Association of HLA-B*41:02 with Henoch-Schönlein Purpura (IgA Vasculitis) in Spanish individuals irrespective of the HLA-DRB1 status

Modern diagnostic methods for early assessment of the abdominal involvement in Schönlein-Henoch disease

INTRODUCTION

Schönlein-Henoch disease is a small vessel vasculitis resulting from IgA-mediated inflammation. It is the most common acute systemic vasculitis in childhood, mainly affecting the skin, gastrointestinal tract, joints, and kidneys. Although the prognosis of Schönlein-Henoch is generally good, gastrointestinal tract involvement is a potential complication, presenting as massive gastrointestinal bleeding, bowel infarction, perforation, as well as intussusception and peritonitis.

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.

HLA Polymorphisms and Clinical Manifestations in IgA Vasculitis

Studies concerning the genetic background of IgA vasculitis (IgAV), a small-vessel vasculitis occurring predominantly in childhood, have confirmed that the HLA-DRB1 gene showed a strong association with disease susceptibility. The objective was to investigate human leukocyte antigen (HLA) polymorphisms among Croatian patients with IgAV and their influence on disease susceptibility and clinical heterogeneity. Thus, 130 children with IgAV and 202 unrelated healthy individuals were enrolled in the study. Genomic DNA was extracted from whole peripheral blood, and HLA-A, -B, -DRB1 and -DQB1 gene polymorphism analysis was performed. HLA-A*03 (21.4% vs. 12.38%, p = 0.0092), HLA-B*37 (2.9% vs. 0.2%, p = 0.0054) and HLA-DRB1*12 (3.1% vs. 0.7%, p = 0.0216) alleles were significantly more frequent in IgAV patients than in controls. High-resolution typing revealed significantly higher frequency of HLA-DRB1*10:01 and -DRB1*11:03 among IgAV patients with gastrointestinal manifestations of the disease in comparison to controls (p = 0.0021 and p = 0.0301, respectively), while HLA-DRB1*14:01P occurred significantly more often in the group of patients who developed nephritis during the course of the disease (17.5% vs. 4.5%, p = 0.0006). Our results demonstrated that there is an association of HLA-A*03, HLA-B*37 and HLA-DRB1*12 alleles with susceptibility to IgAV in the examined Croatian pediatric population. Studies which aim to determine the HLA profile may contribute to the elucidation of the genetic background of autoimmune diseases, including IgAV.

Human leukocyte antigen-DQA1*04:01 and rs2040406 variants are associated with elevated risk of childhood Burkitt lymphoma

Burkitt lymphoma (BL) is responsible for many childhood cancers in sub-Saharan Africa, where it is linked to recurrent or chronic infection by Epstein-Barr virus or Plasmodium falciparum. However, whether human leukocyte antigen (HLA) polymorphisms, which regulate immune response, are associated with BL has not been well investigated, which limits our understanding of BL etiology. Here we investigate this association among 4,645 children aged 0-15 years, 800 with BL, enrolled in Uganda, Tanzania, Kenya, and Malawi. HLA alleles are imputed with accuracy >90% for HLA class I and 85-89% for class II alleles. BL risk is elevated with HLA-DQA1*04:01 (adjusted odds ratio [OR] = 1.61, 95% confidence interval [CI] = 1.32-1.97, P = 3.71 × 10-6), with rs2040406(G) in HLA-DQA1 region (OR = 1.43, 95% CI = 1.26-1.63, P = 4.62 × 10-8), and with amino acid Gln at position 53 versus other variants in HLA-DQA1 (OR = 1.36, P = 2.06 × 10-6). The associations with HLA-DQA1*04:01 (OR = 1.29, P = 0.03) and rs2040406(G) (OR = 1.68, P = 0.019) persist in mutually adjusted models. The higher risk rs2040406(G) variant for BL is associated with decreased HLA-DQB1 expression in eQTLs in EBV transformed lymphocytes. Our results support the role of HLA variation in the etiology of BL and suggest that a promising area of research might be understanding the link between HLA variation and EBV control.

Detection of N‑glycoprotein associated with IgA nephropathy in urine as a potential diagnostic biomarker using glycosylated proteomic analysis

The aim of the present study was to elucidate the potential diagnostic value of urinary N-glycoprotein in patients with IgA nephropathy (IgAN) using mass spectrometry (MS). All procedures were performed between June 2021 and June 2023 at Guangan People's Hospital (Guangan, China). Fresh mid-morning fasting midstream urine samples were collected from a total of 30 patients with IgAN and 30 sex- and age-matched healthy volunteers. Data acquired from 6 participants are available through ProteomeXchange with the identifier PXD041151. By comparison between the IgAN group (n=3) and healthy controls (n=3) and selection criteria of P<0.05 and |log fold-change|>2, a total of 11 upregulated and 22 downregulated glycoproteins in patients with IgAN were identified. The results of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses suggested that glycoproteins are involved in various functions, such as the regulation of cell growth, cell adhesion, cellular component organization and protein binding, as well as multiple pathways, including p53, Notch and mTOR signaling pathways. The urine levels of afamin were further measured by ELISA in a validation cohort to assess the diagnostic performance of the single indicator model. In conclusion, MS-based proteomics of urinary glycoproteins may be an alternative option for diagnosing patients with IgAN. Biomarkers of IgAN may include, but are not limited to, CCL25, PD-L1, HLA-DRB1, IL7RD and WDR82. In addition, the levels of urinary AFM indicators are of diagnostic value for IgAN.

Mucosal Immune Defence Gene Polymorphisms as Relevant Players in the Pathogenesis of IgA Vasculitis?

ITGAM-ITGAX (rs11150612, rs11574637), VAV3 rs17019602, CARD9 rs4077515, DEFA (rs2738048, rs10086568), and HORMAD2 rs2412971 are mucosal immune defence polymorphisms, that have an impact on IgA production, described as risk loci for IgA nephropathy (IgAN). Since IgAN and Immunoglobulin-A vasculitis (IgAV) share molecular mechanisms, with the aberrant deposit of IgA1 being the main pathophysiologic feature of both entities, we assessed the potential influence of the seven abovementioned polymorphisms on IgAV pathogenesis. These seven variants were genotyped in 381 Caucasian IgAV patients and 997 matched healthy controls. No statistically significant differences were observed in the genotype and allele frequencies of these seven polymorphisms when the whole cohort of IgAV patients and those with nephritis were compared to controls. Similar genotype and allele frequencies of all polymorphisms were disclosed when IgAV patients were stratified according to the age at disease onset or the presence/absence of gastrointestinal or renal manifestations. Likewise, no ITGAM-ITGAX and DEFA haplotype differences were observed when the whole cohort of IgAV patients, along with those with nephritis and controls, as well as IgAV patients, stratified according to the abovementioned clinical characteristics, were compared. Our results suggest that mucosal immune defence polymorphisms do not represent novel genetic risk factors for IgAV pathogenesis.

A Joint Saga: Human Leukocyte Antigen (HLA) B27 Ankylosing Spondylitis and Sacroiliitis Association with Henoch-Schönlein Purpura

Henoch-Schönlein purpura (HSP) or IgA vasculitis is a small-vessel vasculitis mediated by IgA deposition, often associated with upper respiratory tract infection and family history. However, there is a rare correlation to human leukocyte antigen (HLA) B27 arthropathy. We present a case of a young boy diagnosed with HSP suffering from arthritis, gait disturbance, and weakness throughout childhood, ultimately diagnosed with ankylosing spondylitis and sacroiliitis clinically, with confirmation through X-ray and supporting HLA B27 testing.

ASSOCIATION BETWEEN HIGH MOBILITY GROUP BOX 1 PROTEIN GENE (rs41369348) POLYMORPHISM AND IMMUNOGLOBULIN A VASCULITIS IN CHILDREN

Immunoglobulin A vasculitis (IgAV) or Henoch-Schönlein purpura is the most prevalent systemic small vessel vasculitis in childhood. High mobility group box 1 protein (HMBG1) is a pleiotropic cytokine that functions as a pro-inflammatory signal, important for the activation of antigen-presenting cells and propagation of inflammation. HMGB1 is implicated in the pathophysiology of a variety of inflammatory diseases. The aim of this study was to investigate the role of single nucleotide polymorphism rs41369348 for HMGB1 gene in the susceptibility and clinical features of patients meeting the classification criteria for IgAV. DNA was extracted from blood cells of 76 children with IgAV and 150 age-matched healthy controls. Clinical data and laboratory parameters were collected for all IgAV patients. Although there was a higher frequency of heterozygous A/delA genotype of this gene polymorphism in IgAV group as compared with control group, no genotype difference was observed between these two groups. No statistically significant genotype differences were disclosed when patients with different IgAV clinical features were compared. In conclusion, in this study, polymorphism rs41369348 for HMGB1 was not associated with increased susceptibility to childhood IgAV, its severity or different clinical manifestations.

Landscape of intestinal microbiota in patients with IgA nephropathy, IgA vasculitis and Kawasaki disease

Objective

To explore the common differential flora of IgAN, Kawasaki disease and IgA vasculitis by screening and analyzing the differential intestinal flora between the three disease groups of IgAN, Kawasaki disease and IgA vasculitis and their healthy controls.

Methods

Papers on 16srRNA sequencing-related intestinal flora of IgAN, Kawasaki disease and IgA vasculitis were searched in databases, the literature was systematically collated and analysed, the original data was download from the relevant databases, and then the operational taxonomic unit and species classification analysis were performed. Besides, Alpha diversity analysis and Beta diversity analysis were performed to screen for IgAN, Kawasaki disease and I1gA vasculitis groups and finally compare the common intestinal differential flora among the three groups.

Results

Among the common differential flora screened, Lachnospiracea_incertae_sedis was lower in both the IgAN and Kawasaki disease groups than in the respective healthy controls; Coprococcus was low in the IgAN group but high in the IgA vasculitis group. Fusicatenibacter was lower in both the Kawasaki disease and IgA vasculitis groups than in their respective healthy controls, and Intestinibacter was low in the Kawasaki disease group, but its expression was high in the IgA vasculitis group.

Conclusion

The dysbiosis of the intestinal flora in the three groups of patients with IgAN, Kawasaki disease and IgA vasculitis, its effect on the immunity of the organism and its role in the development of each disease group remain unclear, and the presence of their common differential flora may further provide new ideas for the association of the pathogenesis of the three diseases.

THE MANAGEMENT OF REPETITIVE SUBACUTE THYROIDITIS IN A MALE PATIENT HAVING HLA-B35:01 AND B41:02 ALLELES

Context

Subacute thyroiditis (SAT) is an inflammatory disease of the thyroid gland and commonly affects females. Despite adequate treatment, the recurrence of SAT can be seen in some patients. Although there is insufficient data about the reasons for recurrences, HLA predisposition is one of the reasons thought to be responsible and is a current issue for clinicians.

Objective

This case report presented the management of 7 SAT attacks of a patient who had HLA-B35:01 and B41:02 alleles in the genotype analysis.

Case Report

A 37-year-old male patient who had consecutive 7 SAT attacks was presented in this report. Corticosteroid or non-steroidal anti-inflammatory drugs were initiated at each recurrence depending on the severity of clinical symptoms and laboratory findings. The genotype analysis showed the positivity for HLA-B35:01 and B41:02 alleles. The anti-thyroglobulin antibody was detected positive after the last attack. The patient was followed up as asymptomatic and euthyroid in the third month after the last attack.

Results

The management of some SAT cases may be challenging for clinicians. Although recurrence can be seen despite adequate treatment, repetitive seven attacks are extraordinary in SAT. HLA genotyping showed co-occurrence of HLA-B35:01 and B41:02 alleles in our patient. The co-occurrence of these alleles has been described firstly in this case. Explaining high recurrence rates of SAT with these HLA alleles is difficult, though the present case may shed light on further studies.

IgA Vasculitis: Influence of CD40, BLK and BANK1 Gene Polymorphisms

CD40, BLK and BANK1 genes involved in the development and signaling of B-cells are identified as susceptibility loci for numerous inflammatory diseases. Accordingly, we assessed the potential influence of CD40, BLK and BANK1 on the pathogenesis of immunoglobulin-A vasculitis (IgAV), predominantly a B-lymphocyte inflammatory condition. Three genetic variants within CD40 (rs1883832, rs1535045, rs4813003) and BLK (rs2254546, rs2736340, rs2618476) as well as two BANK1 polymorphisms (rs10516487, rs3733197), previously associated with inflammatory diseases, were genotyped in 382 Caucasian patients with IgAV and 955 sex- and ethnically matched healthy controls. No statistically significant differences were observed in the genotype and allele frequencies of CD40, BLK and BANK1 when IgAV patients and healthy controls were compared. Similar results were found when CD40, BLK and BANK1 genotypes or alleles frequencies were compared between patients with IgAV stratified according to the age at disease onset or to the presence/absence of gastrointestinal or renal manifestations. Moreover, no CD40, BLK and BANK1 haplotype differences were disclosed between patients with IgAV and healthy controls and between patients with IgAV stratified according to the clinical characteristics mentioned above. Our findings indicate that CD40, BLK and BANK1 do not contribute to the genetic background of IgAV.

Individualized medication based on pharmacogenomics and treatment progress in children with IgAV nephritis

Immunoglobulin A vasculitis (IgAV) nephritis, also known as Henoch-Schönlein purpura nephritis (HSPN), is a condition in which small blood vessel inflammation and perivascular IgA deposition in the kidney caused by neutrophil activation, which more often leads to chronic kidney disease and accounts for 1%–2% of children with end-stage renal disease (ESRD). The treatment principles recommended by the current management guidelines include general drug treatment, support measures and prevention of sequelae, among which the therapeutic drugs include corticosteroids, immunosuppressive agents and angiotensin system inhibitors. However, the concentration range of immunosuppressive therapy is narrow and the individualized difference is large, and the use of corticosteroids does not seem to improve the persistent nephropathy and prognosis of children with IgAV. Therefore, individualized maintenance treatment of the disease and stable renal prognosis are still difficult problems. Genetic information helps to predict drug response in advance. It has been proved that most gene polymorphisms of cytochrome oxidase P450 and drug transporter can affect drug efficacy and adverse reactions (ADR). Drug therapy based on genetics and pharmacogenomics is beneficial to providing safer and more effective treatment for children. Based on the pathogenesis of IgAV, this paper summarizes the current therapeutic drugs, explores potential therapeutic drugs, and focuses on the therapeutic significance of corticosteroids and immunosuppressants in children with IgAV nephritis at the level of pharmacogenomics. In addition, the individualized application of corticosteroids and immunosuppressants in children with different genotypes was analyzed, in order to provide a more comprehensive reference for the individualized treatment of IgAV nephritis in children.

Genome-wide association study of 7661 Chinese Han individuals and fine-mapping major histocompatibility complex identifies HLA-DRB1 as associated with IgA vasculitis

Background

Immunoglobulin‐A vasculitis (IgAV) is an immune‐related systemic vasculitis with an unclear etiology. Genetic predisposition is now considered to be closely associated with the development of the disease, and it is essential to reveal the relationship between them. To explore the role of heredity in the disease, we performed a genome‐wide association study (GWAS) of 496 IgAV cases and 7165 controls using an Illumina Infinium Global Screening Array chip.

Methods

In the first stage of analysis, a significant correlation between the major histocompatibility complex (MHC) and IgAV was observed. Subsequently, human leukocyte antigen (HLA) analysis was conducted using a new large‐scale Han‐MHC reference panel. Fine mapping of IgAV risk in the MHC region indicated that two amino acid positions, 120 and 11, of HLA‐DRB1 and three potential HLA alleles (HLA‐DRB1∗04, HLA‐DRB1∗16, and HLA‐DRB1∗16:02) were significantly associated.

Results

Further stepwise conditional analysis demonstrated that 3 amino acid positions (120, 26, 96) of HLA‐DRB1 and 6 HLA‐DRB1 alleles (HLA‐DRB1*04, HLA‐DRB1*16, HLA‐DRB1*01, HLA‐DRB1*12:02, HLA‐DRB1*10, and HLA‐DRB1*15:02) were independent signals. Among them, the most significant signal was HLA‐DRB1 amino acid Ser120 (OR = 1.59, p = 3.19 × 10⁻⁸); no independent signal in the MHC region except for HLA‐DRB1 was found.

Conclusions

Our study confirms that the pathogenesis of IgAV has a genetic component and that HLA‐DRB1 is strongly associated with susceptibility to IgAV.

Epidemiological and clinical aspects of immunoglobulin A vasculitis in childhood: a retrospective cohort study

Background

A retrospective study was conducted in order to investigate and describe the characteristics of Immunoglobulin A vasculitis (IgAV), previously known as Henoch-Schӧnlein purpura, in the paediatric population of a community-based healthcare delivery system in the Italian region of Abruzzo.

Methods

This is a population-based retrospective chart review of the diagnosis of IgAV in children ages 0 to 18, admitted to the Department of Paediatrics of Chieti and Pescara between 1 January 2000 and 31 December 2016. All children enrolled presented with clinical symptoms and laboratory findings and met the EULAR/PRINTO/PRES 2008 criteria.

Results

Two-hundred-eight children met the criteria for IgAV, with the highest incidence reported among children below 7-years of age. A correlation with recent infections was found in 64% of the cohort; the onset was more frequently during the winter and fall. Purpura had a diffuse distribution in the majority of patients; joint impairment was the second most frequent symptom (43%), whereas the gastrointestinal tract was involved in 28% of patients.

Conclusions

Hereby, we confirm the relative benignity of IgAV in a cohort of Italian children; with regards to renal involvement, we report a better outcome compared to other studies. However, despite the low rate of renal disease, we observed a wide use of corticosteroids, especially for the treatment of persistent purpura.

HLA-DQ and HLA-DRB1 alleles associated with Henoch-Schönlein purpura nephritis in Finnish pediatric population: a genome-wide association study

BACKGROUND

The pathophysiology of Henoch-Schönlein purpura (HSP) is still unclear, but several findings suggest that genetic factors may influence disease susceptibility. We aimed to perform a genome-wide association study (GWAS) in pediatric HSP patients with an emphasis on severe HSP nephritis.

METHODS

The study included 46 HSP patients, 42 of whom had undergone kidney biopsy. Forty-nine pediatric patients with an inflammatory bowel disease (IBD) served as an autoimmune disease control group while Finnish bone marrow and blood donors represented the general reference population (n = 18,757). GWAS was performed for HSP and IBD samples in a case-control manner against the reference population. The analysis also included imputation of human leukocyte antigen (HLA) alleles.

RESULTS

GWAS analysis in HSP revealed several polymorphisms from the HLA region that surpassed the genome-wide significance level. Three HLA class II alleles were also significantly more frequent in HSP than in the reference population: DQA1*01:01, DQB1*05:01, and DRB1*01:01. Haplotype DQA1*01:01/DQB1*05:01/DRB1*01:01 occurred in 43.5% of HSP patients, whereas its frequency was 8.2% in IBD patients and 15.0% in the reference population. HSP patients with this haplotype showed similar baseline clinical findings and outcome as HSP patients negative for the haplotype. In IBD patients, no polymorphism or HLA allele appeared significant at the genome-wide level.

CONCLUSIONS

Our results suggest that haplotype DQA1*01:01/DQB1*05:01/DRB1*01:01 is associated with susceptibility to HSP, but not with the severity of the kidney involvement. These HLA associations did not occur in IBD patients, suggesting that they are specific to HSP and not related to susceptibility to autoimmune diseases in general.

IgA Vasculitis: Etiology, Treatment, Biomarkers and Epigenetic Changes

IgA, previously called Henoch-Schönlein vasculitis, is an essential immune component that drives the host immune response to the external environment. As IgA has the unique characteristic of a flexible response to broad types of microorganisms, it sometimes causes an autoreactive response in the host human body. IgA vasculitis and related organ dysfunction are representative IgA-mediated autoimmune diseases; bacterial and viral infections often trigger IgA vasculitis. Recent drug developments and the presence of COVID-19 have revealed that these agents can also trigger IgA vasculitis. These findings provide a novel understanding of the pathogenesis of IgA vasculitis. In this review, we focus on the characteristics of IgA and symptoms of IgA vasculitis and other organ dysfunction. We also mention the therapeutic approach, biomarkers, novel triggers for IgA vasculitis, and epigenetic modifications in patients with IgA vasculitis.

Streptococcal infection in childhood Henoch-Schönlein purpura: a 5-year retrospective study from a single tertiary medical center in China, 2015-2019

BACKGROUND

The present study focuses on the associations of streptococcal infection with the clinical phenotypes, relapse/recurrence and renal involvement in Henoch-Schönlein purpura (HSP) children.

METHODS

Two thousand seventy-four Chinese children with HSP were recruited from January 2015 to December 2019. Patients' histories associated with HSP onset were obtained by interviews and questionnaires. Laboratory data of urine tests, blood sample and infectious agents were collected. Renal biopsy was performed by the percutaneous technique.

RESULTS

(1) Streptococcal infection was identified in 393 (18.9%) HSP patients, and served as the most frequent infectious trigger. (2) Among the 393 cases with streptococcal infection, 43.0% of them had arthritis/arthralgia, 32.1% had abdominal pain and 29.3% had renal involvement. (3) 26.1% of HSP patients relapsed or recurred more than 1 time within a 5-year observational period, and the relapse/recurrence rate in streptococcal infectious group was subjected to a 0.4-fold decrease as compared with the non-infectious group. (4) No significant differences in renal pathological damage were identified among the streptococcal infectious group, the other infectious group and the non-infectious group.

CONCLUSIONS

Streptococcal infection is the most frequent trigger for childhood HSP and does not aggravate renal pathological damage; the possible elimination of streptococcal infection helps relieve the relapse/recurrence of HSP.

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.

Variation in the Human Leukocyte Antigen system and risk for endemic Burkitt lymphoma in northern Uganda

Endemic Burkitt lymphoma (eBL) is an aggressive childhood B-cell lymphoma associated with Plasmodium falciparum (Pf) malaria and Epstein-Barr virus (EBV) infections. Variation in the Human Leukocyte Antigen (HLA) system is suspected to play a role, but assessments using less accurate serology-based HLA typing techniques in small studies yielded conflicting results. We studied 200 eBL cases and 400 controls aged 0-15 years enrolled in northern Uganda and typed by accurate high-resolution HLA sequencing methods. HLA results were analyzed at one- or two-field resolution. Odds ratios and 95% confidence intervals (aOR, 95% CI) for eBL risk associated with common HLA alleles versus alleles that were rare (<1%) or differed by <2% between the cases and controls as the reference category, were estimated using multiple logistic regression adjusting for age, sex, microgeography, region, malaria positivity and treatment history, and genetic variants associated with eBL. Compared to the controls, eBL cases had a lower frequency of HLA-A*02 (aOR = 0·59, 95% CI 0·38-0·91), HLA-B*41 (aOR = 0·36, 95% CI 0·13-1·00), and HLA-B*58 alleles (aOR = 0·59, 95% CI 0·36-0·97). eBL cases had a lower frequency of HLA-DPB1 homozygosity (aOR = 0·57, 95% CI 0·40-0·82) but a higher frequency of HLA-DQA1 homozygosity (aOR = 2·19, 95% CI 1·42-3·37). Our results suggest that variation in HLA may be associated with eBL risk.

A Case of Adult-onset Henoch-Schönlein Purpura Triggered by Fire Ants

Adult-onset IgA vasculitis, also known as Henoch-Schönlein purpura (HSP), is a rare disease that often presents with a non-blanchable, purpuric rash and can simultaneously affect the gastrointestinal, renal and musculoskeletal systems. The etiology of HSP is unknown. It can be triggered by any entity that creates an immunological insult, including medications, infections and vaccines. We describe a unique case of an adult woman who presented with HSP after experiencing multiple insect bites from fire ants and mosquitos while traveling overseas.

Association of the infectious triggers with childhood Henoch-Schonlein purpura in Anhui province, China

BACKGROUND

Although the specific etiology of Henoch-Schonlein purpura (HSP) is still unknown, several kinds of infectious triggers have been proved to participate in its pathogenesis. The objectives of present study were to analyze the association of the infectious triggers with childhood HSP in Anhui province, China.

METHODS

1200 HSP children were recruited from January 2015 to December 2017. Serum antistreptolysin O titer, TORCH, Epstein-Barr virus, helicobacter pylori (HP), Mycoplasma antibodies (MP-Ab), tubercle bacillus antibody (TB-Ab), respiratory pathogens (legionella pneumophila, chlamydia pneumoniae, adenovirus, respiratory syncytial virus, influenza A virus, influenza B virus, rickettsia, parainfluenza virus) were determined. Patients' histories were obtained by interviews and questionnaires.

RESULTS

The annual incidence of HSP was 8.13-9.17 per 100,000. HSP occurred more commonly in spring and winter than in summer with an obvious west-to-east gradient. On admission, several potential infections were identified in 611 cases (50.92%). The infectious agents including streptococcus, HP, MP, parainfluenza, respiratory syncytial virus, TB and toxoplasma gondii were identified in 205 cases (17.08%), 71 cases (5.92%), 58 cases (4.83%), 6 cases (0.5%), 1 case (0.08%), 1 case (0.08%) and 1 case (0.08%) respectively. 123 cases (10.25%) relapsed or recurred more than one time; the mean number was 2.92, and the mean interval was 11.4 weeks. The infection was the most frequent trigger regardless of clinical phenotypes and relapse/recurrence. Symptomatic treatment plus adjunctive anti-infectious agents could significantly improve the remission rate of purpura in the infectious cases (x²=24.60, p<0.01).

CONCLUSIONS

Streptococcus is the most frequent infectious agent in HSP children regardless of clinical phenotype or relapse/recurrence. The complete elimination of infectious triggers may help relieve cutaneous purpura.

Infection Rates Before and After Diagnosis of IgA Vasculitis in Childhood: A Population-wide Study Using Non-exposed Matched Controls

OBJECTIVE

Clinical data suggest that infections can trigger IgA vasculitis (IgAV), but longterm observations are lacking. We compared rates, types, and microorganisms for serious infection before and after diagnosis for children with IgAV and non-exposed controls.

METHODS

Using population-based administrative linked health datasets we estimated incidence rates (IR) for serious infection per 1000 person-months for patients with IgAV (n = 504, age 5 yrs, 59.1% males) and controls matched for age, sex, and year of presentation (n = 1281, age 6 yrs, 66% males). Time zero (T0) was the date of IgAV diagnosis or equivalent date in controls, lookback (median 38 mos) was the period prior to T0, and followup (median 239 mos) was the period after T0.

RESULTS

During lookback, prevalence of serious infection was similar in patients with IgAV and controls (11.5% vs 9.5%, respectively), but patients with IgAV had a higher rate of upper respiratory tract infections [incidence rate ratio (IRR) 1.79; 95% CI 1.39-2.31] with shorter time between first serious infection and T0 (27 vs 43 mos; p = 0.02). During followup, patients were at a constant increased risk for serious infections (IRR 1.46, 95% CI 1.35-1.58). These rates were higher during followup: sepsis (IRR 12.6), pneumonia (IRR 6.19), upper respiratory tract infections (IRR 2.36), and skin infections (IRR 1.85). There was little overlap between patients with serious infections in the lookback and followup periods.

CONCLUSION

In patients with childhood IgAV there is an increased longterm risk for a broader spectrum of infections, which is unrelated to serious infections prior to diagnosis or treatment. This suggests disease-specific factors may have a lasting effect on immune competence in childhood IgAV.

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.

IgA Vasculitis: Genetics and Clinical and Therapeutic Management

PURPOSE OF REVIEW

The purpose of the study is to perform an update on the current knowledge on genetics, clinical manifestations, and therapy in immunoglobulin A vasculitis (IgAV) (Henoch-Schönlein purpura).

RECENT FINDINGS

A strong genetic predisposition in individuals with IgAV was confirmed. It was due to the association with the HLA class II region that in people of European background is mainly related to HLA-DRB1*01 allele. Recent reports support the claim that kidney disease is more common in adults than in children with IgAV. The clinical spectrum and outcome of adults with IgAV depends on the age of onset. Relapses are not uncommon in IgAV. The presence of renal impairment or proteinuria excretion exceeding 1 g/24 h at the time of disease diagnosis and the degree of renal damage on the kidney biopsy are the best predictors of end-stage renal failure in adults with IgAV. The levels of urinary IgA at the onset of the disease may predict a poor renal outcome. The use of prednisone does not seem to prevent persistent kidney disease in children with IgAV. No additional benefit of adding cyclophosphamide to glucocorticoids in adults with IgAV was found. Rituximab seems to be a promising therapy in the management of adults with IgAV. In this overview, we focus on the genetics, clinical manifestations, and therapy of IgA vasculitis, emphasizing the main differences in the clinical expression of the disease between children and adults.

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.

Incidence of IgA vasculitis in children estimated by four-source capture-recapture analysis: a population-based study

Objectives

The aim was to describe the epidemiological characteristics of childhood IgA vasculitis (IgAV) defined by the EULAR/PRINTO/Paediatric Rheumatology European Society criteria in a population-based sample from France and ascertain its incidence over 3 years by a four-source capture-recapture analysis.

Methods

Cases were prospectively collected in Val de Marne county, a suburb of Paris, with 263 874 residents <15 years old. Children with incident IgAV living in this area from 2012 to 2014 were identified by four sources of case notification (emergency departments, paediatrics departments, private-practice paediatricians and general practitioners). Annual incidence was calculated, and a capture-recapture analysis was used with log-linear modelling to estimate case-finding completeness.

Results

We identified 147 incident cases [78 boys; mean age 6.5 (s.d.:2.6) years]. The annual incidence (95% CI) was 18.6 (13.6, 24.5)/100 000 children. Although only 10% of children were exclusively identified by non-hospital sources, the completeness of case finding was 62%, with an undercount-corrected annual incidence (95% CI) of 29.9 (23.7, 37.3)/100 000 children. The annual distribution of diagnoses consistently showed a trough in summer months; 72% of children had infectious symptoms (mainly upper respiratory tract) a few days before IgAV onset; and 23% had a North African background.

Conclusion

Our study supports secular and geospatial stability in childhood IgAV incidence and adds further indirect evidence for a possible role of a ubiquitous, non-emerging infectious trigger. Incidence studies from understudied areas are needed to disentangle the role of genetic factors better. Capture-recapture analysis suggests that a substantial portion of IgAV cases may remain unrecognized in epidemiological surveys.

Inducible nitric oxide synthase gene polymorphisms are associated with a risk of nephritis in Henoch-Schönlein purpura children

Henoch-Schönlein purpura (HSP) is the most common form of systemic small-vessel vasculitis in children, and HSP nephritis (HSPN) is a major complication of HSP and is the primary cause of morbidity and mortality. Previous studies have suggested that inducible nitric oxide synthase (iNOS) may play an important role in the pathogenesis of HSP. In this study, we performed a detailed analysis to investigate the potential association between iNOS polymorphisms and the risk of HSP and the tendency for children with HSP to develop HSPN in a Chinese Han population. A promoter pentanucleotide repeat (CCTTT)n and 10 functional single-nucleotide polymorphisms (SNPs) from 532 healthy controls and 513 children with HSP were genotyped using the MassARRAY system and GeneScan. The results suggested that the allelic and genotypic frequencies of the rs3729508 polymorphism were nominally associated with susceptibility to HSP. In addition, there was a significant difference in the allelic distribution of the (CCTTT)12 repeats and rs2297518 between the HSP children with and without nephritis; the HSP children with nephritis exhibited a significantly higher frequency of the (CCTTT)12 repeats and A allele of rs2297518 than the HSP children without nephritis (P _FDR = 0.033, OR = 1.624, 95% CI = 1.177-2.241 and P _FDR = 0.030, OR = 1.660, 95% CI = 1.187-2.321, respectively).

CONCLUSION

Our results support that iNOS polymorphisms are associated with the risk of HSP and may strongly contribute to the genetic basis of individual differences in the progression to nephritis among children with HSP in the Chinese Han population. What is Known: • The etiology of HSP is unknown, but the genetic factors may play an important role in the pathogenesis of HSP. • iNOS could contribute to the development and clinical manifestations of HSP, and this has not been studied extensively so far. What is New: • Our results support that iNOS polymorphisms not only are associated with HSP risk but also strongly contribute to the genetic basis of individual differences in the progression of HSP to nephritis among Chinese Han children.

A genome-wide association study suggests the HLA Class II region as the major susceptibility locus for IgA vasculitis

The genetic component of Immunoglobulin-A (IgA) vasculitis is still far to be elucidated. To increase the current knowledge on the genetic component of this vasculitis we performed the first genome-wide association study (GWAS) on this condition. 308 IgA vasculitis patients and 1,018 healthy controls from Spain were genotyped by Illumina HumanCore BeadChips. Imputation of GWAS data was performed using the 1000 Genomes Project Phase III dataset as reference panel. After quality control filters and GWAS imputation, 285 patients and 1,006 controls remained in the datasets and were included in further analysis. Additionally, the human leukocyte antigen (HLA) region was comprehensively studied by imputing classical alleles and polymorphic amino acid positions. A linkage disequilibrium block of polymorphisms located in the HLA class II region surpassed the genome-wide level of significance (OR = 0.56, 95% CI = 0.46–0.68). Although no polymorphic amino acid positions were associated at the genome-wide level of significance, P-values of potential relevance were observed for the positions 13 and 11 of HLA-DRB1 (P = 6.67E-05, P = 1.88E-05, respectively). Outside the HLA, potential associations were detected, but none of them were close to the statistical significance. In conclusion, our study suggests that IgA vasculitis is an archetypal HLA class II disease.

A Case of Henoch-Schonlein Purpura Associated with Rotavirus Infection in an Elderly Asian Male and Review of the Literature

Patient: Male, 73

Final Diagnosis: Henoch-Schönlein purpura (HSP)

Symptoms: Abdominal pain • bloating • blood in stool • nausea • vomiting

Medication: —

Clinical Procedure: EGD • colonoscopy • kidney biopsy • skin biopsy • arthrocentesis

Specialty: Rheumatology

Relapses in patients with Henoch-Schönlein purpura: Analysis of 417 patients from a single center

To further investigate into the relapses of Henoch-Schönlein purpura (HSP), we analyzed the frequency, clinical features, and predictors of relapses in series of 417 unselected patients from a single center. After a median follow-up of 12 (interquartile range [IQR]: 2-38) years, almost one-third of the 417 patients (n = 133; 32%; 85 men/48 women) had experienced at least 1 relapse. At the time of disease diagnosis, patients who later experienced relapses had less commonly infections than those who never suffered flares (30.8% vs 41.9%; P = 0.03). In contrast, patients who experienced relapses had a longer duration of the first episode of palpable purpura than those without relapses (palpable purpura lasting >7 days; 80.0% vs 68.1%; P = 0.04). Abdominal pain (72.3% vs 62.3%; P = 0.03) and joint manifestations (27.8% vs 15.5%; P = 0.005) were also more common in patients who later developed relapses. In contrast, patients who never suffered relapses had a slightly higher frequency of fever at the time of disease diagnosis (9.3% vs 3.8%; P = 0.06). At the time of disease diagnosis, corticosteroids were more frequently given to patients who later had relapses of the disease (44% vs 32% in nonrelapsing patients; P = 0.03). Relapses generally occurred soon after the first episode of vasculitis. The median time from the diagnosis of HSP to the first relapse was 1 (IQR: 1-2) month. The median number of relapses was 1 (IQR 1-3). The main clinical features at the time of the relapse were cutaneous (88.7%), gastrointestinal (27.1%), renal (24.8%), and joint (16.5%) manifestations. After a mean ± standard deviation follow-up of 18.9 ± 9.8 years, complete recovery was observed in 110 (82.7%) of the 133 patients who had relapses. Renal sequelae (persistent renal involvement) was found in 11 (8.3%) of the patients with relapses. The best predictive factors for relapse were joint and gastrointestinal manifestations at HSP diagnosis (odds ratio [OR]: 2.22; 95% confidence interval [CI]: 1.34-3.69, and OR: 1.60; 95% CI: 1.01-2.53, respectively). In contrast, a history of previous infection was a protective factor for relapses (OR: 0.60; 95% CI: 0.38-0.94). In conclusion, joint and gastrointestinal manifestations at the time of diagnosis of HSP are predictors of relapses.

[Significance of detection of biomarker fecal bile acids in the diagnosis and treatment of childhood Henoch-Schönlein purpura]

OBJECTIVE

To investigate the changes and clinical significance of biomarker fecal bile acids (BA) in children with Henoch-Schönlein purpura (HSP).

METHODS

Nineteen children with HSP and twenty-seven healthy children were enrolled in this study. The stool samples were obtained at the acute and remission phases. Fecal BA levels were measured by high performance liquid chromatography mass spectrometry (HPLC-MS).

RESULTS

The fecal cholic acid level in the HSP remission group was significantly higher than in the HSP acute group and the healthy control group (P<0.016). The fecal chenodeoxycholic acid level in the HSP remission group was significantly higher than in the healthy control group (P<0.016). The levels of fecal secondary colonic bile acids, deoxycholic acid and lithocholic acid, in the HSP acute and remission groups were significantly lower than in the healthy control group(P<0.05, P<0.016 respectively). No significant differences were found in the levels of fecal urosodeoxycholic acid among the three groups (P>0.05).

CONCLUSIONS

Fecal secondary colonic bile acids, deoxycholic acid and lithocholic acid, are in decrease in children with HSP at the acute stage, which may be involved in the pathogenesis and treatment outcomes of HSP.

Role of PTPN22 and CSK gene polymorphisms as predictors of susceptibility and clinical heterogeneity in patients with Henoch-Schönlein purpura (IgA vasculitis)

Introduction

To determine whether the PTPN22 (protein tyrosine phosphatase nonreceptor 22)/CSK (c-src tyrosine kinase) pathway is implicated in the susceptibility and clinical heterogeneity of Henoch-Schönlein purpura (HSP) in the largest series of Caucasian HSP patients ever assessed for genetic studies.

Methods

A set of 329 Spanish patients diagnosed with HSP fulfilling the American College of Rheumatology and the Michel et al. classification criteria and 515 sex and ethnically matched controls were recruited in this study. Two well-known CSK (CSK rs34933034 and CSK rs1378942) and two functional PTPN22 (PTPN22 rs2476601 (R620W) and PTPN22 rs33996649 (R263Q)) polymorphisms, previously associated with autoimmunity, were genotyped with TaqMan single nucleotide polymorphism (SNP) genotyping assays.

Results

No significant differences in the genotype and allele frequencies between HSP patients and controls were observed when the CSK rs34933034, CSK rs1378942, PTPN22 rs2476601 (R620W) and PTPN22 rs33996649 (R263Q) polymorphisms were analyzed independently. In keeping with this observation, no significant differences were found when we assessed these polymorphisms combined conforming haplotypes. In addition, there were no differences in the allele or genotype frequencies when HSP patients were stratified according the age at disease onset, sex, presence of arthralgia/arthritis, nephritis or gastrointestinal manifestations.

Conclusions

Our results do not support association between PTPN22/CSK and HSP.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0796-x) contains supplementary material, which is available to authorized users.