Deregulation in adult IgA vasculitis skin as the basis for the discovery of novel serum biomarkers

INTRODUCTION

Immunoglobulin A vasculitis (IgAV) in adults has a variable disease course, with patients often developing gastrointestinal and renal involvement and thus contributing to higher mortality. Due to understudied molecular mechanisms in IgAV currently used biomarkers for IgAV visceral involvement are largely lacking. Our aim was to search for potential serum biomarkers based on the skin transcriptomic signature.

METHODS

RNA sequencing analysis was conducted on skin biopsies collected from 6 treatment-naïve patients (3 skin only and 3 renal involvement) and 3 healthy controls (HC) to get insight into deregulated processes at the transcriptomic level. 15 analytes were selected and measured based on the transcriptome analysis (adiponectin, lipopolysaccharide binding protein (LBP), matrix metalloproteinase-1 (MMP1), C-C motif chemokine ligand (CCL) 19, kallikrein-5, CCL3, leptin, C-X-C motif chemokine ligand (CXCL) 5, osteopontin, interleukin (IL)-15, CXCL10, angiopoietin-like 4 (ANGPTL4), SERPIN A12/vaspin, IL-18 and fatty acid-binding protein 4 (FABP4)) in sera of 59 IgAV and 22 HC. Machine learning was used to assess the ability of the analytes to predict IgAV and its organ involvement.

RESULTS

Based on the gene expression levels in the skin, we were able to differentiate between IgAV patients and HC using principal component analysis (PCA) and a sample-to-sample distance matrix. Differential expression analysis revealed 49 differentially expressed genes (DEGs) in all IgAV patient's vs. HC. Patients with renal involvement had more DEGs than patients with skin involvement only (507 vs. 46 DEGs) as compared to HC, suggesting different skin signatures. Major dysregulated processes in patients with renal involvement were lipid metabolism, acute inflammatory response, and extracellular matrix (ECM)-related processes. 11 of 15 analytes selected based on affected processes in IgAV skin (osteopontin, LBP, ANGPTL4, IL-15, FABP4, CCL19, kallikrein-5, CCL3, leptin, IL-18 and MMP1) were significantly higher (p-adj < 0.05) in IgAV serum as compared to HC. Prediction models utilizing measured analytes showed high potential for predicting adult IgAV.

CONCLUSION

Skin transcriptomic data revealed deregulations in lipid metabolism and acute inflammatory response, reflected also in serum analyte measurements. LBP, among others, could serve as a potential biomarker of renal complications, while adiponectin and CXCL10 could indicate gastrointestinal involvement.

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.

Mendelian randomization analysis reveals causality of inflammatory bowel disease on risks of Henoch-Schönlein purpura and immune thrombocytopenia

BACKGROUND

Emerging clinical evidence has been discovered associating Inflammatory bowel disease (IBD) with Henoch-Schönlein purpura (HSP) and immune thrombocytopenia (ITP). However, it is unclear whether a cause-effect relationship exists between them. We aimed to examine the casual effect of IBD on the risk of HSP and ITP.

METHODS

Based on summary statistics from International IBD Genetics (IIBDG) Consortium and FinnGen study, a two-sample Mendelian randomization study was carried out to determine whether IBD including ulcerative colitis (UC) and Crohn's disease (CD) is causally related to HSP, ITP or secondary thrombocytopenia. To support the results, a variety of sensitivity analyses were performed.

RESULTS

Significant causal relationships between IBD and HSP (odds ratios = 1.20, 95% confidence interval: 1.07-1.36, adjusted P = 0.006) and ITP (odds ratios =1.22, 95% confidence interval: 1.08-1.38, adjusted P = 0.006) were found. Both genetically predicted UC and CD were positively related with ITP, while CD alone may be responsible for the higher risk of HSP. Besides, no significant association was observed between IBD and secondary thrombocytopenia.

CONCLUSIONS

The results of this Mendelian randomization study supported the causal association of IBD with HSP and ITP. Taken together, our findings may present implications for management of IBD.

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.

Long noncoding RNA MEG8 induces an imbalance of Th17/Treg cells through the miR-107/STAT3 axis in Henoch-Schonlein purpura rats

T-helper (Th) 17/ T-regulatory (Treg) cell dysregulation underlies the pathogenesis of Henoch-Schonlein purpura (HSP). This research focused on the implication/s of the long noncoding RNA (lncRNAs) maternally expressed gene 8 (MEG8) in Th17 and Treg cell differentiation in HSP rats. MEG8, miR-107, signal transducer and activator of transcription-3 (STAT3), receptor-related orphan receptor γt (RORγt), and the transcription factor forkhead box P3 (Foxp3) expression levels were detected using real-time quantitative polymerase chain reaction and Western blot analyses. Flow cytometry was employed for measuring Th17 and Treg cells within the CD4+ T cell population. The interaction between miR-107 and MEG8 or STAT3 was examined. A low proportion of MEG8 and Treg cells together with Th17 cells were denoted within HSP rats. Moreover, MEG8 overexpression altered the Th17/Treg imbalance in peripheral blood CD4+ T-cell population, and the miR-107 mimic and STAT3 silencing reversed this effect. Thus, MEG8 served as a sponge for miR-107, lowering binding activity to STAT3 and thus overexpressing the molecule. Taken together, MEG8 induces an imbalance of Th17/Treg cells through the miR-107/STAT3 axis in HSP rats.

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.

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.

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.

Identification of a shared genetic risk locus for Kawasaki disease and immunoglobulin A vasculitis by a cross-phenotype meta-analysis

OBJECTIVES

Combining of genomic data of different pathologies as a single phenotype has emerged as a useful strategy to identify genetic risk loci shared among immune-mediated diseases. Our study aimed to increase our knowledge of the genetic contribution to Kawasaki disease (KD) and IgA vasculitis (IgAV) by performing the first comprehensive large-scale analysis on the genetic overlap between them.

METHODS

A total of 1190 vasculitis patients and 11 302 healthy controls were analysed. First, in the discovery phase, genome-wide data of 405 KD patients and 6252 controls and 215 IgAV patients and 1324 controls, all of European origin, were combined using an inverse variance meta-analysis. Second, the top associated polymorphisms were selected for replication in additional independent cohorts (570 cases and 3726 controls). Polymorphisms with P-values ≤5 × 10-8 in the global IgAV-KD meta-analysis were considered as shared genetic risk loci.

RESULTS

A genetic variant, rs3743841, located in an intron of the NAGPA gene, reached genome-wide significance in the cross-disease meta-analysis (P = 8.06 × 10-10). Additionally, when IgAV was individually analysed, a strong association between rs3743841 and this vasculitis was also evident [P = 1.25 × 10-7; odds ratio = 1.47 (95% CI 1.27, 1.69)]. In silico functional annotation showed that this polymorphism acts as a regulatory variant modulating the expression levels of the NAGPA and SEC14L5 genes.

CONCLUSION

We identified a new risk locus with pleiotropic effects on the two childhood vasculitides analysed. This locus represents the strongest non-HLA signal described for IgAV to date.

LncRNA MEG8 sponging miR-181a-5p contributes to M1 macrophage polarization by regulating SHP2 expression in Henoch-Schonlein purpura rats

BACKGROUND

Long noncoding RNAs (LncRNAs) are regulatory molecules that play important roles in various biological and pathological processes. Herein, we aimed to explore whether maternally expressed gene 8 (MEG8) promotes M1 macrophage polarization among Henoch-Schonlein purpura (HSP) rats, and to investigate the underlying mechanism.

METHODS

Relative mRNA expression of MEG8, miR-181a-5p and suppressor of SH2 domain-containing tyrosine phosphatase 2 (SHP2) were examined using quantitative reverse transcription polymerase chain reaction. Furthermore, expression of SHP2 and the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway-related proteins was identified using western blot. Luciferase activity assay was conducted to evaluate whether miR-181a-5p could bind to MEG8 or SHP2. The macrophage phenotype was determined using flow cytometry and enzyme-linked immunosorbent assay.

RESULTS

We observed macrophage polarization towards the M2 phenotype in the peripheral blood of HSP rats. Furthermore, MEG8 and SHP2 expression were down-regulated, while miR-181a-5p was up-regulated in monocyte-derived macrophages from the HSP rats compared to the control group. Furthermore, MEG8 functioned as a sponge for miR-181a-5p in order to facilitate SHP2 expression. Moreover, miR-181a-5p mimic and SHP2 knockdown significantly reversed the MEG8 overexpression-mediated suppression of JAK2/STAT3 signalling, and promotion of M1 polarization.

CONCLUSIONS

The lncRNA MEG8 sponged miR-181a-5p, which contributes to M1 macrophage polarization by regulating SHP2 expression in HSP rats.Key MessagesLncRNA MEG8 downregulation and M2 polarization in Henoch Schonlein purpura rats.MEG8 upregulation enhances M1 polarization and suppresses JAK2/STAT3 pathway.MEG8 sponges miRNA-181a-5p to regulate SHP2 expression.MiRNA-181a-5p upregulation reverses lncRNA MEG8-mediated enhancement of M1 polarization and inhibition of JAK2/STAT3 pathway.SHP2 downregulation reverses lncRNA MEG8-mediated enhancement of M1 polarization and inhibition of JAK2/STAT3 pathway.

New susceptible locus, rs9428555, is associated with pediatric-onset immunoglobulin A nephropathy and immunoglobulin A vasculitis in Koreans

BACKGROUND

Immunoglobulin A nephropathy (IgAN) is one of the most common primary forms of glomerulonephritis, while IgA vasculitis (IgAV) is the most common systemic vasculitis in children.

OBJECTIVE

Herein we aimed to uncover single nucleotide polymorphism (SNP) markers associated with these two related diseases by applying association tests and Sanger sequencing.

METHODS

Within the discovery stage, genomic DNA in blood samples from 101 enrolled patients were genotyped by the Korean Biobank Array. Association tests were performed with 397 Korean reference genomes. In the validation stage, 26 independent samples were genotyped by Sanger sequencing.

RESULTS

Four SNPs were identified (P < 5 × 10^-8) in the discovery stage. To determine whether the genotypes determined by SNP array were accurate, additional genotyping via Sanger sequencing was performed. As a result, only one SNP, rs9428555, was properly genotyped. In the validation stage, the minor allele (A > G) was found in as many as 15 out of 26 samples (minor allele frequency = 0.288), even though this minor allele is rare in East Asians (< 3%).

CONCLUSIONS

We found rs9428555 as a novel susceptible locus associated with the development of both IgAN and IgAV in Koreans. Though we cannot conclude rs9428555 is the unique susceptible locus of IgAN and IgAV, it is likely a good marker as the minor allele of this SNP occurred much more often in the patient group here versus within East Asians as a whole.

Exploration of susceptible genes associated with Henoch-Schönlein purpura by whole exome sequencing

BACKGROUND

Henoch-Schönlein purpura (HSP) is a systemic small-vessel vasculitis caused by environmental and inherent factors. Although recent research has advanced our understanding of the role of genetic susceptibility in HSP, there are still significant gaps in our knowledge.

OBJECTIVES

In this study, we aimed to explore some susceptibility genes likely associated with HSP.

MATERIAL AND METHODS

Three DNA samples from a family with HSP were used to perform whole exome sequencing with Illumina Hiseq 2500 high-throughput sequencing. The relevant single nucleotide variants (SNVs) were screened according to specific filter conditions and the screened SNVs were then verified with Sanger sequencing. The Sanger sequencing results were further screened according to available literature. Finally, candidate genes were validated in 92 samples from children with HSP, and also in 1 child with HSP from HSP family, using the polymerase chain reaction technique (PCR).

RESULTS

Our analysis revealed that the MIF gene and the MGAT5 gene related to immunity remained after screening. Among the 93 children with HSP, there were 3 patients with MIF mutations and 2 patients with MGAT5 mutations.

CONCLUSIONS

Our findings are helpful for providing new methods and ideas for understanding the pathogenesis of HSP by detecting and analyzing gene mutations at the whole-exome level including multi-generation sequencing. MIF and MGAT5 may be new susceptibility loci for HSP, but their roles in the pathogenesis of HSP are worthy of further study.

MicroRNA expression in the affected skin of adult patients with IgA vasculitis

IgA vasculitis (IgAV) represents a common systemic vasculitis in pediatric and adult population. Our current knowledge of disease pathogenesis is still very limited, without information on miRNAs in IgAV. The aim of our study was to determine the expression of five pre-selected miRNAs (miRNA-146a-5p, miRNA-148-3p, miRNA-155-5p, miRNA-223-3p, and let-7b) in the affected skin of adult IgAV patients. The study included 65 skin samples from consecutive, untreated IgAV patients (61.5% male, median age 67.6 years, range 29-91), diagnosed between October 2014 and September 2016, and 20 samples of normal skin from healthy volunteers. Total RNA was isolated from tissue sections of formalin-fixed, paraffin-embedded samples. Expression of miRNAs was measured using qRT-PCR. To present relative miRNA expression, the ΔΔCT method was used. Skin miRNA expression was correlated to clinical characteristics of adult IgAV patients. We found significantly higher levels of miRNA-155-5p, miRNA-223-3p, and let-7b in the affected skin compared to controls (18.6-fold, 6.4-fold, and 7.9-fold higher respectively). Contrary, the miRNA 148-3p expression was significantly lower (2.2-fold). The expression of the miRNA-146-5p showed near normal levels. Patients with necrotic skin lesions had significantly higher miRNA-223 tissue expression than those with non-necrotic purpura (p = 0.029). Gastrointestinal tract involvement inversely correlated with the expression of miRNA-155-5p and/or miRNA-146a-5p in affected skin. Altered expression of miRNA-148b-3p, miRNA-155-5p, miRNA-223-3p, and let-7b was found in vasculitic skin lesions in IgAV. Additionally, we found a positive association between the severity of purpura and skin miRNA-223-3p expression. Aberrantly expressed miRNAs could represent a biomarker in adult IgAV.

Association between the functional PTPN22 G788A (R263Q) polymorphism and susceptibility to autoimmune diseases: A meta-analysis

This study explored whether the functional protein tyrosine phosphatase nonreceptor 22 (PTPN22) G788A (R263Q) polymorphism is associated with susceptibility to autoimmune diseases. A meta-analysis was conducted using 23 comparative studies with a total of 16,719 patients and 17,783 controls. The meta-analysis showed an association between the A allele of the PTPN22 G788A polymorphism and decreased risk of autoimmune diseases in all subjects (p &lt; 0.001). Analysis after stratification by ethnicity indicated that the PTPN22 788A allele was significantly associated with autoimmune diseases in Europeans (p &lt; 0.001) but not in Latin Americans. Meta-analysis by autoimmune disease type showed a significant negative association between the PTPN22 788A allele and systemic lupus erythematous (SLE) (p = 001), rheumatoid arthritis (RA) (p = 0.008), ulcerative colitis (UC) (p = 0.016), but not Crohn's disease (CD). A single study for each showed no association between the PTPN22 788A allele and systemic sclerosis, giant cell arteritis, Henoch-schonlein purpura, uveitis, and Grave's disease. This meta-analysis demonstrates that the PTPN22 G788A polymorphism confers protection against SLE, RA, and UC, supporting evidence of association of the PTPN22 gene with a subgroup of autoimmune diseases.

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.

Defective activation of the MAPK/ERK pathway, leading to PARP1 and DNMT1 dysregulation, is a common defect in IgA nephropathy and Henoch-Schönlein purpura

Studies on IgA nephropathy (IgAN) have identified, through GWAS, linkage analysis, and pathway scanning, molecular defects in familial and sporadic IgAN patients. In our previous study, we identified a novel variant in the SPRY2 gene that segregates with the disease in one large family. The functional characterization of this variant led us to discover that the MAPK/ERK pathway was defective not only in this family, but also in two sporadic IgAN patients wild type for SPRY2. In the present study, we have deepened the molecular analysis of the MAPK/ERK pathway and extended our evaluation to a larger cohort of sporadic patients and to one additional family. We found that the ERK pathway is defective in IgAN patients and in patients affected by another IgA-mediated disorder, Henoch-Schönlein purpura (HSP). Furthermore, we found that two other proteins, PARP1 and DNMT1, respectively involved in DNA repair and in antibody class switching and methylation maintenance duties, were critically downregulated in IgAN and HSP patients. This study opens up the possibility that defective ERK activation, in some patients, leads to PARP1 and DNMT1 downregulation suggesting that IgAN could be the consequence of a dysregulated epigenetic maintenance leading to the upregulation of several genes. In particular, PARP1 could be used as a potential biomarker for the disease.

Association of ACE, VEGF and CCL2 gene polymorphisms with Henoch-Schönlein purpura and an evaluation of the possible interaction effects of these loci in HSP patients

BACKGROUND

Henoch-Schönlein purpura (HSP) is a multisystem, small vessel, leucocytoclastic vasculitis. It is predominantly a childhood vasculitis, rarely reported in adults. Studies have shown that several different genetic factors such as genes involved in inflammatory system and renin-angiotensin system (RAS) are important in the pathogenesis of Henoch-Schönlein purpura.

OBJECTIVES

The purpose of this study was to evaluate the independent effect of 3 gene polymorphisms including CCL2-2518 C/T, VEGF-634G/C and ACE(I/D) with HSP disease and their possible joint interactions in developing the disease.

MATERIAL AND METHODS

In this case-control study 47 HSP cases and 74 unrelated healthy controls were enrolled for evaluation. All individuals were genotyped for CCL2-2518C/T, VEGF-634G/C and ACE(I/D) gene polymorphisms. The possible association of these polymorphisms with susceptibility to develop HSP disease independently and in different joint combinations was evaluated.

RESULTS

The frequencies of TT genotype and T allele of CCL2-2518C/T gene polymorphism and CC genotype and C allele of VEGF-634G/C gene polymorphism were significantly high in HSP children (p-values = 0.005 and = 0.007 respectively). Interestingly, studying the joint interaction of these 2 genotypes (CC genotype of VEGF G-634C and TT genotype of CCL2 C-2518T) in this cohort showed a more significant effect in the development of the disease (p < 0.000, OR = 6.009). The frequency of TT genotype of CCL2 gene when combined with II genotype of ACE gene in HSP children was significantly higher (p < 0.000, OR = 4.213).

CONCLUSIONS

The results of this pilot study provide evidence of the possible gene-gene interaction effects of CCL2, VEGF and ACE genes in developing HSP disease.

[Association between CTLA-4 gene polymorphism and Henoch-Schönlein purpura in children]

OBJECTIVE

To investigate the association between CTLA-4 gene polymorphism and Henoch-Schönlein purpura (HSP) in children.

METHODS

Sixty children who were diagnosed with HSP were enrolled as the case group, consisting of 33 males and 27 females. Thirty healthy children were enrolled as the control group. The patients were further divided into HSP nephritis (HSPN) and non-HSPN groups (n=30 each) according to the presence or absence of nephritis. Polymerase chain reaction-restriction fragment length polymorphism was used to analyze the genotype and allele frequencies at +49 and -1722 loci.

RESULTS

AA, AG, and GG genotypes were detected at +49; neither genotype nor allele frequencies showed significant differences between the case and control groups, between the HSPN and non-HSPN groups, and between male and female patients (P>0.05). TT, TC, and CC genotypes were detected at -1722; neither genotype nor allele frequencies showed significant differences between the case and control groups and between male and female patients (P>0.05). There were significant differences in CC genotype frequency and T and C allele frequencies between the HSPN and non-HSPN groups (P<0.05). Combinational analysis of +49 A/G and -1722 T/C showed no significant differences in the genotype frequency between the case and control groups and between male and female patients (P>0.05). GG-CC combination showed a significant difference between the HSPN and non-HSPN groups (P<0.05).

CONCLUSIONS

CTLA-4 +49 A/G polymorphism is not associated with HSP. CC genotype and C allele of CTLA-4 -1722 and the combination of GG at +49 A/G and CC at -1722 T/C may be risk factors for HSPN.

[Association of Cosmc gene mutation with susceptibility to Henoch-Schönlein purpura in children]

OBJECTIVE

To investigate the presence of Cosmc gene mutation in children with Henoch-Schönlein purpura (HSP) and the association between Cosmc gene mutation and the susceptibility to HSP.

MESULTS

Eighty-four children who were diagnosed with HSP between March 2014 and December 2015 were selected as the HSP group. Fifty-eight healthy volunteers matched for age and sex were enrolled as the control group. Fasting venous blood (5 mL) from the two groups was collected in EDTA anticoagulated tubes, followed by the isolation of peripheral blood mononuclear cells (PBMCs) through density gradient centrifugation. Genomic DNA was extracted from PBMCs according to the manufacturer's protocol, and the whole exon region of Cosmc gene was amplified by touch-down polymerase chain reaction (touch-down PCR). The PCR products were identified by 1% agarose gel and sequenced in order to further examine the association between Cosmc gene mutation and the susceptibility to HSP.

RESULTS

Sequencing results showed two mutations (c.393T>A and c.72A>G) of Cosmc gene in children with HSP. There were no significant differences in the genotype and allele frequencies at the two loci between the HSP and control groups, and this distribution was not associated with sex.

CONCLUSIONS

The mutations c.393T>A and c.72A>G in the exon region of Cosmc gene in children with HSP are not associated with the onset of HSP.

Lack of Association between Interleukin-8 Gene +781 C/T Polymorphism and Henoch-Schönlein Purpura in Childhood

Henoch-Schönlein purpura (HSP), a common allergic hemorrhagic disease, occurs frequently in children affecting kidney, joint and skin. While interleukin-8 (IL-8) plays an important role in inflammation, the association between IL-8 gene +781 C/T polymorphism and HSP remains unclear. Interleukin-8, an important chemokine related to the initiation and amplification of acute inflammatory responses, has been reported to be involved in the pathogenesis of some autoimmune and inflammatory diseases. In this study, we aimed to investigate whether IL-8 gene +781 C/T (rs2227306) polymorphism has an influence on susceptibility and clinical manifestations of patients to HSP. This hospital-based case-control study comprised 192 patients with HSP and 202 healthy controls. The genotypes of IL-8 gene +781 C/T polymorphism were identified using PCR-TaqMan method. All genotype frequencies of both groups (patients and controls) conformed to the Hardy-Weinberg equilibrium. No significant differences in allele or genotype frequencies of IL-8 gene +781 C/T polymorphism were observed between patients with HSP and controls (p=0.98, χ2=0.000 and p=0.49, χ2=1.432, respectively). When patients were stratified for the presence of joint, gastrointestinal and renal manifestations, genotype frequencies of IL-8 gene polymorphism were found no statistically significant differences (p>0.05). Our findings do not support that IL-8 gene +781 C/T polymorphism has an effect on the susceptibility to HSP in Chinese children.

Interleukin 1 beta (IL1ß) rs16944 genetic variant as a genetic marker of severe renal manifestations and renal sequelae in Henoch-Schönlein purpura

OBJECTIVES

Data from a small series suggested that the Interleukin 1 beta (IL1ß) rs16944 polymorphism may be associated with severe renal involvement and persistent renal damage (renal sequelae) in Henoch-Schönlein purpura (HSP). To confirm this association, we assessed the largest cohort of Caucasian HSP patients ever considered for genetic studies.

METHODS

338 Spanish HSP patients and 635 sex and ethnically matched controls were recruited in this study. All patients were required to have had at least 6 months' follow-up. Patients and controls were genotyped for IL1β rs16944 by TaqMan genotyping assay.

RESULTS

No differences between IL1β rs16944 genotype or allele frequencies were found either in the case/control study or when HSP patients were stratified according to the age at disease onset, presence of nephritis or gastrointestinal manifestations. Nevertheless, 4 (25%) of the 16 HSP patients who developed severe renal manifestations carried the TT genotype versus 29 (9%) of 322 who did not develop this complication (p=0.01, OR=5.48, 95% CI: 1.01-28.10). Accordingly, patients carrying the mutant T allele had an increased risk of developing severe nephropathy (p=0.016, OR=2.35, 95% CI: 1.09-5.07). Additionally, a significant increase of the TT genotype was observed in patients with persistent renal damage when compared with those patients without this complication (25% versus 8.6%, respectively; p=0.0035, OR=4.90, 95% CI: 1.26- 18.51). Moreover, renal sequelae were more common in patients carrying the mutant T allele (p=0.0076, OR=2.20, 95% CI: 1.17-4.14).

CONCLUSIONS

Our results support that the IL1ß rs16944 polymorphism may be a potential marker of severe renal manifestations and renal sequelae in HSP.

[The contribution of genes polymorphism of thrombophilia in clinical variability of hemorrhagic vasculitis]

BACKGROUND

The article is devoted to the study of clinical and laboratory characteristics of the current of hemorrhagic vasculitis in children in the Republic of Buryatia.

PATIENTS AND METHODS

The study included 27 patients aged 7.6 +/- 4.02 years, who conducted clinical and laboratory tests, immunological study of antiphospholipids of antibodies, genetic testing for thrombophilia markers of candidate genes.

RESULTS

The results showed that hemorrhagic vasculitis often affects children of Buryat nationality. In 96% of cases there are mixed clinical forms of the disease. 63% of children of hemorrhagic vasculitis preceded by various factors, a higher percentage of infectious diseases. The first clinical symptom in 63% of patients is a typical purpura hemorrhagic rash. Results of clinical laboratory blood tests revealed no significant deviations. Circulation of lupus anticoagulant was detected in 37% of subjects. The alphaCL IgM detected in 3 children, alphabeta2-GP-I IgA--in 4, alphabeta2-GP-I IgM--in 1 patient. Carriers of thrombophilia polymorphisms were in 95% of children. Noted that homozygous variants of genes polymorphisms of methylenetetrahydrofolatered reductase and plasminogen activator inhibitor-1 correlate with the presence of urinary symptoms and recurrence of the rash.

CONCLUSION

The study shows the risk of recurrent flow of hemorrhagic vasculitis and nefritis of Henoch-Schonlein in children with thrombophilia gene polymorphism.

[Meta-analysis of the association between angiotension-converting enzyme I/D polymorphism and susceptibility to children with Henoch-Schönlein purpura or Henoch-Schölein purpura nephritis]

OBJECTIVE

To explore the relationship between angiotension-converting enzyme (ACE) I/D polymorphism and susceptibility to Henoch-Schönlein purpura or Henoch-Schönlein purpura nephritis (HSP/HSPN) especially among Chinese children.

METHODS

The publications up to December 31, 2013 from PubMed, Embase, Google Scholar, Springer Link, Highwire, Cochrane, ISI, CNKI and Wanfang databases were searched for relevant literature on the association between ACE I/D polymorphism and pediatric HSP/HSPN. Heterogeneity was evaluated. And Stata 12.0 was used to assess the association strength in terms of odds ratio (OR) and 95% CI.

RESULTS

A total of 11 case-control studies fulfilled the inclusion criteria. And 5 articles were indentified for analyzing the relationship between ACE I/D polymorphism and pediatric HSP risk, involving 512 cases and 631 controls.Significantly risks of HSP were found (D/I: OR (95% CI) = 1.23 (1.04-1.46), P < 0.05; DD/DI + II:OR (95% CI) = 1.24 (0.77-2.00), P > 0.05 and II/DD+DI: 0.68 (0.52-0.90), P < 0.05). Nine articles were indentified for analyzing the relationship between ACE I/D polymorphism and pediatric HSPN risk, involving 446 cases and 877 controls.Significant risks of pediatric HSPN were found (D/I: OR (95% CI) = 1.52 (1.14-2.04), P < 0.05; DD/DI+II: OR(95% CI) = 1.85 (1.06-3.21), P < 0.05; II/DD+DI: OR(95%CI) = 0.62 (0.47-0.82), P < 0.05).

CONCLUSIONS

In different ethnic groups, genotype DD of ACE I/D may increase the risk of pediatric HSP/HSPN and thus constitute a risk factor. Genotype II of ACE I/D may decrease the risks of pediatric HSP/HSPN and it may be a constitutively protective factor for pediatric HSP/HSPN.

Interferon-gamma gene polymorphism +874 (a/t) in Chinese children with Henoch-Schonlein purpura

The aim of this study was to investigate the possible influence of Interferon-gamma (IFN-γ) gene polymorphism +874 (A/T) (rs2430561) in the susceptibility and renal complications of patients with Henoch-Schonlein purpura (HSP). We also studied the effects of IFN-γ allelic variation on serum levels of pro-and anti-inflammatory cytokines in HSP patients. The study population comprised 97 patients suffering from HSP and 97 control participants. Patients and controls were genotyped for a single nucleotide polymorphism +874 (A/T) in the first intron of the IFN-γ gene by the TaqMan PCR method. Frequencies of individuals with IFN-γ +874 AA, AT and TT genotypes were 77.3%, 21.6% and 1% in HSP patients and 79.4%, 17.5% and 3.1% in controls, respectively. The frequency of the AA genotype in HSP patients with nephritis was slightly higher (83.3%) than in HSP patients without nephritis (73.8%). The allele A occurred more commonly in HSP patients with nephritis (92%) than in HSP patients without nephritis (86%), but these differences were not statistically significant (p= 0.469 and p= 0.244, respectively). In addition, significant difference in serum IL-10 levels between IFN-γ +874 different genotype groups was found. Our results do not support a role for IFN-γ gene polymorphism +874 (A/T) in the susceptibility to HSP and allelic variation at IFN-γ +874 locus had no effect on serum levels of cytokines in patients with HSP except for IL-10.

VEGFA rSNPs, transcriptional factor binding sites and human disease

Three regulatory SNPs (rSNPs) in the promoter region of the vascular endothelial growth factor-A (VEGFA) gene have been significantly associated with several human diseases or conditions. The rSNP alleles alter the DNA landscape for potential transcriptional factors to attach, resulting in changes in transcriptional factor binding sites (TFBS). These TFBS changes are examined with respect to the human diseases which have been found to be significantly associated with the rSNPs.

[Association of tumor necrosis factor-alpha gene polymorphisms with Henoch-Schonlein purpura nephritis in children]

OBJECTIVE

To study the relationship of tumor necrosis factor-alpha (TNF-α)-308G/A gene polymorphisms with Henoch-Schonlein purpura nephritis (HSPN) in children.

METHODS

Using the direct DNA sequencing method, polymorphisms in the TNF-α promoter region (-308) were genotyped in 110 Han children with Henoch-Schonlein purpura (HSP group), including 52 children with nephritis and 58 children without nephritis. Plasma TNF-α levels were measured using ELISA. Ninety ethnically matched healthy children were used as the control group.

RESULTS

There were no significant differences in the polymorphisms of TNF-α (-308G/A) between the HSP and control groups (P>0.05). The GA genotype (29% vs 10%) and A allele frequency (18% vs 7%) in HSP children with nephritis (HSPN) were more common than in those without nephritis (P<0.05). Plasma TNF-α levels in HSPN children with GA+AA genotype (7.1±2.3 pg/mL) were significantly higher than those with GG genotype (5.7±1.5 pg/mL) (P<0.05).

CONCLUSIONS

TNF-α-308GA genotype and A allele may contribute to the increased risk for the development of nephritis in children with HSP.

MEFV gene mutations (M694V, V726A, M680I, and A744S) in Iranian children with Henoch-Schönlein purpura

INTRODUCTION

Henoch-Schönlein purpura (HSP) is the most common systemic vasculitis in children. Several risk factors play important role in pathogenesis of HSP. We aimed to study the MEFV gene mutations (M694V, V726A, M680I, and A744S) in Iranian children with HSP.

MATERIAL AND METHODS

50 unrelated pediatric cases were studied regarding M694V, V726A, M680I, and A744S mutations using ASO-PCR method.

RESULTS

24% of cases had a mutation. 22% of cases had M694V mutations. One out of 50 (2%) patients had V726A mutation. In 76% of cases no mutation was determined. In other hand, 13 out of 100 alleles (13%) were carrier for one mutation. 12 out of 100 alleles had M694V mutations (% 12) and I out of 100 alleles had V726A mutation (%1). In 87 out of 100 alleles no mutation was detected. M680I and A744S mutations were not found in tested group. Mutation study and analysis demonstrated that the most frequent mutation was M694V (22%). Frequency of alleles were 0.12, 0.01,0,0,0.13, and 0.87 regarding M694V, V726A, M680I, A744S, total mutation, and wild type alleles, respectively. Our findings imply that M694V was dominant mutation.

CONCLUSIONS

This report as the first investigation of its kind in Iranian Azeri Turkish patients implying that M694V mutations are more frequent in tested group in comparison with general population. So it is suggested that investigation of M694V mutations should be considered as genetic test for diagnosis of HSP among Iranian Azeri Turkish patients.

Prevalence of MEFV gene mutations and their clinical correlations in Turkish children with Henoch-Schönlein purpura

AIM

To investigate the frequency of MEFV mutations and their associations with the clinical and laboratory findings in children with Henoch-Schönlein purpura (HSP).

METHODS

One hundred and seven children with HSP were investigated for 12 common MEFV mutations.

RESULTS

Forty-seven patients (43.9%) were found to have one of the MEFV mutations. Eight patients (7.5%) were homozygous for one mutation, 33 (30.8%) were heterozygous for one and six (5.6%) were compound heterozygous for two mutations. There were no age and sex differences between patients with or without mutations. Scrotal involvement was statistically more frequent in patients with mutations. Leucocyte counts, erythrocyte sedimentation rates, serum C-reactive protein (CRP) concentrations, number of patients with increased CRP levels and number of patients with increased immunoglobulin A concentrations were found to be higher in patients with MEFV mutations. p.M694V was the most frequent mutation and was found to have effects on clinical and laboratory findings in children with HSP. Fifteen patients were started on colchicine with the diagnosis of familial Mediterranean fever (FMF).

CONCLUSION

MEFV mutations are more frequent in HSP than in the general population, and mutation carriers may have more severe clinical findings with higher inflammatory response, suggesting a dysregulation of the inflammatory response because of defective gene encoding the protein pyrine. Investigation of these mutations may be beneficial to follow-up the susceptible patients more closely leading to early diagnosis and treatment of FMF.

[P-selectin gene -2123 polymorphism in children with Henoch-Sch-nlein purpura]

OBJECTIVE

To investigate whether P-selectin gene -2123 polymorphism is associated with the pathogenesis of Henoch-Sch-nlein purpura (HSP) in children.

METHODS

Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) is used to identify the distribution of allele and genotype frequencies of P-selectin gene promoter -2123 polymorphism in 86 children with HSP (including 40 cases of purpura nephritis) and 70 healthy controls.

RESULTS

Compared with the healthy controls, the frequencies of GG genotype and G allele of P-selectin promoter -2123 in children with HSP increased significantly (P<0.05). There were no significant differences in P-selectin promoter -2123 genotype and allele frequencies between the patients with and without nephritis.

CONCLUSIONS

P-selectin gene promoter -2123 polymorphism appears to be associated with the pathogenesis of HSP in children.

The CD18 AvaII polymorphic site not associated with Henoch-Schönlein purpura

Henoch-Schönlein purpura (HSP) is an immune complex-mediated systemic vasculitis. Its genetic etiology remains unknown. CD18, the subunit of integrin beta2 in leukocytes, has essential roles in the expression and function of ITGB2, mediating immune responses. CD18 has been proved to be associated with some systemic vasculitides, such as microscopic polyangiitis and Churg-Strauss syndrome. We aimed to assess the influence of CD18 AvaII polymorphism (rs235326, C->T) in the incidence of HSP and determine its possible implication in severe systemic complications by studying 73 patients with HSP and 156 controls in China. Our results showed that AvaII polymorphism was not associated with HSP susceptibility (odd ratio (OR)=0.48, 95% confidence interval (CI)=0.53-1.39, p=0.63) or with HSP nephritic syndrome (OR=0.88, 95%CI=0.35-2.06, p=0.90). Moreover, we did not observe any significant association between serum parameters, such as CRP, IgA, IgE, C3 and C4, and HSP severity. In conclusion, our results suggested that CD18 AvaII is not associated with HSP susceptibility and its clinical outcomes.

MEFV E148Q polymorphism is associated with Henoch-Schönlein purpura in Chinese children

Henoch-Schönlein purpura (HSP) is a multifactorial inflammatory disease whose pathogenesis remains unknown. Pyrin encoded by the MEFV gene (NM_000243; OMIM 608107) is an important active member of the inflammasome and has been shown to affect the expression of many of the genes involved in immune and inflammatory responses. The aim of our study was to elucidate the possible roles of MEFV genetic variants on the susceptibility to HSP and its clinical outcomes in 78 patients with HSP and 189 controls in China. A significant association was found between the E148Q polymorphism (G->C) and HSP susceptibility (odds ratio 2.76, 95% confidence interval 1.76-4.34, P=0.0001). The C allele of E148Q was associated with joint involvement (P=0.014) but not with HSP nephritis (P=0.1). The clinical score was higher in subjects with the CC genotype than in those with the CG or GG genotype (4.13+/-3.53 vs. 1.94+/-1.70, respectively; P=0.011). P369S was not associated with HSP or other phenotypes. M694V and M680I were absent in our patients. Our results suggest that MEFV E148Q could be a contributory genetic factor to HSP and HSP-related joint syndromes.

Effect of paraoxonase 1 gene polymorphisms on clinical course of Henoch-Schönlein purpura

BACKGROUND

Henoch-Schönlein purpura (HSP) is a systemic vasculitis; its pathogenesis is still unknown. Oxidative stress may play a role in the pathogenesis of HSP. Paraoxonase1 (PON1) is an antioxidant enzyme. Two polymorphisms have been defined in the coding region of the PON1 gene, Q/R192 and L/M55. In the present study, we aimed to investigate the effect of PON1 gene polymorphisms on the course and renal involvement of HSP in Turkish children.

METHOD

Forty-six patients with HSP were compared with 34 healthy children regarding the distribution of PON1 polymorphisms.

RESULTS

PON1 Q/R192 genotype distribution was 58.6% QQ, 32.6% QR and 8.8% RR in the HSP group and 14.3% QQ, 50% QR and 35.7% RR in the control group. The frequency of QQ genotype was higher in the HSP group, and the presence of QQ genotype increased the risk by 3.42-fold for developing HSP (p=0.000, Fisher exact test; odds ratio [OR] = 2.048; 95% confidence interval [95% CI], 1.396-3.00). PON1 L/M55 genotype distribution was 50% LL, 43.5% LM and 6.5% MM in the HSP group and 48% LL, 26% LM and 26% MM in the control group. The frequency of MM genotype was lower in the HSP group, and the presence of MM genotype decreased the risk by 7.38-fold for developing HSP (p=0.009, Fisher exact test; OR=7.380, 95% CI, 1.474-36.953).

CONCLUSION

PON1 polymorphisms may contribute to the pathogenesis and course of HSP, but we suggest that further investigations with larger patient groups are required to confirm our results.

Gene polymorphism of vascular endothelial growth factor in children with Henoch-Schonlein purpura nephritis

OBJECTIVE

To study the relationship of -634G/C gene polymorphism of vascular endothelial growth factor (VEGF) with Henoch-Schonlein purpura nephritis (HSPN) in children.

METHODS

One hundred ethnic Han children with HSP, including 50 children with concurrent nephritis (HSPN group) and 50 children without nephritis (HSP without nephritis group), were enrolled. Fifty age-, sex-and ethnics-matched healthy children were used as the control group. VEGF-634G/C genotypes were determined by PCR-RFLP. Plasma VEGF levels were measured using ELISA.

RESULTS

CC genotype distribution (32%) and C allele frequency (56%) in the HSPN group were significantly higher than those in the control group (10% and 35% respectively) and the HSP without nephritis group (10% and 33% respectively) (P<0.01). The incidence of nephritis in HSP patients with CC genotype increased significantly when compared with those with GG genotype (76% vs 31%; P<0.01). Plasma VEGF levels in patients with CC genotype (180.5+/- 40.7 pg/mL) were significantly higher than those in patients with CG (145.2+/- 48.3 pg/mL) and GG (101.5+/- 26.5 pg/mL) genotypes (P<0.05).

CONCLUSIONS

VEGF-634G/C gene polymorphism may be associated with the development of HSPN. C allele may a susceptible gene of HSPN.

CTLA-4 +49 A/G genotype and HLA-DRB1 polymorphisms in Turkish patients with Henoch-Schönlein purpura

The pathogenesis of Henoch-Schönlein purpura (HSP) remains unknown; however, it is generally considered to be an immune complex-mediated disease. Cytotoxic T lymphocyte-associated protein 4 (CTLA-4) is expressed on activated T cells, and, thus, it is critically involved in the immune response. We aimed to investigate the possible influence of CTLA-4 polymorphisms for susceptibility to HSP and determine if there were associations with human leukocyte antigen (HLA)-DRB1 genotypes. Using polymerase chain reaction-based DNA genotyping, we investigated the polymorphisms located in the genes encoding CTLA-4 in 100 patients with HSP and 156 ethnically matched healthy controls. When CTLA-4 +49 A/G polymorphism of HSP patients and control group was compared, no associations with joint, gastrointestinal or renal manifestations, or susceptibility to HSP, were observed. However, patients with nephrotic proteinuria had higher HLA-DRB1*13 positivity [odds ratio (OR) = 3.76, 95% confidence interval (95%CI) = 1.25-11.23, P = 0.025]. When the patients were stratified according to CTLA-4 polymorphism, a significant association between nephrotic proteinuria patients and carriage of the AG genotype was also found (OR = 15.42, 95%CI = 1.59-148.82, P = 0.008). These results suggested that CTLA-4 +49 A/G polymorphism does not contribute to susceptibility to HSP; however, the presence of CTLA-4 AG genotype and HLA-DRB1*13 could be a risk factor for developing nephrotic-range proteinuria in these patients.

HLA-DRB1 alleles and Henoch-Schönlein purpura: susceptibility and severity of disease

OBJECTIVE

The genetic basis of susceptibility to Henoch-Schönlein purpura (HSP) may be conferred by a number of gene loci, including the MHC. Associations between human leukocyte antigen (HLA) and disease can help to establish a basis for susceptibility and assist in the prediction of the outcome and clinical heterogeneity. We aimed to investigate the implications of the HLA-DRB1 locus and the susceptibility to HSP, and to determine if there are associations with joint, gastrointestinal, and renal manifestations of the disease.

METHODS

We studied 110 Turkish patients (men/women: 66/44) with HSP. Patients and ethnically matched controls with respect to age and sex (n = 250) were HLA-DRB1 genotyped from DNA determined using molecular based methods.

RESULTS

HLA-DRB1 genotype differences between patients with HSP and controls were observed. The frequency of HLA-DRB1 11/14 was higher [odds ratio (OR) 1.97, 95% confidence interval (95% CI) 1.25-3.12, p = 0.003; OR = 1.83, 95% CI = 1.02-3.28, p = 0.035, respectively] and the frequency of HLA-DRB1 10/17 was lower (OR = 1.04, 95% CI = 1.01-1.86, p = 0.035; OR = 3.96, 95% CI = 1.17-13.33, p = 0018, respectively) in patients with HSP compared to controls. No HLA-DRB1 associations with gastrointestinal and renal manifestations were found (p > 0.05). In contrast, HLA-DRB1*11 positivity was increased and HLA-DRB1 14 positivity reduced in HSP patients with joint manifestations (OR = 2.68, 95% CI = 1.09-6.66, p = 0.029; OR = 9.34, 95% CI = 3.38-25.64, p = 0.000, respectively). Also, HLA-DRB1 13 positivity was found to be increased in patients with nephrotic proteinuria (OR = 3.76, 95% CI = 1.25-11.23, p = 0.025).

CONCLUSION

These results suggest that genetic factors from HLA-DRB1 genotypes might be related to the susceptibility to HSP for Turkish children but not to the severity of this disease. Additional studies are required to confirm the association of alleles encoded in the HLA region with the disease progression and severity.

Lack of association of a functional single nucleotide polymorphism of PTPN22, encoding lymphoid protein phosphatase, with susceptibility to Henoch-Schönlein purpura

OBJECTIVE

To assess the possible association between the PTPN22 gene 1858C-->T polymorphism and the susceptibility to Henoch-Schönlein purpura (HSP) and determine if this polymorphism is implicated in the severity of this systemic vasculitis.

PATIENTS AND METHODS

Fifty-seven unselected patients from Northwest Spain with primary systemic vasculitis, classified as HSP according to previously proposed criteria, with a follow-up of at least 2 years and 229 healthy controls, were included in this study. All the individuals were of Spanish Caucasian origin. Genotyping of the PTPN22 gene 1858C-->T polymorphism was performed by real time PCR technology, using TaqMan 5' allelic discrimination assay.

RESULTS

No significant differences in allele or genotype distribution frequencies for the PTPN22 gene polymorphism were observed between HSP patients and controls. It was also the case when HSP patients were stratified for the presence of severe gastrointestinal complications (n = 46), nephritis (n= 37) or permanent renal involvement (renal sequelae) (n = 12).

CONCLUSION

Our results do not support a potential implication of the PTPN22 gene polymorphism in the susceptibility to and clinical expression of HSP.

Childhood Henoch Schonlein purpura in Middle East countries

HSP is the most common systemic vasculitis in children that is characterized by small vessel leukocytoclastic vasculitis. However, it is a self limiting disease, with few documented cases in Middle Eastern countries. Classic symptoms of the disease have been established in the literature, but new clinical features have recently been reported from Middle Eastern countries which include penile swelling, temperomandibular joint involvement, skin rash over the flexor surfaces of the extremities and pleural hemorrhagic effusion. Familial Mediterranean fever (FMF) may present as HSP. The prevalence of the FMF gene in Middle Eastern countries raises interesting questions regarding the use of colchicine in HSP patients.

HLA class 1 associations in Henoch Schonlein purpura: increased and decreased frequencies

Henoch Schonlein purpura (HSP) is the most common vasculitis of childhood. Susceptibility to HSP and associated clinical heterogeneity in HSP may be conferred by a number of genetic loci, including the major histocompatibility complex. We aimed to investigate the implications of the human leukocyte antigen (HLA) class 1 alleles in susceptibility to HSP and determine the possible associations with renal, gastrointestinal (GI), and joint manifestations of the disease. 110 children with HSP (66 boys, 44 girls) and 250 unrelated healthy controls were enrolled in the study. The mean age was 8.65 +/- 3.59 years. HSP was diagnosed on the basis of clinical and laboratory data according to the American College of Rheumatology classification. The diagnosis was supported with skin and/or kidney in most of the patients. Clinical and laboratory findings revealed: skin involvement in 110 (100%), joint manifestations in 82 (74.5%), GI symptoms in 58 (52.7%), and hematuria and/or proteinuria in 36 (32.7%) patients. HLA class 1 alleles were identified by DNA amplification, hybridized with specific primer sequences. Comparison of frequencies between patients and controls were made by using the Fisher's exact test. Odds ratio (OR) was used as the measure of association. HLA A2, A11, and B35 antigens showed an increased risk for predisposition to HSP (OR = 1.714, 95%CI = 1.088-2.700, p = 0.020; OR = 2.185, 95%CI = 1.289-3.703, p = 0.003; and OR = 2.292, 95%CI = 1.451-3.619, p = 0.000, respectively), while HLA A1, B49, and B50 antigens revealed decreased risk for predisposition to HSP (OR = 4.739, 95%CI = 1.828-12.345, p = 0.001; OR = 3.268, 95%CI = 0.955-11.236, p = 0.047; and OR = 7.462, 95%CI = 0.975-55.555, p = 0.024, respectively). Considering the renal involvement and severity of proteinuria, there was no association with HLA class 1 alleles. Our results suggest that the increased frequency of HLA A2, A11, and B35 alleles in unselected pediatric HSP patient population and miscarrying of HLA A1, B49, and B50 could be considered as a risk factor for susceptibility to HSP.

Lack of association between NPHS2 gene polymorphisms and Henoch-Schönlein purpura nephritis

Henoch-Schönlein purpura (HSP) is one of the most common forms of small-vessel vasculitis in childhood, and renal involvement (HSP nephritis, HSPN) is the main determinant of morbidity after acute phase. Considering the racial diversity and clinical heterogeneity in the prevalence, genetic factors might play a role in pathogenesis of HSP and HSPN. Direct sequencing was performed after PCR amplification of all 8 exons of the NPHS2 gene in 20 Chinese children with HSPN and 30 controls in present study. The genetic analyses revealed 3 polymorphisms (954T > C heterozygous, 1038A > G heterozygous and homozygous, all in exon 8) in 7 out of 20 patients studied, but there was no significant difference in the genotypic and allelic frequencies of these polymorphisms between the patients and controls. The result did not support the possible role of the NPHS2 gene in susceptibility to HSPN in the population studied. Studies in a larger sample population with different genetic backgrounds will be necessary in the future.

Negative pressure dressing for promoting wound healing of purpura fulminans in a newborn with homozygous protein C deficiency

A negative pressure dressing to promote wound healing of purpura fulminans in a girl aged 35 days with homozygous protein C deficiency is reported. Two wounds of 11 x 11 cm2 at the abdominal wall and 14 x 14 cm2 at the left trunk were covered with sterile sponges embedded with a multiple-hole drain tube and transparent plastic film. The exposed end of the drain was then connected to the wall suction apparatus to create negative pressure at -120 mmHg. The dressing was changed every 2 days. Within 4-6 weeks, the wounds were completely healed and skin grafting was not required.