG at time of diagnosis (p< 0.001) and increased incidence of relapses (p= 0.004) after seroconversion. Necrotizing granulomatous inflammation on biopsy in ANCA-negative GPA patients was identified as a risk factor for subsequent seroconversion to ANCA-positivity. CONCLUSION: Patients with ANCA-negative GPA have milder disease and a lower frequency of relapse than those with ANCA-positive GPA. ANCA appearance portended higher disease severity and an increased frequency of relapses.

Treatment of Antineutrophil Cytoplasmic Antibody-Associated Vasculitis With Diffuse Alveolar Hemorrhage With Avacopan.

OBJECTIVE: Avacopan, an activated complement factor 5 receptor antagonist, has been approved as adjunct therapy for severe active antineutrophil cytoplasmic antibody-associated vasculitis (AAV). Current evidence supports the management of AAV presenting with diffuse alveolar hemorrhage (DAH) by administering glucocorticoids combined with either rituximab or cyclophosphamide in addition to supportive care. The role of avacopan in patients with DAH as a primary severe disease manifestation of AAV has not been well established. Furthermore, concerns remain regarding timely access to avacopan, the best glucocorticoid tapering regimen, and long-term efficacy and safety of the drug. We sought to identify clinical features and outcomes of patients presenting with DAH secondary to AAV who received avacopan in addition to glucocorticoids and rituximab or cyclophosphamide. METHODS: We performed a retrospective cohort study of all consecutive patients presenting with DAH as part of active severe granulomatosis with polyangiitis or microscopic polyangiitis. Demographic and clinical characteristics were collected at presentation and follow-up. RESULTS: Fifteen patients met inclusion criteria and were observed for a median time of 17 weeks (interquartile range [IQR] 6-37 weeks) after initiation of avacopan. Patients were predominantly female and White, had never smoked, and were a median age of 66 years (IQR 52-72 years) at diagnosis. The majority had newly diagnosed severe AAV with renal involvement. Three patients progressed to respiratory failure. The timing of avacopan introduction and patterns of glucocorticoid tapers varied widely in this cohort. Two serious adverse events related to infection were observed, including one opportunistic infection leading to the patient's death, although neither was directly attributed to avacopan administration. CONCLUSION: We describe the clinical course of patients who presented with the severe AAV disease manifestation of DAH and received avacopan as adjunct therapy. Most patients achieved remission during follow-up, and adverse events, including infection, were observed.

Predictive Factors of Renal Recovery and Progression to End-Stage Kidney Disease in Patients With Antineutrophil Cytoplasmic Autoantibody-Associated Vasculitis With Severe Kidney Disease.

Introduction: A significant number of patients with antineutrophil cytoplasmic antibodies (ANCA)- associated vasculitis (AAV) with glomerulonephritis (AAV-GN) still progress to end-stage kidney disease (ESKD, estimated glomerular filtration rate [eGFR] <15 ml/min per 1.73 m2) despite advances in remission-induction treatment. Methods: This is a retrospective cohort study on myeloperoxidase (MPO)-ANCA or proteinase 3 (PR3)-ANCA positive patients with AAV (microscopic polyangiitis, MPA; or granulomatosis with polyangiitis, GPA) and eGFR <15 ml/min per 1.73 m2 or ESKD at presentation. Renal recovery, dialysis discontinuation, and persistence of ESKD after standard remission-induction, with or without the use of plasma exchange (PLEX) were analyzed. Results: We analyzed 166 patients with biopsy-proven active AAV-GN and eGFR <15 ml/min per 1.73 m2 at the time of diagnosis. Patients received glucocorticoids with cyclophosphamide (CYC) (n = 84) or with rituximab (RTX) (n = 72) for remission-induction, and 49 received PLEX. The predictors of renal recovery were erythrocyte sedimentation rate, serum creatinine (SCr) at diagnosis, and minimal or mild chronicity changes. We further analyzed 71 patients who started dialysis with or without PLEX within 4 weeks of AAV-GN diagnosis. The predictors of dialysis discontinuation were minimal chronicity changes in kidney biopsy at diagnosis (odds ratio = 6.138; 95% confidence interval [CI]: 1.389-27.118; P = 0.017). Predictors of persistence of ESKD within 12 months included higher SCr at diagnosis (incidence rate ratio [IRR] = 1.086; 95% CI: 1.005-1.173; P = 0.037), and moderate (IRR = 3.797; 95% CI: 1.090-13.225; P = 0.036), or severe chronicity changes in kidney biopsy (IRR = 5.883; 95% CI: 1.542-22.439; P =0.009). Conclusion: In our cohort, kidney recovery, dialysis discontinuation, and persistence of ESKD in patients with AAV-GN and eGFR <15 ml/min per 1.73 m2 depended on SCr and histologic findings on kidney biopsies at the time of diagnosis and was not affected by the addition of PLEX.

Impact of Glucocorticoid Dose on Complete Response, Serious Infections, and Mortality During the Initial Therapy of Lupus Nephritis: A Systematic Review and Meta-Analysis of the Control Arms of Randomized Controlled Trials.

OBJECTIVE: Our objective was to evaluate the effect of glucocorticoid regimens on renal response, infections, and mortality among patients with lupus nephritis (LN). METHODS: We performed a systematic review and meta-analysis of the control arms of randomized clinical trials (RCTs). We included RCTs of biopsy-proven LN that used a protocolized regimen of glucocorticoids in combination with mycophenolic acid analogs or cyclophosphamide and reported the outcomes of complete response (CR), serious infections, and death. The starting dosage of glucocorticoids, tapering method, and administration of glucocorticoid pulses were abstracted. Meta-analysis of proportions, meta-regression, and subgroup meta-analysis were performed at 6 and 12 months for all outcomes. RESULTS: Fifty RCT arms (3,231 patients with LN) were included. The predicted rates of CR, serious infections, and death when starting on oral prednisone at 25 mg/day without pulses were 19.5% (95% confidence interval [CI] 7.3-31.5), 3.2% (95% CI 2.4-4.0), and 0.2% (95% CI 0.0-0.4), respectively. Starting on prednisone at 60 mg/day (without pulses) increased the rates to 34.6% (95% CI 16.9-52.3), 12.1% (95% CI 9.3-14.9), and 2.7% (95% CI 0.0-5.3), respectively. Adding glucocorticoid pulses increased the rates of CR and death but not serious infections. We observed a dose-response gradient between the initial glucocorticoid dosage and all the outcomes at six months after accounting for the administration of glucocorticoid pulses, underlying immunosuppressant, and baseline proteinuria. CONCLUSION: A higher exposure to glucocorticoids during the initial therapy of LN was associated with better renal outcomes at the cost of increased infections and death.

Diagnostic yield of exome and genome sequencing after non-diagnostic multi-gene panels in patients with single-system diseases.

BACKGROUND: Though next-generation sequencing (NGS) tests like exome sequencing (ES), genome sequencing (GS), and panels derived from exome and genome data (EGBP) are effective for rare diseases, the ideal diagnostic approach is debated. Limited research has explored reanalyzing raw ES and GS data post-negative EGBP results for diagnostics. RESULTS: We analyzed complete ES/GS raw sequencing data from Mayo Clinic's Program for Rare and Undiagnosed Diseases (PRaUD) patients to assess whether supplementary findings could augment diagnostic yield. ES data from 80 patients (59 adults) and GS data from 20 patients (10 adults), averaging 43 years in age, were analyzed. Most patients had renal (n=44) and auto-inflammatory (n=29) phenotypes. Ninety-six cases had negative findings and in four cases additional genetic variants were found, including a variant related to a recently described disease (RRAGD-related hypomagnesemia), a variant missed due to discordant inheritance pattern (COL4A3), a variant with high allelic frequency (NPHS2) in the general population, and a variant associated with an initially untargeted phenotype (HNF1A). CONCLUSION: ES and GS show diagnostic yields comparable to EGBP for single-system diseases. However, EGBP's limitations in detecting new disease-associated genes underscore the necessity for periodic updates.

Rituximab or cyclosporine a for the treatment of membranous nephropathy: Economic evaluation of the MENTOR trial.

BACKGROUND AND HYPOTHESIS: The MENTOR trial (MEmbranous Nephropathy Trial Of Rituximab) showed that rituximab was noninferior to cyclosporine in inducing complete or partial remission of proteinuria and was superior in maintaining proteinuria remission. However, the cost of rituximab may prohibit first-line use for some patients and health care payers. METHODS: A Markov model was used to determine the incremental cost-effectiveness ratio (ICER) of rituximab compared with cyclosporine for the treatment membranous nephropathy from the perspective of a health care payer with a life-time time horizon. The model was informed by data from the MENTOR trial where possible; additional parameters including cost and utility inputs were obtained from the literature. Sensitivity analyses were performed to evaluate the impact of reduced cost biosimilar rituximab. RESULTS: Rituximab for the treatment of membranous nephropathy was cost-effective (assuming a willingness-to-pay threshold of ${\$}$50 000 per quality adjusted life year (QALY) gained; ${\$}$US 2021) compared with cyclosporine, with an ICER of ${\$}$8 373/QALY over a lifetime time horizon. The incremental cost of rituximab therapy was ${\$}$28 007 with an additional 3.34 QALYs compared with cyclosporine. Lower cost of rituximab biosimilars resulted in a more favourable ICER, and in some cases resulted in rituximab being dominant (lower cost and great benefit) compared to cyclosporine. CONCLUSIONS: Despite the greater cost of rituximab, it may be a cost-effective option for the treatment of membranous nephropathy when compared with cyclosporine. The cost-effectiveness of rituximab is further improved with the use of less expensive biosimilars.

Apolipoprotein E is enriched in dense deposits and is a marker for dense deposit disease in C3 glomerulopathy.

C3 glomerulopathy (C3G) is a rare disease resulting from dysregulation of the alternative pathway of complement. C3G includes C3 glomerulonephritis (C3GN) and dense deposit disease (DDD), both of which are characterized by bright glomerular C3 staining on immunofluorescence studies. However, on electron microscopy (EM), DDD is characterized by dense osmiophilic mesangial and intramembranous deposits along the glomerular basement membranes (GBM), while the deposits of C3GN are not dense. Why the deposits appear dense in DDD and not in C3GN is not known. We performed laser microdissection (LCM) of glomeruli followed by mass spectrometry (MS) in 12 cases each of DDD, C3GN, and pretransplant kidney control biopsies. LCM/MS showed marked accumulation of complement proteins C3, C5, C6, C7, C8, C9 and complement regulating proteins CFHR5, CFHR1, and CFH in C3GN and DDD compared to controls. C3, CFH and CFHR proteins were comparable in C3GN and DDD. Yet, there were significant differences. First, there was a six-to-nine-fold increase of C5-9 in DDD compared to C3GN. Secondly, an unexpected finding was a nine-fold increase in apolipoprotein E (ApoE) in DDD compared to C3GN. Most importantly, immunohistochemical and confocal staining for ApoE mirrored the dense deposit staining in the GBM in DDD but not in C3GN or control cases. Validation studies using 31 C3G cases confirmed the diagnosis of C3GN and DDD in 80.6 % based on ApoE staining. Overall, there is a higher burden of terminal complement pathway proteins in DDD compared to C3GN. Thus, our study shows that dense deposits in DDD are enriched with ApoE compared to C3GN and control cases. Hence, ApoE staining may be used as an adjunct to EM for the diagnosis of DDD and might be valuable when EM is not available.

Kidney Diseases Associated With Inflammatory Bowel Disease: Impact of Chronic Histologic Damage, Treatments, and Outcomes.

Introduction: Kidney disease is a well-known extraintestinal manifestation (EIM) associated with inflammatory bowel disease (IBD), with a variety of underlying etiologies. However, little is known about the overall outcomes and predictors. Methods: This is a retrospective, observational cohort study. Patients with IBD in whom a native kidney biopsy was performed at Mayo Clinic (Rochester, MN) between 1994 and 2022, were included. Demographic, clinical, and histologic characteristics of prognostic interest were collected. The main outcomes were kidney failure, disease remission, kidney function changes at last follow-up, and death. Results: From a total cohort of 318 patients, we selected a study group of 111 patients followed-up with at our institution (45 ulcerative colitis [UC] and 66 Crohn's disease [CD]), with a mean age of 48 ± 17 years (40% females). IgA nephropathy (IgAN), chronic interstitial nephritis (CIN), and acute interstitial nephritis (AIN) were the most common diagnoses (22%, 19%, 13%, respectively). Median estimated glomerular filtration rate (eGFR) at presentation was 30 ml/min per 1.73 m2 (interquartile range [IQR]: 17-54) and urinary protein-to-creatinine ratio [UPCR] 0.8 g/g (0.3-3.4), without differences between IBD types. During a median follow-up of 59 months (12-109), 29 patients (26%) reached kidney failure. By multivariable analysis, the main predictors of kidney failure were age (hazard ratio [HR]: 1.04; P = 0.002), baseline eGFR (HR: 0.94; P = 0.003) and histologic chronicity score (HR: 4.01; P < 0.001). Therapeutic management varied according to underlying etiology. Global survival (kidney failure + death) was significantly better in patients who achieved complete or partial remission, or stabilization or improvement of kidney function. Conclusion: One-fourth of patients with IBD with kidney disease may reach kidney failure, and the main determinants of this outcome is age, baseline eGFR, and degree of chronicity in kidney biopsy.

Histologic and Clinical Factors Associated with Kidney Outcomes in IgA Vasculitis Nephritis.

BACKGROUND: Nephritis is a common manifestation of IgA vasculitis and is morphologically indistinguishable from IgA nephropathy. While MEST-C scores are predictive of kidney outcomes in IgA nephropathy, their value in IgA vasculitis nephritis has not been investigated in large multiethnic cohorts. METHODS: Biopsies from 262 children and 99 adults with IgA vasculitis nephritis ( N =361) from 23 centers in North America, Europe, and Asia were independently scored by three pathologists. MEST-C scores were assessed for correlation with eGFR/proteinuria at biopsy. Because most patients ( N =309, 86%) received immunosuppression, risk factors for outcomes were evaluated in this group using latent class mixed models to identify classes of eGFR trajectories over a median follow-up of 2.7 years (interquartile range, 1.2-5.1). Clinical and histologic parameters associated with each class were determined using logistic regression. RESULTS: M, E, T, and C scores were correlated with either eGFR or proteinuria at biopsy. Two classes were identified by latent class mixed model, one with initial improvement in eGFR followed by a late decline (class 1, N =91) and another with stable eGFR (class 2, N =218). Class 1 was associated with a higher risk of an established kidney outcome (time to ≥30% decline in eGFR or kidney failure; hazard ratio, 5.84; 95% confidence interval, 2.37 to 14.4). Among MEST-C scores, only E1 was associated with class 1 by multivariable analysis. Other factors associated with class 1 were age 18 years and younger, male sex, lower eGFR at biopsy, and extrarenal noncutaneous disease. Fibrous crescents without active changes were associated with class 2. CONCLUSIONS: Kidney outcome in patients with biopsied IgA vasculitis nephritis treated with immunosuppression was determined by clinical risk factors and endocapillary hypercellularity (E1) and fibrous crescents, which are features that are not part of the International Study of Diseases of Children classification.

Points of view in nephrology: personalized management of IgA nephropathy, beyond KDIGO.

IgA nephropathy is the most common primary glomerulonephritis worldwide, and an important cause of kidney failure, as 20-40% of patients progress to renal replacement therapy 20-30 years after diagnosis. Its clinical presentation ranges from isolated microscopic hematuria to nephrotic syndrome, and even to a rapidly progressive course. Ethnicity and epigenetics play a key role in its clinical aggressiveness. Selection of patients at risk needing immunosuppressive treatment is a challenge for the nephrologist. Some active and chronic kidney lesions detected on kidney biopsy have been demonstrated to have prognostic value according to the Oxford Classification of IgA nephropathy, later validated by numerous studies. However, KDIGO 2021 guidelines still consider persistent proteinuria > 1 g/24 h to be the most relevant risk factor for the progression of IgA nephropathy and the only one requiring immunosuppressive treatment. KDIGO guidelines have proposed a therapeutic algorithm, but many patients present peculiar characteristics that are not addressed by the current guidelines, pointing to the need for alternative approaches. In these cases, a tailored approach to each patient should be followed in which clinical, histological, laboratory, social and ethical aspects must be considered. In this manuscript we present three cases of IgA nephropathy from different countries, highlighting many of the aspects encountered in clinical practice that illustrate an individualized approach to the treatment of these patients.

Rim e doenças sistêmicas / Kidney and sistemic diseases

Aspectos clínicos, fisiopatológicos, histopatológicos e terapêuticos de doenças sistêmicas que comprometem o rim säo descritos sumariamente. A revisäo da literatura se destina a dar uma orientaçäo a estudantes e generalistas para o estudo deste importante grupo de patologias: como exemplos, as nefropatias do diabete, lupus eritematoso sistêmico, mieloma múltiplo e amiloidose säo abordadas