IgA vasculitis update: Epidemiology, pathogenesis, and biomarkers

Clinicopathological features and prognosis of IgA vasculitis nephritis with nephrotic-range proteinuria in children

BACKGROUND

To investigate the clinical features, kidney pathology, treatment regimens, and clinical outcomes of IgA vasculitis nephritis (IgAVN) with nephrotic-range proteinuria in children.

METHODS

A retrospective review of children diagnosed with IgAVN between January 2019 and December 2022 was conducted. Participants were divided into two groups based on their urine protein/creatinine (UPCR) levels. Biodata, clinical characteristics, laboratory findings, pathologic features, treatment regimens, and outcomes were abstracted from case records and analyzed.

RESULTS

A total of 255 children were identified, 94 with nephrotic-range proteinuria (UPCR ≥ 200 mg/mmol) and 161 with non-nephrotic proteinuria (UPCR < 200 mg/mmol). Patients in the nephrotic-range proteinuria group were significantly younger and had worse grades of glomerular and acute tubulointerstitial injury compared to those in the non-nephrotic proteinuria group. Higher levels of blood urea nitrogen (BUN), D-dimer (DD), and fibrin degradation products (FDP), and lower levels of total protein (TP), albumin (ALB), urine creatinine (Cr), prothrombin time (PT), activated partial thromboplastin time (APTT), IgG, CD3 + cells, and CD4 + cells were found in patients in the nephrotic-range proteinuria group. Clinical outcome of patients with nephrotic-range proteinuria was significantly associated with ISKDC grading, proportion of glomerular crescents and severity of acute tubulointerstitial injury.

CONCLUSIONS

Children with nephrotic-range proteinuria exhibit more severe disordered immunologic function, hypercoagulability, glomerular and tubulointerstitial pathological damage, and have worse outcomes than those with lower proteinuria levels. Clinicians should pay great attention to the kidney injury and more extensive studies are required to identify optimal treatment regimens to improve outcomes in patients.

IgA vasculitis after COVID-19: a case-based review

IgA-associated vasculitis (IgAV) known as Henoch - Schönlein purpura (HSP) disease is an inflammatory disorder of small blood vessels. It's the most common type of systemic vasculitis in children which can be associated with the inflammatory process following infections. IgA vasculitis is a rare and poorly understood systemic vasculitis in adults. Coronavirus disease 2019 (COVID-19) has been associated with HSP in both adults and children. A 58-year-old woman was diagnosed with HSP, fulfilling the clinical criteria: palpable purpura, arthritis, hematuria. The disclosure of the HSP disease was preceded by a infection of the respiratory tract. COVID-19 infection was confirmed via the presence of IgM and IgG antibodies. This case indicates the possible role of SARS-CoV-2 in the development of HSP. The clinical course of IgAV in adults appears to be different from pediatric IgAV, especially due to higher risk of renal complications. Symptoms of the disease quickly resolved with low-dose of steroids.

Exploring potential predictors of Henoch-Schönlein purpura nephritis: a pilot investigation on urinary metabolites

Henoch-Schönlein purpura nephritis (HSPN) is the most severe manifestation of Henoch-Schönlein purpura (HSP). This study aimed to determine the role of urine metabolomics in predicting HSPN and explore the potential mechanisms of HSP. A liquid chromatography-tandem mass spectrometry-based untargeted metabolomics analysis was performed to investigate the urinary metabolic profiles of 90 participants, comprising 30 healthy children (group CON) and 60 patients with HSP, including 30 HSP patients without renal involvement (group H) and 30 HSPN patients (group HSPN). The differentially expressed metabolites (DEMs) were identified using orthogonal partial least squares discriminant analysis (OPLS-DA), and subsequent bioinformatics analysis was conducted to elucidate the perturbed metabolic pathways. A total of 43 DEMs between H and HSPN groups were analyzed by the Kyoto Encyclopedia of Gene and Genome (KEGG) database, and the result indicates that glycine, serine and threonine metabolism, and cysteine and methionine metabolism were significantly disturbed. A composite model incorporating propionylcarnitine and indophenol sulfate was developed to assess the risk of renal involvement in pediatric patients with HSP.   Conclusion: This study reveals the metabolic alterations in healthy children, HSPN patients, and HSP patients without renal involvement. Furthermore, propionylcarnitine and indophenol sulfate may be potential predictive biomarkers of the occurrence of HSPN. What is Known: • HSP is the predominant type of vasculitis observed in children. The long-term prognosis of HSP is contingent upon the extent of renal impairment. In severe nephritis, a delay in appropriate treatment may lead to fibrosis progression and subsequent development of chronic kidney disease (CKD), even leading to renal failure. • The application of metabolomics in investigating diverse renal disorders has been documented. Urine is a robust and sensitive medium for metabolomics detection. What is New: • The metabolic profiles were identified in urine samples of healthy children and those with HSP at the early stage of the disease. Different metabolites were identified between HSP patients without nephritis and those who developed HSPN. • These different metabolites may affect oxidative stress in the progression of HSPN.

Immunoglobulin A Vasculitis With Intussusception in Children

BACKGROUND

Immunoglobulin A (IgA) vasculitis with intussusception is acute and severe vasculitis combined with acute abdomen in children. The diagnosis of the disease depends on the results of imaging examinations, and its treatment mainly includes enema and surgery. The literature summarized the detailed diagnosis and treatment data in previous literature reports.

METHODS

We described the clinical manifestations, ultrasonic features, and treatment of patients admitted to a single center and reviewed previous literature regarding cases with detailed clinical data in the PubMed database within the past 20 years.

RESULTS

The review included 36 patients, including 22 boys and 14 girls. A total of 32 patients were diagnosed using ultrasound (88.9%). The main sites of intussusception were the ileum and ileocolon in 16 (44.4%) and 11 (30.6%) cases, respectively. Thirteen patients (36.1%) were treated with enema, with 6 responding to the treatment. 26 patients (72.2%) underwent surgical treatment. Patients with ileal intussusception were more likely to be treated with surgery than those with colonic intussusception (P < .05). The single-center clinical data of 23 patients showed that there was no significant difference in laboratory test findings between patients with and without surgical treatment (P > .05). Patients with long insertion lengths were more likely to require surgery and resection (P < .05).

CONCLUSIONS

Ultrasonography is the first-line investigation for diagnosis. The main sites of intussusception were ileum and ileocolon. The length of intubation was related to surgery; treatment is according to the intussusception site. Air enema is not suitable for intussusception of the small intestine.

Associations of MEFV gene variants, IL-33, and sST2 with the risk of Henoch-Schönlein purpura in children

Objective

Henoch-Schönlein purpura (HSP) is the most common systemic vasculitis in children. HSP is a multifactorial inflammatory disease, but its pathogenesis is still unclear. The pathogenicity of familial Mediterranean fever gene (MEFV) variants in HSP remains controversial. The objective of this study was to evaluate relationships between MEFV variants and susceptibility to HSP and their associations with clinical outcomes. We also investigated levels of IL-33 and soluble suppression of tumorigenicity 2 (sST2) in children with HSP and their clinical significance.

Methods

We selected 100 children with HSP as the case group. The control group consisted of 50 children who visited the hospital for physical health examinations. All subjects were screened for MEFV gene exon mutations, and levels of IL-33 and sST2 were measured.

Results

The frequency of MEFV variants was significantly greater in HSP patients than in healthy controls. The variant with the highest frequency was E148Q. The frequency of the C allele of the MEFV variant E148Q was 32 % in HSP patients and 18 % in controls (P-adjust = 0.04). Patients with the MEFV E148Q variant had more frequent joint involvement and recurrent purpura and higher levels of IL-33 and C-reactive protein (CRP). Levels of IL-33 and sST2 in children with HSP were significantly higher than those in the control group, and the sST2/IL-33 ratio in children with HSP was unbalanced (P-adjust <0.05). Logistic regression analysis revealed the presence of E148Q and an unbalanced sST2/IL-33 ratio to be independent risk factors for HSP.

Conclusion

The results of this study suggest that the MEFV variant E148Q is associated with HSP susceptibility in Chinese children and that carriers of the variant may have more severe clinical manifestations and greater inflammatory responses. E148Q and the sST2/IL-33 ratio may play important roles in the pathogenesis of HSP.

A Case Series of Unusual IgA Vasculitis

Introduction

Immunoglobulin A vasculitis (IgA)is a rare condition characterized by palpable purpura, often involving the skin, gastrointestinal tract, joints, and kidneys. Presentation is usually acute and is more common in children and adolescents of Southeast Asian and European descent. In the adult population, it is less common and therapies are not as well-established.

Case Presentation

Disease prevalence of IgA vasculitis outside Southeast Asian and European populations is not well-documented. In this case series, we present 2 cases of IgA vasculitis in 2 older adult males, one of Native American descent and one of African American descent.

Conclusion

IgA vasculitis must be considered within the adult population, and it is not limited to certain ethnic groups. Further research is needed to give clarity on the best treatment options for adults with IgA vasculitis. We believe that patients presenting with IgA vasculitis are best managed in a multidisciplinary approach, especially those patients with limited improvement despite the initiation of corticosteroids. Our 2 cases should raise awareness of IgA vasculitis in patients with skin rashes and elevated creatinine levels.

Common Seasonal Pathogens and Epidemiology of Henoch-Schönlein Purpura Among Children

Importance

Henoch-Schönlein purpura (HSP) is the most common type of vasculitis in children. The factors that trigger the disease are poorly understood. Although several viruses and seasonal bacterial infections have been associated with HSP, differentiating the specific associations of these pathogens with the onset of HSP remains a challenge due to their overlapping seasonal patterns.

Objective

To analyze the role of seasonal pathogens in the epidemiology of HSP.

Design, Setting, and Participants

This cohort study comprised an interrupted time-series analysis of patient records from a comprehensive national hospital-based surveillance system. Children younger than 18 years hospitalized for HSP in France between January 1, 2015, and March 31, 2023, were included.

Exposure

Implementation and relaxation of nonpharmaceutical interventions (NPIs) for the COVID-19 pandemic, such as social distancing and mask wearing.

Main Outcomes and Measures

The main outcomes were the monthly incidence of HSP per 100 000 children, analyzed via a quasi-Poisson regression model, and the estimated percentage of HSP incidence potentially associated with 14 selected common seasonal pathogens over the same period.

Results

The study included 9790 children with HSP (median age, 5 years [IQR, 4-8 years]; 5538 boys [56.4%]) and 757 110 children with the infectious diseases included in the study (median age, 0.7 years [IQR, 0.2-2 years]; 393 697 boys [52.0%]). The incidence of HSP decreased significantly after implementation of NPIs in March 2020 (-53.6%; 95% CI, -66.6% to -40.6%; P < .001) and increased significantly after the relaxation of NPIs in April 2021 (37.2%; 95% CI, 28.0%-46.3%; P < .001). The percentage of HSP incidence potentially associated with Streptococcus pneumoniae was 37.3% (95% CI, 22.3%-52.3%; P < .001), the percentage of cases associated with Streptococcus pyogenes was 25.6% (95% CI, 16.7%-34.4%; P < .001), and the percentage of cases associated with human rhino enterovirus was 17.1% (95% CI, 3.8%-30.4%; P = .01). Three sensitivity analyses found similar results.

Conclusions and Relevance

This study found that significant changes in the incidence of HSP simultaneously with major shifts in circulating pathogens after NPIs for the COVID-19 pandemic indicated that approximately 60% of HSP incidence was potentially associated with pneumococcus and group A streptococcus. This finding suggests that preventive measures against these pathogens could reduce the incidence of pediatric HSP.

Taxonomic and functional shifts of gut microbiome in immunoglobulin A vasculitis children and their mothers

Objectives

To examine the gut microbiota characteristics in children with immunoglobulin A vasculitis and their interrelationships with the host, while evaluate the vertical inheritance of microbiota in the development and progression of IgA vasculitis.

Methods

This study investigated the gut microbiome of 127 IgA vasculitis mother-child pairs and 62 matched healthy mother-child pairs, and compared the gut microbial composition of different groups. The pathway enrichment analysis evaluated potential gut microbiome-mediated pathways involved in the pathophysiology of IgA vasculitis. The Spearman correlation analysis illustrated the relationships between clinical variables and bacterial biomarkers.

Results

This study identified distinct intestinal microbiome in IgA vasculitis children compared to healthy children, and further pointed out the association in gut microbiota between IgA vasculitis children's and their mother's. The relative abundance of Megamonas and Lactobacillus in IgAV children was positively correlated with that in their mothers. The pathway enrichment analysis found microbial biosynthesis of vitamins and essential amino acids was upregulated in children with IgA vasculitis. Correlation analysis showed bacterial biomarkers were correlated with indicators of blood coagulation.

Conclusion

Children with IgA vasculitis have unique bacterial biomarkers and may affect coagulation function, and their gut microbiome was closely associated with that of their mothers. The observed association in gut microbiota between IgA vasculitis children and their mothers suggested a potential intergenerational influence of the maternal microbiota on the development or progression of IgA vasculitis in children.

Predictors of Gastrointestinal Involvement in Children with IgA Vasculitis: Results from a Single-Center Cohort Observational Study

Background and objective: IgA vasculitis (IgAV), a predominantly pediatric leukocytoclastic disease, has an unpredictable, though largely benign, evolution. The aim of this study was to retrospectively investigate any potential clinical or laboratory predictors of gastrointestinal involvement in a single-center cohort of children with IgAV. Patients and methods: A total of 195 children with a history of IgAV, regularly followed-up for an average period of 1 ± 2.6 years via outpatients clinics of the pediatric rheumatology unit in our University, were assessed, analyzing their clinical and laboratory variables in relationship with their disease evolution and outcome. Results: Univariate analysis showed that a higher neutrophil granulocyte count and lower lymphocyte count (expressed as a percentage of the total white blood cells) were significantly associated with the presence of gastrointestinal involvement at the first examination (65.2 ± 13% versus 58.8 ± 12%, p = 0.02, and 26.4 ± 11% versus 32.1 ± 11%, p = 0.02, respectively). A positive pharyngeal swab for Streptococcus pyogenes, a deficiency of 25-hydroxyvitamin D, a persistence of purpuric rash for more than 1 month, and purpuric lesions in the genital area were also associated with gastrointestinal involvement (p = 0.0001, p = 0.0001, p = 0.007 and p = 0.001, respectively). However, multiple logistic regressions with correction for the patients' sex and age showed that lower 25-hydroxyvitamin D levels, persistent rash, and genital lesions were independently and significantly associated with signs of gastrointestinal involvement. We then performed a secondary analysis (both univariate and multivariate) to investigate whether vitamin D deficiency was associated with other IgAV manifestations: we found that only 25-hydroxyvitamin D deficiency remained significantly associated with gastrointestinal involvement in IgAV. Conclusions: Patients with IgAV and vitamin D deficiency might be more prone to developing gastrointestinal manifestations of variable severity.

Transcriptome profile analysis in spinal cord injury rats with transplantation of menstrual blood-derived stem cells

Introduction

Menstrual blood-derived stem cells (MenSCs) are vital in treating many degenerative and traumatic disorders. However, the underlying molecular mechanisms remain obscure in MenSCs-treating spinal cord injury (SCI) rats.

Methods

MenSCs were adopted into the injured sites of rat spinal cords at day 7 post surgery and the tissues were harvested for total RNA sequencing analysis at day 21 after surgery to investigate the expression patterns of RNAs. The differentially expressed genes (DEGs) were analyzed with volcano and heatmap plot. DEGs were sequentially analyzed by weighted gene co-expression network, functional enrichment, and competitive endogenous RNAs (ceRNA) network analysis. Next, expression of selected miRNAs, lncRNAs, circRNAs and mRNAs were validated by quantitative real-time polymerase chain reaction (qRT-PCR). Bioinformatics packages and extra databases were enrolled to scoop the genes functions and their interaction relationships.

Results

A total of 89 lncRNAs, 65 circRNAs, 120 miRNAs and 422 mRNAs were significantly upregulated and 65 lncRNAs, 72 circRNAs, 74 miRNAs, and 190 mRNAs were significantly downregulated in the MenSCs treated rats compared to SCI ones. Current investigation revealed that MenSCs treatment improve the recovery of the injured rats and the most significantly involved pathways in SCI regeneration were cell adhesion molecules, nature killer cell mediated cytotoxicity, primary immunodeficiency, chemokine signaling pathway, T cell receptor signaling pathway and B cell receptor signaling pathway. Moreover, the lncRNA-miRNA-mRNA and circRNA-miRNA-mRNA ceRNA network of SCI was constructed. Finally, the protein-protein interaction (PPI) network was constructed using the top 100 DE mRNAs. The constructed PPI network included 47 nodes and 70 edges.

Discussion

In summary, the above results revealed the expression profile and potential functions of differentially expressed (DE) RNAs in the injured spinal cords of rats in the MenSCs-treated and SCI groups, and this study may provide new clues to understand the mechanisms of MenSCs in treating SCI.

Association between TRAF1/C5 Gene Polymorphisms and IgA Vasculitis in Chinese Children

OBJECTIVE

To investigate the association between loci rs3761847 and rs10818488 of tumor necrosis factor receptor-associated factor 1/complement C5 (TRAF1/C5) gene and the susceptibility to IgAV.

METHODS

100 blood samples of children with IgAV and 100 blood samples of healthy children were collected from the Third Xiangya Hospital of Central South University from June 2017 to June 2019. The target gene fragment was amplified by polymerase chain reaction (PCR), and the single nucleic acid gene polymorphism of the gene loci was detected by PCR sequencing based typing technique. The association between gene polymorphism of each locus and susceptibility to IgAV was analyzed.

RESULTS

There were significant differences in both genotype (P < .05) and allele frequencies （P < .05) of rs3761847 of TRAF1/C5 gene between the IgAV group and the control group.Besides, the risks of developing IgAV in children with the TT genotype was 0.495 times and in children with the C allele was 1.627 times of that in children with other genotypes and alleles, respectively (P < .05). For IgAV patients, renal involvement risk in children with CC genotype was 5.859 times of that in children with other genotypes (P < .05). There were no significant differences in genotype (P > .05) and allele frequencies (P > .05) of rs10818488 of TRAF1/C5 gene between the IgAV group and the control group. IgAV patients with TT genotype had a 3.2 times higher risk of renal involvement than those with other genotypes (P < .05).

CONCLUSIONS

There is an association between locus rs3761847 of TRAF1/C5 gene single nucleotide polymorphisms and susceptibility to IgAV. The T allele at locus rs3761847 of TRAF1/C5 gene may be a protective factor for IgAV. The C allele at locus rs3761847 and the T allele at locus rs10818488 of TRAF1/C5 gene may be associated with kidney injury in IgAV.

[Research advances in the etiology and pathogenesis of immunoglobulin A vasculitis]

Immunoglobulin A vasculitis (IgAV), also known as Henoch-Schönlein purpura, has complex etiology and pathogenesis which have not been fully clarified. The latest research shows that SARS-CoV-2 and related vaccines, human papilloma vaccine, and certain biological agents can also induce IgAV. Most studies believe that the formation of galactose-deficient IgA1 (Gd-IgA1) and Gd-IgA1-containing immune complex plays a crucial role in the pathogenesis of IgAV. It is hypothesized that the pathogenesis of IgAV is associated with the binding of IgA1 to anti-endothelial cell antibodies. In addition, genetics also constitutes a major focus of IgAV research. This article reviews the new advances in the etiology of IgAV and summarizes the role of Gd-IgA1, Gd-IgA1-containing immune complex, anti-endothelial antibody, IgA1 conjugates, T lymphocyte immunity, and genetic factors in the pathogenesis of IgAV.

Analysis of IL-1β, TGF-β, IL-5, ACE, PTPN22 gene polymorphisms, and gene expression levels in Turkish children with IgA vasculitis

OBJECTIVE

Immunoglobulin-A vasculitis (IgAV) is an inflammatory disease that affects small blood vessels. This study was performed to identify an association between protein tyrosine phosphatase non-receptor type 22 (PTPN22) + 788G > A (rs33996649), transforming growth factor-beta (TGF-β) -509C > T (rs18004069), interleukin 1-beta (IL-1β) -511C > T (rs16944), interleukin 5 (IL-5) -746C/T (rs2069812), and angiotensin-converting enzyme (ACE) I/D (rs4646994) gene polymorphisms, susceptibility to IgAV, as well as the mRNA levels of IL-1β, IL-1β, and TGF-β.

METHOD

A total of 53 patients with IgAV and 50 healthy controls were enrolled. PTPN22, TGF-β, IL-1β, ACE gene polymorphisms, ACE gene I/D polymorphisms, and mRNA expression levels were analyzed using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method, allele-specific PCR, and real-time PCR with TaqMan kits, respectively.

RESULTS

PTPN22, TGF-β, IL-1β, IL-5, and ACE variants showed no genotype or allele differences between patients with IgAV and controls. Increased levels of IL-1β and TGF-β mRNA expressions were observed in patients with IgAV (p < 0.001). Patients with the IL-1β AG genotype showed significantly increased amounts of arthritis than patients with non-AG (p = 0.004). Age at disease onset was found to be significantly different in patients with IgAV according to the presence of TGF-β TT genotype (p = 0.047).

CONCLUSION

Polymorphisms in PTPN22, TGF-β, IL-5, IL-1β, and ACE genes are unlikely to confer susceptibility to IgAV. However, the presence of the AG genotype of IL-1β is associated with susceptibility to IgAV-related arthritis. This is the first study to report a significant increase in serum mRNA levels of IL-1β and TGF-β in IgAV patients, supporting a susceptibility to IgAV in childhood.

New insights into epidemiological data and impact of the COVID-19 pandemic on IgA vasculitis in children and adults: a French nationwide cohort

IgA vasculitis (IgAV) is a small size vasculitis for which epidemiologic data are strikingly lacking, especially about the adult form. Additionally, the COVID-19 pandemic seems to have profoundly modified the incidence of this disease. Here, we aimed to establish some relevant epidemiological data in both pediatric and adult IgAV. We performed an observational study using a national database called "BNDMR" on IgAV, which gathers patients managed in the French network of experts on rare diseases. We primarily performed descriptive statistics over the 2010-2022 period. Then, we compared the North-South geographical areas, the seasonality, and the impact of COVID-19 with that of other patients reported in the same centers. We collected data from 1988 IgAV patients. The sex ratio was 1.57 for adults and 1.05 for children. The annual incidence in 2021 was 0.06 for 100,000 adults and 0.50 for 100,000 children. Compared with other diseases reported into the BNDMR, IgAV was more common in the South than in the North of France (OR 4.88 [4.17-5.74] in adults and OR 1.51 [1.35-1.68] in children). IgAV was also observed more frequently in winter and autumn. Strikingly, we observed a decrease in incidence during the COVID-19 pandemic period in children (OR 0.62 [0.47-0.81]). Our study provides both new insights and confirmations of IgAV epidemiological data: winter and autumn seasonality, more pronounced male predominance in adults, decreasing incidence of pediatric IgAV during the COVID-19 pandemic and increasing incidence in the South of France.

Causal relationships between circulating inflammatory factors and IgA vasculitis: a bidirectional Mendelian randomization study

Background

IgA vasculitis (IgAV) is an immune-associated vasculitis, yet its exact etiology remains unclear. Here, we explore the interaction between IgAV and inflammatory factors using bidirectional Mendelian randomization (MR).

Methods

We conducted a bidirectional summary-level MR analysis to delineate the causality of C-reactive protein (CRP), procalcitonin (PCT), and 41 circulating inflammatory regulators with IgAV. Data on genetic variants related to inflammation were obtained from three genome-wide association studies (GWASs) on CRP, PCT, and human cytokines, whereas data on IgAV was from large meta-analyses of GWAS among 216 569 FinnGen Biobank participants. The primary MR analysis was performed using the inverse-variance weighted (IVW) approach, and the sensitivity analyses were carried out using MR-Egger, weighted median, weighted mode, and MR-pleiotropy residual sum and outlier.

Results

This study revealed the association of CRP higher levels with increased risk of IgAV through IVW method (Estimate odds ratio [OR] = 1.41, 95% confidence interval [CI]: 1.01-1.98, P = 0.04), MR-Egger (OR = 1.87, CI: 1.15-3.02, P = 0.01), weighted median (OR = 2.00, CI: 1.21-3.30, P = 0.01) and weighted mode (OR = 1.74, CI: 1.13-2.68, P = 0.02). Furthermore, elevated IL-8 was strongly implicated with a higher risk of IgAV (IVW OR = 1.42, CI: 1.05-1.92; P = 0.02). Conversely, genetically predicted IgAV was associated with decreased levels of TNF-β (IVW estimate β = -0.093, CI: -0.178 - -0.007; P = 0.033). Additionally, no such significant statistical differences for other inflammatory factors were found.

Conclusion

Our current study using bidirectional MR analysis provides compelling evidence for a causal effect of CRP, PCT, and circulating inflammatory regulators on IgAV. These findings contribute to a better understanding of the pathogenesis of IgAV and emphasize the potential of targeting inflammatory factors for therapeutic interventions.

Diagnostic and prognostic value of galactose-deficient IgA1 in patients with IgA nephropathy: an updated systematic review with meta-analysis

Objectives

Galactose-deficient IgA1 (Gd-IgA1) is a critical effector molecule in the pathogenesis of IgA nephropathy (IgAN), a leading renal disease without noninvasive assessment options. This updated systematic review aimed to determine the diagnostic and prognostic value of Gd-IgA1 assessment in biological fluids in patients with IgAN.

Methods

PRISMA guidelines were followed in this review. We searched PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, China Biology Medicine disc, VIP Information/China Science and Technology Journal Database, and WANFANG for studies published between database inception and January 31, 2023. Eligible studies that evaluated aberrant IgA1 glycosylation in IgAN patients relative to controls were identified, and random effects meta-analyses were used to compare Gd-IgA1 levels in different groups. The quality of the evidence was assessed using the Newcastle-Ottawa Scale. This study was registered on PROSPERO (CRD42022375246).

Findings

Of the 2727 records identified, 50 were eligible and had available data. The mean Newcastle-Ottawa Scale score was 7.1 (range, 6-8). Data synthesis suggested that IgAN patients had higher levels of blood and/or urine Gd-IgA1 compared with healthy controls (standard mean difference [SMD]=1.43, 95% confidence interval [CI]=1.19-1.68, P<0.00001), IgA vasculitis patients (SMD=0.58, 95% CI=0.22-0.94, P=0.002), and other kidney disease patients (SMD=1.06, 95% CI=0.79-1.33, P<0.00001). Moreover, patients with IgAN had similar levels of serum Gd-IgA1 compared to first-degree relatives (SMD=0.38, 95% CI= -0.04-0.81, P=0.08) and IgA vasculitis with nephritis patients (SMD=0.12, 95% CI= -0.04-0.29, P=0.14). In addition, ten studies demonstrated significant differences in serum Gd-IgA1 levels in patients with mild and severe IgAN (SMD= -0.37, 95% CI= -0.64--0.09, P=0.009).

Conclusions

High serum and urine Gd-IgA1 levels suggest a diagnosis of IgAN and a poor prognosis for patients with this immunological disorder. Future studies should use more reliable and reproducible methods to determine Gd-IgA1 levels.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022375246, identifier CRD42022375246.

[Clinical characteristics, pathology, and prognosis of children with diffuse endocapillary proliferative Henoch-Schönlein purpura nephritis]

OBJECTIVES

To investigate the clinical characteristics, pathology, and prognosis of children with diffuse endocapillary proliferative Henoch-Schönlein purpura nephritis (DEP-HSPN).

METHODS

A retrospective analysis was performed on the clinical, pathological, and prognosis data of 44 children with DEP-HSPN and 765 children without DEP-HSPN. The children with DEP-HSPN were diagnosed by renal biopsy in Jiangxi Provincial Children's Hospital from January 2006 to December 2021.

RESULTS

Among the 809 children with purpura nephritis, 44 (5.4%) had DEP-HSPN, with a mean age of (8±3) years, and there were 29 boys (65.9%) and 15 girls (34.1%). Compared with the non-DEP-HSPN group, the DEP-HSPN group had a significantly shorter time from onset to renal biopsy and a significantly higher proportion of children with respiratory infection or gross hematuria, and most children had nephrotic syndrome. The DEP-HSPN group had significantly higher levels of 24-hour urinary protein, urinary protein grading, microscopic hematuria grading, serum creatinine, and blood urea nitrogen and significantly lower levels of serum albumin and complement C3 (P<0.05). The DEP-HSPN group had a higher pathological grading, with predominant deposition of IgA in the mesangial area and capillary loops, and higher activity scores in the modified semi-quantitative scoring system (P<0.05). The Kaplan-Meier survival analysis showed that there was no significant difference in the renal complete remission rate between the two groups (P>0.05).

CONCLUSIONS

Children with DEP-HSPN have a rapid onset, severe clinical manifestations and pathological grading, and high activity scores in the modified semi-quantitative scoring system. However, most of the children with DEP-HSPN have a good prognosis, with a comparable renal complete remission rate to the children without DEP-HSPN.

The Spectrum and Age-Sex Patterns Among Outpatients with Allergic Diseases - Yichang City, Hubei Province, China, 2018-2021

What is already known about this topic?

Allergic diseases have affected an estimated 40% of the population in China. However, our understanding of the full spectrum of these diseases remains insufficient.

What is added by this report?

Between 2018 and 2021, Yichang City documented 625,929 outpatient visits mainly related to skin and mucous membrane allergies (77.90%) and allergic respiratory conditions (19.64%). In 2021, the occurrence of outpatient visits for conditions such as allergic rhinitis, acute atopic conjunctivitis, and atopic dermatitis increased. The demographic analysis revealed that male patients comprised the majority of the under 18 age bracket (56.05%), while female patients were predominantly represented in the 18 to 65 age bracket (61.79%).

What are the implications for public health practice?

This constitutes the first analysis of the spectrum of allergic diseases, utilizing regional outpatient data, which has substantial implications for understanding the disease burden.

Mortal Dangers of Adult-Onset IgA Vasculitis

IgA vasculitis (IgAV), previously known as Henoch Schoenlein purpura (HSP), is a leukocytoclastic vasculitis subtype predominantly amongst the pediatric patient population involving IgA dominant immune complex deposits attacking small vessel walls. While it oftentimes follows upper respiratory infections and presents with palpable purpuras, IgAV can also present in the adult patient population and lead to systemic inflammation. In this case report, we present the case of an adult-onset IgAV complicated via gastrointestinal perforation, acute kidney injury secondary to IgA nephritis, and circulatory shock. A review of prognosis, complicating factors, and treatment methods was also conducted for reported adult-onset IgAV with an aim to elucidate similarities and differences to pediatric-onset IgAV. While there is no unified treatment approach, glucocorticoids and immunosuppressors such as rituximab have been observed to be an effective protocol.

Pathophysiology and clinical manifestations of immune complex vasculitides

Immune complex (IC) vasculitides present inflammations of vessel walls associated with perivascular deposition of immunoglobulins (Igs), mostly ICs. They encompass systemic and skin-limited variants of IgA vasculitis (IgAV), cryoglobulinemic vasculitis (CV), rheumatoid, lupus, and hypocomplementemic vasculitides, serum sickness cutaneous IgM/IgG (non-IgA) vasculitis, and recurrent macular (hypergammaglobulinemic or exertion-induced) vasculitis. Serum sickness and CV fulfill the criteria of a type III hypersensitivity immune reaction as large lattices of the IC precipitate at vessel walls and activate polymorphonuclear neutrophils (PMNs). Immunoglobulin-A vasculitis differs with regard to the causes of perivascular deposition of ICs since here many IgA1 molecules are hypoglycosylated (Gd-IgA1), which appears to facilitate their perivascular deposition in skin and mesangium (via e.g. CD71). The reasons for increased generation of immunoglobulins or formation of IC and their perivascular deposition in either skin or systemic organs are different and not fully explored. A common denominator of OC vasculitides is the activation of PMNs near the vessel wall via Fcy or Fcα receptors. Acute episodes of IgAV additionally require PMNs to become preactivated by IgA1 or by IC already in circulation. This intravascular priming results in increased adherence and subsequently vessel-destructive NETosis when they encounter IgA deposited at the vessel walls. Binding of IgA1 to PMNs in blood stream is associated with increased serum levels of hypogalactosidated IgA1. The characteristic clinical picture of IgAV (and also of so-called IgG/IgM vasculitis) comprises palpable or retiform purpura with a clear predilection for lower legs, probably due to stasis-related reduction in blood velocity, while in other IC vasculitides, additional factors influence the sites of vasculitides. Our knowledge of distinct forms and different pathophysiological pathways of IC vasculitides may lead to in efficacious or targeted therapies. Antibodies to complement components or intestinal budesonide for IgAV are promising agents (the latter suppresses the pathophysiologically related IgA nephropathy by reducing the generation of mucosal IgA.

Immunoglobulin a vasculitis with testicular/epididymal involvement in children: A retrospective study of a ten-year period

The clinical characteristics and risk factors for testicular/epididymal involvement in 73 children with immunoglobulin A vasculitis (IgAV) who were admitted to our hospital between January 2012 and November 2022 were reviewed. The demographic data, laboratory parameters, and follow-up data of the patients were compared to those of 146 males without testicular/epididymal involvement. A logistic regression analysis was performed to determine the variables associated with testicular/epididymal involvement. The prevalence of testicular/epididymal involvement among male patients with IgAV was 1.3% (73/5,556). Increased blood flow in the testes and/or epididymis on ultrasound was found in 71 patients. The remaining two patients underwent surgical exploration for loss or reduction of testicular blood flow. One patient underwent orchiectomy for intraoperative confirmation of complete right testicular infarction. Pathological findings revealed IgA immune complex deposition in the testis. Patient age (odds ratio [OR] = 0.792; 95% confidence interval [CI]: 0.682-0.919, p = 0.002), platelet count (OR = 1.011; 95% CI: 1.002-1.020, p = 0.013), and immunoglobulin M (IgM) levels (OR = 0.236; 95% CI: 0.091-0.608, p = 0.003) were strongly associated with the occurrence of testicular/epididymal involvement in IgAV. Therefore, young age, increased platelet count, and low IgM levels in patients with IgAV are potential risk factors for testicular/epididymal involvement. Doppler ultrasound can help differentiate IgAV from acute scrotum. Most patients with testicular/epididymal involvement have good prognoses, although serious complications such as testicular infarction may occur.