What is the difference between IgA nephropathy and Henoch-Schönlein purpura nephritis?

Navigating the microbial maze: unraveling the connection between gut microbiome and pediatric kidney and urinary tract disease

The gut microbiome is made up of trillions of bacteria, viruses, archaea, and microbes that play a significant role in the maintenance of normal physiology in humans. Recent research has highlighted the effects of the microbiome and its dysbiosis in the pathogenesis and maintenance of kidney disease, especially chronic kidney disease (CKD) and its associated cardiovascular disease. While studies have addressed the kidney-microbiome axis in adults, how dysbiosis may uniquely impact pediatric kidney disease patients is not well-established. This narrative review highlights all relevant studies focusing on the microbiome and pediatric kidney disease that were published between 7/2015 and 7/2023. This review highlights pediatric-specific considerations including growth and bone health as well as emphasizing the need for increased pediatric research. Understanding microbiome-kidney interactions may allow for novel, less invasive interventions such as dietary changes and the use of probiotics to improve preventive care and ameliorate long-term morbidity and mortality in this vulnerable population.

Characterization of glomerular basement membrane components within pediatric glomerular diseases

Background

Disruptions in gene expression associated with the glomerular basement membrane (GBM) could precipitate glomerular dysfunction. Nevertheless, a comprehensive understanding of the characterization of GBM components within pediatric glomerular diseases and their potential association with glomerular function necessitates further systematic investigation.

Methods

We conducted a systematic analysis focusing on the pathological transformations and molecular attributes of key constituents within the GBM, specifically Collagen IV α3α4α5, Laminin α5β2γ1, and Integrin α3β1, across prevalent pediatric glomerular diseases.

Results

We observed upregulation of linear expression levels of COL4A3/4/5 and Laminin 5α proteins, along with a partial reduction in the linear structural expression of Podocin in idiopathic nephrotic syndrome (INS), encompassing minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS), but showing a reduction in IgA nephropathy (IgAN), IgA vasculitis nephritis (IgAVN) and lupus nephritis (LN). Furthermore, our study revealed reductions in Laminin β2γ1 and Integrin α3β1 in both primary and secondary childhood glomerular diseases.

Conclusion

In INS, notably MCD and FSGS, there is a notable increase in the linear expression levels of COL4A3/4/5 and Laminin 5α proteins. In contrast, in IgAN, IgAVN, and LN, there is a consistent reduction in the expression of these markers. Furthermore, the persistent reduction of Laminin β2γ1 and Integrin α3β1 in both primary and secondary childhood glomerular diseases suggests a shared characteristic of structural alterations within the GBM across these conditions.

Immunoglobulin A vasculitis nephritis: Current understanding of pathogenesis and treatment

The clinical spectrum of immunoglobulin A vasculitis nephritis (IgAVN) ranges from the relatively common transitory microscopic hematuria and/or low-grade proteinuria to nephritic or nephrotic syndrome, rapidly progressive glomerulonephritis, or even renal failure. Clinical and experimental studies have shown a multifactor pathogenesis: Infection triggers, impaired glycosylation of IgA1, complement activation, Toll-like-receptor activation and B cell proliferation. This knowledge can identify IgAVN patients at a greater risk for adverse outcome and increase the evidence for treatment recommendations.

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.

Acute Kidney Injury and Diffuse Pulmonary Hemorrhage Secondary to IgA Nephropathy and Henoch-Schönlein Purpura: A Case Report

IgA nephropathy (IgAN), characterized as immune complex-mediated glomerulonephritis, can occasionally manifest alongside the pulmonary-renal syndrome. Henoch-Schönlein purpura (HSP), an inflammatory condition affecting small vessels through leukocytoclastic vasculitis, exhibits a close association with IgA nephropathy. Nonetheless, HSP's infrequent complications encompass pulmonary hemorrhage. Notably, the onset of pulmonary hemorrhage can rapidly precipitate a grave decline in the patient's health status, carrying a potentially fatal outcome for both disorders. Moreover, the existing literature regarding this specific complication and its management, particularly among adults, remains relatively limited. We report a rare case of a 43-year-old male with acute renal failure secondary to IgA nephropathy associated with HSP, whose condition was further complicated by pulmonary hemorrhage. He was treated with extensive plasmapheresis, pulse steroids, rituximab, and cyclophosphamide, which led to the successful recovery of his kidney function. Recognizing the potential of various presentations can significantly contribute to early diagnosis and prompt treatment, potentially leading to an improved prognosis for these patients.

Successful treatment of nephrotic syndrome due to pregnancy-related crescentic IgA nephropathy: a case report

BACKGROUND

Crescentic immunoglobulin A (IgA) nephropathy, defined as > 50% of the glomeruli with crescents, often has a poor renal prognosis. Because of the high prevalence of pre-eclampsia in the second trimester of pregnancy, we often fail to investigate the new onset of glomerulonephritis and the aggravation of subclinical nephropathies. We report a case of nephrotic syndrome suggestive of crescentic IgA nephropathy possibly triggered by pregnancy.

CASE PRESENTATION

A 33-year-old multipara was referred for persistent proteinuria, hematuria, and hypoalbuminemia two months postpartum. The patient was diagnosed with proteinuria for the first time at 36 weeks of gestation. The patient was normotensive during pregnancy. Renal biopsy revealed crescentic IgA nephropathy, with cellular crescents in 80% of the glomeruli and no global sclerosis. After treatment with pulse steroids followed by high-dose oral glucocorticoids and tonsillectomy, a gradual improvement was seen in proteinuria, hematuria, and hypoalbuminemia.

CONCLUSION

Although the precise mechanism remains unclear, pregnancy possibly triggered the new onset of crescentic IgA nephropathy or the aggravation of subclinical IgA nephropathy.

Efficacy and Safety of Plasma Exchange as an Adjunctive Therapy for Rapidly Progressive IgA Nephropathy and Henoch-Schönlein Purpura Nephritis: A Systematic Review

Patients with IgA nephropathy (IgAN), including Henoch-Schönlein purpura nephritis (HSP), who present with rapidly progressive glomerulonephritis (RPGN) have a poor prognosis despite aggressive immunosuppressive therapy. The utility of plasmapheresis/plasma exchange (PLEX) for IgAN/HSP is not well established. This systematic review aims to assess the efficacy of PLEX for IgAN and HSP patients with RPGN. A literature search was conducted using MEDLINE, EMBASE, and through Cochrane Database from inception through September 2022. Studies that reported outcomes of PLEX in IgAN or HSP patients with RPGN were enrolled. The protocol for this systematic review is registered with PROSPERO (no. CRD42022356411). The researchers systematically reviewed 38 articles (29 case reports and 9 case series articles) with a total of 102 RPGN patients (64 (62.8%) had IgAN and 38 (37.2%) had HSP). The mean age was 25 years and 69% were males. There was no specific PLEX regimen utilized in these studies, but most patients received at least 3 PLEX sessions that were titrated based on the patient's response/kidney recovery. The number of PLEX sessions ranged from 3 to 18, and patients additionally received steroids and immunosuppressive treatment (61.6% of patients received cyclophosphamide). Follow-up time ranged from 1 to 120 months, with the majority being followed for at least 2 months after PLEX. Among IgAN patients treated with PLEX, 42.1% (n = 27/64) achieved remission; 20.3% (n = 13/64) achieved complete remission (CR) and 18.7% (n = 12/64) partial remission (PR). 60.9% (n = 39/64) progressed to end-stage kidney disease (ESKD). Among HSP patients treated with PLEX, 76.3% (n = 29/38) achieved remission; of these, 68.4% (n = 26/38) achieved CR and 7.8% achieved (n = 3/38) PR. 23.6% (n = 9/38) progressed to ESKD. Among kidney transplant patients, 20% (n = 1/5) achieved remission and 80% (n = 4/5) progressed to ESKD. Adjunctive plasmapheresis/plasma exchange with immunosuppressive therapy showed benefits in some HSP patients with RPGN and possible benefits in IgAN patients with RPGN. Future prospective, multi-center, randomized clinical studies are needed to corroborate this systematic review's findings.

Bullous Henoch-Schönlein Purpura and Associated Nephritis: A Pathological Case Report

Henoch-Schönlein purpura (HSP) is the most common vasculitis in childhood, presenting with purpura, predominantly of the lower extremities and occasionally with renal involvement as well. Although associated with childhood, HSP, although rarely, can also develop in adults as well. Here we present a patient in his sixties, presenting with a myriad of rash units on his lower extremities, including bullous ones, and a constellation of chronic kidney failure. Skin and renal biopsy specimens revealed morphological changes and immune depositions representative of HSP. Despite treatment, the patient's kidney failure slowly progressed, and he expired eight months after his presentation due to associated complications. Although rare, the bullous form of HSP can be viewed as a more aggressive form of the disease, as seen by the presentation constellation and rapid progression in our case.

Clinical relevance of glomerular C4d deposition in children with early IgA nephropathy or Henoch-Schönlein purpura nephropathy

BACKGROUND

Both IgA nephropathy (IgAN) and Henoch-Schönlein purpura nephropathy (HSPN) are characterized by glomerular mesangial IgA deposition. Several large studies on adults have suggested that glomerular C4d deposition has prognostic value in IgAN. However, there are few relevant studies on the clinical value of C4d deposition in children with IgAN or HSPN.

METHODS

We performed a retrospective cohort study in pediatric patients with IgAN or HSPN. Clinicopathological data were collected at the time of kidney biopsy. Kidney C4d deposition was analyzed by immunohistochemistry. The end point was defined as a ≥ 20% decrease in estimated glomerular filtration from baseline.

RESULTS

We enrolled 75 children, including 36 children with IgAN and 39 with HSPN. The prevalence of C4d deposition was 36% (27/75). C4d deposition was more abundant in children with proteinuria ≥ 50 mg/kg/day (51.9% versus 20.8%, P = 0.006) or nephrotic syndrome (37.0% versus 10.4%, P = 0.006). Mesangial hypercellularity (hazard ratio [HR], 5.745, 95% confidence interval [CI], 1.670-19.761, P = 0.006) and IgM deposition (HR, 4.522, 95% CI, 1.321-15.478, P = 0.016) were associated with C4d deposition. After a median follow-up of 22 months, seven (19.4%) IgAN patients and one (2.6%) HSPN patient had decreased kidney function. In children with IgAN, positive C4d was associated with decreased kidney function (P = 0.047).

CONCLUSION

Glomerular C4d deposition was associated with mesangial hypercellularity and glomerular IgM deposition in IgAN and HSPN. Glomerular C4d deposition may be a risk factor for eGFR decline in children with IgAN. A higher resolution version of the Graphical abstract is available as Supplementary information.

Diagnostic and Management Strategies of IgA Vasculitis Nephritis/Henoch-Schönlein Purpura Nephritis in Pediatric Patients: Current Perspectives

IgA vasculitis (IgAV) or Henoch-Schönlein purpura (HSP) is the most common vasculitis in children, and nephritis (IgAVN or HSPN) is the most important and only chronic manifestation of the disease. Despite this, there are no diagnostic criteria and we rely on the European League Against Rheumatism/Paediatric Rheumatology International Trials Organization/Paediatric Rheumatology European Society-endorsed Ankara 2008 classification criteria in our daily practice. Basic investigations that should be done in every patient with IgAVN include blood pressure measurement, estimated glomerular filtration rate and urinalysis. Kidney biopsy is still the gold standard for the diagnosis of IgAVN since noninvasive confirmation of nephritis is still pending. According to the Single Hub and Access point for pediatric Rheumatology in Europe (SHARE) recommendations, the first-line treatment for with mild forms of IgAVN is oral glucocorticoids, for patients with moderate IgAVN parenterally administrated glucocorticoids in pulsed doses, while initial treatment for patients with the most severe forms of IgAVN include pulsed doses of glucocorticoids in combination with intravenous cyclophosphamide pulses. New therapeutic options are currently being tested, aiming to reduce the production of galactose-deficient IgA₁ and autoantibodies or suppress the alternative or lectin complement pathway and blocking mesangial cell activation.

IgA Nephropathy: Pleiotropic impact of Epstein-Barr virus infection on immunopathogenesis and racial incidence of the disease

IgA nephropathy (IgAN) is an autoimmune disease in which poorly galactosylated IgA1 is the antigen recognized by naturally occurring anti-glycan antibodies, leading to formation of nephritogenic circulating immune complexes. Incidence of IgAN displays geographical and racial disparity: common in Europe, North America, Australia, and east Asia, uncommon in African Americans, many Asian and South American countries, Australian Aborigines, and rare in central Africa. In analyses of sera and cells from White IgAN patients, healthy controls, and African Americans, IgAN patients exhibited substantial enrichment for IgA-expressing B cells infected with Epstein-Barr virus (EBV), leading to enhanced production of poorly galactosylated IgA1. Disparities in incidence of IgAN may reflect a previously disregarded difference in the maturation of the IgA system as related to the timing of EBV infection. Compared with populations with higher incidences of IgAN, African Americans, African Blacks, and Australian Aborigines are more frequently infected with EBV during the first 1-2 years of life at the time of naturally occurring IgA deficiency when IgA cells are less numerous than in late childhood or adolescence. Therefore, in very young children EBV enters "non-IgA" cells. Ensuing immune responses prevent infection of IgA B cells during later exposure to EBV at older ages. Our data implicate EBV-infected cells as the source of poorly galactosylated IgA1 in circulating immune complexes and glomerular deposits in patients with IgAN. Thus, temporal differences in EBV primo-infection as related to naturally delayed maturation of the IgA system may contribute to geographic and racial variations in incidence of IgAN.

Clinicopathological Spectrum of Henoch-Schönlein Purpura Vasculitis: An Experience from a Tertiary Care Center

Henoch-Schönlein purpura (HSP) is a small vessel vasculitis with multiorgan involvement. Renal involvement is the key factor predicting morbidity. We have aimed to analyze the clinicopathological spectrum of HSP vasculitis and HSP nephritis to assess the risk factors associated with kidney involvement. This retrospective study was performed in the department of pathology with collaboration of department of dermatology and department of nephrology of a tertiary care center. All clinical details along with biopsy findings were retrieved. Starting materials of the study were cases of leukocytoclastic vasculitis with only perivascular IgA deposit of more than ++ in the absence of other immunoglobulin and trace complements. To investigate the possible factors that are influential on the development of biopsy-proven HSP nephritis, we divided the whole study population in two groups -group 1: with and group 2: without biopsy-proven nephritis. One-way analysis of variance was carried out during comparative analysis between two groups using IBM SPSS statistics software, version 19 and MedCalc software, version 12.3.0.0. HSP vasculitis comprised 11.6% (n = 19) of total cutaneous vasculitis in 2 years (164 cases) with a mean age of 13.52 ± 8.10 (range: 4-33 years). Three cases developed de novo kidney disease (15.79%). A correlation analysis revealed that predictors were seasonal variation (P = 0.018), severe gastrointestinal involvement (P = 0.03), and subcutaneous edema (P = 0.005). Various clinical and laboratory parameters were associated with renal consequences. Occult nephritis was the most common presentation with crescent as a constant histopathological feature.

Biologics for immunoglobulin A vasculitis: targeting vasculitis or comorbid disease?

In this study, we aimed to evaluate the clinical features and treatments, including the use of biological disease-modifying anti-rheumatic drugs (bDMARDs) in a large cohort of pediatric and adult immunoglobulin A vasculitis (IgAV). Since data on the use of bDMARDs in IgAV are very limited, we collated the reasons for use of bDMARDs during the disease course. Patients who were enrolled in the Hacettepe University Vasculitis Research Centre (HUVAC) registry were included. In this prospective database dating from 2014, there were 436 IgAV patients classified as IgAV according to Ankara 2008 and/or American College of Rheumatology 1990 criteria. 88 adults and 330 pediatric IgAV patients were included as the main study group. Concomitant spondyloarthritis (SpA) was observed only in adult patients (10% vs 0% in children, p < 0.001). IgAV relapse was more common in adults than in children (p: 0.017). Adult patients were mostly treated with corticosteroid (p < 0.001) and conventional synthetic disease-modifying anti-rheumatic drug treatment (< 0.001), while more than half of the pediatric patients were followed up without immunosuppressive treatment. Ten (11%) adult patients used biologics. Among them, two patients used rituximab due to IgAV disease activity, three used infliximab due to SpA, three used etanercept due to SpA (one patient had a pediatric onset enthesitis-related arthritis), and two used anakinra due to recurrent familial Mediterranean fever attacks. This is the first study evaluating the use of all bDMARDs for any reason in the IgAV cohorts in the literature. None of the pediatric patients used biologics. Our data suggest biologics are mainly used for comorbid inflammatory diseases over refractory vasculitis in adult IgAV.

Neutrophil-to-lymphocyte ratio as an independent inflammatory indicator for poor renal prognosis in adult IgA vasculitis with nephritis

BACKGROUND

Skin-limited IgAV patients usually present self-limiting disease and good prognosis, while adult IgA vasculitis with nephritis (IgAV-N) present severe phenotype and poor prognosis. Previous studies showed that neutrophil-to-lymphocyte ratio (NLR) was an inflammatory indicator for predicting systemic involvement in children IgAV patients. In this study, we focused on adult IgAV-N patients to explore the relationship of NLR with disease phenotype and long-term renal prognosis.

METHODS

In this study, 245 IgAV-N patients, 1151 IgAN patients and 251 healthy controls were recruited. Composite endpoint was defined as 30% eGFR declined or end stage kidney disease.

RESULTS

IgAV-N patients presented increased white blood cells (WBC), neutrophils (NE), platelet-to-lymphocyte ratio (PLR), and NLR levels, while decreased lymphocyte (LY) than healthy controls. When compared to clinical and pathological features matched IgAN patients, IgAV-N patients still showed higher WBC, NE, and NLR levels. NLR showed the best performance for the diagnosis of IgAV-N with the highest area under the ROC curves (0.738). IgAV-N patients in high NLR group (>2.41) presented with sever baseline manifestations and more acute pathological lesions than low NLR group (≤2.41). 77 patients with regular follow-up were used for survival analysis. After adjusting some well-known risk factors, NLR levels remained as an independent risk factor for poor renal outcome in adult patients with IgAV-N (HR, 1.913; 95% CI, 1.314 to 2.787, P = 0.001).

CONCLUSIONS

NLR levels were associated with the clinical and pathological phenotypes, and NLR may serve as an independent risk factor for poor renal outcome in adult IgAV-N patients.

Efficacy and Safety of Tacrolimus in the Treatment of Pediatric Henoch-Schönlein Purpura Nephritis

BACKGROUND

Children with severe Henoch-Schönlein purpura nephritis (HSPN) may progress to end-stage renal disease without appropriate treatment.

OBJECTIVE

This study aimed to investigate the efficacy and safety of tacrolimus combined with glucocorticoids in the treatment of pediatric HSPN.

METHODS

A total of 87 HSPN patients with urinary protein ≥ 0.75 g/24 h received standard of care, including angiotensin II receptor blockers/angiotensin-converting enzyme inhibitors and glucocorticoids. Patients were divided into three groups and additionally received tacrolimus (n = 30), cyclophosphamide (n = 31), or mycophenolate mofetil (MMF) (n = 26). We monitored outcome measures, including proteinuria, hematuria, and renal function and analyzed the efficacy and side effects in each group.

RESULTS

At 2-month follow-up, the overall efficacy was 93.3%, 83.9%, and 61.5% for tacrolimus, cyclophosphamide, and MMF, respectively (P < 0.05). Urinary protein significantly decreased for all groups. Urinary red blood cell counts significantly decreased for patients treated with tacrolimus (P < 0.001) and cyclophosphamide (P < 0.05), whereas no significant decrease was seen for those receiving MMF (P = 0.09). Although urine β2-microglobulin significantly decreased following 2 months of treatment with all medications, efficacy was greater with tacrolimus than with cyclophosphamide and MMF (P < 0.001). Major adverse events were respiratory and urinary infections, with MMF having the highest infection rate. The cyclophosphamide group also experienced additional adverse events, including arrhythmia, hemorrhagic cystitis, leukocytosis, thrombocytopenia, and hyperglycemia.

CONCLUSIONS

These results indicate that tacrolimus is more effective at reducing proteinuria and hematuria and improving renal function, with relatively milder side effects, in the treatment of pediatric HSPN.

CLINICAL TRIAL REGISTRATION NUMBER

ChiCTR2200055323, retrospectively registered on January 7, 2022.

Serum immunoglobulin profiles in Chinese children with Henoch-Schönlein purpura

OBJECTIVE

The present study focuses on the associations of serum immunoglobulin with disease activity, relapse/recurrence and renal involvement in Henoch-Schönlein purpura (HSP) children.

METHODS

1683 Chinese children with HSP were recruited from January 2015 to January 2021. Laboratory data of blood samples and urine tests were collected. Renal biopsy was performed by the percutaneous technique. Patients' histories associated with HSP onset were obtained by interviews and questionnaires.

RESULTS

(1) IgA and IgE were dramatically elevated in HSP patients as compared with their normal values, and subject to a 1.75-3.09 fold and a 1.97-2.61 fold increase, respectively. (2) No significant correlation of the disease activity with IgA and IgE was determined, respectively. (3) The serum IgA levels were significantly lower in patients with relapse/recurrence than that in patients without relapse/recurrence, which may be attributed to the transmission of IgA-mediated immune complexes from blood to vessel walls. (4) No significant correlation was found between serum IgA, IgE levels and the pathological classification.

CONCLUSIONS

HSP children have marked disorders of serum immunoglobulin profiles, characterized by significant increases in IgA and IgE. The detection of serum IgA may be applicable to predict relapse/recurrence of HSP, whereas not associated with disease activity and renal involvement.

Management of IgA Nephropathy in Pediatric Patients

The onset of IgA nephritis in childhood and adolescence often develops into chronic glomerulonephritis with declining renal function. Although these long-term consequences are known, there is still a lack of evidence-based treatment recommendations in this age group. We report data from 22 pediatric patients who were biopsied to confirm the diagnosis of IgAN at our clinical center. 14 of them were treated with corticosteroids according to the recommendations for IgA nephritis vasculitis of the German Society of Pediatric Nephrology (GPN). Improvement was achieved in the majority of all cases, with a significant reduction in proteinuria five months after initiation of therapy. Our data suggest that treatment regimens for acute IgA nephritis and IgA vasculitis nephritis may be unified and are discussed in the context of current studies.

Urinary Protein Array Analysis to Identify Key Inflammatory Markers in Children with IgA Vasculitis Nephritis

Chronic kidney disease is a recognised complication of immunoglobulin A vasculitis, (IgAV; formerly Henoch–Schonlein purpura—HSP). The pathophysiology of IgAV and why some patients develop significant renal involvement remains largely unknown. Identifying urinary inflammatory markers could direct targets for earlier intervention. The aim of this cross-sectional exploratory study was to perform a large protein array analysis to identify urinary markers to provide insight into the mechanisms of kidney inflammation in children with established IgAV nephritis (IgAVN). Determination of the relative levels of 124 key proteins was performed using commercially available proteome profiler array kits. Twelve children were recruited: IgAVN, n = 4; IgAV without nephritis (IgAVwoN), n = 4; healthy controls (HCs), n = 4. The urinary concentrations of twenty proteins were significantly different in IgAVN compared to IgAVwoN. The largest fold changes were reported for B-cell activating factor (BAFF), Cripto-1, sex-hormone-binding globulin and angiotensinogen. The urinary levels of complement components C5/C5a and factor D were also significantly elevated in patients with IgAVN. A total of 69 urinary proteins significantly raised levels in comparisons made between IgAVN vs. HCs and nine proteins in IgAVwoN vs. HCs, respectively. This study identified key urinary proteins potentially involved in IgAVN providing new insight into the pathophysiology. Further longitudinal studies with larger cohorts are needed to quantitatively analyse these biomarkers.

IgA vasculitis with nephritis: update of pathogenesis with clinical implications

IgA vasculitis with nephritis (IgAVN) shares many pathogenetic features with IgA nephropathy (IgAN). The purpose of this review is to describe our current understanding of the pathogenesis of pediatric IgAVN, particularly as it relates to the four-hit hypothesis for IgAN. These individual steps, i.e., hits, in the pathogenesis of IgAN are (1) elevated production of IgA1 glycoforms with some O-glycans deficient in galactose (galactose-deficient IgA1; Gd-IgA1), (2) generation of circulating IgG autoantibodies specific for Gd-IgA1, (3) formation of pathogenic circulating Gd-IgA1-containing immune complexes, and (4) kidney deposition of the Gd-IgA1-IgG immune complexes from the circulation and induction of glomerular injury. Evidence supporting the four-hit hypothesis in the pathogenesis of pediatric IgAVN is detailed. The genetics, pediatric outcomes, and kidney histopathologic features and the impact of these findings on future treatment and potential biomarkers are discussed. In summary, the evidence points to the critical roles of Gd-IgA1-IgG immune complexes and complement activation in the pathogenesis of IgAVN. Future studies are needed to characterize the features of the immune and autoimmune responses that enable progression of IgA vasculitis to IgAVN.

Adult-Onset Immunoglobulin A Vasculitis With Renal Involvement

A 50-year-old male presented with worsening bilateral lower extremities swelling for a month, associated with a purpuric rash over bilateral upper and lower extremities, joint pain over bilateral hands and ankles, and intermittent generalized abdominal pain. Physical examination was notable for pitting edema in bilateral lower extremities and palpable, non-blanching purpuric rashes and crusts, joint tenderness over bilateral hands/wrists/ankles, and mild generalized abdominal tenderness. Laboratory tests were remarkable for sub-nephrotic range proteinuria and microscopic hematuria. The skin biopsy revealed leukocytoclastic vasculitis. Renal biopsy showed mild mesangial expansion and immunoglobulin A (IgA)-dominant mesangial deposits. The patient was diagnosed with IgA vasculitis (IgAV) nephritis (IgAVN) and was subsequently treated with oral prednisone 80 mg daily for seven days followed by slow tapering doses, oral lisinopril 2.5 mg daily, and oral furosemide 40 mg daily. At the one-month follow-up as an outpatient, his skin rash and lower extremity swelling had resolved along with an improvement of proteinuria.

[Update on immunoglobulin A vasculitis]

Die Immunglobulin-A-Vaskulitis (IgAV) ist eine systemische Vaskulitis der kleinen Gefäße mit Ig(Immunglobulin)A-Immunkomplexbildung und einem breiten Spektrum klinischer Konstellationen. Typische Manifestationen sind Purpura, Arthralgien oder Arthritiden, Enteritis und Glomerulonephritis. Die IgAV ist die häufigste Vaskulitis im Kindesalter mit meist unkompliziertem und selbstlimitierendem Verlauf. Erwachsene erkranken deutlich seltener an einer IgAV, wobei die Verläufe insbesondere bei renaler oder gastrointestinaler Manifestation komplizierter sind. Verschiedene Trigger der IgAV, darunter Infektionen, wurden beschrieben, wobei eine gestörte Glykosylierung von IgA1 mit konsekutiver Freilegung von Bindungsstellen für Autoantikörper die pathophysiologische Voraussetzung für die Vaskulitis ist. Therapeutische Strategien mit Immunsuppressiva sind bisher mit geringer Evidenz unterlegt, berücksichtigen die Schwere der Organmanifestationen und orientieren sich an den Empfehlungen zur Behandlung anderer Vaskulitiden der kleinen Gefäße. Benigne Verläufe werden symptomatisch behandelt. Die langfristige Prognose der IgAV ist von der renalen Manifestation beeinflusst.

The Usefulness of Vanin-1 and Periostin as Markers of an Active Autoimmune Process or Renal Fibrosis in Children with IgA Nephropathy and IgA Vasculitis with Nephritis-A Pilot Study

This study aimed to evaluate the usefulness of vanin-1 and periostin in urine as markers of the autoimmune process in kidneys and renal fibrosis in IgA nephropathy (IgAN) and IgA vasculitis with nephritis (IgAVN). From a group of 194 patients from the Department of Pediatrics and Nephrology, who were included in the Polish Pediatric Registry of IgAN and IgAVN, we qualified 51 patients (20 with IgAN and 31 with IgAVN) between the ages of 3 and 17, diagnosed based on kidney biopsy, for inclusion in the study. All of the patients received glucocorticosteroids, immunosuppressive drugs, or renoprotective therapy. The control group consisted of 18 healthy individuals. The concentration of vanin was significantly higher in the IgAN and IgAVN groups than in the control group. The concentration of vanin/creatinine correlates positively with the level of IgA and negatively with the serum level of C3 at the end of the observation. Urinary vanin-1 concentration may be useful as a marker of the active autoimmune process in IgAN and IgAVN in children, but the study needs confirmation on a larger group of children, along with evaluation of the dynamics of this marker. Urinary periostin is not a good marker for children with IgAN and IgAVN, especially in stage 1 and 2 CKD.

New Insights and Challenges Associated With IgA Vasculitis and IgA Vasculitis With Nephritis-Is It Time to Change the Paradigm of the Most Common Systemic Vasculitis in Childhood?

What are the challenges ahead and how have we responded so far when it comes to the non-granulomatous systemic vasculitis, characterized mainly by deposits of IgA immune complexes in the endothelium of small blood vessels-IgA vasculitis (IgAV)? That is the question to which we tried to answer. We summarized existing knowledge about epidemiology, pathogenesis, genetics, diagnostic tests and therapy in this somewhat neglected entity in pediatric rheumatology. Since etiopathogenesis of IgA vasculitis is complex, with factors other than galactose-deficient IgA₁-containing immune complexes also being important, and may involve numerous interactions between environmental and genetic factors, genomics alone cannot explain the entirety of the risk for the disease. The incidence of IgAV and nephritis varies worldwide and may be a consequence of overlapping genetic and environmental factors. In addition to the role of the HLA class II genes, some studies have pointed to the importance of non-HLA genes, and modern geostatistical research has also indicated a geospatial risk distribution, which may suggest the strong influence of different environmental factors such as climate, pathogen load, and dietary factors. The application of modern geostatistical methods until recently was completely unknown in the study of this disease, but thanks to the latest results it has been shown that they can help us a lot in understanding epidemiology and serve as a guide in generating new hypotheses considering possible environmental risk factors and identification of potential genetic or epigenetic diversity. There is increasing evidence that an integrative approach should be included in the understanding of IgA vasculitis, in terms of the integration of genomics, proteomics, transcriptomics, and epigenetics. This approach could result in the discovery of new pathways important for finding biomarkers that could stratify patients according to the risk of complications, without an invasive kidney biopsy which is still the gold standard to confirm a diagnosis of nephritis, even if biopsy findings interpretation is not uniform in clinical practice. Ultimately, this will allow the development of new therapeutic approaches, especially important in the treatment of nephritis, for which there is still no standardized treatment.

Pathogenesis of IgA Vasculitis: An Up-To-Date Review

Immunoglobin A (IgA) vasculitis (IgAV), formerly called the Henoch-Schönlein purpura (HSP), is a small vessel vasculitis, characterized by IgA1-dominant immune deposition at diseased vessel walls. IgAV is the most common form of vasculitis in children; typical symptoms include palpable purpura, arthritis or arthralgia, abdominal pain, and hematuria or proteinuria. Galactose-deficient IgA1 is detected in the tissues of the kidney and skin in patients with IgAV; it forms immune complexes leading to subsequent immune reactions and injuries. This report provides the recent advances in the understanding of environmental factors, genetics, abnormal innate and acquired immunity, and the role of galactose-deficient IgA1 immunocomplexes in the pathogenesis of IgAV.

Comparison of clinical, pathological and long-term renal outcomes of children with Henoch-Schonlein purpura nephritis and IgA nephropathy

PURPOSE

To compare clinical, pathological, and long-term renal outcomes of children with Henoch-Schonlein purpura nephritis (HSPN) and IgA nephropathy (IgAN).

METHODS

The medical records of patients diagnosed as HSPN and IgAN during childhood were evaluated retrospectively. HSPN and IgAN groups were compared in terms of gender, age, upper respiratory infection history, blood pressure; presence of nephrotic and/or nephritic syndrome; hemoglobin level, leukocyte count, C-reactive protein (CRP), serum albumin (sAlb), creatinine, complement 3 (sC3), complement 4 (sC4) and immunoglobulin A (sIgA) levels; estimated glomerular filtration rate (eGFR) and proteinuria levels; and renal pathology findings at the onset of disease; total follow-up time; and blood pressure, eGFR and proteinuria levels at the last visit.

RESULTS

Fifty-four patients were enrolled in the study [38 (70%) HSPN and 16 (30%) IgAN]. The median follow-up time was 60.5 and 72.0 months in HSPN and IgAN groups, respectively (p > 0.05). The HSPN and IgAN groups were also not different in terms of gender, age at the onset; leukocyte count, eGFR, sC3-sC4-sIgA levels; and the presence of endocapillary, extracapillary and mesangial proliferation, tubular atrophy, interstitial fibrosis and IgA, IgM, C3 accumulation in renal tissue. Upper respiratory tract infection history was more common in children with IgAN (8/16 vs 8/38, p = 0.045). sAlb (3.96 ± 0.58 vs 4.40 ± 0.46 g/dL, p = 0.005), hemoglobin (12.1 ± 1.3 vs 13.3 ± 1.2 g/dL, p = 0.004,) and the incidence of mesangial IgG deposition (15/38 vs 11/16, p = 0.049) were lower, while CRP (16.3 ± 7.2 vs 7.8 ± 4.4 mg/L, p = 0.002) and proteinuria (72.1 ± 92.4 vs 34.2 ± 37.9 mg/m²/24 h, p = 0.041) was higher in HSPN group at the onset of disease. Proteinuria and eGFR were similar between the two groups at last visit.

CONCLUSION

Children with HSPN and IgAN have little clinical and histological differences in our population. The most prominent difference at presentation with nephritis was higher proteinuria in HSPN probably associated with inflammation due to systemic vasculitis. Long-term renal outcome was good in both HSPN and IgAN.

Reactivation of IgA vasculitis following COVID-19 vaccination

A 23-year-old man presented to the acute assessment unit with acute-onset haematuria within 24 hours of receiving his second dose of the Pfizer-BioNTech COVID-19 vaccine. He had been diagnosed with IgA vasculitis 8 months previously. IgA vasculitis is an autoimmune condition characterised by palpable purpura affecting the lower limbs, abdominal pain, arthralgia and renal disease. He was diagnosed with an acute exacerbation of IgA vasculitis and was discharged with oral prednisolone. Reactivation or first presentation of IgA vasculitis is a rare but increasingly recognised complication of COVID-19 vaccination. This is an important new differential in the assessment of patients with haematuria following COVID-19 vaccination.

Imbalanced Th17/Treg in peripheral blood of adult patients with immunoglobulin A vasculitis nephritis

Introduction

Adult immunoglobulin A vasculitis nephritis (IgAVN) was observed to be more severe than the disease in children because it tended to result in a poor prognosis. The present study analyzed the Th17/Treg cell axis in peripheral blood of adult IgAVN patients, aiming to provide new immunological viewpoints for the pathogenesis of adult IgAVN.

Material and methods

Th17 cell and Treg cell frequencies in peripheral blood of healthy subjects (n = 13) and adult IgAVN patients (n = 12) were analyzed by flow cytometry. Foxp3 mRNA in peripheral blood of healthy subjects and adult IgAVN patients was detected by RT-PCR. Interleukin (IL)-17 and IL-10 in peripheral blood serum of healthy subjects and adult IgAVN patients were examined by ELISA.

Results

The percentages of CD4⁺ Th17⁺ cells in peripheral blood of healthy subjects and adult IgAVN patients were 2.65 ±1.55% and 4.37 ±1.68% respectively. The percentages of Treg cells in peripheral blood of healthy subjects and adult IgAVN patients were 6.44 ±2.90% and 3.91 ±1.94% respectively. The ratio of Th17/Treg in adult IgAVN patients was significantly higher than that of healthy subjects (p = 0.0030). Meanwhile, the Foxp3 mRNA expression of adult IgAVN patients was significantly lower than that of healthy subjects. There was a significant difference in the ratio of IL-17/IL-10 between healthy subjects and adult IgAVN patients (p < 0.0001). A significant correlation between red blood cell distribution width (RDW) and the ratio of Th17/Treg in adult IgAVN patients was observed in Spearman correlation analysis (r = 0.6970, p = 0.0145).

Conclusions

Imbalanced Th17/Treg contributed to the complex pathogenesis of adult IgAVN.

KM55 in the Evaluation of IgA-Containing Glomerular Diseases

Introduction

Mucosal-derived galactose-deficient IgA is central to the pathogenesis of primary IgA nephropathy (IgAN). Recent reports suggest similar pathogenesis in Henoch-Schonlein purpura (HSP) and secondary IgAN. Its role in other IgA-containing glomerular diseases is still under investigation. It can be detected in glomeruli with the recently described antibody KM55. We aimed to evaluate the role of KM55 by immunostaining a wide spectrum of IgA-containing glomerular diseases.

Methods

After standardization and colocalization in a case of IgAN, a spectrum of 60 cases including IgAN, HSP, chronic liver disease (CLD)-related IgAN, other secondary IgAN, IgA-dominant/codominant membranoproliferative glomerulonephritis (MPGN), and lupus nephritis were subjected to immunofluorescence with KM55. KM55 was used to resolve diagnostic dilemma in cases of IgA deposition with confounding histology.

Results

The group of primary IgAN (17 cases), HSP (4 cases), and secondary IgAN (19 cases) including CLD showed 2-3+ granular staining with KM55, suggesting mucosal-derived IgA. In contrast, cases of IgA-dominant/codominant MPGN (8 cases) and lupus nephritis (12 cases) were negative for KM55, suggesting systemic derivation of IgA. In cases of IgA deposition with confounding histology such as membranoproliferative or diffuse endocapillary proliferative pattern, KM55 helped to resolve the diagnosis.

Discussion/Conclusion

This cross-sectional study concludes that KM55 is useful in the evaluation of IgA-containing glomerular diseases from a pathogenetic perspective and is a practical tool in resolving differential diagnosis in cases with overlapping histopathological features.

IgA Vasculitis with Nephritis in Adults: Histological and Clinical Assessment

Patients with IgA vasculitis (IgAV), an immune complex-mediated disease, may exhibit kidney involvement-IgAV with nephritis (IgAVN). The kidney-biopsy histopathologic features of IgAVN are similar to those of IgA nephropathy, but little is known about histopathologic disease severity based on the interval between purpura onset and diagnostic kidney biopsy. We assessed kidney histopathology and clinical and laboratory data in a cohort of adult patients with IgAVN (n = 110). The cases were grouped based on the interval between the onset of purpura and kidney biopsy: Group 1 (G1, <1 month, n = 14), Group 2 (G2, 1-6 months, n = 58), and Group 3 (G3, >6 months, n = 38). Glomerular leukocytes were more common in G1 than in the other groups (p = 0.0008). The proportion of neutrophils among peripheral-blood leukocytes was the highest in the patients biopsied within a month after onset of purpura (G1: 71 ± 8%). In the patients with an interval >6 months, the neutrophil proportion was lower, 60%. Moreover, the glomerular mesangial proliferation score correlated with the serum total IgA concentration (p = 0.0056). In conclusion, IgAVN patients biopsied <1 month from purpura onset showed an elevated percentage of blood neutrophils and glomerular leukocytes, consistent with an acute-onset inflammatory reaction. In all IgAVN patients, the mesangial proliferation score correlated with the serum IgA level.

Relationship between Gd-IgA1 and TNFR1 in IgA nephropathy and IgA vasculitis nephritis in children - multicenter study

AIM OF THE STUDY

To evaluate the relationship between serum Gd-IgA1 (sGd-IgA1) and serum and urine TNFR1 (sTNFR1, uTNFR1) levels as possible prognostic factors in IgA nephropathy (IgAN) and IgA vasculitis nephritis (IgAVN).

MATERIAL AND METHODS

From 299 patients from the Polish Registry of Pediatric IgAN and IgAVN, 60 children (24 IgAN and 36 IgAVN) were included in the study. The control group consisted of 20 healthy children. Proteinuria, haematuria, serum creatinine as well as IgA and C3 levels were measured and glomerular filtration rate (GFR) was calculated at onset and at the end of the follow-up. Kidney biopsy findings were evaluated using the Oxford classification. Serum Gd-IgA1 and serum and urine TNFR1 levels were measured at the end of follow-up.

RESULTS

Serum Gd-IgA1 level was significantly higher in IgAN and IgAVN patients in comparison to the control group. Urine TNFR1 was significantly higher in IgAN than in IgAVN and the control group. We did not observe any differences in sTNFR1 level between IgAN, IgAVN and control groups. We found a positive correlation between Gd-IgA1 and creatinine (r = 0.34), and negative between Gd-IgA1 and GFR (r = -0.35) at the end of follow-up. We observed a negative correlation between uTNFR1/creatinine log and albumin level and protein/creatinine ratio. We did not find any correlations between Gd-IgA1 and TNFR1.

CONCLUSIONS

The prognostic value of sGd-IgA1 in children with IgAN and IgAVN has been confirmed. TNFR1 is not associated with Gd-IgA1 and is not a useful prognostic marker in children with IgAN/IgAVN and normal kidney function.

IgA vasculitis

IgA vasculitis (IgAV) is an inflammation of small vessels caused by perivascular deposition of IgA and activation of neutrophils. It may present as systemic vasculitis (IgAV - Henoch-Schönlein purpura) or as a variant restricted to the skin (skin-limited IgAV), while IgA nephropathy presents a variant restricted to the kidneys. Systemic IgAV affects children more frequently than adults (150 to 200 for 1; incidence 1 in 1 million/year). In the latter, disease more often leads to chronic renal disease. The dominant clinical features include round or oval and retiform palpable purpura predominantly on the lower legs, arthralgia or arthritis, gastrointestinal bleeding or pain and glomerulonephritis with mesangial IgA deposits (IgAVN). Pulmonary, cardiac, genital and neurological involvement occurs, but is rare. Immune complexes containing galactose-deficient IgA1 play a pivotal role in the pathophysiology of IgAV; via the Fc alpha receptor (CD89), they induce neutrophilic inflammation around cutaneous vessels and mesangial proliferation and inflammation in the glomerulus. In case of self-limited disease, only symptomatic treatment is recommended. Treatment of severe IgAV, nephritis or gastrointestinal manifestations, is not established, but some studies reported a benefit of corticosteroids, combined with immunosuppressive drugs. Short-term outcome depends on the severity of gastrointestinal manifestations, while long-term prognosis depends on the severity of nephritis.

Predictability of the Oxford classification of IgA nephropathy in Henoch-Schonlein purpura nephritis

BACKGROUND

Whether the Oxford classification of immunoglobulin A nephropathy can be utilized to predict the adverse renal outcome of Henoch-Schonlein purpura nephritis (HSPN) has been long-debated. We, therefore, performed a meta-analysis to evaluate the prognostic value of Oxford classification lesions in HSPN.

METHODS

We systematically searched Medline, EMBASE, Web of Science, and the Cochrane Library for articles published from January 1970 to August 2020. Cohort and case-control studies investigating the correlation between the Oxford classification and renal outcome were included, the quality of which was assessed by the Newcastle-Ottawa scale criteria. The pooled odds ratios (ORs) with their 95% confidence intervals (CIs) were calculated with a random-effects model or a fixed-effects model depending on the heterogeneity.

RESULTS

A total of 485 papers were reviewed and eventually 9 comparisons were included, providing data of 1688 patients with HSPN. ORs for adverse renal events were 2.83 (95% CI 1.84-4.35; P < 0.001), 1.96 (95% CI 1.28-2.98; P < 0.05), and 5.45 (95% CI, 3.15-9.45; P < 0.001) for patients with lesions of endocapillary hypercellularity (E), segmental sclerosis (S), and tubular atrophy /interstitial fibrosis (T), respectively, without significant heterogeneity (E: I² = 0.0%; P = 0.498; S: I² = 22.4%; P = 0.258; T: I² = 33.6%; P = 0.171). Subgroup analysis adjusted for age also supported the results that E, S, and T lesions could serve as poor predictors (P < 0.05). Additionally, crescents (C) were strongly associated with renal outcome (OR 2.22; 95% CI 1.62-3.04; P < 0.001), with moderate heterogeneity (I² = 49.3%; P = 0.066). However, it should be noted that it is not the presence but the proportions of crescent lesions that were related to the high risk of progression to adverse renal events, because the predictability of lower rates of crescent (C1, with crescents > 0 and ≤ 25%) was uncertain (OR 2.21; 95% CI 0.75-6.51; P > 0.05). Although the pooled OR revealed that lesions of mesangial hypercellularity (M) were correlated with poor renal prognosis (OR 2.41; 95% CI 1.07-5.43; P < 0.05), subgroup analysis separating children from adults indicated that there seemed to be no significant difference.

CONCLUSIONS

Oxford classification, especially for E, S, T, and C, might be recommended for patients with HSPN, regardless of children and adults.

Deposition of the Membrane Attack Complex in Healthy and Diseased Human Kidneys

The membrane attack complex-also known as C5b-9-is the end-product of the classical, lectin, and alternative complement pathways. It is thought to play an important role in the pathogenesis of various kidney diseases by causing cellular injury and tissue inflammation, resulting in sclerosis and fibrosis. These deleterious effects are, consequently, targeted in the development of novel therapies that inhibit the formation of C5b-9, such as eculizumab. To clarify how C5b-9 contributes to kidney disease and to predict which patients benefit from such therapy, knowledge on deposition of C5b-9 in the kidney is essential. Because immunohistochemical staining of C5b-9 has not been routinely conducted and never been compared across studies, we provide a review of studies on deposition of C5b-9 in healthy and diseased human kidneys. We describe techniques to stain deposits and compare the occurrence of deposits in healthy kidneys and in a wide spectrum of kidney diseases, including hypertensive nephropathy, diabetic nephropathy, membranous nephropathy, IgA nephropathy, lupus nephritis, C3 glomerulopathy, and thrombotic microangiopathies such as the atypical hemolytic uremic syndrome, vasculitis, interstitial nephritis, acute tubular necrosis, kidney tumors, and rejection of kidney transplants. We summarize how these deposits are related with other histological lesions and clinical characteristics. We evaluate the prognostic relevance of these deposits in the light of possible treatment with complement inhibitors.

Using MEST-C Scores and the International Study of Kidney Disease in Children Classification to Predict Outcomes of Henoch-Schönlein Purpura Nephritis in Children

Introduction: Henoch-Schönlein purpura nephritis (HSPN) and IgA nephropathy (IgAN) bear similarities in some aspects. The histological classification of HSPN was built on the International Study of Kidney Disease in Children (ISKDC) criteria, while IgAN was established on the 2016 Oxford classification (MEST-C scores). The purpose of this paper was to discuss the predictive value of the ISKDC classification and MEST-C scores in children with HSPN. Methods: We performed a retrospective study of 877 children with HSPN in a single center between 2001 and 2019. The primary outcome was defined as chronic kidney disease-estimated glomerular filtration rate (eGFR) <90 ml/min/1.73 m². Results: During the follow-up period of 23.3 (10.9-47.9) months, 51 (5.8%) patients reached the primary outcome. As revealed in a Kaplan-Meier plot, segmental glomerulosclerosis (S) (P < 0.001) and tubular atrophy/interstitial fibrosis (T) (P < 0.001) significantly predict poor renal outcome. Other Oxford lesions and the ISKDC classification, however, did not show a significant difference in a worse outcome. In a multivariate Cox model adjusted for pathological and clinical factors, eGFR [hazard ratio (HR) = 2.831, 95% confidence interval (95% CI) = 1.359-5.896], S lesion (HR = 3.936, 95% CI = 2.078-7.457), and T lesion (HR = 4.002, 95% CI = 1.733-9.242) were independent risk factors for the renal outcome. Conclusion: This series constitutes the largest series reported so far in the literature of such patients. According to our findings, S and T of the Oxford classification, which are ignored by the ISKDC classification, could be applied to predict the renal prognosis of children with HSPN.

Henoch-Schönlein purpura in a patient with oesophageal cancer: A case report

RATIONALE

Understanding the association between Henoch-Schönlein purpura (HSP) and malignancy is essential for early diagnosis and treatment of the potential lethal disease. To the best of our knowledge, there has been only one published case of HSP coexisting with oesophageal cancer. Here, we report another patient diagnosed with HSP and oesophageal squamous carcinoma simultaneously.

PATIENT CONCERNS

A 60-year-old Chinese male was referred to our hospital because of intermittent abdominal pain, abdominal distension, melena, lower extremities purpura. Positive laboratory values included pancytopenia, microscopic hematuria, nephrotic proteinuria, hematochezia, hypoalbuminemia, hyperlipidaemia, hypocomplementemia, and increased levels of hepatobiliary enzymes and immunoglobulin (Ig) A. Gastrocolonoscopy showed multiple erosion lesion on descending duodenum, terminal ileum, and ileal flap. Biopsy of these lesions suggested non-specific inflammation.

DIAGNOSES

HSP (IIIb type) was diagnosed based on renal pathology examination in accordance with the International Study of Kidney Disease in Children (ISKDC) classification. Liver biopsy confirmed the diagnosis of nodular cirrhosis (Ishak 5). Gastroscopy unintentionally revealed three oesophagus lesions. Pathology study suggested intermediate differentiated squamous cell carcinoma (cTNM IB).

INTERVENTIONS

Before admission, he was administered intravenous Ig 10 g once daily(qd) for 10 days, methylprednisolone 40 mg qd for a week, followed by prednisolone 50 mg qd for almost 8 weeks. Endoscopic submucosal dissection (ESD) was performed to remove all lesions with negative margin after prednisolone was tapered (5 mg per week until 10 mg qd).

OUTCOMES

Despite prednisone being tapered to 2.5 mg qd within 2 months, complete remission of HSP and esophageal malignancy was achieved after the resection of the esophagus lesions during 12 months follow-up.

LESSONS

We report a rare case of oesophageal squamous cell carcinoma initially presented as HSP. This case suggests the importance of evaluating adult patients with HSP for an underlying malignancy.

IgA Vasculitis Nephritis: A Case Series and Comparison of Treatment Guidelines

Immunoglobulin A (IgA) vasculitis nephritis (IgAVN) and IgA nephropathy (IgAN) share many pathological parallels and are viewed as related diseases by many groups. Current treatment guidelines remain vague, controversial, and without consensus, especially regarding the role of immunosuppressive medications. We present five cases of IgAVN encountered at our tertiary care center between 2016 and 2020, which were treated with different immunosuppression regimens. Infection was the leading cause of death in this series. These cases provide evidence that IgAVN should be distinguished from IgAN on a spectrum of IgA-associated glomerulonephritis. The outcomes presented herein suggest that the morbidity and systematic involvement IgAVN is greater than previously believed and that these substantial risks should be reflected in contemporary treatment guidelines.

Predictive biomarkers of IgA vasculitis with nephritis by metabolomic analysis

BACKGROUND

IgA vasculitis (IgAV) is the most common vasculitis of childhood. Renal involvement defines late morbidity of the disease. A better understanding of the pathophysiology of the progression to kidney disease and predictive biomarkers are required for better management of IgAV and its nephritis (IgAVN).

OBJECTIVES

An untargeted metabolomics approach was performed to reveal the underlying molecular mechanism of disease pathogenesis and to define potential biomarkers from plasma samples from IgAV and IgAVN patients.

METHODS

Forty-five active IgAV patients (H) and six healthy controls (C) were enrolled in the study. Plasma samples were collected on the same day of diagnosis and before any immunosuppressive treatment was initiated. At the time of diagnosis and sample collection, none of the patients had renal involvement. We used Quadrupole Time of Flight Mass Spectrometry (Q-TOF LC/MS) to investigate the alterations in plasma metabolomic profiles. Three separate pools were created: healthy controls (group C), active IgAV patients who did not develop renal involvement (group H), and patients who developed IgAVN at follow up (group N). Peak picking, grouping, and comparison parts were performed via XCMS (https://xcmsonline.scripps.edu/) software.

RESULTS

At follow-up, IgAVN developed in 6 out of 45 IgAV patients. The median time of renal involvement development is 23 days (range 5-45 days). Of these, 3 had nephritic proteinuria, one had nephrotic proteinuria, and 2 had microscopic hematuria. There were no significant differences in gender, age, clinical manifestations, and laboratory findings between the six patients who developed renal involvement and those who did not. In multivariate analysis, there was no significant association between any of the defined demographic and clinical characteristics (male sex, gastrointestinal system involvement, joint involvement, CRP, WBC, PLT) and the occurrence of renal involvement. Totally 2618 peaks were detected for group H, N, and C. Among them, 355 peaks were found to be statistically significant and reliable (p<0.05), and 155 of these peaks were found to be changed (fold change >1.5) between the groups C and H, and 66 peaks were found to be changed (fold change >1.5) between the groups H and N. The number of the peaks on the intersection of the peaks found to be different between the groups (C and H) and (H and N) was 39. Based on putative identification results, 15 putatively identified metabolites matched with 11 peaks were presented as biomarker candidates after careful evaluation with a clinical perspective.

CONCLUSION

We suggest that DHAP (18:0), prostaglandin D2/I2, porphobilinogen, 5-methyltetrahydrofolic acid, and N-Acetyl-4-O-acetylneuraminic acid/N-Acetyl-7-O-acetylneuraminic acid may serve as biomarkers for predicting kidney disease. Future studies with larger groups of IgAV patients are needed to validate the identified metabolic profile.

Serum levels of galactose-deficient IgA1 in Chinese children with IgA nephropathy, IgA vasculitis with nephritis, and IgA vasculitis

OBJECTIVE

IgA nephropathy (IgAN) and IgA vasculitis with nephritis (IgAV-N) are related diseases. Galactose-deficient IgA1 (Gd-IgA1) plays an important role in the pathology of IgAV-N and IgAN, so we aim to compare the serum levels of Gd-IgA1 in Chinese pediatric patients with IgAN, IgAV-N, and IgAV.

METHODS

We retrospectively enrolled 52 patients with IgAN, 57 patients with IgAV-N, 26 patients with IgAV, and 40 healthy children. The serum levels of Gd-IgA1 were measured at the time of biopsy using a lectin-based ELISA method.

RESULTS

Gd-IgA1 levels in IgAV-N patients and IgAN patients were higher than in healthy controls (303.94 ± 39.37 U/ml, 314.91 ± 47.79 U/ml vs. 273.57 ± 48.29 U/ml, P < 0.001), and Gd-IgA1 levels in IgAV-N patients were higher than in IgAV patients (303.94 ± 39/ml vs. 286. 21 ± 38.81 U/ml, P = 0.059), but the latter result is not statistically significant. The Gd-IgA1 levels in IgAV patients were comparable with those in healthy controls (286.21 ± 38.81 U/ml vs. 273.57 ± 48.29 U/ml, P = 0.267). Among the four groups, we did not observe significant correlations of Gd-IgA1 levels with eGFR, proteinuria, or the MEST-C score.

CONCLUSION

Serum Gd-IgA1 maybe involved in the pathogenesis of the IgAV-N and IgAN. However, we found no statistically significant correlation between Gd-IgA1 levels and clinical and pathological features.

Use of liquid chromatography-tandem mass spectrometry to perform urinary proteomic analysis of children with IgA nephropathy and Henoch-Schönlein purpura nephritis

The emerging technology of urinary proteomics has become an efficient biological approach for identifying biomarkers and characterizing pathogenesis in renal involvement. In this study, we attempted to elucidate the relationship between IgAN and HSPN in children, employing LC-MS/MS to perform urinary proteomic analyses using the DIA method. Early-morning spot urine was collected from patients with biopsy-proven IgAN (n = 19) and HSPN (n = 19) prior to treatment and renal biopsy in the Department of Pediatrics, Jinling Hospital, Nanjing, China, and did healthy volunteers (n = 14), from June 2018 to December 2019. Two hundred seventy-six urinary proteins and 125 urinary proteins were determined to be differentially expressed in children with IgAN (n = 4) and HSPN (n = 4), respectively, compared to the urinary proteins of healthy children (n = 4) (p < 0.05). GO analysis demonstrated that the differentially expressed proteins of the two groups, which were located in the extracellular matrix and cell membrane, were primarily involved in biological processes, including metabolic processes, immune system processes, cellular adhesion, cell proliferation, signaling, and biological regulation. KEGG analysis revealed that the differentially expressed proteins of the two groups were associated with cell adhesion molecules, ECM-receptor interactions, the PI3K-Akt signaling pathway, the complement and coagulation cascades, regulation of actin cytoskeleton, cholesterol metabolism, and platelet activation. The target proteins (alpha-1B-glycoprotein (A1BG) and afamin (AFM)), which participated in the complement and coagulation cascades and the regulation of complement activation, were further investigated in the independent validation cohort by ELISA. These proteins were significantly increased in children with IgAN (n = 15) and HSPN (n = 15) compared with the proteins observed in healthy controls (n = 10, P < 0.05). The validated results were consistent with the mass spectrometry results. SIGNIFICANCE: IgAN and HSPN both result from the glomerular deposition of abnormally glycosylated IgA1 with mesangial proliferative changes, and both diseases are common glomerulopathies in the pediatric population that are believed to be correlated. Interestingly, our data, by combining urinary proteomic analyses, showed that several uniform enrichment pathways played an important role in the progression of IgAN and HSPN, suggesting that we might reduce the renal involvement of the two diseases in children through these pathways. The same urinary proteins along these pathways were observed to be differentially expressed in children with IgAN and HSPN, implying that these proteins may be potential biomarkers to identify the two diseases. Future studies examining larger cohorts are warranted to confirm the validity of our findings.

IgA Vasculitis With Underlying Liver Cirrhosis: A French Nationwide Case Series of 20 Patients

OBJECTIVE

Immunoglobulin A vasculitis (IgAV) and nephropathy (IgAN) share common immunological mechanisms. Liver cirrhosis is well known to be associated with IgAN. Here, we aimed to describe the presentation and outcome of IgAV patients with underlying cirrhosis.

METHODS

We conducted a French nationwide retrospective study of adult patients presenting with both IgAV and cirrhosis. Baseline characteristics were compared to those of the 260 patients included in the French nationwide IgAV registry (IGAVAS).

RESULTS

Twenty patients were included, and 7 (35%) were female. The mean ± SD age was 62.7 ± 11 years. At baseline, compared with IGAVAS patients, patients with underlying cirrhosis were older (62.7 ± 11 vs 50.1 ± 18, P < 0.01) and displayed more constitutional symptoms (weight loss 25% vs 8%, P = 0.03). Patients with underlying cirrhosis were also more likely to exhibit elevated serum IgA levels (5.6 g/L vs 3.6 g/L, P = 0.02). Cirrhosis and IgAV were diagnosed simultaneously in 12 patients (60%). Cirrhosis was mainly related to alcohol intake (n = 15, 75%), followed by nonalcoholic steato-hepatitis (n = 2), chronic viral hepatitis (n = 1), hemochromatosis (n = 1), and autoimmune hepatitis (n = 1). During follow-up with a median of 17 months (IQR 12-84), 10/13 (77%) exhibited IgAV remission at Month 3. One patient presented a minor relapse. Six patients died, but no deaths were related to IgAV.

CONCLUSION

We report the first case series of IgAV patients with underlining cirrhosis, to our knowledge, which was mainly alcohol related. The liver disease did not seem to affect baseline vasculitis characteristics. Physicians should investigate the existence of liver cirrhosis at IgAV diagnosis, especially in the context of alcohol abuse.

Evaluation of the Oxford classification in immunoglobulin A vasculitis with nephritis: a cohort study and meta-analysis

Background

Similarities in clinicopathological presentations in immunoglobulin A (IgA) nephropathy and IgA vasculitis with nephritis (IgAVN) raise the question of the utility of the Oxford classification in the latter. The aim of this study was to evaluate the Oxford classification in IgAVN.

Methods

We conducted a retrospective cohort study and meta-analysis following systematic searching of the MEDLINE and Excerpta Medica Database (EMBASE) databases between January 2009 and September 2019. We modeled the association of 30 and 50% decline in estimated glomerular filtration rate or end-stage renal disease with pathologic lesions of the Oxford classification including mesangial hypercellularity (M), endocapillary hypercellularity (E), segmental glomerulosclerosis (S), interstitial fibrosis/tubular atrophy (T) and crescents (C). Results were pooled using random-effects meta-analysis.

Results

The cohort study included 132 patients, and only T lesion was an independently risk factor in IgAVN. The meta-analysis yielded six retrospective studies with 721 patients and 139 endpoints. In multivariate model, T lesion was significantly associated with renal outcome (hazard ratio = 2.45, P = 0.007). M and C lesions could not predict renal outcome without evidence of heterogeneity. E and S lesions could not predict renal outcome with evidence of heterogeneity (I ² = 66.6%; P = 0.01, and I ² = 65.8%; P = 0.03, respectively). Subgroup analysis showed that the possible reasons to the heterogeneity were from usage of immunosuppressant, sample size and follow-up time.

Conclusions

The study suggests that the Oxford classification could not be fully validated in IgAVN. Higher portion of immunosuppressant especially before renal biopsy might be the main confounder for the predictive value of Oxford classification in IgAVN.

A Rare Case of Helicobacter pylori Infection Complicated by Henoch-Schonlein Purpura in an Adult Patient

Henoch-Schonlein purpura (HSP) is known as a leukocytoclastic vasculitis of small vessels, resulting in skin, joint, gastrointestinal (GI) and renal involvement. It is the most common acute vasculitis in children but is relatively uncommon in adults. The pathogenesis of HSP remains unclear, but a wide variety of conditions such as bacterial or viral infections, vaccinations, drugs and other environmental exposures may be responsible for the onset. A few previous case reports have described an association between gastric Helicobacter pylori (HP) infection and HSP. A 30-year-old Indian man who migrated to the USA from India 3 years prior to this presentation with a past medical history of psoriasis on remission, not on any medications presented to the emergency department with sudden onset constant abdominal pain for 5 days. The pain was in the right upper quadrant, spasmodic in nature. The abdominal examination was normal. The patient was evaluated with complete blood count, comprehensive metabolic panel, urinalysis, computed tomography scan of abdomen and pelvis, and right upper quadrant ultrasound, all of which were negative except for leukocytosis. He was discharged on pantoprazole and tramadol. Pain continued despite treatment. Patient was readmitted 2 days later, when he noticed a new maculopapular rash on both legs. Upper GI endoscopy was done showing non-bleeding small gastric ulcer with multiple duodenal erosions. Gastric biopsy came back positive for HP and he was started on clarithromycin, amoxicillin and lansoprazole. Pain persisted after finishing antibiotic course. Rash continued to spread to involve the thighs, flanks, around the umbilicus and extensor surfaces of arms. Immunological workup was negative. A skin biopsy of the skin rash came back positive for leukocytoclastic vasculitis. HSP diagnosis was made by exclusion. Patient was started on prednisone 40 mg daily and improved drastically on the following day. He was continued steroids taper for 8 weeks. Rash as well as abdominal pain resolved completely. In conclusion, HSP involves the skin, GI tract, joints and kidneys. It is a pediatric disease and rarely occurs in adults. It can be associated with underlying malignancy in adults. HP infection can trigger HSP in pediatric and adult patients. Detection of the carrier state is crucial in HSP patients in areas where HP is endemic. Eradication of HP infection is usually associated with the resolution of HSP. In resistant cases with GI and renal involvement, corticosteroids use results in resolution of symptoms and reduction of the duration of mild nephritis.

IgA vasculitis and anti-GBM disease: two ends of a spectrum of immune complex vasculitis

Two immune complex vasculitides, IgA vasculitis (IgAV) and anti-GBM disease, represent polar extremes with regard to our understanding of disease pathogenesis, standardized management protocols and outcomes. This report compares our current approach to these uncommon entities in adults. Both diseases demonstrate degrees of small vessel necrosis and glomerular crescent formation. IgAV has an antibody response directed against unknown antigens, is often treated conservatively and has poorly studied long term renal outcomes. By contrast, anti-GBM disease presents with rapidly progressive glomerulonephritis and often results in end stage renal failure, despite intensive immunosuppression. Rarely, some cases of anti-GBM disease may be IgA predominant and bind other α-chains present in the GBM, but their clinical course is as for other anti-GBM disease patients but not IgAV, suggesting that the antigenic target rather than the antibody subclass is the critical factor in determining disease outcome. However, both conditions are associated with increased mortality in adults and result in significant chronic kidney disease and hypertension.

MEST-C pathological score and long-term outcomes of child and adult patients with Henoch-Schönlein purpura nephritis

BACKGROUND

Henoch-Schönlein purpura nephritis (HSPN), a small-vessel vasculitis, shares renal pathological features with immunoglobulin A nephropathy. Oxford classification of immunoglobulin A nephropathy pathology has been updated to the MEST-C score, but its application in HSPN remains unresolved.

METHODS

Two hundred and thirteen patients with biopsy-proven HSPN were retrieved from the Seoul National University Hospital between 2000 and 2017. Renal outcome risks (i.e., end-stage renal disease or doubling of serum creatinine) were evaluated according to MEST-C scores after stratification by age: 113 children aged < 18 years (9.2 ± 3.6 years) and 100 adults aged ≥18 years (38.6 ± 18.3 years). We pooled our data with four previous cohort studies in which MEST or MEST-C scores were described in detail.

RESULTS

Twenty-one child (19%) and 16 adult (16%) patients reached the renal outcome during the median follow-up periods of 12 years and 13 years, respectively (maximum 19 years). In children, M1 and T1/T2 scores revealed worse renal outcomes than did M0 and T0 scores, respectively, whereas the T score was the only factor related to worse outcomes in adult patients after adjusting for multiple clinical and laboratory variables. The pooled data showed that M1, S1, and T1/T2 in children and E1 and T1/T2 in adults were correlated with poorer renal outcomes than those of their counterpart scores.

CONCLUSIONS

The Oxford classification MEST-C scores can predict long-term renal outcomes in patients with HSPN.

Does MEST-C score predict outcomes in pediatric Henoch-Schönlein purpura nephritis?

BACKGROUND

Children with Henoch-Schönlein purpura nephritis (HSPN) have an increased risk of chronic kidney disease (CKD). Renal biopsy diagnostic of HSPN is graded using the International Study of Kidney Disease in Children criteria, which do not predict outcomes. The 2016 Oxford Classification's MEST-C scoring system predicts outcomes in adults with histologically identical IgA nephropathy, but evidence of its utility in pediatric HSPN is lacking. Our hypothesis was that MEST-C scores predict outcomes in children with HSPN.

METHODS

A retrospective cohort analysis of data from 32 children with HSPN who underwent renal biopsy was performed. We used logistic regression and receiver operator characteristic curves to analyze the ability of MEST-C to predict the composite outcome of hypertension (blood pressure ≥ 95% for age/sex/height), CKD (estimated glomerular filtration rate < 90 mL/min/1.73 m²), or proteinuria (urine protein-to-creatinine ratio > 0.2 mg/mg).

RESULTS

The median age at diagnosis was 7.9 years (IQR 5.8, 11.7); 56% were male, 19% were Hispanic, and 9% were Black. After a median follow-up of 2.7 years, 38% of patients (n = 12) reached the outcome. S1 score was significantly associated with the outcome (OR 7.9, 95% CI 1.5-42.6). S1 accurately predicted the outcome (area under the curve 0.72, 95% CI 0.55-0.88) with 58.3% sensitivity and 85.0% specificity, indicating a positive predictive value of 70.0% and a negative predictive value of 77.3%.

CONCLUSIONS

S1 accurately predicted our composite outcome of hypertension, CKD, and proteinuria in a diverse cohort of U.S. children with HSPN. Further investigation is warranted to validate these findings.

Bevacizumab-induced immunoglobulin A vasculitis with nephritis: A case report

RATIONALE

Bevacizumab-an inhibitor of vascular endothelial growth factor-is effective against various advanced cancers. However, it is associated with the development of hypertension and high-grade proteinuria during thrombotic microangiopathy of the kidney. In addition, there are several reports of immunoglobulin A deposition in the glomeruli, but the etiology is unclear.

PATIENT CONCERNS

A 67-year-old Japanese man with metastatic rectal cancer underwent low anterior rectal resection, followed by treatment with bevacizumab and SOX (S-1 plus oxaliplatin). Six months later, the patient developed hematuria, nephrotic syndrome, and purpura.

DIAGNOSES

Renal biopsy revealed endocapillary proliferative glomerulonephritis. Immunofluorescence analyses showed granular mesangial deposition of galactose-deficient immunoglobulin A1. Skin biopsy revealed leukocytoclastic vasculitis.

INTERVENTIONS

We ceased bevacizumab treatment, while continuing the remaining chemotherapy regimen, as we suspected bevacizumab-induced nephropathy.

OUTCOMES

Proteinuria and purpura improved immediately after cessation of bevacizumab. We identified this as a case of bevacizumab-induced immunoglobulin A vasculitis with nephritis.

LESSONS

To our knowledge, this is the first case of bevacizumab-related immunoglobulin A vasculitis with nephritis, as evidenced by galactose-deficient immunoglobulin A1. When a patient's urine tests are abnormal during bevacizumab treatment, clinicians should consider not only thrombotic microangiopathy but also vasculitis.

Early recognition and treatment of Henoch-Schönlein purpura in children

Henoch-Schönlein purpura (HSP) is characterised by a non-blanching rash, which commonly affects the lower limbs of children aged 3-15 years. It is the most common vasculitis in children. HSP often develops after an upper respiratory tract infection and is more likely to present in autumn, winter and spring. The majority of cases resolve with symptomatic treatment although some cases may progress to serious complications, including renal involvement. A case study is presented and differential diagnoses are explored. The pathophysiology of HSP is discussed. Nurses are often the first to assess patients so they are in an ideal position to recognise and treat HSP early on. Admission of a child into hospital is a stressful event for the parents and child; the nurse can help by ensuring prompt admission to hospital and offering support and reassurance to the family.