Biomarkers of histologic severity in children with severe or atypical acute post-streptococcal glomerulonephritis

BACKGROUND

Acute post-streptococcal glomerulonephritis (APSGN) is a common cause of acute kidney injury (AKI) in children; however, in a small subgroup, the presentation is one of rapidly progressive glomerulonephritis (RPGN) deteriorating kidney function associated with severe oligo-anuria or a mixed nephritic-nephrotic picture. This study reviewed potential clinical and laboratory factors which may assist the treating clinician to identify patients at high risk of severe disease.

METHODS

All kidney biopsies for APSGN performed between 1996 and 2020 were obtained from a departmental biopsy database. Clinical and laboratory data were extracted from the patients' clinical records. Kidney biopsies were reviewed and scored independently by a renal histopathologist.

RESULTS

Thirty of 53 (56.6%) patients had stage 3 AKI at initial presentation with a median estimated glomerular filtration rate (eGFR) 27 (IQR 11-41), falling to 20 ml/min/1.73 m2 (IQR 13.3-43) at time of biopsy. Patients who had either a pre-biopsy eGFR < 35 ml/min/1.73 m2 or a ≥ 25% fall in eGFR between admission and biopsy were more likely to have glomerular crescents (p = 0.004). Multivariate regression analysis and receiver operating curve showed the pre-biopsy eGFR most accurately predicted glomerular crescents (p = 0.047, ROC 0.757). There were no significant predictors of nephrotic proteinuria or nephrotic syndrome during the acute phase.

CONCLUSIONS

Severe APSGN is associated with a pronounced reduction in eGFR. Calculation of eGFR in this small group of patients may assist in identifying which patient should have an urgent kidney biopsy to facilitate a more accurate clinical diagnosis and management plan.

Apoptosis in post-streptococcal glomerulonephritis and mechanisms for failed of inflammation resolution

Post-streptococcal glomerulonephritis is a condition resulting from infection by group A beta-hemolytic streptococcus. The main mechanism involves the formation of immune complexes formed in the circulation or in situ on the glomerular basement membrane, which activates complement and causes various inflammatory processes. Cellular mechanisms have been reported in the induction of kidney damage represented by the infiltration of innate cells (neutrophils and monocyte/macrophages) and adaptive cells (CD4 + lymphocytes and CD8 + lymphocytes) of the immune system. These cells induce kidney damage through various mechanisms. It has been reported that nephritogenic antigens are capable of inducing inflammatory processes early, even before the formation of immune complexes. Usually, this disease progresses towards clinical and renal normalization; however, in a smaller number of patients, it evolves into chronicity and persistent kidney damage. Hypotheses have been proposed regarding the mechanisms underlying this progression to chronicity including failure to induce apoptosis and failure to phagocytose apoptotic cells, allowing these cells to undergo membrane permeabilization and release pro-inflammatory molecules into the environment, thereby perpetuating renal inflammation. Other mechanisms involved include persistent infection, genetic background of the host's complement system, tubulointerstitial changes, and pre-existing kidney damage due to old age and comorbidities.

Angiotensin II and post-streptococcal glomerulonephritis

BACKGROUND

Post-streptococcal glomerulonephritis (PSGN) is a consequence of the infection by group A beta-hemolytic streptococcus. During this infection, various immunological processes generated by streptococcal antigens are triggered, such as the induction of antibodies and immune complexes. This activation of the immune system involves both innate and acquired immunity. The immunological events that occur at the renal level lead to kidney damage with chronic renal failure as well as resolution of the pathological process (in most cases). Angiotensin II (Ang II) is a molecule with vasopressor and pro-inflammatory capacities, being an important factor in various inflammatory processes. During PSGN some events are defined that make Ang II conceivable as a molecule involved in the inflammatory processes during the disease.

CONCLUSION

This review is focused on defining which reported events would be related to the presence of this hormone in PSGN.

Evaluation of the significance of complement-related genes mutations in atypical postinfectious glomerulonephritis: a pilot study

BACKGROUND

Postinfectious glomerulonephritis with C3-dominant glomerular deposition (C3-PIGN) involves C3-dominant glomerular deposition without immunoglobulin. Atypical C3-PIGN involves persistent hypocomplementemia. We investigated the clinical features and explored complement-related gene mutations in atypical PIGN patients.

METHODS

We enrolled atypical C3-PIGN patients and collected data regarding the clinical presentation and pathological characteristics and follow-up data. We measured the levels of complement associated antibodies and performed whole-exome sequencing (WES) to detect mutations in complement-related genes.

RESULTS

The analysis included six atypical C3-PIGN patients. All patients were antistreptolysin-O (ASO) positive. All patients had varying degrees of hematuria, and four patients had proteinuria. None of the patients were positive for complement-related antibodies. All patients possessed mutations of genes related to the complement pathway, including alternative complement pathway genes-CFI, CFH, CFHR3, CFHR5; the lectin pathway gene-MASP2; and the common complement pathway gene-C8A. The rare variant of CFHR3 has been reported in C3 glomerulonephritis. During 56-73 months of follow-up, the levels of urine markers in three patients recovered within 6 months, and the remaining patients had abnormal urine test results over 12 months. Patients who received glucocorticoid therapy recovered faster.

CONCLUSIONS

Our study suggested that complement-related gene mutations may be an important cause of persistent hypocomplementemia in atypical C3-PIGN patients. In addition to variations in alternate pathway-related genes, we also found variations in lectin pathway-related genes, especially MASP2 genes. Although the overall prognosis was good, atypical C3-PIGN patients exhibited a longer period for recovery. Our results suggested that atypical C3-PIGN patients should receive more medical attention and need testing for mutations in complement-related genes.

C3 glomerulopathy in a patient with a history of post-infectious glomerulonephritis

Post-infectious glomerulonephritis (PIGN) is an immune complex mediated glomerular injury occurring because of an infection, most commonly with group A beta-hemolytic streptococcus in children. C3 glomerulopathy (C3G) is a distinct clinicopathological entity occurring secondary to dysregulation of alternate complement pathway encompassing both C3 glomerulonephritis (C3GN) and dense deposit disease (DDD). While most patients with PIGN attain complete remission with normalized complement levels by 6-8 weeks after presentation, patients with C3G continue to have hypocomplementemia with high rates of progressive kidney disease. Here, we report a patient diagnosed with dense deposit disease after his initial presentation with PIGN three years prior. While current literature continues to explore the overlapping and distinguishing features of PIGN and C3G, including how underlying defects in the alternate complement pathway may commonly contribute to both diseases, this case further exemplifies the importance of recognizing the clinico-pathogenic features of PIGN and C3G in pediatric patients with glomerulonephritis.

Acute interstitial nephritis caused by ANCA-associated vasculitis: a case based review

Antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) typically manifests as rapidly progressive glomerulonephritis with crescent formation. In this report, we present a local case of myeloperoxidase (MPO)-AAV-associated acute interstitial nephritis (AIN), showing slight pauci-immune glomerulonephritis and positive MPO-ANCA. This case is characterized by foot process effacement of podocytes in the glomerulus, a favorable prognosis, and an absence of crescentic formation. To further understand this condition, we conducted a comprehensive literature search on Google Scholar and PubMed, employing both free text words and MeSH terms related to "AAV and AIN." This search yielded 24 cases, which we analyzed for their clinical features, laboratory findings, renal pathological characteristics, and therapeutic outcomes. AAV-associated interstitial nephritis predominantly affects elderly patients and is often associated with anemia, proteinuria, hematuria, and nonspecific manifestations, including fever, anorexia, fatigue, edema, and weight loss. Most of the cases in our review were MPO-ANCA-positive and exhibited isolated interstitial inflammation. These patients typically presented with relatively lower levels of serum creatinine, 24-h urine protein levels, and MPO-ANCA titers. All patients in our study received immunosuppressive therapy, including glucocorticoids, immunosuppressants, and rituximab, with the majority achieving clinical remission. Isolated AIN in the context of AAV is a rare occurrence, but it displays distinct clinical, laboratory, and pathological features. Patients with this presentation show a positive response to immunosuppressive treatment. Nevertheless, the establishment of definitive therapy guidelines for AAV-associated AIN remains uncertain and necessitates further investigation to develop comprehensive treatment guidelines. AIN, particularly when lacking typical glomerulus lesions, may represent a novel subgroup within MPO-AAV warranting additional research and clinical attention. Key Points • This study contributes valuable scientific insights by highlighting that MPO-AAV-associated interstitial nephritis, even without crescentic formation, can exhibit podocyte foot process effacement and respond well to treatment. • The presence of AIN, independent of crescentic glomerulonephritis, suggests the potential emergence of a new subclass within MPA-AAV. • Notably, some cases of MPO-AAV-associated AIN may present with normal levels of Scr (Table 5, cases 5, 6, and 17). • This observation highlights the importance of considering renal biopsy, diagnosis, and therapy in a timely manner to prevent the development of chronic kidney disease (CKD).

ANCA-associated glomerulonephritis and lupus nephritis following COVID-19 vaccination: a case report and literature review

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.

SARS-CoV-2 infection associated with antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (ANCA-GN): a systematic review and two case reports

BACKGROUND

It has been observed that SARS-CoV-2 infections are associated with the development of various de-novo autoimmune diseases; little is known on new-onset antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (ANCA-GN) after SARS-CoV-2 infections.

METHODS

We conducted a systematic review of previously reported cases with a presumed association of new-onset antineutrophil cytoplasmic antibody-associated glomerulonephritis (ANCA-GN). No language restrictions were applied during the search. The eligible articles included reports of biopsy-proven pauci-immune glomerulonephritis that occurred following SARS-CoV-2 infection. The review was registered in PROSPERO database (CRD42023407786). Two further cases are reported.

RESULTS

The mean age of SARS-CoV-2 infection-associated ANCA-GN was 48 ± 19 years. Fifty-six percent of patients showed positivity for myeloperoxidase (MPO)-ANCA. Among tested patients, 36% had concomitantly positive antinuclear antibodies, and 100% had positive rheumatoid factor. Eleven out of the 21 cases (55%) were diagnosed with ANCA-GN during hospitalization due to SARS-CoV-2 infection. The remaining cases were diagnosed after a median of 2.1 months following COVID-19. Seventy-one percent of patients showed improvement in kidney function following different treatments.

CASE REPORTS

one patient had positive p-ANCA and cryoglobulin. Another case had positive MPO-ANCA, c-ANCA, cryoglobulinemia, and rheumatoid factor.

CONCLUSION

SARS-CoV-2 infection-associated ANCA-GN patients are younger than primary ANCA-GN patients. The presence of atypical ANCA along with co-positivity with other autoantibodies can raise suspicion for SARS-CoV-2 infection-associated ANCA-GN.

Impact of Pretransplant Dialysis Modality on Posttransplant Outcomes: A Single-Center Experience

OBJECTIVES

It remains unclear whether posttransplant outcomes differ according to the pretransplant dialysis modality (peritoneal dialysis vs hemodialysis). Our aim was to assess posttransplant outcomes in patients with different predialysis modalities.

MATERIALS AND METHODS

Two thousand two hundred fifty-eight kidney recipients following up in Hamed Alessa Organ transplant center in Kuwait were included and divided into two groups according to pre-transplant dialysis modality: Group 1: those who received hemodialysis (HD) and group 2: those with peritoneal dialysis (PD). Demographics, pretransplant and posttransplant comorbidities, and patient and graft outcomes were studied.

RESULTS

There were 1956 patients on hemodialysis, and 302 patients were on peritoneal dialysis. Most were male patients (1456 vs 802 female patients), with comparable mean age (P = .34). Chronic glomerulonephritis and diabetic nephropathy represented the most common original kidney disease before transplant (27.6% and 21.4%, respectively), with higher prevalence of glomerulonephritis in group 1 and diabetic nephropathy in group 2 (P = .001). The 2 groups were comparable with regard to immunosuppression (induction and maintenance) (P > .05). Posttransplant diabetes and hypertension were significantly higher in the hemodialysis group (P = .004 and P = 003, respectively). There was no significant difference between the 2 groups with regard to the graft outcome (P = .86). However, patient survival was significantly higher in the hemodialysis group (81.2% vs 64.4%).

CONCLUSIONS

Compared with peritoneal dialysis, pretransplant hemodialysis is associated with better posttransplant patient survival despite no difference in the graft outcome. Diabetes-related complications could be attributed to such outcomes.

A case report: Infection-related glomerulonephritis and mantle cell lymphoma due to mycobacterium avium complex infection

RATIONALE

Mycobacterium avium complex (MAC) infection is common in lung, liver and skin. However, MAC presenting with peritonitis is uncommon and is particularly rare in immunocompetent patients. We report a case of infection-associated glomerulonephritis and mantle cell lymphoma caused by peritonitis due to MAC.

PATIENT CONCERNS

We report a case of a 73-year-old elderly man with fever and abdominal pain for 2 days and gradually developed anuria, ascites, and abdominal lymphadenopathy.

DIAGNOSES

The initial diagnosis was peritonitis and acute renal failure. There was no significant relief of symptoms after empirical anti-infective therapy and hemodialysis. infection-associated glomerulonephritis, mantle cell lymphoma, and peritonitis due to MAC were diagnosed by renal biopsy, abdominal lymph node biopsy, and metagenomics next-generation sequencing.

INTERVENTIONS

The patient received empirical antibiotic therapy, hemodialysis, and anti-MAC therapy.

OUTCOMES

Unfortunately, the patient eventually died of septic shock after the 21st day of admissiom.

LESSONS

Early diagnosis of MAC infection is essential. When the cause of fever is unknown, metagenomics next-generation sequencing can be considered.

The five types of glomerulonephritis classified by pathogenesis, activity and chronicity (GN-AC)

Glomerulonephritis (GN) is a diverse group of immune-mediated disorders. Currently, GN is classified largely by histological patterns that are difficult to understand and teach, and most importantly, do not indicate treatment choices. Indeed, altered systemic immunity is the primary pathogenic process and the key therapeutic target in GN. Here, we apply a conceptual framework of immune-mediated disorders to GN guided by immunopathogenesis and hence immunophenotyping: (i) infection-related GN require pathogen identification and control; (ii) autoimmunity-related GN, defined by presence of autoantibodies and (iii) alloimmunity-related GN in transplant recipients both require the suppression of adaptive immunity in lymphoid organs and bone marrow; (iv) autoinflammation-related GN, e.g. inborn errors of immunity diagnosed by genetic testing, requires suppression of single cytokine or complement pathways; and (v) Monoclonal gammopathy-related GN requires B or plasma cell clone-directed therapy. A new GN classification should include disease category, immunological activity to tailor the use of the increasing number of immunomodulatory drugs, and chronicity to trigger standard chronic kidney disease care including the evolving spectrum of cardio-renoprotective drugs. Certain biomarkers allow diagnosis and the assessment of immunological activity and disease chronicity without kidney biopsy. The use of these five GN categories and a therapy-focused GN classification is likely to overcome some of the existing hurdles in GN research, management and teaching by reflecting disease pathogenesis and guiding the therapeutic approach.

CKD therapy to improve outcomes of immune-mediated glomerular diseases

The management of immunoglobulin A nephropathy, membranous nephropathy, lupus nephritis, anti-neutrophil cytoplasmic antibody-associated vasculitis, C3 glomerulonephritis, autoimmune podocytopathies and other immune-mediated glomerular disorders is focused on two major treatment goals, preventing overall mortality and the loss of kidney function. Since minimizing irreversible kidney damage best serves both goals, the management of immune-mediated kidney disorders must focus on the two central pathomechanisms of kidney function decline, i.e., controlling the underlying immune disease process (e.g. with immunotherapies) and controlling the non-immune mechanisms of chronic kidney disease (CKD) progression. Here we review the pathophysiology of these non-immune mechanisms of CKD progression and discuss non-drug and drug interventions to attenuate CKD progression in immune-mediated kidney disorders. Non-pharmacological interventions include reducing salt intake, normalizing body weight, avoiding superimposed kidney injuries, smoking cessation and regular physical activity. Approved drug interventions include inhibitors of the renin-angiotensin-aldosterone system and sodium-glucose cotransporter-2. Numerous additional drugs to improve CKD care are currently being tested in clinical trials. Here we discuss how and when to use these drugs in the different clinical scenarios of immune-mediated kidney diseases.

De Novo ANCA-Negative Pauci-Immune Crescentic Glomerulonephritis After COVID-19 mRNA Vaccination: A Case Report

To prevent the spread of the coronavirus disease 2019 (COVID-19) pandemic, vaccines have been authorized for emergency use and implemented worldwide. We present a case of de novo glomerulonephritis (GN) after use of the COVID-19 mRNA vaccine BNT162b2. A 48-year-old man with no relevant medical history was referred for sudden and persistent worsening of renal insufficiency 1.5 months after the second vaccine dose. He had arthralgia and skin rash a week after vaccination. Abdominal pain and diarrhea started 2 weeks later, and he was admitted to the hospital for enteritis treatment. Colonoscopy showed multiple ulcerations and petechiae suggestive of vasculitis in the terminal ileum. After prednisolone therapy, his gastrointestinal symptoms improved, but his renal function continued to deteriorate. Based on kidney biopsy findings and nephrotic-range proteinuria (5,306 mg/24 hours), he was diagnosed with anti-neutrophil cytoplasmic autoantibody (ANCA)-negative pauci-immune crescentic GN (CrGN). He received high-dose steroid pulse therapy and oral cyclophosphamide, and then, gradually underwent steroid tapering, with improvement in proteinuria and renal function over several weeks. Several cases of GN suspected to be related to COVID-19 vaccines have been reported. To our knowledge, this is the first case report of ANCA-negative pauci-immune crescentic CrGN with extrarenal involvement after COVID-19 mRNA vaccination. Our finding expands the spectrum of COVID-19 vaccine-associated GN.

Clinical profile of children with acute post-streptococcal glomerulonephritis

BACKGROUND

Acute post-streptococcal glomerulonephritis (APSGN) is common in developing countries with a high hospitalization rate. Most patients have acute nephritic syndrome features, although some occasionally present with unusual clinical features. This study aims to describe and analyze clinical features, complications, and laboratory parameters in children diagnosed with APSGN at presentation, 4 and 12 weeks later, in a resource-limited setting.

METHODS

This cross-sectional study was conducted among children < 16 years with APSGN between January 2015 and July 2022. Hospital medical records and outpatient cards were reviewed for clinical findings, laboratory parameters, and kidney biopsy results. Descriptive analysis of multiple categorical variables was performed using SPSS version 16.0 and presented as frequencies and percentages.

RESULTS

The study included 77 patients. Most (94.8%) were older than five years, and age group 5-12 years had highest prevalence (72.7%). Boys were affected more frequently than girls (66.2% vs. 33.8%). Edema (93.5%), hypertension (87%), and gross hematuria (67.5%) were the most frequent presenting symptoms, and pulmonary edema (23.4%) was the most common severe complication. Anti-DNase B and anti-streptolysin O titers were positive in 86.9% and 72.7%, respectively, and 96.1% had C3 hypocomplementemia. Most clinical features resolved in three months. However, at 3 months, 6.5% of patients had persistent hypertension, impaired kidney function, and proteinuria alone or in combination. Most patients (84.4%) had an uncomplicated course; 12 underwent kidney biopsy, 9 required corticosteroids, and 1 required kidney replacement therapy. There was no mortality during the study period.

CONCLUSION

Generalized swelling, hypertension, and hematuria were most common presenting features. Persistent hypertension, impaired kidney function, and proteinuria persisted in a small proportion who had a significant clinical course and required kidney biopsy. A higher resolution version of the Graphical abstract is available as Supplementary information.

Glomerulonephritis

Glomerulonephritis (GN) encompasses several disorders that cause glomerular inflammation and injury through an interplay of immune-mediated mechanisms, host characteristics, and environmental triggers, such as infections. GN can manifest solely in the kidney or in the setting of a systemic illness, and presentation can range from chronic and relatively asymptomatic hematuria to fulminant renal failure. Classic acute GN is characterized by hematuria, edema, and hypertension, the latter 2 of which are the consequence of sodium and water retention in the setting of renal impairment. Although presenting signs and symptoms and a compatible clinical history can suggest GN, serologic and urinary testing can further refine the differential diagnosis, and renal biopsy can be used for definitive diagnosis. Treatment of GN can include supportive care, renin-angiotensin-aldosterone system blockade, immunomodulatory therapy, and renal transplant. Prognosis is largely dependent on the underlying cause of GN and can vary from a self-limited course to chronic kidney disease. This review focuses on lupus nephritis, IgA nephropathy, IgA vasculitis, and postinfectious GN.

Malignancy risk in kidney transplant recipients exposed to immunosuppression pre-transplant for the treatment of glomerulonephritis

BACKGROUND

Kidney transplant patients with glomerulonephritis (GN) as their native disease may receive significant amounts of pre-transplant immunosuppression (PTI), which could increase the risk for development of malignancy post-transplant.

METHODS

We conducted a single-center, retrospective study of kidney transplant recipients from January 2005 until May 2020. Patients with GN as their native kidney disease who received PTI for treatment of GN (n = 184) were compared with a control cohort (n = 579) of non-diabetic, non-PTI-receiving kidney transplant patients. We calculated hazard ratios (HR) with 95% confidence intervals (95% CI) for outcomes of first occurrence of solid or hematologic malignancy, non-melanoma skin cancer (NMSC) and post-transplant lymphoproliferative disorder (PTLD).

RESULTS

Over a median follow-up of 5.7 years, PTI for GN was associated with significantly increased risk for malignancy compared with controls [13.0%  vs 9.7%, respectively; adjusted HR 1.82 (95% CI 1.10-3.00)], but not for NMSC [10.3% vs 11.4%, respectively; adjusted HR 1.09 (95% CI 0.64-1.83)] or PTLD [3.3% vs 3.1%, respectively; adjusted HR 1.02 (95% CI 0.40-2.61)]. The risk for malignancy was significantly increased in those who received cyclophosphamide [HR 2.59 (95% CI 1.48-4.55)] or rituximab [HR 3.82 (95% CI 1.69-8.65)] pre-transplant, and particularly in those who received both cyclophosphamide and rituximab, but not for calcineurin inhibitors or mycophenolate.

CONCLUSION

The use of PTI for treatment of GN, especially cyclophosphamide or even with rituximab, is associated with increased risk for development of solid or hematologic malignancy post-transplant. These data highlight potential risks with treatment of GN and underscore the importance of post-transplant malignancy surveillance in this patient population.

[Nephrotic syndrome during pregnancy. Is it chronic glomerulonephritis or preeclampsia? Case report]

Nephrotic syndrome (NS) during pregnancy is a fairly rare pathology and its descriptions in the literature are few. For a long time, NS was associated only with an exacerbation of chronic glomerulonephritis or de novo nephritis, however, the experience of recent years has shown that NS can be a manifestation of the classical obstetric pathology - preeclampsia (PE). The appearance of massive proteinuria with the development of NS is most typical for early PE, which, of course, makes diagnosis difficult, especially if PE develops at an unusually early time (up to 20 weeks). To describe PE that does not fit into the classical criteria, the term "atypical" PE is now used, the development of which can be promoted by both obstetric and somatic risk factors. The presented clinical observation describes the development of early (within 14 weeks) severe PE with the NS at the onset of the disease in a patient with the first multiple pregnancy and complete hydatidiform mole (HM) of one of the fetuses. The progression of nephropathy with the addition of thrombotic microangiopathy and HELLP syndrome made it possible to assume the diagnosis of PE with a high probability. The rapid relief of all clinical manifestations after delivery confirmed this assumption. The role of HM as the main trigger of unusually early PE is discussed. Apparently, the patient's trophoblast disease in the form of hydatidiform mole caused the formation of a severe angiogenic imbalance already in the early stages of pregnancy, which led to the development of PE, which manifested NS as a consequence of podocytopathy due to VEGF deficiency. Thus, the development of NS in a pregnant patient without a history of kidney disease dictates, first of all, the exclusion of PE, until proven otherwise.

A case of Sjögren syndrome and anti-neutrophil cytoplasmic antibody-associated vasculitis

Sjögren's syndrome (SS) is a rare disease with the highest reported prevalence of 0.01-0.09%. Anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) is another rare auto-immune disease (prevalence of 0.0009-0.01%). The co-occurrence of these two separate clinical entities in one patient might rarely be encountered as an overlap syndrome. Here, we present the case of a 60-year-old female patient who had complaints of headache, nausea, weakness, gritty sensation in her eyes, and dry mouth [unstimulated saliva production of 0.033 mL/minute (normal; >0.1 mL/minute)] with a blood pressure of 190/110 mmHg, hypertensive retinopathy, proteinuric kidney disease, positivity of myeloperoxidase anti-neutrophil cytoplasmic antibodies, anti-Ro-52, anti-Ro, and anti-La antibodies. Pauci-immune crescentic proliferative glomerulonephritis was found in a kidney biopsy and successfully treated with cyclophosphamide and methylprednisolone. The co-occurrence of these diseases was first reported in 1992 by Böttinger et al. Since then, nearly 37 cases of SS and AAV have been reported. By reporting this case of primary SS and AAV, we emphasize the importance of auto-antibody tests in searching for the etiology of patients with proteinuria.

Glomerulonephritis: immunopathogenesis and immunotherapy

'Glomerulonephritis' (GN) is a term used to describe a group of heterogeneous immune-mediated disorders characterized by inflammation of the filtration units of the kidney (the glomeruli). These disorders are currently classified largely on the basis of histopathological lesion patterns, but these patterns do not align well with their diverse pathological mechanisms and hence do not inform optimal therapy. Instead, we propose grouping GN disorders into five categories according to their immunopathogenesis: infection-related GN, autoimmune GN, alloimmune GN, autoinflammatory GN and monoclonal gammopathy-related GN. This categorization can inform the appropriate treatment; for example, infection control for infection-related GN, suppression of adaptive immunity for autoimmune GN and alloimmune GN, inhibition of single cytokines or complement factors for autoinflammatory GN arising from inborn errors in innate immunity, and plasma cell clone-directed or B cell clone-directed therapy for monoclonal gammopathies. Here we present the immunopathogenesis of GN and immunotherapies in use and in development and discuss how an immunopathogenesis-based GN classification can focus research, and improve patient management and teaching.

Incidence of new onset glomerulonephritis after SARS-CoV-2 mRNA vaccination is not increased

Numerous cases of glomerulonephritis manifesting shortly after SARS-CoV-2 vaccination have been reported, but causality remains unproven. Here, we studied the association between mRNA-based SARS-CoV-2 vaccination and new-onset glomerulonephritis using a nationwide retrospective cohort and a case-cohort design. Data from all Swiss pathology institutes processing native kidney biopsies served to calculate incidence of IgA nephropathy, pauci-immune necrotizing glomerulonephritis, minimal change disease, and membranous nephropathy in the adult Swiss population. The observed incidence during the vaccination campaign (January to August 2021) was not different from the expected incidence calculated using a Bayesian model based on the years 2015 to 2019 (incidence rate ratio 0.86, 95% credible interval 0.73-1.02) and did not cross the upper boundary of the 95% credible interval for any month. Among 111 patients 18 years and older with newly diagnosed glomerulonephritis between January and August 2021, 38.7% had received at least one vaccine dose before biopsy, compared to 39.5% of the general Swiss population matched for age and calendar-time. The estimated risk ratio for the development of new-onset biopsy-proven glomerulonephritis was not significant at 0.97 (95% confidence interval 0.66-1.42) in vaccinated vs. unvaccinated individuals. Patients with glomerulonephritis manifesting within four weeks after vaccination did not differ clinically from those manifesting temporally unrelated to vaccination. Thus, vaccination against SARS-CoV-2 was not associated with new-onset glomerulonephritis in these two complementary studies with most temporal associations between SARS-CoV-2 vaccination and glomerulonephritis likely coincidental.

Acute Postinfectious Glomerulonephritis

Postinfectious glomerulonephritis (PIGN) is a leading cause of acute glomerulonephritis in children. The presentation of PIGN can vary from asymptomatic microscopic hematuria incidentally detected on routine urinalysis to nephritic syndrome and a rapidly progressive glomerulonephritis. Treatment involves supportive care with salt and water restriction, and the use of diuretic and/or antihypertensive medication, depending on the severity of fluid retention and the presence of hypertension. PIGN resolves completely and spontaneously in most children, and the long-term outcomes are typically good with preserved renal function and no recurrence.

A case of smoldering antineutrophil cytoplasmic antibody-associated vasculitis development during the course of primary Sjögren's syndrome

Various forms of glomerular lesions have been described in primary Sjögren's syndrome (pSjS); however, myeloperoxidase (MPO)-antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis is rarely reported, and the disease onset and clinical course of ANCA-associated vasculitis (AAV) complicated by pSjS are not well understood. A 51-year-old woman was referred to our hospital because of mild proteinuria and microscopic hematuria. She fulfilled the classification criteria for pSjS. We performed a kidney biopsy; however, it revealed no characteristic findings for pSjS, vasculitis, or other autoimmune diseases, including systemic lupus erythematosus. After 9 months, urinalysis abnormalities worsened and renal function was slowly declining, and ANCA was found to be positive. A second kidney biopsy was performed, revealing MPO-ANCA-associated pauci-immune segmental necrotizing glomerulonephritis with crescent formation. Even though immunofluorescence microscopy did not reveal any positive findings, additional electron microscopy demonstrated the presence of mesangial electron-dense deposits in both kidney biopsies. Based on kidney biopsy results and sequential serum ANCA measurements, we considered that smoldering ANCA-associated vasculitis had developed in this patient as this can develop during the clinical course of pSjS. She responded well to steroid therapy. Serum measurement, especially perinuclear, ANCA levels can be useful in patients with pSjS to detect the onset of ANCA-associated vasculitis, even in the absence of acute renal deterioration or severe urinary abnormalities.

Immune complex-mediated glomerulonephritis post COVID-19 vaccination in a patient with concomitant Brucellosis

COVID vaccinations have been an important step in controlling the COVID-19 pandemic. Despite the fact they were generally safe and effective, a few case reports of renal disorders have been published following COVID vaccines. We report a 29-year-old man with history of Chronic Kidney Disease who presented to our center with flank pain after receiving AstraZeneca COVID vaccine. He also had history of raw milk ingestion. His initial investigations showed high creatinine with high level of proteinuria. A renal biopsy was consistent with immune complex-mediated glomerulonephritis on top of renal fibrosis. His brucella serology also showed high titer. He was started on treatment for Brucellosis and planned for follow-up afterwards for further therapy. To the best of our knowledge, this is the first reported case of concomitant Brucellosis and post COVID vaccine glomerulonephritis.

Use of a B-cell depleting regimen for antifactor H autoantibody-mediated membranoproliferative glomerulonephritis in a paediatric patient

A male child presented initially well with a mixed nephrotic-nephritic syndrome and was commenced on standard high-dose oral corticosteroids. Clinical deterioration occurred 3 weeks later with rapidly progressing renal dysfunction, seizures and diminished urinary output, requiring renal replacement therapy. Once stabilised, renal biopsy demonstrated mesangial and capillary C3, minimal IgG deposition, with mesangial electron dense deposits felt consistent with postinfectious glomerulonephritis or C3 glomerulopathy. Further investigations identified circulating autoantibody directed against factor H, as a plausible aetiology of the membranoproliferative glomerulonephritis (MPGN). Treatment with rituximab and mycophenolate mofetil was associated with a reduction in antibody titres and a concurrent reduction in proteinuria and normalisation of renal function.Subsequent monitoring of antibody titres prompted further administrations of rituximab, with reduction in titres demonstrated after repeat doses. Atypical presentations or complications of nephrotic syndrome or MPGN should prompt detailed investigations for the cause with consideration of antifactor H antibodies.

Case Report: Endocapillary Glomerulopathy Associated With Large Granular T Lymphocyte Leukemia

Large granular T lymphocyte leukemia (T-LGLL) is a rare indolent lymphocyte leukemia. The clonal proliferation of T cells, which is related to STAT3 gene mutation and abnormal Fas-mediated apoptosis pathway after cell activation, plays a major role in disease progression. Some studies have found that the exogenous and continuous stimulation of endogenous antigens, such as virus infection, is related to the pathogenesis of T-LGLL. The renal pathological manifestations of T-LGLL have rarely been described. In this study, we report a case of T-LGLL with kidney involvement as proteinuria, acute kidney injury, with the appearance of circulating T-LGL infiltrating intra-glomerular capillaries, and endocapillary glomerulopathy. We also summarize reported cases of renal injury associated with LGLL.

Use of Immunosuppressive Therapy in the Treatment of IgA-dominant Infection-related Glomerulonephritis

A 51-year-old Japanese man who experienced colon cancer recurrence following primary and metastatic lesion resection was hospitalized due to facial cellulitis with febrile neutropenia and purpura on his lower extremities after chemotherapy. It was complicated by rapidly progressive glomerulonephritis. He was diagnosed with immunoglobulin A (IgA)-dominant endocapillary proliferative glomerulonephritis based on kidney histology. His glomeruli were positive for the nephritis-associated plasmin receptor, plasmin activity and galactose-deficient IgA1 (Gd-IgA1). A skin biopsy immunofluorescence study revealed IgA deposition within perivascular regions but no Gd-IgA1 deposition. The final diagnosis was IgA-dominant infection-related glomerulonephritis (IRGN). The patient's renal function returned to normal after receiving immunosuppressive therapy that consisted of a glucocorticoid and a cyclophosphamide. Immunosuppressive therapy should be considered in cases of IRGN if the patient's infection is completely under control.

Chronic catheter-related bacteremia of Pseudomonas stutzeri etiology as the cause of membranous-proliferative glomerulonephritis (MPGN) - a case report

Secondary membranous - proliferative glomerulonephritis most often develops in the course of viral infections (HCV, HBV), autoimmune diseases, paraproteinemia, and also in the course of chronic bacterial infections. Infections with Pseudomonas stutzeri (P. stutzeri) are extremely rare and usually mildly symptomatic. The natural habitat of this bacterium is soil and water. Nevertheless, in the case of P. stutzeri infection, especially in patients frequently hospitalized or receiving immunosuppressive medications, environmental contamination in healthcare facilities should be taken into account when looking for the source of the infection.

A CASE REPORT

A 60-year-old man with a previous history of nicotinism and arterial hypertension with a vascular port in the vena cava superior (VCS) after treatment for bladder cancer (stage G2/G3) several years ago was described. The patient underwent the TURBT procedure, and then received intravesical infusions with BCG for 3 years, followed by complications in the form of severe dysuria and lower abdominal pain. Due to severe nausea and the inability to take analgesics orally, the patient was ordered to insert a vascular port into the VCS in order to continue the analgesic and anti - inflammatory therapy. Several years later, after the onset of massive edema of lower limbs, the patient was subjected to a 24-hour urine collection, in which proteinuria amounted to approx. 13 g/day, followed by a diagnostic kidney biopsy. Histopathological examination described membranoproliferative glomerulonephritis (MPGN). Other renal parameters were also abnormal, i.e. serum creatinine concentration was 1.9 mg/ dl and serum urea concentration was 116 mg/dl. Immunosuppressive treatment was initiated. Patient received methylprednisolone intravenously followed by prednisone orally and cyclosporine orally. During the initial period of immunosuppressive therapy, the serum levels of cyclosporine were insufficient (starting from 26.34 ng/ml), which resulted in increasing its dose, ultimately reaching 175 mg/day. After several months of therapy, the patient was hospitalized again, due to infection of the respiratory tract that had lasted for several weeks and was not amenable to antibiotic therapy. Deterioration of renal parameters and increased inflammatory markers suggested diagnosis of catheter - related sepsis. P. stutzeri was grown from the material collected from the catheter and the patient's blood. Appropriate antibiotic therapy was initiated and after the patient's condition improved, cyclosporine therapy was restarted, which was discontinued after the diagnosis of bacteremia. Rapid remission was achieved, allowing the discontinuation of immunosuppressive drugs.

CONCLUSIONS

Chronic, asymptomatic infection with a rare pathogen, like Pseudomonas stutzeri, was probably the cause of the glomerulonephritis. After removal of the port and antibiotic therapy, disease remission was achieved.

A case report of PR-3-ANCA-positive glomerulonephritis with histological features of GPA associated with infectious endocarditis

RATIONALE

Several renal diseases are associated with infectious endocarditis. However, there are few reports on patients with granulomatosis with polyangiitis (GPA) associated with infectious endocarditis, and there is no consensus for appropriate treatment.

PATIENTS CONCERNS

A 35 -years-old man with congenital ventricular septal defect presented severe anemia, hematuria and proteinuria. The blood and urine examinations showed elevated white blood cells (12,900 cells/μL), C-reactive protein level (13.1 mg/dL) and proteinase 3-anti-neutrophil cytoplasmic antibody (PR3-ANCA) level (11.0 IU/mL), severe anemia (hemoglobin: 6.1 g/dL) and renal dysfunction [estimated glomerular filtration rate (eGFR): 12.7 ml/min.1.78 m2 with hematuria and proteinuria].

DIAGNOSES

The patient was diagnosed with crescentic glomerulonephritis with histological features of GPA associated with infectious endocarditis by renal biopsy and transthoracic echocardiography.

INTERVENTIONS

Antibacterial drugs (ampicillin-sulbactam) were administrated. No immunomodulating agents were used because immunosuppressive drugs may worsen infectious endocarditis. Subsequently, renal function and urinary findings improved. However, infectious endocarditis was not improved. Therefore, valve replacements and ventricular septal closure surgery were conducted.

OUTCOMES

Thereafter, his postoperative course was uneventful, renal function improved (eGFR: 64.3 ml/min.1.78 m2), and PR3-ANCA level normalized.

LESSONS

We reported a case report of PR3-ANCA positive glomerulonephritis with histological features of GPA associated with infectious endocarditis. Physicians might note this renal complication when they manage infectious endocarditis.

Nephritis-associated plasmin receptor (NAPlr)-positive glomerulonephritis in a case of ANCA-negative small vessel vasculitis

A 75-year-old man with fever was diagnosed with alveolar hemorrhage. Antineutrophil cytoplasmic antibodies for myeloperoxidase and proteinase 3 were absent. He received corticosteroid therapy, which immediately improved his symptoms and chest radiological findings. After the discontinuation of corticosteroids, fever and general fatigue relapsed, and renal function deteriorated with hematuria and proteinuria. A nerve conduction study revealed mononeuritis multiplex. Renal biopsy demonstrated focal necrotizing crescentic glomerulonephritis with endocapillary proliferative lesions, immunofluorescence C3 deposits, and electron-microscopic subepithelial hump-like deposits. Nephritis-associated plasmin receptor (NAPlr) and plasmin activity, biomarkers of infection-related glomerulonephritis, were positive in glomeruli. Although pathological findings suggested infection-related glomerulonephritis (IRGN), clinical manifestations, such as alveolar hemorrhage and mononeuritis multiplex, suggested systemic small vessel vasculitis. After corticosteroid therapy, systemic symptoms disappeared, and the gradual amelioration of hematuria and proteinuria was observed. Based on the clinical symptoms for which steroid therapy was effective, the patient was considered to have systemic small vessel vasculitis, the etiology of which may have been associated with infection.

Recurrent glomerulonephritis after kidney transplantation: a practical approach

PURPOSE OF REVIEW

This review will provide a practical approach in the assessment of kidney failure patients with primary glomerulonephritides (GN) being considered for kidney transplantation, focusing on high-risk subtypes of immunoglobulin A nephropathy, focal segmental glomerulosclerosis, idiopathic membranous glomerulonephritis and membranoproliferative glomerulonephritis.

RECENT FINDINGS

Recurrent glomerulonephritis remains one of the most common causes of allograft loss in kidney transplant recipients. Although the epidemiology and clinical outcomes of glomerulonephritis recurrence occurring after kidney transplantation are relatively well-described, the natural course and optimal treatment strategies of recurrent disease in kidney allografts remain poorly defined. With a greater understanding of the pathophysiology and treatment responses of patients with glomerulonephritis affecting the native kidneys, these discoveries have laid the framework for the potential to improve the management of patients with high-risk glomerulonephritis subtypes being considered for kidney transplantation.

SUMMARY

Advances in the understanding of the underlying immunopathogenesis of primary GN has the potential to offer novel therapeutic options for kidney patients who develop recurrent disease after kidney transplantation. To test the efficacy of novel treatment options in adequately powered clinical trials requires a more detailed understanding of the clinical and histological characteristics of kidney transplant recipients with recurrent glomerulonephritis.

Prognostic Factors and Long-Term Outcome with ANCA-Associated Kidney Vasculitis in Childhood

BACKGROUND AND OBJECTIVES

ANCA-associated vasculitis is extremely rare in children. We report the clinicopathologic features, long-term outcomes, and prognostic factors of a large pediatric cohort of patients with ANCA-associated kidney vasculitis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This retrospective study included 85 consecutive patients with kidney biopsy specimen-proven ANCA-associated vasculitis from tertiary referral centers in Italy and Canada. Kidney biopsy specimens were categorized as focal, crescentic, sclerotic, or mixed, according to the Berden classification. The prognostic significance of baseline clinical, laboratory, and histologic findings was analyzed with respect to kidney failure or CKD stage 3-5/kidney failure.

RESULTS

A total of 53 patients had microscopic polyangiitis (62%), and 32 had granulomatosis with polyangiitis (38%). Rapidly progressive GN was the most frequent presentation (39%); a third of the patients also had nephrotic-range proteinuria. Kidney biopsy specimens were classified as focal in 21% of the patients, crescentic in 51%, sclerotic in 15%, and mixed in 13%. Remission-induction therapies included cyclophosphamide in 78% of patients. A total of 25 patients (29%) reached kidney failure. The median (interquartile range) time to kidney failure or last follow-up was 35 (6-89) months in the whole cohort, and 73 (24-109) months among the patients who did not reach this outcome. Patients whose biopsy specimens showed sclerotic histology had significantly shorter kidney survival (hazard ratio, 11.80; 95% confidence interval, 2.49 to 55.99) and survival free of CKD stage 3-5 (hazard ratio, 8.88; 95% confidence interval, 2.43 to 32.48), as compared with those with focal/mixed histology. Baseline eGFR, low serum albumin, hypertension, central nervous system complications, and sclerotic histology, which reflected severe kidney involvement, were associated with both kidney failure and CKD stage 3-5/kidney failure at unadjusted analysis; no independent prognostic factors emerged at multivariable analysis.

CONCLUSIONS

Children with ANCA-associated kidney vasculitis often have aggressive presentation; a third of such children progress to kidney failure and this usually occurs early during follow-up. A severe clinical presentation is associated with the development of CKD or kidney failure.

IgA-Dominant Infection-Associated Glomerulonephritis Following SARS-CoV-2 Infection

The renal involvement of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been reported. The etiology of kidney injury appears to be tubular, mainly due to the expression of angiotensin-converting enzyme 2, the key joint receptor for SARS-CoV-2; however, cases with glomerular implication have also been documented. The multifactorial origin of this renal involvement could include virus-mediated injury, cytokine storm, angiotensin II pathway activation, complement dysregulation, hyper-coagulation, and microangiopathy. We present the renal histological findings from a patient who developed acute kidney injury and de novo nephrotic syndrome, highly suggestive of acute IgA-dominant infection-associated glomerulonephritis (IgA-DIAGN) after SARS-CoV-2 infection, as evidenced by the presence of this virus detected in the renal tissue of the patient via immunohistochemistry assay. In summary, we document the first case of IgA-DIAGN associated to SARS-CoV-2. Thus, SARS-CoV-2 S may act as a super antigen driving the development of multisystem inflammatory syndrome as well as cytokine storm in patients affected by COVID-19, reaching the glomerulus and leading to the development of this novel IgA-DIAGN.

Autoimmunity in Acute Poststreptococcal GN: A Neglected Aspect of the Disease

Acute poststreptococcal GN (APSGN) is the prototype of immune complex GN and is associated with manifestations of autoimmune reactivity that have been neglected as epiphenomena. Recently, studies have demonstrated transient antifactor B autoantibodies that activate the alternative complement pathway, bringing self-immunity to a central position in the pathogenesis of APSGN. Therefore, examining other manifestations of autoimmunity that have been reported in association with poststreptococcal GN is of interest. This article reviews the renal and extrarenal manifestations of autoimmune reactivity in APSGN and considers their potential relevance in modifying the usually benign clinical course of the disease. It also discusses related aspects of the nephritogenic antigens, complement activation, and genetic elements associated with immune reactivity and their potential relevance to the familial incidence of the disease.

Staphylococcus-induced glomerulonephritis: potential role for corticosteroids

Staphylococcus aureus is a troublesome pathogen, responsible for a broad range of clinical manifestations, ranging from benign skin infections to life-threatening conditions such as endocarditis and osteomyelitis. The kidney can be affected through a rapidly progressive glomerulonephritis mediated by an inflammatory reaction against a superantigen deposited in the glomerulus during the infection's course. This glomerulopathy has a poor prognosis, often leading to chronically impaired kidney function, eventually progressing to end-stage renal disease. Treatment rests on antibiotherapy. Despite the inflammatory role in this disease's pathophysiology, most authors discourage a simultaneous immunosuppressive approach given the concomitant infection. However, there are some reports of success after administration of systemic corticosteroids in these patients. We present a 66-year-old man with a staphylococcus-induced glomerulonephritis brought on by a vascular graft infection, with rapidly deteriorating kidney function despite extraction of the infected graft and 3 weeks of antibiotherapy with achievement of infection control. Kidney function improved after the introduction of corticosteroids. This case highlights the potential role of corticosteroids in selected cases of staphylococcus-induced glomerulonephritis, particularly those in which the infection is under control.

Staphylococcus-associated acute glomerulonephritis in a patient with dermatomyositis

Staphylococcus-associated glomerulonephritis (SAGN) occurs as a complication of staphylococcal infection elsewhere in the body. Dermatomyositis (DM) can be associated with glomerulonephritis due to the disease per se. We report a case of a 40-year-old male patient with DM who presented with acute kidney injury, and was initially pulsed with methylprednisolone for 3 days, followed by dexamethasone equivalent to 1 mg/kg/day prednisolone. He was subsequently found to have SAGN on kidney biopsy along with staphylococcus bacteraemia and left knee septic arthritis. With proof of definitive infection, intravenous immunoglobulin 2 g/kg over 2 days was given and steroids were reduced. He was treated with intravenous vancomycin. With treatment, the general condition of the patient improved. On day 38, he developed infective endocarditis and died of congestive heart failure subsequently. Undiagnosed staphylococcal sepsis complicating a rheumatological disease course can lead to complications like SAGN, infective endocarditis and contribute to increased morbidity and mortality, as is exemplified by our case.

Recurrent Glomerulonephritis after Renal Transplantation: The Clinical Problem

Glomerulonephritis (GN) continues to be one of the main causes of end-stage kidney disease (ESKD) with an incidence rating from 10.5% to 38.2%. Therefore, recurrent GN, previously considered to be a minor contributor to graft loss, is the third most common cause of graft failure 10 years after renal transplantation. However, the incidence, pathogenesis, and natural course of recurrences are still not completely understood. This review focuses on the most frequent diseases that recur after renal transplantation, analyzing rate of recurrence, epidemiology and risk factors, pathogenesis and bimolecular mechanisms, clinical presentation, diagnosis, and therapy, taking into consideration the limited data available in the literature. First of all, the risk for recurrence depends on the type of glomerulonephritis. For example, recipient patients with anti-glomerular basement membrane (GBM) disease present recurrence rarely, but often exhibit rapid graft loss. On the other hand, recipient patients with C3 glomerulonephritis present recurrence in more than 50% of cases, although the disease is generally slowly progressive. It should not be forgotten that every condition that can lead to chronic graft dysfunction should be considered in the differential diagnosis of recurrence. Therefore, a complete workup of renal biopsy, including light, immunofluorescence and electron microscopy study, is essential to provide the diagnosis, excluding alternative diagnosis that may require different treatment. We will examine in detail the biomolecular mechanisms of both native and transplanted kidney diseases, monitoring the risk of recurrence and optimizing the available treatment options.

Henoch-Schönlein Purpura (IgA Vasculitis): Rapid Evidence Review

Henoch-Schönlein purpura, now called immunoglobulin A (IgA) vasculitis, is a systemic, immune complex-mediated, small-vessel leukocytoclastic vasculitis characterized by nonthrombocytopenic palpable purpura, arthritis, and abdominal pain. It is the most common vasculitis in children but can also occur in adults. Diagnostic testing is required only to exclude other etiologies of purpura, to identify renal involvement, and, if indicated, to determine its extent with biopsy. Imaging or endoscopy may be needed to assess organ complications. IgA vasculitis spontaneously resolves in 94% of children and 89% of adults, making supportive treatment the primary management strategy. However, a subset of patients experience renal involvement that can persist and relapse years later. Additional complications can include gastrointestinal bleeding, orchitis, and central nervous system involvement. Systematic reviews have shown that steroids do not prevent complications and should not be used prophylactically. However, randomized trials have demonstrated success with high-dose steroids, cyclosporine, and mycophenolate in treating glomerulonephritis and other complications. Long-term prognosis depends on the extent of renal involvement. Six months of follow-up is prudent to assess for disease relapse or remission.

Incidence of Acute Post-Streptococcal Glomerulonephritis in Hawai'i and Factors Affecting Length of Hospitalization

Acute post-streptococcal glomerulonephritis (APSGN) is a disorder of inflammation in the glomeruli and vasculature of the kidneys that is caused by immune-complex formation after Streptococcus pyogenes infection. Most patients with APSGN present with macroscopic hematuria, edema, and hypertension, however presentation can vary from no symptoms to severe proteinuria, or even acute renal failure. This study sought to estimate the incidence of APSGN among children in Hawai'i, to identify populations at increased risk for APSGN, and to recognize risk factors correlated with the length of hospitalization by subtype of APSGN (eg, pyoderma-associated, pharyngitis-associated). This retrospective review of 106 patients found that the incidence of APSGN in Hawai'i is greater than 4 per 100,000 children, which is significantly higher than the incidence of APSGN in high-income countries at 0.3 per 100,000 children. This increased incidence may be due to Hawai'i's unique racial group composition and therefore the unique immunologic response of the children of Hawai'i (particularly Pacific Islanders, who represent 62% of patients with APSGN in this study, but only represent 10% of Hawai'i's general population). In addition, there may be increased prevalence of nephritogenic strains of Streptococcus pyogenes in Hawai'i. The length of hospitalization was significantly increased in children with elevated serum creatinine levels (P <.0001) and lower bicarbonate levels (P =.0003).

The glomerular crescent: triggers, evolution, resolution, and implications for therapy

PURPOSE OF REVIEW

Crescents are classical histopathological lesions found in severe forms of rapidly progressive glomerulonephritis, also referred to as crescentic glomerulonephritis (CGN). Crescent formation is a consequence of diverse upstream pathomechanisms and unraveling these mechanisms is of great interest for improving the management of patients affected by CGN. Thus, in this review, we provide an update on the latest insight into the understanding on how crescents develop and how they resolve.

RECENT FINDINGS

Cellular crescents develop from activated parietal epithelial cells (PECs) residing along Bowman's capsule and their formation has as a consequence the decline in glomerular filtration rate (GFR). Cellular crescents can be reversible, but when multilevel growth of PECs associate with an epithelial--mesenchymal transition-like change in cell phenotype, fibrous crescents form, and crescents become irreversible also in terms of GFR recovery. Different molecular pathways trigger the activation of PECs and are a prime therapeutics target in CGN. First, crescent formation requires also vascular injury causing ruptures in the glomerular basement membrane that trigger plasmatic coagulation within Bowman's space. This vascular necrosis can be triggered by different upstream mechanisms, such as small vessel vasculitides, immune complex glomerulonephritis, anti-GBM disease, and C3 glomerulonephritis, that all share complement activation but involve diverse upstream immune mechanisms outside the kidney accessible for therapeutic intervention.

SUMMARY

Knowing the upstream mechanisms that triggered crescent formation provides a tool for the development of therapeutic interventions for CGN.

Rapidly progressive glomerulonephritis due to systemic lupus erythematosus and ANCA-associated vasculitis overlap

Systemic lupus erythematosus (SLE) and ANCA-associated vasculitis (AAV) are different autoimmune diseases. While vasculitis can be seen in the SLE clinical course as a secondary phenomenon, and may indicate a severe disease, primary vasculitis such as AAV rarely occurs in association with SLE. We present a 44-year-old woman who presented with rapidly progressive glomerulonephritis which was histologically identified as a combination of crescentic and lupus nephritis in the presence of myeloperoxidase ANCA antibody. The frequency of this association is very rare. The clinical, histological and immunological features are different in SLE/AAV overlap syndrome and need different treatment options, which may include rituximab, to achieve complete recovery. Since SLE/AAV overlap can be serious at presentation, the physician must be aware of this syndrome.