Pathogenesis of Henoch-Schönlein purpura nephritis

Recalcitrant intussusception: exploring potential associations with Helicobacter pylori infection - a case report and literature review

BACKGROUND

Intussusception, a common cause of abdominal pain in children, often lacks clear underlying causes and is mostly idiopathic. Recurrence, though rare, raises clinical concerns, with rates escalating after each episode. Factors like pathological lead points and Henoch-Schönlein purpura (HSP) are associated with recurrent cases. On the other hand, the prevalence of Helicobacter pylori (H. pylori), often asymptomatic, in children has been declining. Although its infection is reported to be linked with HSP, its role in recurrent intussusception remains unexplored. Further research is needed to understand the interplay among H. pylori (culprit pathogen), HSP (trigger), and intractable intussusception so as to develop effective management strategies.

CASE PRESENTATION

A two-year-old girl experienced four atypical episodes of intussusception at distinct locations, which later coincided with HSP. Despite treatment with steroids, recurrent intussusception persisted, suggesting that HSP itself was not a major cause for intractable presentations. Subsequent identification of H. pylori infection and treatment with triple therapy resulted in complete resolution of her recalcitrant intussusception.

CONCLUSION

This instructive case underscored a sequence wherein H. pylori infection triggered HSP, subsequently resulting in recurrent intussusception. While H. pylori infection is not common in young children, the coexistence of intractable intussusception and steroid-resistant recurrent HSP necessitates consideration of H. pylori infection as a potential underlying pathogen.

Erythrocyte Glutathione S-Transferase Activity as a Sensitive Marker of Kidney Function Impairment in Children with IgA Vasculitis

IgA vasculitis (IgAV) is the most common childhood vasculitis. The main cause of morbidity and mortality in children with IgAV is nephritis (IgAVN), but the risk of its development, severity, and chronicity remain unclear. Erythrocyte glutathione S-transferase (e-GST) activity has been previously detected as a sensitive marker of kidney function impairment in several diseases. We spectrophotometrically assessed and correlated e-GST activity between 55 IgAV patients without nephritis (IgAVwN), 42 IgAVN patients, and 52 healthy controls. At disease onset, e-GST activity was significantly higher in IgAVN patients (median (interquartile range)) (5.7 U/gHb (4.4-7.5)) than in IgAVwN patients (3.1 U/gHb (2.2-4.2); p < 0.001), and controls (3.1 U/gHb (1.9-4.2); p < 0.001). Therewithal, there were no differences between the IgAVwN patients and controls (p = 0.837). e-GST activity was also significantly higher in the IgAVN patients than in the IgAVwN patients after 3 months (5.0 U/gHb (4.2-6.2) vs. 3.3 U/gHb (2.3-4.1); p < 0.001) and 6 months (4.2 U/gHb (3.2-5.8) vs. 3.3 U/gHb (2.1-4.1); p < 0.001) since the disease onset. Consistent correlations between e-GST activity and serum creatinine, estimated glomerular filtration rate (eGFR), and proteinuria levels were not detected. In conclusion, increased e-GST activity can serve as a subtle indicator of kidney function impairment in children with IgAV.

A Review of IgA Vasculitis (Henoch-Schönlein Purpura) Past, Present, and Future

The clinical association of purpura, arthralgia, and arthritis was first described in 1837 in a publication by Johann Lukas Schönlein, a German physician. In 1874, Eduard Henoch, a student of Schönlein, reported cases of children with purpura, abdominal pain, bloody diarrhea, and joint pain. IgA vasculitis, or Henoch-Schönlein purpura, is a systemic hypersensitivity vasculitis caused by the deposition of immune complexes in small blood vessels, including the renal glomeruli and mesangium. In the skin, the presentation is with non-thrombocytopenic purpura or urticaria. Worldwide, IgA nephropathy is the most common cause of primary glomerulonephritis. Detection of IgA deposition in small blood vessels and the renal glomeruli is diagnostic in most cases. This article aims to review the history, current classification, epidemiology, presentation, and diagnosis of IgA vasculitis and nephropathy, disease associations or trigger factors, including infections, vaccines, and therapeutic agents, and highlights some future approaches to improve diagnosis and clinical management.

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.

Proanthocyanidins: A novel approach to Henoch‑Schonlein purpura through balancing immunity and arresting oxidative stress via TLR4/MyD88/NF‑κB signaling pathway (Review)

Henoch-Schonlein purpura (HSP), a recurrent and immunoglobulin (Ig)A-mediated vasculitis, presents not only as skin lesions but also as systemic involvement that can be life-threatening. Although the etiology of HSP remains unknown, immune imbalance and oxidative stress (OS) are primary contributors to its pathogenesis, alongside the abnormal activation of Toll-like receptor (TLR)/myeloid differentiation primary response gene 88 (MyD88)/nuclear factor-κB (NF-κB) pathway. TLRs, especially TLR4, stimulate downstream signaling molecules such as NF-κB and proinflammatory cytokines, which are released when TLRs combine with the key adapter molecule MyD88. This leads to the activation of T helper (Th) cell 2/Th17 and overproduction of reactive oxygen species (ROS). The function of regulatory T (Treg) cells is suppressed in the process. Th17/Treg imbalance then produces various inflammatory cytokines to promote proliferation and differentiation of B cells and the secretion of antibodies. IgA is secreted, and it binds to vascular endothelial surface receptors where the complex induces injury of the vascular endothelial cells. Additionally, excessive ROS creates OS that leads to an inflammatory response and vascular cell apoptosis or necrosis, thereby contributing to vascular endothelial damage and HSP occurrence. Proanthocyanidins are active compounds naturally enriched in fruits, vegetables and plants. Proanthocyanidins have diverse properties, including anti-inflammatory, antioxidant, antibacterial, immunoregulatory, anticarcinogenic and vascular protective effects. Proanthocyanidins are used in the management of various diseases. Proanthocyanidins regulate T cells, equilibrate immunity and arrest OS by inhibiting the TLR4/MyD88/NF-κB signaling pathway. Considering the pathogenesis of HSP and the properties of proanthocyanidins, the present study hypothesized that these compounds may potentially lead to HSP recovery through modulating the immune equilibrium and preventing OS by inhibiting the TLR4/MyD88/NF-κB pathway. To the best of our knowledge, however, little is known about the positive effects of proanthocyanidins against HSP. The present review summarizes the potential of proanthocyanidins to treat HSP.

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.

IgA Vasculitis Following COVID-19 Vaccination

As new variants of SARS-CoV-2 continue to emerge worldwide, countries are striving to fully vaccinate their population in a bid to prevent severe disease, subsequent hospitalizations, and the associated strain on their healthcare systems and death. In this context, there is growing evidence of rare, potential side effects associated with COVID-19 vaccines. IgA vasculitis is a systemic, IgA-mediated vasculitis characterized by palpable purpura, arthralgia, abdominal pain, and renal involvement. It is the most common type of vasculitis in childhood, sporadically affecting the adult population. However, there have been multiple reports of IgA vasculitis following vaccination against COVID-19. Herein, we present the case of a 72-year-old patient with palpable purpura that developed two weeks after receiving the Pfizer BioNTech vaccine. Laboratory investigations revealed elevated serum creatinine (2.6 mg/dL), macroalbuminuria (8.6 g/24 h), and macroscopic hematuria. Histopathological examination confirmed necrotizing vasculitis, and a diagnosis of IgA vasculitis was established. Considering the clinical presentation, the laboratory and histopathological findings, and the time interval between the vaccination and the development of symptoms, we strongly believe that IgA vasculitis in this patient arose as a side effect of the Pfizer BioNTech vaccine.

Identification of key genes and imbalance of immune cell infiltration in immunoglobulin A associated vasculitis nephritis by integrated bioinformatic analysis

Background

IgAV, the most common systemic vasculitis in childhood, is an immunoglobulin A-associated immune complex-mediated disease and its underlying molecular mechanisms are not fully understood. This study attempted to identify differentially expressed genes (DEGs) and find dysregulated immune cell types in IgAV to find the underlying pathogenesis for IgAVN.

Methods

GSE102114 datasets were obtained from the Gene Expression Omnibus (GEO) database to identify DEGs. Then, the protein-protein interaction (PPI) network of the DEGs was constructed using the STRING database. And key hub genes were identified by cytoHubba plug-in, performed functional enrichment analyses and followed by verification using PCR based on patient samples. Finally, the abundance of 24 immune cells were detected by Immune Cell Abundance Identifier (ImmuCellAI) to estimate the proportions and dysregulation of immune cell types within IgAVN.

Result

A total of 4200 DEGs were screened in IgAVN patients compared to Health Donor, including 2004 upregulated and 2196 downregulated genes. Of the top 10 hub genes from PPI network, STAT1, TLR4, PTEN, UBB, HSPA8, ATP5B, UBA52, and CDC42 were verified significantly upregulated in more patients. Enrichment analyses indicated that hub genes were primarily enriched in Toll-like receptor (TLR) signaling pathway, nucleotide oligomerization domain (NOD)-like receptor signaling pathway, and Th17 signaling pathways. Moreover, we found a diversity of immune cells in IgAVN, consisting mainly of T cells. Finally, this study suggests that the overdifferentiation of Th2 cells, Th17 cells and Tfh cells may be involved in the occurrence and development of IgAVN.

Conclusion

We screened out the key genes, pathways and maladjusted immune cells and associated with the pathogenesis of IgAVN. The unique characteristics of IgAV-infiltrating immune cell subsets were confirmed, providing new insights for future molecular targeted therapy and a direction for immunological research on IgAVN.

Bibliometric analysis of IgA vasculitis nephritis in children from 2000 to 2022

Background

IgA vasculitis Nephritis (IgAVN) is a kidney-damaging disease that occurs during the course of IgA vasculitis (IgAV) and is the most serious complication of IgAV. However, there is a lack of reports of bibliometric analysis of IgAVN in children. The purpose of this study is to conduct a bibliometric analysis of IgAVN in children from 2000 to 2022, to explore the current status and cutting-edge trends in the field of IgAVN in children, and to establish new directions for subsequent research.

Methods

Screening the literature in the field of IgAVN in children in the Web of Science Core Collection (WoSCC) from 2000 to 2022. Visual analysis of their annual publications, countries, institutions, authors, journals, keywords, and references were using CiteSpace5.8.R3 and VOSviewer1.6.18.

Results

A total of 623 publications were included in the study, since the beginning of 2014, there has been an overall increasing trend in the number of articles issued. The most prolific country and institution were China and Zhejiang University. The most frequently cited author was Coppo R, with 331 citations, who has made great contributions to IgAVN. Mao Jianhua, Lee JS and Wyatt Robert J were the most prolific authors, all with 9 articles. Pediatric Nephrology was the most published and cited journal. The highest burst strength keyword is IgA vasculitis, and the highest burst strength reference is Davin JC, 2014.

Conclusion

The research hotspots and trends predicted by the analysis of this study provide a reference for in-depth research in this field with a view to promoting the development of IgAVN research in children.

Mycophenolate Mofetil for Severe IgA Vasculitis Nephropathy in Children: An Observational Study

Rationale & Objective

Individuals with IgA vasculitis nephritis (IGAVN) may develop rapidly progressive glomerulonephritis and/or nephrotic-range proteinuria, which are associated with worse prognosis. We report our experience of treatment of children with IGAVN with nephrotic-range proteinuria.

Study Design

Case series.

Setting & Participants

We retrospectively analyzed all children who presented with IGAVN, cutaneous purpura, and nephrotic-range proteinuria from January 1, 2000 until December 31, 2018.

Outcome

We evaluated time required to achieve remission of proteinuria, resolution of hematuria, and glomerular filtration rate (GFR) at 12 months and last follow-up.

Results

Twelve patients, 8 boys and 4 girls, mean age 7.5 years (range 4-15) were included in the study. Mean urinary protein to creatinine ratio (UPC) was 12.5 ± 8.7 mg/mg and GFR 90.7 ± 19.1 mL/min/1.73 m² before initiation of immunosuppression. All patients were treated with steroids and mycophenolate mofetil. Mean UPC declined progressively from 12.5 mg/mg to 4.6, 2.7, 0.3, and 0.2 mg/mg after 1, 3, 6, and 12 months, respectively. All patients achieved remission of proteinuria (UPC <0.3 mg/mg) and normalization of kidney function (GFR 102.2 ± 8.0 mL/min/1.73 m²) at 12 months. Immunosuppression was successfully withdrawn in all patients, and at last follow-up (mean 33.5 months), all patients except one remained in remission. All patients except one that relapsed maintained normal GFR at the last follow-up.

Limitations

Retrospective study, single-center experience, no standard immunosuppressive protocol, lack of control group.

Conclusions

Remission can be achieved in patients with IGAVN and nephrotic-range proteinuria using mycophenolate mofetil-based immunosuppression. Magnitude of proteinuria is a key laboratory finding that correlates with time to achieve remission. Prolonged follow-up of patients with severe IGAVN is warranted.

Integrated analysis of immune- and apoptosis-related lncRNA-miRNA-mRNA regulatory network in children with Henoch Schönlein purpura nephritis

BACKGROUND

Long noncoding RNAs (lncRNAs) play important roles in the regulation of immunological and apoptotic function. This study aimed to explore the critical immune- and apoptosis-related lncRNAs in the occurrence and development of Henoch-Schönlein purpura nephritis (HSPN) in children.

METHODS

Differential analysis was employed to identify the differentially expressed lncRNAs, as well as the immune- and apoptosis-related mRNAs in children with HSPN. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were used to validate the immunological and apoptotic roles of the differentially expressed immune- and apoptosis-related lncRNAs and mRNAs. Spearman's correlation analysis was performed to analyze the differentially expressed lncRNAs and immune- and apoptosis-related messenger RNAs (mRNAs). Based on the competing endogenous RNA (ceRNA) mechanism, the immune- and apoptosis-related lncRNA-microRNA (miRNA)-mRNA regulatory network was then constructed in children with HSPN. The expression levels of the lncRNAs in the lncRNA-miRNA-mRNA regulatory network were further confirmed by quantitative real-time polymerase chain in the peripheral blood samples of children with HSPN.

RESULTS

By intersecting the differentially expressed immune-related and apoptosis-related genes through GO and KEGG analyses, a total of 43 genes were identified in children with HSPN, and 100 lncRNAs highly correlated with the above genes were identified by correlation analysis. The immune- and apoptosis-related lncRNA-miRNA-mRNA regulatory network was then established based on ceRNA mechanism. Dysregulation of a total of 11 lncRNAs were discovered, including upregulated SNHG3, LINC00152, TUG1, GAS5, FGD5-AS1, DLEU2, and SCARNA9; and downregulated SNHG1, NEAT1, DISC1-IT1, and PVT1. The validation conducted in the clinical samples also suggested that the above lncRNAs in the specific regulatory network may act as potential biomarkers with prognosis in children with HSPN.

CONCLUSIONS

LncRNAs may play essential regulatory roles in the occurrence and development of HSPN in children, and the immune- and apoptosis-related lncRNA-miRNA-mRNA regulatory network might be the underlying molecular mechanism that dissects the disease pathogenesis. In addition, the dysregulated lncRNAs in the regulatory network may be novel biomarkers for the diagnosis and therapy of HSPN in children.

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.

The pathogenesis of COVID-19-induced IgA nephropathy and IgA vasculitis: A systematic review

OBJECTIVE

IgA nephropathy (IgAN) and IgA vasculitis (IgAV) are part of a similar clinical spectrum. Both clinical conditions occur with the coronavirus disease 2019 (COVID-19). This review aims to recognize the novel association of IgAN and IgAV with COVID-19 and describe its underlying pathogenesis.

METHODS

We conducted a systematic literature search and data extraction from PubMed, Cochrane, ScienceDirect, and Google Scholar following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

Our search identified 13 cases reporting IgAV and IgAN associated with COVID-19 infection and 4 cases of IgAN following COVID-19 vaccination. The mean, mode, and median ages of patients were 23.8, 4, and 8 years, respectively. Most cases associated with COVID-19 infection were reported in males (77%). Rash and purpura (85%) were the most common clinical features, followed by gastrointestinal symptoms (62%). In symptomatic cases, skin or renal biopsy and immunofluorescence confirmed the diagnosis of IgAN or IgAV. Most patients were treated with steroids and reported recovery or improvement; however, death was reported in two patients.

CONCLUSION

There is a paucity of scientific evidence on the pathogenesis of the association of IgAN and IgAV with COVID-19, which thus needs further study. Current research suggests the role of IgA-mediated immune response, evidenced by early seroconversion to IgA in COVID-19 patients and the role of IgA in immune hyperactivation as the predominant mediator of the disease process. Clinicians, especially nephrologists and paediatricians, need to recognize this association, as this disease is usually self-limited and can lead to complete recovery if prompt diagnosis and treatment are provided.

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.

The Involvement of Neutrophil Extracellular Traps in Disease Activity Associated With IgA Vasculitis

Objectives

This aim of this study was to determine whether neutrophil extracellular traps (NETs) are involved in the pathogenesis of IgA vasculitis (IgAV) and investigate whether the circulating NETs levels are associated with disease activity in children.

Methods

We performed a case-control study and collected blood samples from 193 children with different stages of IgAV (61 were at the onset stage, 64 at the remission stage, 43 at the active stage, and 25 were undergoing drug withdrawal). A total of 192 healthy children were recruited as controls. Circulating cell free DNA (cf-DNA) was obtained from the plasma and quantified by using the Quant-iT PicoGreen DNA quantification kit. NETs-associated myeloperoxidase-DNA (MPO-DNA), citrullinated-histone H3 (cit-H3), neutrophil elastase (NE), and the deoxyribonuclease I (DNase I) concentrations were measured using enzyme-linked immunosorbent assays. The presence of NETs in the kidney and gastrointestinal tissues of onset and active IgAV patients was determined by multiple immunofluorescence staining in 15 IgAV nephritis patients and 9 IgAV patients without IgAV nephritis, respectively. NETs degradation potency of collected sera samples from IgAV patients were checked in vitro. Relationships between circulating levels of cf-DNA with MPO-DNA, NE, and DNase I and the patients were analyzed.

Results

Circulating levels of cf-DNA in onset and active IgAV patients were significantly higher than those in remission and drug withdrawal patients as well as healthy controls. The results were similar for MPO-DNA and NE. The levels of circulating cf-DNA correlated significantly with MPO-DNA, NE and DNase I. A significantly decreased degradation of NETs from the onset and active IgAV patients was observed, but was normal in healthy controls. Furthermore, presence of NETs was also confirmed in all renal and gastrointestinal tissues obtained from the onset and active IgAV patients but not control samples.

Conclusions

Our data showed that NETs were released into the circulation of IgAV patients and are involved in the disease activity. The circulating levels of NETs maybe used to assess disease severity in children with IgAV.

Management of IgA Vasculitis with Nephritis

Immunoglobulin A (IgA) vasculitis (IgAV), previously called Henoch-Schönlein purpura, is characterized by IgA-dominant immune deposits affecting small vessels and often involves the skin, gastrointestinal tract, joints, and kidneys. IgAV is the most common cause of systemic vasculitis in children. The long-term prognosis is dependent on renal involvement: IgAV with nephritis (IgAVN) can progress to renal failure. IgAVN is an inflammatory disease, providing a rationale for the use of corticosteroids. However, data supporting the use of corticosteroids in patients with established IgAVN of any severity remain limited, although most clinicians use them. Even in patients with severe forms of IgAVN, methylprednisolone pulses added to oral corticosteroids appears to improve renal outcomes. Considering the multihit hypothesis for the pathogenesis of IgAVN, involving many other immune agents, there is a strong rationale for the use of other immunosuppressive drugs in patients with IgAVN, including mycophenolic acid, cyclophosphamide, rituximab, calcineurin inhibitors, and complement inhibitors. Thus, these immunosuppressive treatments have also been evaluated in IgAVN, usually in corticosteroid-dependent or corticosteroid-resistant forms and in small retrospective studies. However, their efficacy has not been proven. Thus, the risk of progression to renal failure and the ongoing debate about the best management of IgAVN justifies the interest in investigating and identifying treatments that can potentially preserve renal function in patients with IgAVN. This review reports on the efficacy of the different drugs currently used for the treatment of IgAVN in adults and children.

Complement in Renal Disease as a Potential Contributor to Arterial Hypertension

OBJECTIVE

Complement deposition is prevalent in kidney biopsies of patients with arterial hypertension and hypertensive nephropathy, but an association of hypertension and complement deposition or involvement of complement in the pathogenesis of hypertensive nephropathy has not been shown to date.

METHODS

In this study, we analyzed complement C1q and C3c deposition in a rat model of overload and hypertension by subtotal nephrectomy (SNX) and in archival human renal biopsies from 217 patients with known hypertension and 91 control patients with no history of hypertension using semiquantitative scoring of C1q and C3c immunohistochemistry and correlation with parameters of renal function. To address whether complement was only passively deposited or actively expressed by renal cells, C1q and C3 mRNA expression were additionally analyzed.

RESULTS

Glomerular C1q and C3c complement deposition were significantly higher in kidneys of hypertensive SNX rats and hypertensive compared to nonhypertensive patients. Mean arterial blood pressure (BP) in SNX rats correlated well with the amount of glomerular C1q and C3c deposition and with left ventricular weight, as an indirect parameter of high BP. Quantitative mRNA analysis showed that C3 was not only deposited but also actively produced by glomerular cells of hypertensive SNX rats and in human renal biopsies. Of note, in patients CKD-stage correlated significantly with the intensity of glomerular C3c staining, but not with that of C1q.

CONCLUSION

Renal complement deposition correlated with experimental hypertension as well as the presence of hypertension in a variety of renal diseases. To answer the question, if and how exactly renal complement is causative for the pathogenesis of arterial hypertension in men, further studies are needed.

Penile involvement of immunoglobulin a vasculitis/Henoch-Schönlein purpura

BACKGROUND

Immunoglobulin A vasculitis/Henoch-Schönlein purpura (IgAV/HSP) is a leukocytoclasia vasculitis of childhood, predominantly affecting the skin, joints, gastrointestinal tract, and kidneys. The involvement of the penis is rare.

OBJECTIVE

We aimed to describe this rare manifestation of IgAV/HSP and to review the previous studies, including similar cases.

METHODS

Clinical data were reviewed for two children of penile involvement of IgAV/HSP in our hospital. More clinical cases were retrieved from the databases of PubMed/MEDLINE and Scopus from database inception to February 1, 2020.

RESULTS

We presented two boys aged three and five years both of whom had penile lesions after presenting with the typical rash of IgAV/HSP on lower extremities. The penile lesions improved entirely in a few days without treatment in one and with corticosteroid treatment in the other. The literature review revealed 12 articles describing 20 patients with penile involvement of IgAV/HSP. The penile findings were edema, erythema, ecchymosis, purpuric rash, edema, color change, stiffness of the shaft or prepuce, and tenderness. Penile lesions appeared before the purpuric rash of IgAV/HSP in three of 22 patients. The penile involvement could make the diagnosis challenging especially if the penile lesions appear before the typical rash of the disease. The lesions improved entirely in the short term in all patients; in five without treatment in fifteen after corticosteroid or immunosuppressive drug treatment.

CONCLUSIONS

It is important to raise awareness about this rare manifestation among health care providers. It is not clear whether corticosteroid treatment should be initiated for treatment since it seems as a self-limited feature. Treatment with corticosteroids could be considered in the treatment of selected cases especially with systemic involvement.

Immunoglobulin A Glycosylation and Its Role in Disease

Human IgA is comprised of two subclasses, IgA1 and IgA2. Monomeric IgA (mIgA), polymeric IgA (pIgA), and secretory IgA (SIgA) are the main molecular forms of IgA. The production of IgA rivals all other immunoglobulin isotypes. The large quantities of IgA reflect the fundamental roles it plays in immune defense, protecting vulnerable mucosal surfaces against invading pathogens. SIgA dominates mucosal surfaces, whereas IgA in circulation is predominately monomeric. All forms of IgA are glycosylated, and the glycans significantly influence its various roles, including antigen binding and the antibody effector functions, mediated by the Fab and Fc portions, respectively. In contrast to its protective role, the aberrant glycosylation of IgA1 has been implicated in the pathogenesis of autoimmune diseases, such as IgA nephropathy (IgAN) and IgA vasculitis with nephritis (IgAVN). Furthermore, detailed characterization of IgA glycosylation, including its diverse range of heterogeneity, is of emerging interest. We provide an overview of the glycosylation observed for each subclass and molecular form of IgA as well as the range of heterogeneity for each site of glycosylation. In many ways, the role of IgA glycosylation is in its early stages of being elucidated. This chapter provides an overview of the current knowledge and research directions.

Fine Particulate Matter (PM2.5) and Chronic Kidney Disease

The impact of ambient particulate matter (PM) on public health has become a great global concern, which is especially prominent in developing countries. For health purposes, PM is typically defined by size, with the smaller particles having more health impacts. Particles with a diameter <2.5 μm are called PM_2.5. Initial research studies have focused on the impact of PM_2.5 on respiratory and cardiovascular diseases; nevertheless, an increasing number of data suggested that PM_2.5 may affect every organ system in the human body, and the kidney is of no exception. The kidney is vulnerable to particulate matter because most environmental toxins are concentrated by the kidney during filtration. According to the high morbidity and mortality related to chronic kidney disease, it is necessary to determine the effect of PM_2.5 on kidney disease and its mechanism that needs to be identified. To understand the current status of PM_2.5 in the atmosphere and their potential harmful kidney effects in different regions of the world this review article was prepared based on peer-reviewed scientific papers, scientific reports, and database from government organizations published after the year 1998. In this review, we focus on the worldwide epidemiological evidence linking PM_2.5 with chronic kidney disease and the effect of PM_2.5 on the chronic kidney disease (CKD) progression. At the same time, we also discuss the possible mechanisms of PM_2.5 exposure leading to kidney damage, in order to emphasize the contribution of PM_2.5 to kidney damage. A global database on PM_2.5 and kidney disease should be developed to provide new ideas for the prevention and treatment of kidney disease.

Involvement of activated cytotoxic T lymphocytes and natural killer cells in Henoch-Schönlein purpura nephritis

Objectives

Immunoglobulin A vasculitis/Henoch–Schönlein purpura (IgAV/HSP) is a major cause of vasculitis in children. It is often accompanied by nephritis (HSPN) and could progress to chronic kidney disease. Galactose‐deficient IgA₁ was recently reported to be involved in the pathogenesis of HSPN, for which immunosuppressive drugs are considered key treatment. However, the involvement of immune cells in the development of HSPN remains unclear.

Methods

We compared gene expressions of peripheral blood mononuclear cells (PBMCs) among healthy controls (n = 10), IgAV/HSP patients (n = 21) and HSPN patients (n = 8), which required nephritis development within 3 months of IgAV/HSP onset. Immunohistochemistry analysis and flow cytometry were performed to assess renal biopsy specimens and PBMCs, respectively. Serum CX3CL1 levels were measured by ELISA.

Results

GNLY and GZMB expressions increased in HSPN patients, consistent with increased number of glomerular granulysin‐ and/or granzyme B‐positive cells demonstrated by immunohistochemistry analysis. Additionally, circulating cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells were activated with the up‐regulated surface expressions of human leucocyte antigen DR (HLA‐DR) and CX3CR1 in HSPN patients with severe proteinuria. Renal biopsies demonstrated increased number of CD8⁺ cells and/or CD56⁺ cells and up‐regulated expression of glomerular CX3CL1, a specific ligand for CX3CR1, along with increased serum CX3CL1 level.

Conclusion

Activated CTLs and NK cells play roles in the development of nephritis in IgAV/HSP patients and can be used as novel biomarkers for HSPN.

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.

Pathophysiology and therapy of systemic vasculitides

Systemic vasculitides represent uncommon conditions characterized by the inflammation of blood vessels that can lead to different complex disorders limited to one organ or potentially involving multiple organs and systems. Systemic vasculitides are classified according to the diameter of the vessel that they mainly affect (small, medium, large, or variable). The pathogenetic mechanisms of systemic vasculitides are still partly unknown, as well as their genetic basis. For most of the primary systemic vasculitides, a single gold standard test is not available, and diagnosis is often made after having ruled out other mimicking conditions. Current research has focused on new management protocol and therapeutic strategies aimed at improving long-term patient outcomes and avoiding progression to multiorgan failure with irreversible damage. In this narrative review, authors describe different forms of systemic vasculitides through a review of the literature, with the aim of highlighting the current knowledge and recent findings on etiopathogenesis, diagnosis and therapy.

A case of Henoch-Schönlein purpura associated with scrub typhus

BACKGROUND

Henoch-Schönlein purpura (HSP) may be caused by several allergens. However, to date, HSP caused by Orientia tsutsugamushi has not been reported. Here, we report an unusual rash with features of HSP caused by Orientia tsutsugamushi.

CASE PRESENTATION

A man visited a tertiary hospital with bilateral symmetrical purpura and fever. He presented with an eschar in the left popliteal fossa and proteinuria. He was diagnosed with tsutsugamushi disease by indirect fluorescent antibody and positive polymerase chain reaction tests. Purpura biopsy demonstrated a feature of leukocytoclastic vasculitis and IgA deposition in dermal vessels, indicative of HSP.

CONCLUSIONS

When examining patients with unique rashes, such as in this case, we suggest investigating out-door activities and evidence of mite bites. Furthermore, differential diagnosis of tsutsugamushi disease should be considered when necessary.

Analysis of O-glycoforms of the IgA1 hinge region by sequential deglycosylation

A common renal disease, immunoglobulin A (IgA) nephropathy (IgAN), is associated with glomerular deposition of IgA1-containing immune complexes. IgA1 hinge region (HR) has up to six clustered O-glycans consisting of Ser/Thr-linked N-acetylgalactosamine with β1,3-linked galactose and variable sialylation. IgA1 glycoforms with some galactose-deficient (Gd) HR O-glycans play a key role in IgAN pathogenesis. The clustered and variable O-glycans make the IgA1 glycomic analysis challenging and better approaches are needed. Here, we report a comprehensive analytical workflow for IgA1 HR O-glycoform analysis. We combined an automated quantitative analysis of the HR O-glycopeptide profiles with sequential deglycosylation to remove all but Gd O-glycans from the HR. The workflow was tested using serum IgA1 from healthy subjects. Twelve variants of glycopeptides corresponding to the HR with three to six O-glycans were detected; nine glycopeptides carried up to three Gd O-glycans. Sites with Gd O-glycans were unambiguously identified by electron-transfer/higher-energy collision dissociation tandem mass spectrometry. Extracted ion chromatograms of isomeric glycoforms enabled quantitative assignment of Gd sites. The most frequent Gd site was T²³⁶, followed by S²³⁰, T²³³, T²²⁸, and S²³². The new workflow for quantitative profiling of IgA1 HR O-glycoforms with site-specific resolution will enable identification of pathogenic IgA1 HR O-glycoforms in IgAN.

Off-label use of tacrolimus in children with glomerular disease: Effectiveness, safety and pharmacokinetics

Glomerular diseases are leading causes of end-stage renal disease in children. Tacrolimus is frequently used off-label in the treatment of glomerular diseases. The effectiveness, safety and pharmacokinetic data of tacrolimus in the treatment of glomerular diseases in children are reviewed in this paper to provide evidence to support its rational use in clinical practice. The remission rates in previously published studies were different. In 19 clinical trials on children with nephrotic syndrome, the overall remission rate was 52.6-97.6%. In four clinical trials on children with lupus nephritis, the overall remission rate was 81.8-89.5%. In a pilot study with paediatric Henoch-Schönlein purpura nephritis patients, the overall remission rate was 100.0%. Infection, nephrotoxicity, gastrointestinal symptoms and hypertension are the most common adverse events. Body weight, age, CYP3A5 genotype, cystatin-C and daily dose of tacrolimus may have significant effects on the pharmacokinetics of tacrolimus in children with glomerular disease. More prospective controlled trials with long follow-up are needed to demonstrate definitely the effectiveness, safety and pharmacokinetics of tacrolimus in children with glomerular diseases.

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.

Autoantibodies Specific for Galactose-Deficient IgA1 in IgA Vasculitis With Nephritis

Introduction

Patients with IgA nephropathy (IgAN) have elevated serum levels of galactose-deficient IgA1 (Gd-IgA1) that are bound by Gd-IgA1–specific autoantibodies in pathogenic immune complexes. Renal biopsy histopathologic features of IgA vasculitis (IgAV) with nephritis (IgAV-N) are similar to those of IgAN. Mucosal infections often are associated with clinical onset and exacerbation in both diseases. We investigated whether patients with IgAV-N share pathogenic characteristics of IgAN.

Methods

We generated IgA1- and IgG-secreting cell lines from Epstein-Barr virus (EBV)–immortalized cells of patients with IgAV without nephritis (IgAV-woN), IgAV-N, and IgAN and from healthy individuals. Sera and cell-culture supernatants were used for analysis of Gd-IgA1 and Gd-IgA1–specific IgG autoantibodies.

Results

IgA1-producing cells from patients with IgAV-N, like cells from patients with IgAN, secreted more Gd-IgA1 than did cells from patients with IgAV-woN or healthy control subjects, in agreement with elevated serum Gd-IgA1 levels in patients with IgAV-N and IgAN. IgA1-producing cells from patients with IgAV-N had altered expression of genes involved in O-glycan biosynthesis: decreased for core 1 synthase (glycoprotein-N-acetylgalactosamine 3-β-galactosyltransferase 1; C1GALT1) and C1GALT1 Specific Chaperone 1 (C1GALTC1; COSMC) and elevated for N-acetylgalactosaminide α-2,6-sialyltransferase 2 (ST6GALNAC2). Levels of Gd-IgA1–specific IgG in sera and supernatants of IgG-producing cells were similar for patients with IgAV-N and IgAN and higher than those for IgAV-woN patients or healthy control subjects. Moreover, patients with IgAV-N who had active disease, manifested by hematuria and substantial proteinuria, had higher serum levels of Gd-IgA1–specific IgG autoantibodies than did patients with IgAV-N who had inactive disease.

Conclusion

Serum levels and cellular production of Gd-IgA1 and Gd-IgA1–specific IgG autoantibodies were elevated in patients with IgAV-N, supporting the hypothesis that IgAV-N and IgAN share pathogenic features.

Henoch-Schonlein purpura associated with HLA-B27 positive axial spondyloarthritis in a young man

Axial spondyloarthropathies are characterised by bilateral sacroiliitis, asymmetric oligoarthritis, association with the human leucocyte antigen (HLA)-B27, enthesitis and dactylitis. Although IgA nephropathy has a well-documented association with seronegative spondyloarthropathies, the association with Henoch-Schonlein purpura (HSP) has been documented only in few case reports. The present case is that of a 26-year-old man who presented with fever, lower limb arthritis, abdominal pain, palpable purpura over the buttocks and lower limbs, and clinical features of sacroiliitis. His blood tests showed elevated inflammatory markers and rheumatoid factor was negative. CT scan of the sacroiliac joints confirmed sacroiliitis. Skin biopsy revealed neutrophilic small vessel vasculitis. HLA-B27 was positive in blood. A diagnosis of HSP with HLA-B27 positive axial spondyloarthritis was made. HSP can be associated with HLA-B27 positive axial spondyloarthritis and has to be considered while evaluating for causes of cutaneous small vessel vasculitis in such patients.

IgA1 isolated from Henoch-Schönlein purpura children promotes proliferation of human mesangial cells in vitro

Previous studies show that the proliferation of human mesangial cells (HMCs) played a significant part in the pathogenesis of Henoch-Schönlein purpura nephritis (HSPN). The aim of this study was to explore the proliferation of HMCs induced by IgA1 isolated from the sera of HSP patients. HMCs were cultured in three different types of media, including IgA1 from patients with HSP (HSP IgA1 group), healthy children (healthy IgA1 group) and medium (control group). The proliferation of HMCs incubated with IgA1 was determined by cell counting kit-8 assay and bromodeoxyuridine incorporation. The expression of ERK1/2 and phosphatidylinositol 3 kinase/protein kinase B/mammalian targets of the rapamycin (PI3K/AKt/mTOR) signals and transferrin receptor (TfR/CD71) was detected with the methods of immunoblotting. The results indicated that the proliferation of HMCs significantly increased in the HSP IgA1 group compared with that in the control group or the healthy IgA1 group (P < 0.001). Moreover, we found that IgA1 isolated from HSP patients activated ERK and PI3K/AKt/mTOR signals, and markedly increased TfR/CD71 expression in HMCs. These effects induced by IgA1 isolated from patients with HSP were inhibited by human TfR polyclonal antibody (hTfR pAb) and soluble human transferrin receptor (sTfR), indicating that IgA1-induced HMC proliferation and ERK1/2 and PI3K/AKt/mTOR activation were dependent on TfR/CD71 engagement. Altogether, these data suggested that TfR/CD71 overexpression and ERK1/2 and PI3K/AKt/mTOR activation were engaged in HMC proliferation induced by IgA1 from HSP patients, which might be related to the mesangial injury of HSPN.

Updated Oxford classification and the international study of kidney disease in children classification: application in predicting outcome of Henoch-Schönlein purpura nephritis

Background

Henoch-Schönlein purpura nephritis (HSPN) shares many similarities with IgA nephropathy. We aimed to analyze the predictive value of the International Study of Kidney Disease in Children (ISKDC) classification and the updated Oxford classification for IgA nephropathy in HSPN patients.

Methods

Data of 275 HSPN patients (aged≥14 years) were retrieved, and all of them underwent a renal biopsy. We re-classified the biopsies according to the ISKDC classification and the updated Oxford classification to analyze their correlations with clinical features and renal outcomes. The renal endpoints were defined as ≥30% reduction in baseline estimated glomerular filtration rate (eGFR) in 2 years, doubling of serum creatinine (Scr) or end stage renal disease.

Results

During follow-up period of 56(30,86) months, 30(10.9%) patients reached renal endpoints. Segmental sclerosis was the only pathological feature independently associated with renal endpoints (HR 4.086, 95%CI 1.111–15.026, P = 0.034). Tubular atrophy/ interstitial fibrosis was associated with eGFR and Scr levels, and its correlation with renal endpoints was found by univariate analysis. Endocapillary hypercellularity was associated with 24 h urine protein and is of prognostic value in univariate analysis. Mesangial hypercellularity was not associated with clinical features or renal endpoints. Crescents were associated with 24 h urine protein, Scr and eGFR levels, but both ISKDC and updated Oxford classifications of crescents were not associated with renal endpoints by multivariate analysis.

Conclusions

The updated Oxford classification can help in disease management and renal outcome prediction of HSPN.

Electronic supplementary material

The online version of this article (10.1186/s13000-019-0818-0) contains supplementary material, which is available to authorized users.

Approach to the Child with Hematuria

The causes of macroscopic and microscopic hematuria overlap; both are often caused by urinary tract infections or urethral/bladder irritation. Coexistent hypertension and proteinuria should prompt investigation for glomerular disease. The most common glomerulonephritis in children is postinfectious glomerulonephritis. In most patients, and especially with isolated microscopic hematuria, the diagnostic workup reveals no clear underlying cause. In those cases whereby a diagnosis is made, the most common causes of persistent microscopic hematuria are thin basement membrane nephropathy, immunoglobulin A nephropathy, or idiopathic hypercalciuria. Treatment and long-term prognosis varies with the underlying disease.

Acute renal insufficiency and pancreatitis in a child with atypical Henoch-Schönlein purpura: efficacy of a single dose of cyclophosphamide

A 9-year-old boy with petechiae on the legs and abdominal pain was unsuccessfully treated with steroids. He was admitted to our hospital for the onset of fever, ecchymosis, and arthralgia. Skin lesions suggested vasculitis, but they were not typical of Henoch–Schönlein purpura. He showed ecchymosis of the scrotal bursa, diffusion of petechiae to the trunk and arms, vomiting, severe abdominal pain, oliguria with hyponatremia, hypoalbuminemia, low C3 levels, high levels of creatinine, blood urea nitrogen, and tubular enzymes, proteinuria, and glycosuria. The urinary sediment showed macrohaematuria, and hyaline and cellular casts. Ultrasound showed polyserositis. He was treated with intravenous furosemide, albumin, and methylprednisolone. He underwent colonoscopy and gastroscopy because of development of acute pancreatitis and severe anaemia. Typical lesions of Henoch–Schönlein purpura were observed in the small intestine and colon mucosa. He received three high doses of methylprednisolone, followed by intravenous cyclophosphamide. A dramatic and persistent response was observed after these doses. A single high dose of cyclophosphamide is appropriate in Henoch–Schönlein purpura with acute renal failure and severe pancreatitis that are non-responsive to high-dose steroids.

Analysis of seasonal tendencies in pediatric Henoch-Schönlein purpura and comparison with outbreak of infectious diseases

Henoch-Schönlein purpura (HSP) is one of the most common vasculitis in children. This study was aimed at identifying seasonal trends and epidemiologic features of pediatric HSP patients through public data to analyze the correlation of HSP and prevalence of a specific respiratory or enteric virus.We extracted information on pediatric HSP patients categorized into 4 age groups and data on 8 respiratory and 4 enteric viruses were extracted from national data. We used the decomposition of time series analysis and correlation analysis to identify the incidence of HSP and the prevalence of each virus.From 2013 to 2016, 16,940 patients under the age of 18 were diagnosed with HSP in Korea, 6203 (36.6%) were diagnosed with HSP in middle childhood. Spring had the largest number of patients (5252, 31.0%), and summer had the smallest number of patients (3224, 19.0%). The largest and smallest number of cases occurred in March (1949, 11.5%) and August (959, 5.7%), respectively. However, among the adolescents, more patients were diagnosed in the summer (985, 24.8%) than in the fall (760, 19.1%). The positive detection counts of most viruses showed apparent seasonal variations. Depending on the age group, the epidemic patterns of influenza and rotaviruses were temporally and statistically similar to that of HSP.We have confirmed that the occurrence of pediatric HSP in Korea shows a seasonal tendency, which is age-dependent and related to exposure to infectious agents and suggest some respiratory or enteric viruses may play an important role in pathophysiology.

Off-label use of tacrolimus in children with Henoch-Schönlein purpura nephritis: a pilot study

BACKGROUND

Tacrolimus is used off-label in the treatment of Henoch-Schönlein purpura nephritis (HSPN) in children, with limited evidence-based data. Based on clinical empirical experience and mechanism of action, tacrolimus might be promoted as treatment for childhood HSPN. The objectives of this pilot study were to assess its effectiveness and safety, and to explore the potential impact of CYP3A5 genotype.

METHODS

Children with HSPN receiving tacrolimus as empirical treatment were included in this prospective, observational study. Effectiveness was classified as complete remission, partial remission or non-response. General safety data analyses during and after study drug exposure included adverse events, reasons for discontinuation, deaths, laboratory data and vital signs. Trough concentration was determined using high-performance liquid chromatography with tandem mass spectrometry. Pharmacogenetic analysis was performed on the CYP3A5 gene.

RESULTS

A total of 20 patients with a mean age of 7.5 (SD 2.1) years participated in the whole process of the study. Twelve patients reached complete remission and eight patients reached partial remission at the end of 6-month treatment. No patients discontinued tacrolimus treatment due to adverse events, and no drug-related adverse events were shown to have a causal association with tacrolimus therapy. Dose-adjusted trough concentration was significantly higher in children with CYP3A5*1 allele as compared with patients with CYP3A5*3/*3 genotype (170.7±100.9 vs 79.8±47.4 (ng/mL)/(mg/kg)).

CONCLUSION

This pilot study showed that tacrolimus might be an effective and well-tolerated drug for the treatment of HSPN in children. CYP3A5 polymorphism had a significant impact on tacrolimus concentration.

[Comparison of age-based clinical and abnormal immune parameters in patients with Henoch-Schönlein purpura]

Objective: To explore age-based clinical and immune parameters in Henoch-Schönlein purpura (HSP) to determine clinically useful markers reflecting disease characteristic. Methods: A cohort of 502 patients with HSP were enrolled into this retrospective study to evaluate their clinical and immune data. Results: Majority HSP cases occurred at age ≤14 years and showed significant immune imbalances of ESR, CD3(+) cells, CD4(+) cells, CD3(-)CD16(+)CD56(+) cells, CD4(+)/CD8(+) cells, IgG, IgA, IgM, IgE, complements C3/C4 and ASO in the acute phase. Compared to patients aged >14 years, symptoms of joint were more frequent at disease onset in patients aged ≤14 years (20.8% vs 7.6%, χ(2)=13.547, P<0.001) , and involvement of digestive tract and joint were also more frequent (57.4% vs 33.8%, χ(2)=24.106, P<0.001; 55.9% vs 32.5%, χ(2)=23.768, P<0.001, respectively) , but not for involvement of kidney (21.4% vs 51.3%, χ(2)=42.440, P<0.001) . The patients aged ≤14 years had distinct immune state, reductions of CD3(+) cells, CD4(+) cells and IgG were more frequent than patients aged >14 years, also increase of ASO (33.1% vs 20.0%, χ(2)=6.656, P=0.010) , but not increase of IgA (2.6% vs 39.4%, χ(2)=15.582, P<0.001) . In addition, reduction of IgG and increase of IgE were positively associated with digestive tract involvement (P<0.001, P=0.001, respectively) , reduction of CD3(+)CD4(+) cells and normal IgM were positively associated with joint involvement (P=0.004, P=0.003, respectively) , increase of CD3(+)CD8(+) cells and normal CD3(+) cells were positively associated with kidney involvement (P=0.032, P=0.014, respectively) . Conclusion: HSP showed significant immune imbalance in the acute phase, patients between aged ≤14 and >14 years had distinct clinical and immune characteristic, and abnormal immune parameters were significantly associated with organ involvements.

Correlation between Traditional Chinese Medicine Symptom Patterns and the Renal Function, Immunologic Function Index, and Blood Coagulation Index in Patients with Henoch-Schönlein Purpura Nephritis

Objective

We investigate the correlation between the patterns of traditional Chinese medicine (TCM) syndromes and the damage of renal function, immunologic function index, and blood coagulation index in patients with Henoch-Schönlein purpura nephritis (HSPN) and thus provide the therapeutic effects of Chinese herbs decoction on HSPN.

Methods

We studied 262 hospitalized patients diagnosed with HSPN between 1 February 2016 and 1 January 2017. Indexes like renal function, immunologic function, and blood coagulation were measured. The patients were classified into four different patterns of TCM symptoms.

Results

In a total of 262 patients with HSPN, dampness-heat accumulation accounted for 59.5%, which is the highest proportion of TCM symptom patterns, liver-kidney yin deficiency accounted for 17.6%, qi and yin deficiency ratio reached 12.6%, and blood-heat bleeding accounted for 9.9%. 24-hour proteinuria was heavier in the dampness-heat accumulation patients who had immune disorders and were in hypercoagulative state and hyperfibrinolysis conditions.

Conclusion

We analyzed and summarized the clinical characteristics of patients with HSPN and found that dampness-heat accumulation was dominant in patients and was always accompanied by immune disorders and coagulation disorders. These results provided the largest therapeutic effects of Chinese herbs decoction for clinical treatment.

Incidence and risk factors for recurrent Henoch-Schönlein purpura in children from a 16-year nationwide database

BACKGROUND

The recurrence rate of Henoch-Schönlein purpura (HSP) is 2.7%-30%, with varied average intervals between the first and second episodes. Few studies have explored the incidence and risk factors for recurrent HSP.

METHODS

We used a 16-year nationwide database to analyze the incidence of recurrent HSP. Patients with HSP were identified, and risk factors for recurrent HSP were explored. Kaplan-Meier and Cox regression model analyses were performed, and covariates were adjusted in the multivariate model.

RESULTS

From January 1, 1997 to December 31, 2012, among 2,886,836 individuals in the National Health Insurance Research Database, 1002 HSP patients aged < 18 years were identified. Among them, 164 had ≥2 HSP episodes (recurrence rate, 16.4%; incidence of recurrent HSP, 7.05 per 100 person-years); 83.6% patients with one HSP episode remained free of secondary HSP. The average time intervals between the first and second and second and third HSP episodes were 9.2 and 6.4 months, respectively. After adjusting for demographic parameters, comorbidities, and socioeconomic status, recurrent HSP was found to occur more frequently in patients who had renal involvement (adjusted hazard ratio, 2.41; 95% confidence interval [CI], 1.64-3.54; p < 0.001), were receiving steroid therapy for > 10 days (adjusted hazard ratio, 8.13; 95%CI, 2.51-26.36; p < 0.001), and had allergic rhinitis (adjusted hazard ratio, 1.63; 95%CI, 1.06-2.50; p = 0.026).

CONCLUSIONS

The annual incidence of recurrent HSP was low. However, children who had underlying allergic rhinitis, presented with renal involvement, and received steroid treatment for > 10 days should be notified regarding the possibility of recurrence.

Vasculitis update: pathogenesis and biomarkers

Better understanding of the pathogenesis and treatment of primary systemic vasculitides (PSV) has led to the development of many potentially clinically relevant biomarkers. Genome-wide association studies have highlighted that MHC class II polymorphisms may influence the development of particular anti-neutrophil cytoplasmic antibody (ANCA) serotypes, but not the clinical phenotype of ANCA-associated vasculitis (AAV). Although ANCAs are overall poor biomarkers of disease activity, they may be useful for the prediction of flares of renal and/or pulmonary vasculitis. Moreover, patients with proteinase 3 (PR3)-AAV may respond better to rituximab than cyclophosphamide. Newer biomarkers of renal vasculitis in AAV include urinary soluble CD163, and may in the future reduce the requirement for renal biopsy. Better understanding of dysregulated neutrophil activation in AAV has led to the identification of novel biomarkers including circulating microparticles, and neutrophil extracellular traps (NETs), although their clinical utility has not yet been realised. Studies examining endothelial injury and repair responses have additionally revealed indices that may have utility as disease activity and/or prognostic biomarkers. Last, next-generation sequencing technologies are revealing monogenic forms of vasculitis, such as deficiency of adenosine deaminase type 2 (DADA2), and are profoundly influencing the approach to the diagnosis and treatment of vasculitis in the young.

IgA nephropathy and IgA vasculitis with nephritis have a shared feature involving galactose-deficient IgA1-oriented pathogenesis

Galactose-deficient IgA1 has been proposed as an important effector molecule in IgA nephropathy (IgAN). We previously showed that the galactose-deficient IgA1-specific monoclonal antibody KM55 can detect circulating galactose-deficient IgA1 in patients with IgAN, enabling us to study the molecular roles of galactose-deficient IgA1. Herein, we further examined the pathophysiological significance of galactose-deficient IgA1 in glomerular deposits of patients with IgAN by immunohistochemistry using KM55. Immunostaining of galactose-deficient IgA1 with KM55 was performed in paraffin-embedded sections of renal biopsy specimens from 48 patients with IgAN and 49 patients with other renal diseases such as lupus nephritis, HCV-related nephropathy, IgA vasculitis with nephritis (IgA-VN), and membranous nephropathy. Glomerular galactose-deficient IgA1 was specifically detected in IgAN and IgA-VN but not in the other renal diseases. Galactose-deficient IgA1 was localized predominantly in the mesangial region as IgA deposition. However, galactose-deficient IgA1 was not detected in patients with lupus nephritis accompanied by glomerular IgA deposition. Thus, our study strongly suggests that IgAN and IgA-VN have a shared feature regarding galactose-deficient IgA1-oriented pathogenesis.

New insights in the pathogenesis of immunoglobulin A vasculitis (Henoch-Schönlein purpura)

Immunoglobulin A vasculitis (IgAV), also referred to as Henoch-Schönlein purpura, is the most common form of childhood vasculitis. The pathogenesis of IgAV is still largely unknown. The disease is characterized by IgA1-immune deposits, complement factors and neutrophil infiltration, which is accompanied with vascular inflammation. Incidence of IgAV is twice as high during fall and winter, suggesting an environmental trigger associated to climate. Symptoms can resolve without intervention, but some patients develop glomerulonephritis with features similar to IgA nephropathy that include hematuria, proteinuria and IgA deposition in the glomerulus. Ultimately, this can lead to end-stage renal disease. In IgA nephropathy immune complexes containing galactose-deficient (Gd-)IgA1 are found and thought to play a role in pathogenesis. Although Gd-IgA1 complexes are also present in patients with IgAV with nephritis, their role in IgAV is disputed. Alternatively, it has been proposed that in IgAV IgA1 antibodies are generated against endothelial cells. We anticipate that such IgA complexes can activate neutrophils via the IgA Fc receptor FcαRI (CD89), thereby inducing neutrophil migration and activation, which ultimately causes tissue damage in IgAV. In this Review, we discuss the putative role of IgA, IgA receptors, neutrophils and other factors such as infections, genetics and the complement system in the pathogenesis of IgA vasculitis.

Usefulness of urinary collagen IV excretion for predicting the severity of Henoch-Schönlein nephropathy children

The aim of the study

The aim of the study was to evaluate the usefulness of urinary collagen IV (Col IV) excretion for predicting the severity of autoimmune renal inflammation in children with HSN (Henoch-Schönlein nephritis).

Material and methods

We studied 26 children, in whom HSN was diagnosed based on kidney biopsy. In all patients, urinalysis was performed and 24-hour urinary protein excretion was measured at the onset of the disease. All kidney biopsies were also scored using the Oxford classification: M – mesangial hypercellularity score (M0 absent, M1 present); E – presence of endocapillary proliferation (E0 absent, E1 present), S – segmental glomerulosclerosis/adhesion (S0 absent, S1 present), T – tubular atrophy/interstitial fibrosis (T0 ≤ 25%, T1 26-50%, T2 > 50%). The MEST score was calculated as the sum of M + E + S + T.

Results

Urinary Col IV level was significantly higher in the study group than in control group. Urinary Col IV level was insignificantly higher in group A (nephrotic proteinuria) compared to the B (non-nephrotic proteinuria) and C (without proteinuria).We found no significant differences in the age at the disease onset, severity of proteinuria, and Col IV between groups 1 (S0, T0) and 2.(S1,T1/T2). The MEST score was significantly higher in group 2 than group 1.

Conclusions

Urinary Col IV excretion in children with HSN may be related to the lesions severity by the Oxford classification but seems to be associated with the mean value (the MEST score).

In younger children, a more aggressive disease course is observed, and thus earlier and more aggressive treatment should be considered in this group.

Association of Endothelial Nitric Oxide Synthase Gene Polymorphism with Susceptibility and Nephritis Development of Henoch-Schönlein Purpura in Chinese Han Children

OBJECTIVE

Henoch-Schönlein purpura (HSP) is the most common form of systemic small-vessel vasculitis in children. Previous studies suggested endothelial nitric oxide synthase (eNOS) plays an important role in the pathogenesis and clinical manifestations of HSP. This study aimed to investigate the potential association between 10 single-nucleotide polymorphisms (SNPs) within the eNOS gene and HSP risk and nephritis development in a Chinese Han population.

MATERIALS AND METHODS

A case-control study was conducted including 459 healthy children and 423 children with HSP. SNPs were genotyped by using the MassARRAY system.

RESULTS

The genotypic frequency of rs11771443 was nominally associated with the risk of HSP (p = 0.010), and the C allele significantly increased the risk of HSP (p = 0.003, odds ratio [OR] = 1.331, confidence interval [95% CI] = 1.104-1.605). There was a significant difference in allelic and genotypic distribution of rs1799983 between children with HSP and healthy controls (p = 0.002 and 0.0001, respectively). Strong linkage disequilibrium was observed in two blocks. Significantly fewer T-A-G haplotypes (p = 0.0001, OR = 0.593, 95% CI = 0.448-0.786) were found in children with HSP. No significant association was identified between the 10 SNPs and the pathogenesis of HSP progression to HSP nephritis (HSPN).

CONCLUSIONS

The polymorphisms of eNOS contribute to genetic susceptibility to HSP, but may have no effect on children with HSP progressing to HSPN.

Evaluation of Mycophenolate Mofetil and Low-Dose Steroid Combined Therapy in Moderately Severe Henoch-Schönlein Purpura Nephritis

Background

The most appropriate management of Henoch-Schönlein Purpura (HSP) nephritis with nephrotic-range proteinuria remains uncertain. The aim of this study was to evaluate the clinical therapeutic effects of mycophenolate mofetil and low-dose steroid in Henoch-Schönlein purpura nephritis (HSPN) with nephrotic-range proteinuria and pathological classification less than IV in children.

Material/Methods

The clinical effects of MMF and low-dose steroid therapy were studied in children with Henoch-Schönlein purpura nephritis manifested with nephrotic-range proteinuria, normal kidney function, and <50% crescents or sclerosing lesions on renal biopsy. We enrolled 32 boys and 29 girls with nephrotic-range proteinuria, normal kidney function, and pathological classification less than IV on renal biopsy. We treated 41 cases (67.2%) with mycophenolate mofetil and low-dose prednisone combined therapy and 20 cases (32.8%) were treated with full-dose prednisone alone.

Results

Short-term response was significantly different between 2 groups (χ²=4.371, P=0.037), while no significant difference was found in long-term prognosis (χ²=0.419, P=0.522) after follow-up. The ROC curve showed that the most appropriate cutoff value was 30.67 μg·h/ml for MPA-AUC and the area under the ROC curve was 0.731, with 85.2% sensitivity and 64.3% specificity.

Conclusions

Mycophenolate mofetil and low-dose prednisone combined therapy is a reasonable treatment choice which can promote the remission of proteinuria without increasing obvious adverse reactions in pediatric HSPN with nephrotic state and pathological classification less than grade IV. MPA-AUC more than 30 μg·h/ml was an appropriate value for MMF in the combined therapy with MMF and steroid for treating children with HSPN.

Expression of Acid-Sensing Ion Channels in Renal Tubular Epithelial Cells and Their Role in Patients with Henoch-Schönlein Purpura Nephritis

Background

Acid-sensing ion channels (ASICs) are ligand-gated cation channels activated by extracellular protons. However, the role of ASICs in kidney diseases remains uncertain. This study investigated ASICs expression in kidney tissues and their role in the development of Henoch-Schönlein purpura nephritis (HSPN).

Material/Methods

The expression of ASIC subunits was examined by immunochemical techniques in the kidney tissue from HSPN patients. Acid-induced ASICs expression in cultured renal tubular epithelial cells was determined by quantitative RT-PCR analysis. The expression of K7 and K18 protein in renal tubular epithelial cells was used to evaluate acid-induced cell injury. In addition, we observed the effect of blocking ASICs on acid-induced cell injury to assess the role of ASICs in renal tubular epithelial cell injury.

Results

The results showed that ASIC1, ASIC2, and ASIC3 proteins were obviously expressed in renal tubular cells from HSPN patients. ASIC1 expression and 24-h urine protein level were higher in the pathological grade ISKD III group than in the ISKD II group. ASIC1, ASIC2, and ASIC3 mRNA, and K7 and K18 protein expression in cultured renal tubular epithelial cells were increased when exposed to pH 6.5. K7 and K18 protein expression was closely related to ASIC1 expression, and ASICs blockers reduced K7 and K18 protein expression in tubular epithelial cells.

Conclusions

These findings suggest ASICs are most highly expressed in renal tubular cells of HSPN patients, which is closely related to renal tubular injury. ASICs might be involved in the development of HSPN.

Pathophysiology of IgA Nephropathy

Immunoglobulin (Ig)A nephropathy is the most prevalent primary chronic glomerular disease in the world. Studies of molecular and cellular interactions involved in the pathogenesis of IgA nephropathy have revealed several inherent abnormalities in the production and subsequent handling of IgA1. In patients with this disease, altered glycan structures in the unique hinge region of the heavy chains of IgA1 molecules lead to the exposure of antigenic determinants, which are recognized by naturally occurring antiglycan antibodies of the IgG and/or IgA1 isotype. In addition, due to a homing abnormality there is a gradual shift of mucosal IgA1 producing lymphoplasma cells from mucosal lymphoid tissue to bone marrow resulting in excess production of mucosal-type IgA1 in the systemic circulation. As a result, nephritogenic immune complexes form in the circulation and deposit in the glomerular mesangium. Deposited immune complexes induce proliferation of resident mesangial cells with increased production of extracellular matrix proteins. A number of inflammatory cytokines produced by the mesangial cells damage the filtration barrier resulting in hematuria and proteinuria ultimately leading to progressive renal damage.

[Clinical effect of gamma globulin pulse therapy for abdominal Henoch-Schönlein purpura in children]

OBJECTIVE

To study the clinical effect of high-dose gamma globulin pulse therapy for abdominal Henoch-Schönlein purpura (HSP).

METHODS

Thirty-three children with abdominal HSP were randomly assigned to dexamethasone group (15 children) and gamma globulin group (18 children). The children in the dexamethasone group were treated with dexamethasone and conventional treatment, and those in the gamma globulin group were treated with high-dose gamma globulin pulse therapy in addition to the conventional treatment. Clinical outcome and recurrence rate were observed in both groups.

RESULTS

Compared with the dexamethasone group, the gamma globulin group had a significantly shorter onset time of rash, a significantly shorter time to complete regression of rash, a significantly shorter time to abdominal pain remission, and a significantly shorter time to disappearance of bloody stool, as well as comparable time to vomiting remission and length of hospital stay. The gamma globulin group had a significantly higher response rate than the dexamethasone group (95% vs 65%; P<0.05) and a significantly lower recurrence rate within 6 months than the dexamethasone group (5.6% vs 33.3%; P<0.05).

CONCLUSIONS

High-dose gamma globulin pulse therapy has a marked clinical effect in the treatment of abdominal HSP. It is safe and reliable and has a low recurrence rate, and therefore, it holds promise for clinical application.