Antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (GN) is an immune-mediated kidney disease characterized by the inflammation of small blood vessels in the kidney, leading to renal impairment and potentially irreversible damage. Concerns have been raised over the reports of myeloperoxidase/perinuclear (MPO/p) ANCA GN following the coronavirus disease 2019 (COVID-19) vaccination. Our study provides a comprehensive insight into perinuclear anti-neutrophil cytoplasmic antibodies (p-ANCA) GN after COVID-19 vaccination. We conducted a comprehensive literature search on PubMed, Cochrane Library, and EMBASE using the Medical Subject Headings (MeSH) terms related to \"covid-19 vaccine,\" \"glomerulonephritis,\" \"p-ANCA,\" and \"MPO-ANCA\" up to March 5, 2024, to include cases of p-ANCA-associated GN following COVID-19 vaccination. Of the 4,102 articles, we included 29, reporting 35 patients demonstrating COVID-19 vaccine-induced p-ANCA GN, with 23 (65.7%) females and a median age of 69 years (mean ± SD = 63.22 ± 16). Twenty-six (74.28%) patients received the mRNA vaccine (Pfizer = 19, Moderna = 7). Seventeen (48.57%) patients presented with p-ANCA GN after the second dose of the COVID-19 vaccine, with a median gap of 19 days (1-84 days). Constitutional symptoms (54.28%) and acute kidney injury (42.85%) were the most reported initial presentations, and elevated serum creatinine (mean peak serum creatinine = 4.98 ± 5.02 mg/dL), hematuria, and proteinuria were the laboratory findings. MPO/p-ANCA was positive in 31 (88.6%) patients. All patients underwent renal biopsy, and crescentic GN was the most common finding among 27 (77.14%) patients. Management of p-ANCA GN included steroids in 30 (85.71%) patients, followed by rituximab (28.57%), and plasmapheresis (22.86%). Most patients responded well to treatment, with complete remission in 29 (82.86%) and relapse in four (11.42%) patients. Two patients did not achieve remission and became dialysis dependent. ANCA-associated GN is a rare and life-threatening complication of the COVID-19 vaccine, necessitating urgent evaluation and management. COVID-19 vaccine-induced p-ANCA GN should be included in the differential diagnoses of patients presenting with kidney injury after vaccination.

Immune checkpoint inhibitors (ICIs) dramatically improve the prognosis of many malignancies but at the cost of numerous side effects, which may limit their benefits. Acute kidney injury associated with immune checkpoint inhibitors most frequently are acute tubulointerstitial nephritis (ATIN), but various cases of glomerulonephritis have also been reported. Herein, we report a case of severe IgA nephropathy (IgAN) associated with ICIs and carry out a literature review. IgAN was diagnosed in a median time of 5 months (range 1-12 months) after the initiation of ICIs, with heterogeneous severity, and usually treated by corticosteroid and discontinuation of ICIs. In contrast to our case, renal outcomes in literature were often favorable, with recovery of renal function and a reduction in proteinuria on treatment. Although IgAN related to ICIs is a much rarer complication than ATIN, it may still be underdiagnosed. Careful questioning and screening for asymptomatic hematuria should be performed before using ICIs.

BACKGROUND: IgA nephropathy (IgAN) is a common cause of chronic kidney disease (CKD) and end-stage renal disease (ESRD). Outcomes are highly variable and predicting risk of disease progression at an individual level is challenging. Accurate risk stratification is important to identify individuals most likely to benefit from treatment. The Kidney Failure Risk Equation (KFRE) has been extensively validated in CKD populations and predicts the risk of ESRD at 2 and 5 years using non-invasive tests; however, its predictive performance in IgAN is unknown. The Oxford classification (OC) describes pathological features demonstrated on renal biopsy that are associated with adverse clinical outcomes that may also inform prognosis. The objective of this systematic review is to compare the KFRE with the OC in determining prognosis in IgAN.
METHODS: A systematic review will be conducted and reported in line with PRISMA guidelines (PRISMA-P checklist attached as Additional file 1). Inclusion criteria will be cohort studies that apply the KFRE or OC to determine the risk of CKD progression or ESRD in individuals with IgAN. Multiple databases will be searched in duplicate to identify relevant studies, which will be screened first by title, then by abstract and then by full-text analysis. Results will be collated for comparison. Risk of bias and confidence assessments will be conducted independently by two reviewers, with a third reviewer available if required.
CONCLUSIONS: Identifying individuals at the highest risk of progression to ESRD is challenging in IgAN, due to the heterogeneity of clinical outcomes. Risk prediction tools have been developed to guide clinicians; however, it is imperative that these aids are accurate and reproducible. The OC is based on observations made by specialist renal pathologists and may be open to observer bias, therefore the utility of prediction models incorporating this classification may be diminished, particularly as in the future novel biomarkers may be incorporated into clinical practice.
BACKGROUND: PROSPERO CRD42022364569.

BACKGROUND: Glomerulonephritis inherently leads to the development of chronic kidney disease. It is the second most common diagnosis in patients requiring renal replacement therapy in the United Kingdom. Metabolomics and proteomics can characterise, identify and quantify an individual\'s protein and metabolite make-up. These techniques have been optimised and can be performed on samples including kidney tissue, blood and urine. Utilising omic techniques in nephrology can uncover disease pathophysiology and transform the diagnostics and treatment options for glomerulonephritis.
OBJECTIVE: To evaluate the utility of metabolomics and proteomics using mass spectrometry and nuclear magnetic resonance in glomerulonephritis.
METHODS: The systematic review was registered on PROSPERO (CRD42023442092). Standard and extensive Cochrane search methods were used. The latest search date was March 2023. Participants were of any age with a histological diagnosis of glomerulonephritis. Descriptive analysis was performed, and data presented in tabular form. An area under the curve or p-value was presented for potential biomarkers discovered.
RESULTS: Twenty-seven studies were included (metabolomics (n = 9)), and (proteomics (n = 18)) with 1818 participants. The samples analysed were urine (n = 19) blood (n = 4) and biopsy (n = 6). The typical outcome themes were potential biomarkers, disease phenotype, risk of progression and treatment response.
CONCLUSIONS: This review shows the potential of metabolomic and proteomic analysis to discover new disease biomarkers that may influence diagnostics and disease management. Further larger-scale research is required to establish the validity of the study outcomes, including the several proposed biomarkers.

In this editorial, we comment on the article by Meng et al published in the World Journal of Clinical Cases. We comprehensively review immunoglobulin A nephropathy (IgAN), including epidemiology, clinical presentation, diagnosis, and management. IgAN, also known as Berger\'s disease, is the most frequent type of primary glomerulonephritis (GN) globally. It is mostly found among the Asian population. The presentation can be variable, from microscopic hematuria to a rapidly progressive GN. Around 50% of patients present with single or recurring episodes of gross hematuria. An upper respiratory infection and tonsillitis often precede these episodes. Around 30% of patients present microscopic hematuria with or without proteinuria, usually detected on routine examination. The diagnosis relies on having a renal biopsy for pathology and immunofluorescence microscopy. We focus on risk stratification and management of IgAN. We provide a review of all the landmark studies to date. According to the 2021 KDIGO (kidney disease: Improving Global Outcomes) guidelines, patients with non-variant form IgAN are first treated conservatively for three to six months. This approach consists of adequate blood pressure control, reduction of proteinuria with renin-angiotensin system blockade, treatment of dyslipidemia, and lifestyle modifications (weight loss, exercise, smoking cessation, and dietary sodium restrictions). Following three to six months of conservative therapy, patients are further classified as high or low risk for disease progression. High-risk patients have proteinuria ≥ 1 g/d or < 1 g/d with significant microscopic hematuria and active inflammation on kidney biopsy. Some experts consider proteinuria ≥ 2 g/d to be very high risk. Patients with high and very high-risk profiles are treated with immunosuppressive therapy. A proteinuria level of < 1 g/d and stable/improved renal function indicates a good treatment response for patients on immunosuppressive therapy.

BACKGROUND: IgA nephropathy (IgAN) is the most prevalent primary glomerulonephritis worldwide and a leading cause of chronic kidney failure. There are currently no definitive therapeutic regimens to treat or prevent the progression of IgAN. However, biologic agents offer novel therapeutic approaches that target immunological mechanisms to slow or halt disease progression. The objective of this study is to evaluate the efficacy and safety of biologic agents in patients with IgA nephropathy.
METHODS: We will systematically search PubMed, EMbase, Web of Science, Cochrane Library, and www.clinicaltrials.gov for randomized controlled trials of biologic agents for the treatment of IgA nephropathy. The search period will span from the establishment of each database until October 2023. The quality assessment of included studies will be performed individually using the revised Cochrane risk-of-bias tool for randomized trials (RoB 2), and meta-analysis will be conducted using Revman 5.4.1 software.
CONCLUSIONS: The results of this study will provide evidence-based medical evidence for the clinical application of biologic agents in patients with IgA nephropathy.
UNASSIGNED: CRD42023400450.

Anti-glomerular basement membrane (GBM) disease is a rare autoimmune condition characterized by the presence of positive anti-GBM autoantibodies, linear deposition of immunoglobulin G (IgG) along the GBM and severe kidney injury. In a limited number of cases, the association of anti-GBM disease with other glomerulonephritis has been reported. Herein, we present the case of a 66-year-old female patient with progressive worsen kidney function and decreased urine output. A renal biopsy revealed crescent glomerulonephritis with lineal IgG deposition along the GBM and mesangial IgA deposition, which supported the diagnosis of concurrent anti-GBM disease and IgA nephropathy (IgAN). In an extensive literature review, we identified a total of thirty-nine patients were reported anti-GBM disease combined with IgAN. The clinical characteristics of these patients demonstrate that the anti-GBM disease combined with IgAN tends to be milder with a more indolent course and a better prognosis than the classic anti-GBM disease, and its potential pathogenesis deserves to be further explored.

With the coverage of COVID-19 vaccination, it has been possible to observe the potential side effects of SARS-CoV-2 vaccines, with the most common ones being fever, myalgia, headache, and fatigue. However, an association has been observed between new and recurrent kidney injuries, mainly glomerulonephritis and lupus nephritis associated with ANCA, with the Pfizer-BioNTech, Moderna, Sinovac, and AstraZeneca vaccines, although the relationship between them is not clear. We report a case of ANCA-related vasculitis and lupus glomerulonephritis after the second dose of the AstraZeneca vaccine. The elderly patient presented significant worsening of kidney function after immunosuppression and complications after a new onset COVID-19 infection that led to death. We provide a literature review about kidney damage related to ANCA vasculitis after COVID-19 vaccine, aiming for a better understanding of the pathophysiological mechanism of kidney injury, its presentation, and treatment.

Cutis laxa is a rare connective tissue disorder, characterized by a reduced number and abnormal properties of elastic fibers throughout the dermis, creating a clinical appearance of premature aging. It can be subdivided into inherited and acquired, the latter rarer than the former, and skin involvement may be localized or generalized. The etiology of acquired cutis laxa (ACL) remains unknown and there is no definitive treatment. We present the case of a 30-year-old man diagnosed with type I ACL with progressive systemic involvement at the renal, pulmonary, and digestive levels. Histological analysis of the skin revealed reduction and fragmentation of elastic fibers. Immunosuppressive treatment was started with prednisone, cyclophosphamide, and rituximab, with which a complete response to proteinuria was achieved and the progression of lung damage was limited. Autoimmune, infectious, and neoplastic diseases were ruled out.

BACKGROUND: Acute post-streptococcal glomerulonephritis (APSGN) is the most common cause of acute nephritis in children globally and, in some cases, may be associated with progressive kidney injury and failure, cumulating in the need for long-term dialysis and/or kidney transplantation.
METHODS: Our retrospective study describes the occurrence of APSGN among children (< 14 years) admitted to a tertiary children\'s hospital in Cape Town, South Africa, from January 2015 to December 2020.
RESULTS: Of 161 children who presented with acute nephritis (haematuria, oedema, oliguria, and hypertension), 100 met the inclusion criteria. Demographic, clinical features, laboratory findings, management, and outcome data were collected. APSGN was defined by the clinical presentation of at least two clinical signs of acute nephritis, and low serum complement 3 (C3) level or evidence of a recent streptococcal infection. Most cases of APSGN were associated with streptococcal skin infections: 55/100 (55%); 10/100 (10%) children presented with hypertensive seizures; C3 levels were low in 86/92 (93.5%) children; 94/94 (100%) children had elevated anti-deoxyribonuclease-B (anti-DNase-B) levels; and 80/94 (85%) also had elevated anti-streptolysin O titre (ASOT) at presentation. Eleven (11%) children had a percutaneous kidney biopsy; 4/11 (36%) showed histological features of post-infectious nephritis, and 7/11(64%) also had crescentic glomerulonephritis with immune complex deposits. Sixty-two (62%) children confirmed recovered, and five (5%) progressed to kidney failure, but 29 presumed recovered as they did not return for follow-up to our institution.
CONCLUSIONS: Childhood APSGN remains an important health problem in South Africa (SA) with favourable outcomes in most, apart from those with crescentic glomerulonephritis who progressed to kidney failure.