Mayo Clinic consensus report on membranous nephropathy: proposal for a novel classification.

Membranous nephropathy (MN) is a pattern of injury caused by autoantibodies binding to specific target antigens, with accumulation of immune complexes along the subepithelial region of glomerular basement membranes. The past 20 years have brought revolutionary advances in the understanding of MN, particularly via the discovery of novel target antigens and their respective autoantibodies. These discoveries have challenged the traditional classification of MN into primary and secondary forms. At least 14 target antigens have been identified, accounting for 80%-90% of cases of MN. Many of the forms of MN associated with these novel MN target antigens have distinctive clinical and pathologic phenotypes. The Mayo Clinic consensus report on MN proposes a 2-step classification of MN. The first step, when possible, is identification of the target antigen, based on a multistep algorithm and using a combination of serology, staining of the kidney biopsy tissue by immunofluorescence or immunohistochemistry, and/or mass spectrometry methodology. The second step is the search for a potential underlying disease or associated condition, which is particularly relevant when knowledge of the target antigen is available to direct it. The meeting acknowledges that the resources and equipment required to perform the proposed testing may not be generally available. However, the meeting consensus was that the time has come to adopt an antigen-based classification of MN because this approach will allow for accurate and specific MN diagnosis, with significant implications for patient management and targeted treatment.

Antimalarials in Lupus Nephritis: How Strong is the Evidence?

Systemic lupus erythematosus is a chronic multisystem autoimmune disease that affects the kidneys in approximately 50% of patients, with prevalence rising to as high as 70% in certain populations, such as African Americans and Asians. Antimalarials -and particularly hydroxychloroquine- are currently considered a mainstay of therapy, together with immunosuppressants. Over the last decades, several studies have extensively investigated the mechanisms of action of antimalarial agents, and their potential beneficial properties in patients with SLE in general. However, the evidence for the therapeutic benefit of hydroxychloroquine in patients with lupus nephritis (LN) derives mainly from observational studies, conducted in an era prior to the refinement of induction and maintenance protocols for immunosuppressive therapy. Despite the paucity of high-quality evidence on its efficacy in LN, the nephrology community widely supports the universal use of hydroxychloroquine in LN patients, and recommendations for its use are firmly entrenched in various clinical practice guidelines. Nonetheless, the use of antimalarials may also carry inherent risks, underscoring the importance of personalized approaches in these patients. Herein, we comprehensively review the available literature on antimalarials in LN aiming to update the current evidence, limitations, and future perspectives for the use of antimalarials in adults.

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.

Future landscape for the management of membranous nephropathy.

Among all glomerular diseases, membranous nephropathy (MN) is perhaps the one in which major progress has been made in recent decades, in both the understanding of the pathogenesis and treatment. Despite the overall significant response rates to these therapies-particularly rituximab and cyclical regimen based on corticosteroids and cyclophosphamide-cumulative experience over the years has shown, however, that 20%-30% of cases may confront resistant disease. Thus, these unmet challenges in the treatment of resistant forms of MN require newer approaches. Several emerging new agents-developed primarily for the treatment of hematological malignancies or rheumatoid diseases-are currently being evaluated in MN. Herein we conducted a narrative review on future therapeutic strategies in the disease. Among the different novel therapies, newer anti-CD20 agents (e.g. obinutuzumab), anti-CD38 (e.g. daratumumab, felzartamab), immunoadsorption or anti-complement therapies (e.g. iptacopan) have gained special attention. In addition, several technologies and innovations developed primarily for cancer (e.g. chimeric antigen receptor T-cell therapy, sweeping antibodies) seem particularly promising. In summary, the future therapeutic landscape in MN seems encouraging and will definitely move the management of this disease towards a more precision-based approach.

Low switched memory B cells are associated with no humoral response after SARS-CoV-2 vaccine boosters in kidney transplant recipients.

Introduction: The humoral response after SARS-CoV-2 vaccination and boosters in kidney transplant recipients (KTRs) is heterogeneous and depends on immunosuppression status. There is no validated immune measurement associated with serological response in clinical practice. Multicolor flow cytometric immunophenotyping could be useful for measuring immune response. This study aimed to study B- and T-cell compartments through Standardized EuroFlow PID Orientation after SARS-CoV-2 vaccination and their association with IgG SARS-CoV-2 seropositivity status after two doses or boosters. Methods: We conducted a multicenter prospective study to evaluate humoral response after SARS-CoV-2 vaccination in KTRs. Heterologous regimen: two doses of inactivated SARS-CoV-2 and two boosters of BNT162b2 mRNA (n=75). Homologous vaccination: two doses of BNT162b2 mRNA and one BNT162b2 mRNA booster (n=13). Booster doses were administrated to KTRs without taking into account their IgG SARS-CoV-2 seropositivity status. Peripheral blood samples were collected 30 days after the second dose and after the last heterologous or homologous booster. A standardized EuroFlow PID Orientation Tube (PIDOT) and a supervised automated analysis were used for immune monitoring cellular subsets after boosters. Results: A total of 88 KTRs were included and divided into three groups according to the time of the first detected IgG SARS-CoV-2 seropositivity: non-responders (NRs, n=23), booster responders (BRs, n=41), and two-dose responders (2DRs, n=24). The NR group was more frequent on mycophenolate than the responder groups (NRs, 96%; BRs, 80%; 2DRs, 42%; p=0.000). Switched memory B cells in the 2DR group were higher than those in the BR and NR groups (medians of 30, 17, and 10 cells/ul, respectively; p=0.017). Additionally, the absolute count of central memory/terminal memory CD8 T cells was higher in the 2DR group than in the BR and NR groups. (166, 98, and 93 cells/ul, respectively; p=0.041). The rest of the T-cell populations studied did not show a statistical difference. Conclusion: switched memory B cells and memory CD8 T-cell populations in peripheral blood were associated with the magnitude of the humoral response after SARS-CoV-2 vaccination. Boosters increased IgG anti-SARS-CoV-2 levels, CM/TM CD8 T cells, and switched MBCs in patients with seropositivity after two doses. Interestingly, no seropositivity after boosters was associated with the use of mycophenolate and a lower number of switched MBCs and CM/TM CD8 T cells in peripheral blood.

Mayo Clinic Consensus Report on Membranous Nephropathy: Proposal for a Novel Classification.

Membranous nephropathy (MN) is a pattern of injury caused by autoantibodies binding to specific target antigens, with accumulation of immune complexes along the subepithelial region of glomerular basement membranes. The past 20 years have brought revolutionary advances in the understanding of MN, particularly via the discovery of novel target antigens and their respective autoantibodies. These discoveries have challenged the traditional classification of MN into primary and secondary forms. At least 14 target antigens have been identified, accounting for 80%-90% of cases of MN. Many of the forms of MN associated with these novel MN target antigens have distinctive clinical and pathologic phenotypes. The Mayo Clinic consensus report on MN proposes a 2-step classification of MN. The first step, when possible, is identification of the target antigen, based on a multistep algorithm and using a combination of serology, staining of the kidney biopsy tissue by immunofluorescence or immunohistochemistry, and/or mass spectrometry methodology. The second step is the search for a potential underlying disease or associated condition, which is particularly relevant when knowledge of the target antigen is available to direct it. The meeting acknowledges that the resources and equipment required to perform the proposed testing may not be generally available. However, the meeting consensus was that the time has come to adopt an antigen-based classification of MN because this approach will allow for accurate and specific MN diagnosis, with significant implications for patient management and targeted treatment.

Comparison of antibody response to SARS-CoV-2 after two doses of inactivated virus and BNT162b2 mRNA vaccines in kidney transplant.

BACKGROUND: Antibody response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) after mRNA or adenoviral vector-based vaccines is weak in kidney transplant (KT) patients. However, few studies have focused on humoral response after inactivated virus-based vaccines in KT. Here, we compare antibody response following vaccination with inactivated virus (CoronaVac®) and BNT162b2 mRNA. METHODS: A national multicentre cross-sectional study was conducted. The study group was composed of patients from all KT centres in Uruguay, vaccinated between 1 and 31 May 2021 (CoronaVac®, n = 245 and BNT162b2, n = 39). The control group was constituted of 82 healthy individuals. Participants had no prior confirmed coronavirus disease 2019 (COVID-19) test. Blood samples were collected between 30 and 40 days after the second dose. Serum-specific immunoglobulin G (IgG) antibodies against the receptor-binding domain (RBD) of SARS-CoV-2 Spike protein were determined using the COVID-19 IgG QUANT ELISA Kit. RESULTS: Only 29% of KT recipients showed seroconversion (36.5% BNT162b2, 27.8% inactivated virus, P = 0.248) in comparison with 100% in healthy control with either vaccine. Antibody levels against RBD were higher with BNT162b mRNA than with inactivated virus [median (interquartile range) 173 (73-554) and 29 (11-70) binding antibody units (BAU)/mL, P < 0.034] in KT and 10 times lower than healthy control [inactivated virus: 308 (209-335) and BNT162b2: 2638 (2608-3808) BAU/mL, P < 0.034]. In multivariate analysis, variables associated with negative humoral response were age, triple immunosuppression, estimated glomerular filtration rate and time post-KT. CONCLUSION: Seroconversion was low in KT patients after vaccination with both platforms. Antibody levels against SARS-CoV-2 were lower with inactivated virus than BNT162b mRNA. These findings support the need for strategies to improve immunogenicity in KT recipients after two doses of either vaccine.

Nefritis lúpica: experiencia con dosis reducidas de glucocorticoides en una unidad de enfermedades autoinmunes sistémicas / Lupus nephritis: low-dose glucocorticoids in a systemic autoimmune diseases unit / Nefritis lúpica: experiência con doses reduzidas de glicocorticoides em uma unidade de doenças autoinmunes sistémicas

Resumen: Introducción: las recomendaciones actuales del tratamiento de la nefritis lúpica (NL) apuntan a dosis de glucocorticoides más bajas para lograr el control de la enfermedad y evitar el daño acumulado. Objetivo: conocer y comparar la respuesta al tratamiento de pacientes con NL proliferativa en su etapa de inducción con dos pautas de tratamiento con prednisona (PDN): dosis iniciales reducidas 30 mg/d. Método: se compararon variables clínicas, analíticas y terapéuticas de pacientes con NL proliferativa categorizados en dos grupos según la dosis inicial de prednisona (PDNi) estándar o reducida. Resultados: se estudiaron 21 pacientes con NL proliferativa (n=12 PDNi reducida vs. n=9 PDNi estándar). No hubo diferencias significativas en las variables clínicas y analíticas. Se observó una diferencia estadísticamente significativa en el número de pulsos de metilprednisolona (5 ± 2,95 PDNi 30 mg/d, p = 0,041) y en la dosis de prednisona acumulada a 6 meses (12,8 mg ± 4,9 PDNi 30 mg/d, p =0,008). No hubo diferencias significativas en la proporción de pacientes que alcanzaron la respuesta completa, en el tiempo hasta alcanzarla ni en los efectos adversos entre ambos grupos. Conclusiones: el esquema terapéutico del grupo PDNi <30 mg/d se asoció a una menor dosis acumulada de prednisona y una respuesta al tratamiento comparable, lo que hace presumir menor daño acumulado relacionado al uso de glucocorticoides.

Abstract: Introduction: current recommendations to treat lupus nephritis (LN) point to low-dose glucocorticoids to control the disease and avoid cumulativedamage. Objective: to learn about and compare the response of patients with proliferative LN who are treated following two prednisone therapy guidelines: reduced initial doses 30 mg/d during the induction stage. Method: clinical, analytical and therapeutic guidelines of patients with proliferative LN were compared and classified into two groups according to the standard or low-dose initial prednisone dose. Results: 21 patients with proliferative LN were studied (n=12 low-dose initial prednisonevs. n=9 standard initial prednisone). No significant differences were found between clinical and analytical variables, although a significantly different statistic difference was observed in the number of methylprednisone pulses (5 ± 2.95 initial prednisone 30 mg/d, p = 0.041) and in the prednisone dose accumulated in 6 months (12.8 mg ± 4.9 initial prednisone 30 mg/d, p =0.008). No significant differences were seen between both groups in the proportion of patients who achieved complete response, neither in terms of the time it took to achieve it or in the side effects. Conclusions: the treatment plan for the initial prednisone <30 mg/d was associated to a lower cumulative dose of response prednisone considering the comparable treatment, what suggests there being smaller cumulative harm as a consequence of the use of glucocorticoids.

Resumo: Introdução: as recomendações atuais para o tratamento da nefrite lúpica (NL) estão orientadas a doses de glicocorticoides mais baixas para controlar a enfermidade e evitar o dano acumulado. Objetivo: conhecer e comparar a resposta ao tratamento de pacientes com NL proliferativa na etapa de indução com duas pautas de tratamento com prednisona (PDN): doses iniciais reduzidas 30 mg/d. Método: foram comparadas variáveis clínicas, analíticas e terapêuticas de pacientes com NL proliferativa divididos em dois grupos segundo a dose inicial de prednisona (PDNi) padrão ou reduzida. Resultados: 21 pacientes com NL proliferativa (n=12 PDNi reduzida vs. n=9 PDNi estândar) foram estudados. Não foram observadas diferenças significativas nas variáveis clínicas e analíticas. Observou-se uma diferença estatisticamente significativa no número de pulsos de metilprednisolona (5 ± 2,95 PDNi 30 mg/d, p = 0,041) e nas doses de prednisona acumulada aos 6 meses (12,8 mg ± 4,9 PDNi 30 mg/d, p =0,008). Não foram observadas diferenças significativas na proporção de pacientes que alcançaram a resposta completa, no tempo até alcançá-la nem nos efeitos adversos entre ambos grupos. Conclusões: o esquema terapêutico do grupo PDNi <30 mg/d foi associado a uma menor dose acumulada de prednisona em resposta ao tratamento comparável, o que sugere menos dano cumulativo relacionado ao uso de glicocorticoides.