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.

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-ß (IVW estimate ß = -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.

HERV-K and W expression in peripheral mononuclear cells of children with Henoch-Schönlein purpura and relation with TLR activation.

BACKGROUND: HERVs expression seems impaired in several diseases, ranging from autoimmune to neoplastic disorders. However, various stimuli may re-activate HERVs transcription. Henoch-Schönlein purpura is the most common cause of vasculitis in children. The role of microbial antigens in the pathogenesis of HSP remains elusive. Toll-like receptors (TLRs) are the first line of defense for the host to initiate an immune and inflammatory response. We aimed to investigate HERV, K and W expression in peripheral mononuclear cells of children with HSP and relation with TLRs activation. METHODS: The study enrolled 63 children affected by HSP. We used RT-PCR to detect GAPDH in the peripheral blood mononuclear cells samples to normalize the data. Subsequently, the viral pol gene HERVs and TLRs transcripts in the same samples were assessed. RESULTS: HERV K and W was expressed in all samples analyzed but the level of expression was much lower in the HSP that in HC P=0.0006 and P=0.0004 for HERV-K and -W respectively. TLR2 was hyper-expressed in 39 vs. 63 (62%) of the HSP, TLR3 in 23 vs. 63 (42%), TLR4 in 42 vs. 63 (66%) and TLR9 in 32 vs. 63 (52%). The different expression was statistically significant only for TLR4 (P=0.0276) no for TLR2,3 and 9 (P=0.1251; 0.3964 and 0.1882 respectively). Spearman's test demonstrated no correlation between the low expression of HERV-K and HERV-W and high expression of TLRs. CONCLUSIONS: The results of the present study demonstrated that mRNA expression of HERV-K and -W and TLRs did not directly correlated.

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.

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.

Apoptosis inhibitor of macrophage as a biomarker for disease activity in Japanese children with IgA nephropathy and Henoch-Schönlein purpura nephritis.

BACKGROUND: To evaluate the apoptosis inhibitor of macrophage (AIM) deposition patterns on the kidneys of children with IgA nephropathy (IgAN) and Henoch-Schönlein purpura nephritis (HSPN) and to investigate the clinical usefulness of serum and/or urinary AIM levels as biomarkers for the disease activity. METHODS: Immunohistochemical study was performed in the kidneys of 37 patients with IgAN and 10 patients with HSPN. Serum and urinary AIM levels in the patients and 20 healthy controls (HCs) were quantified by enzyme-linked immunosorbent assay. The results were compared with clinical features. RESULTS: In patients with IgAN and HSPN, AIM expression was observed in various areas, including the glomerular mesangial and capillary areas, the proximal and distal tubular epithelial cells, and on infiltrating macrophages in the glomeruli and interstitial areas. Serum and urinary AIM levels were significantly elevated in these patients compared with the HCs. Urinary AIM levels were positively correlated with the histological severity and degree of proteinuria and hematuria as well as urinary ß2 microglobulin and urinary N-acetyl-ß-D-glucosaminidase levels. CONCLUSIONS: AIM plays an important role in the pathogenesis of IgAN and HSPN. Urinary AIM levels can potentially reflect active renal inflammation in these diseases and may represent a useful biomarker for disease activity. IMPACT: Urinary AIM levels may represent a useful biomarker for disease activity of IgAN and HSPN. AIM expression was observed in the glomeruli, tubular epithelial cells, and infiltrating macrophages in glomeruli and interstitial area. U-AIM/Cr were significantly correlated not only with proteinuria, hematuria, and u-ß2MG and u-NAG levels but also with the activity index of histological findings in kidney biopsy specimens. Our results can emphasize the important role of AIM in the pathogenesis of IgAN and HSPN.

SATB1 and PTEN expression patterns in biopsy proven kidney diseases.

BACKGROUND: In present study we investigated expression pattern of the special tissue markers. SATB1 and PTEN to evaluate possible influence in pathophysiology and development of various biopsy proven kidney diseases. METHODS: The 32 kidney biopsy samples were analysed using light, immunofluorescence and electron microscopy. There were 19 samples in proliferative and 13 samples in non- proliferative group of renal diseases. As control group, 9 specimens of healthy kidney tissue taken after surgery of kidney tumour were used. SATB1 and PTEN markers were used for immunofluorescence staining. Analysed tissue structures were glomeruli, proximal convoluted tubules (PCT) and distal convoluted tubules (DCT). The number of SATB1 and PTEN cells were calculated and the data compared between kidney structures, disease groups and control specimens. RESULTS: Both markers were positive in all investigated kidney structures, with expression generally, more prominent in tubular epithelial cells than in glomeruli, with the highest staining intensity rate as well as highest rate of both markers in DCT of proliferative diseases group (SATB1 64.5 %, PTEN 52 %). There was statistically significant difference in SATB1 expression in all tissue structures of interest in proliferative as well as non- proliferative group compared to control group (p < 0.01-p < 0.0001). PTEN expression were found significantly decreased in PCT of both disease groups in regard to control (PTEN 25.3 % and 23.8 % vs. 41.1 % (p < 0.01 and p < 0.001 respectively). CONCLUSION: SATB1 and PTEN could be considered as markers influenced in kidney disease development. SATB1/PTEN expression should be further investigated as useful markers of kidney disease activity as well as potential therapeutic target.

Comorbidities in familial Mediterranean fever: analysis of 2000 genetically confirmed patients.

OBJECTIVES: FMF is the most common periodic fever syndrome, characterized by recurrent episodes of fever and serosal inflammation accompanied with high acute phase reactants. The analysis of possible comorbidities is important to understand the impact of these conditions on clinical care and whether they share a common aetiological pathway. In this study, we aimed to evaluate the comorbidities associated with FMF patients in a large genetically diagnosed cohort. METHODS: We retrospectively evaluated the medical and genetic records of FMF patients who were followed up by rheumatologists in Hacettepe University for 15 years. The FMF patients who had homozygous or compound heterozygous mutations were included in the study. Comorbidities associated with FMF were divided into three groups: (i) comorbidities directly related to FMF, (ii) comorbidities due to increased innate inflammation, and (iii) comorbidities that were regarded as being incidental. RESULTS: A total of 2000 patients with a diagnosis of FMF were enrolled in the study. Among them 636 were children (31.8%) and M694V was the most common mutation in patients with associated inflammatory conditions. The frequency of AS, Iga Vasculitis (Henoch-Schönlein purpura), juvenile idiopathic arthritis, polyarteritis nodosa, multiple sclerosis and Behçet's disease were increased in patients with FMF when compared with those in the literature. CONCLUSION: This study represents the largest genetically confirmed cohort and compares the frequencies with existing national and international figures for each disease. The increased innate immune system inflammation seen in FMF may be considered as a susceptibility factor since it predisposes to certain inflammatory conditions.

MEFV gene mutations in children with Henoch-Schönlein purpura and their correlations-do mutations matter?

OBJECTIVE: To explore the frequency of MEFV gene mutations in children with Henoch-Schönlein purpura who had no prior familial Mediterranean fever diagnosis and to evaluate the association of MEFV mutations with the clinical and laboratory features of Henoch-Schönlein purpura. METHODS: Data of 1120 patients diagnosed with Henoch-Schönlein purpura were reviewed retrospectively. The spectrum and degree of organ involvement and acute phase reactant levels were documented for each patient. Blood for MEFV gene mutation analysis was obtained either at the time of the Henoch-Schönlein purpura diagnosis or during follow-up visits. Pathological specimens of patients who underwent biopsy (renal/skin) were evaluated with special consideration for immunofluorescent examinations. RESULTS: Two hundred and thirty-eight (21.3%) patients were found to have one of the MEFV mutations in which exon 10 mutations were the most common (16.7%). Abdominal pain, joint involvement, scrotal involvement, and relapse were more frequent, and acute-phase reactant levels were significantly high in patients with MEFV mutations. More severe characteristics were observed in the presence of homozygous exon 10 mutations. There was no significant association between exon 2 variants and clinical course of Henoch-Schönlein purpura. Patients carrying MEFV mutations did not have significantly higher levels of IgA deposits in the biopsy materials. CONCLUSION: Henoch-Schönlein purpura in patients with homozygous exon 10 MEFV mutations seems to be more severe than that in patients carrying other mutations. In patients with exon 10 MEFV mutations, Henoch-Schönlein purpura might be considered as an associated presentation of familial Mediterranean fever rather than a separate clinical entity. Key points • p.M694V mutation is more common in Henoch-Schönlein purpura than in the general population. • p.E148Q variants have no impact on clinical symptoms and laboratory findings in Henoch-Schönlein purpura patients. • The majority of Henoch-Schönlein purpura patients with familial Mediterranean fever have no IgA deposits. • Henoch-Schönlein purpura in familial Mediterranean fever patients may be considered as an integral clinical feature of familial Mediterranean fever.

Mutaciones en el gen MEFV y evolución clínica en pacientes pediátricos con púrpura de Schonlein-Henoch / MEFV gene mutations and clinical course in pediatric patients with Henoch-Schonlein purpura

Objetivo. Determinar la frecuencia de mutaciones del gen MEFV en niños con diagnóstico de púrpura de Schonlein-Henoch y evaluar el efecto que tienen en el pronóstico. Materiales y métodos. Estudio transversal que incluyeron pacientes pediátricos de entre 2 y 11 años, con diagnóstico de púrpura de Schonlein-Henoch. Se estudiaron para detectar 6 mutaciones en el gen MEFV (M694V, M680I, A744S, R202Q, K695R y E148Q). Resultados. Se incluyeron ochenta pacientes, de los cuales el 55% eran de sexo masculino (n= 44). La media de edad fue 6,44 ± 2,52 años. Durante el seguimiento, 9 pacientes presentaron recurrencia de la enfermedad, 5 sufrieron invaginación intestinal y 1 paciente tuvo convulsiones. Aproximadamente la mitad de los pacientes recibió corticoides. En 44 pacientes (55%) no se detectaron mutaciones en el gen MEFV. En 19 pacientes (22%) hubo una mutación heterocigota. Se encontró E148Q en 8 pacientes, M694V en 5 pacientes, A744S en 4 pacientes y la mutación heterocigota R202Q en 2 pacientes. En 1 paciente se detectó la mutación heterocigota M608I y en otro paciente se encontró la mutación homocigota M694V. En 15 pacientes se encontraron mutaciones heterocigotas compuestas en el gen MEFV. Las mutaciones en el gen MEFV no se correlacionaban con la frecuencia de compromiso renal y gastrointestinal ni con el pronóstico, desarrollo de complicaciones y uso de corticoides. Conclusiones. Las mutaciones en el gen MEFV no se correlacionan con la evolución clínica ni con las complicaciones en pacientes pediátricos con púrpura de Schonlein-Henoch en Turquía.

Objective. To determine the frequency of the MEFV gene mutations in pediatric patients diagnosed with HSP and to assess the effect of the MEFV gene mutations on their prognosis. Material and Methods. Ccross-sectional study; pediatric patients between 2-11 years diagnosed with HSP were included. These cases were investigated for 6 MEFV gene mutations (M694V, M680I, A744S, R202Q, K695R, E148Q). Results. Eighty cases were included in the study of which 55% were male (n= 44). The mean age was 6.44 ± 2.52 years. Disease recurrence occurred in 9 patients, invagination in 5 patients and convulsion in 1 patient during follow-up. Approximately half of the patients received steroids. The MEFV gene mutations was not detected in 44 (55%) of the patients. There was a heterozygous mutation in 19 (22%). E148Q was found in 8 patients, M694V in 5 patients, A744S in 4 patients, and the R202Q heterozygous mutation in 2 patients. The M608I homozygous mutation was detected in 1 patient and the M694V homozygous mutation in 1 patient. The compound heterozygous MEFV gene mutations was found in 15 patients. The presence of the MEFV gene mutations was not correlated with the frequency of renal and gastrointestinal involvement and prognosis, the development of complications and the use of steroids. Conclusion. The presence of the MEFV gene mutations does not correlate with the clinical course and complication in Turkish pediatric patients with HSP.

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 < 0.001). Analysis after stratification by ethnicity indicated that the PTPN22 788A allele was significantly associated with autoimmune diseases in Europeans (p < 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.

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.

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

BACKGROUND Acid-sensing ion channels (ASICs) are ligand-gated cation channels activated by extracellular protons. However, the role of ASICs in kidney diseases remains uncertain. This study investigated ASICs expression in kidney tissues and their role in the development of Henoch-Schönlein purpura nephritis (HSPN). MATERIAL AND METHODS The expression of ASIC subunits was examined by immunochemical techniques in the kidney tissue from HSPN patients. Acid-induced ASICs expression in cultured renal tubular epithelial cells was determined by quantitative RT-PCR analysis. The expression of K7 and K18 protein in renal tubular epithelial cells was used to evaluate acid-induced cell injury. In addition, we observed the effect of blocking ASICs on acid-induced cell injury to assess the role of ASICs in renal tubular epithelial cell injury. RESULTS The results showed that ASIC1, ASIC2, and ASIC3 proteins were obviously expressed in renal tubular cells from HSPN patients. ASIC1 expression and 24-h urine protein level were higher in the pathological grade ISKD III group than in the ISKD II group. ASIC1, ASIC2, and ASIC3 mRNA, and K7 and K18 protein expression in cultured renal tubular epithelial cells were increased when exposed to pH 6.5. K7 and K18 protein expression was closely related to ASIC1 expression, and ASICs blockers reduced K7 and K18 protein expression in tubular epithelial cells. CONCLUSIONS These findings suggest ASICs are most highly expressed in renal tubular cells of HSPN patients, which is closely related to renal tubular injury. ASICs might be involved in the development of HSPN.

Heat shock protein 70-2 and tumor necrosis factor-α gene polymorphisms in Chinese children with Henoch-Schönlein purpura.

BACKGROUND: Henoch-Schönlein purpura (HSP) or IgA-associated vasculitis is related to immune disturbances. Polymorphisms of the heat shock protein 70-2 gene (HSP70-2) and the tumor necrosis factor-a gene (TNF-α) are known to be associated with immune diseases. The purpose of this study was to investigate the likely association of HSP70-2 (+1267A/G) and TNF-α (+308A/G) gene polymorphisms with HSP in children. METHODS: The polymerase chain reaction restriction fragment length polymorphism method was used to detect the HSP70-2 and TNF-α polymorphisms in 205 cases of children with HSP and 53 controls; and the association of these polymorphisms with HSP and HSP nephritis (HSPN) was analyzed. RESULTS: The G/G genotypic frequencies at the +1267A/G position of HSP70-2 in the HSP group (22.9%) were significantly higher than those in the healthy control group (9.4%) (χ(2)=4.764, P<0.05). The frequencies of the A/A, A/G and G/G genotypes of HSP70-2 in patients in the nephritis-free group and the HSPN group showed no statistically significant difference. The A/A genotype frequency at the +308G/A position of TNF-α in the HSP group was 8.3%, which was higher than that in the control group (χ(2)=6.447, P<0.05). The A allele frequency of TNF-α in the HSP group was higher than that in the control group, with a statistically significant difference (χ(2)=7.241, P<0.05). CONCLUSIONS: The HSP70-2 (+1267A/G) and TNF-α (+308G/A) gene polymorphisms were associated with HSP in children. The G/G homozygosity of HSP70-2 and the A/A homozygosity of TNF-α may be genetic predisposing factors for HSP.

Expansion of Circulating T Follicular Helper Cells in Children with Acute Henoch-Schönlein Purpura.

Henoch-Schönlein purpura (HSP) is a common systemic small vessel vasculitis in children with disorder autoimmune responses. T follicular helper (TFH) cells play crucial roles in regulating immune responses. The aim of our study was to investigate the probable role of TFH cells in the pathogenesis of children with HSP. In this study, the frequency of circulating CXCR5(+)CD4(+)TFH cells with inducible costimulator (ICOS) expression in the children with acute HSP was significantly higher than that in healthy controls (HCs) but not CXCR5(+)CD4(+)TFH cells with programmed death-1 (PD-1) expression. Moreover, serum levels of IL-21 and IL-6 cytokines, IgA, and C3 in HSP children were also significantly higher than those in HCs. A positive correlation was observed between the frequencies of circulating ICOS(+)CXCR5(+)CD4(+)TFH cells and the serum IL-21 or IgA levels of acute HSP children, respectively. Additionally, the mRNA expression levels of interleukin- (IL-) 21, IL-6, and transcriptional factors (B-cell lymphoma-6, Bcl-6) were also significantly increased in peripheral blood from acute HSP children compared to HCs. Taken together, these findings suggest that TFH cells and associated molecules might play critical roles in the pathogenesis of HSP, which are possible therapeutic targets in HSP children.

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.