Increased excretion of tumor necrosis factor alpha and interleukin 1 beta in urine from patients with IgA nephropathy and Schönlein-Henoch purpura

Interleukin Variants Are Associated with the Development and Progression of IgA Nephropathy: A Candidate-Gene Association Study and Meta-Analysis

The interleukin-1 gene cluster encodes cytokines, which modulate mesangial cell proliferation and matrix expansion, both constituting central factors in the development and progression of immunoglobulin A nephropathy (IgAN). A candidate-gene study was performed to examine the association of polymorphisms of the interleukin-1 gene cluster with the risk of progressive IgAN. To gain deeper insights into the involvement of interleukin genes in IgAN, a meta-analysis of genetic association studies (GAS) that examine the association between interleukin variants and IgAN was conducted. Association study: The case-control study consisted of 121 unrelated Caucasians with sporadic, histologically diagnosed IgAN and of 246 age- and sex-matched healthy controls. Persistent proteinuria (>2 g/24 h) and/or impaired kidney function (serum creatinine > 1.5 mg/dL) defined progressive (n = 67) vs. non-progressive (n = 54) IgAN cases. Genotypes were assessed for two promoter-region single-nucleotide polymorphisms, C-899T (rs1800587) in IL1A and C-511T (rs16944) in IL1B, and for one penta-allelic variable-length tandem repeat polymorphism (VNTR 86 bp intron 2) in IL1RN. The association of these variants with the susceptibility of IgAN and the development of progressive IgAN (healthy status, IgAN, progressive IgAN) was tested using the generalized odds ratio (ORG) metric. Linkage disequilibrium and haplotype analysis were also performed. Meta-analysis: We included in the meta-analysis 15 studies investigating association between 14 interleukin variants harbored in eight different genes and IgAN. The ORG was used to evaluate the association between interleukin variants and IgAN using random effects models. The present case-control study revealed association of IL1B C-511T (rs16944) with the progression of IgAN (p = 0.041; ORG = 2.11 (1.09-4.07)). On haplotype analysis, significant results were derived for the haplotypes C-C-1 (p = 0.005; OR = 0.456 (0.261~0.797)) and C-T-2 (p = 0.003; OR = 4.208 (1.545-11.50)). Regarding association and meta-analysis results, variants in IL1B (rs1143627 and rs16944), IL1RN (rs928940, rs439154, and rs315951) and IL10 (rs1800871) were associated with IgAN based on either genotype or allele counts. Genetic variants and haplotypes in the IL1B, IL1RN, and IL10 genes might contribute to an increased risk for development and progression of IgAN.

Tumor Necrosis Factor-α G-308A Polymorphism and Sporadic IgA Nephropathy: A Meta-Analysis Using a Genetic Model-Free Approach

Tumor necrosis factor-α (TNF-α) is a potent pro-inflammatory cytokine, involved in the pathogenesis and progression of immunoglobulin A nephropathy (IgAN). A bi-allelic polymorphism in the promoter region, at position -308 (G/A) of the TNF-α gene (rs1800629) is associated with an increased TNF-a production. However, several previous association studies of TNF-α G-308A polymorphism and IgAN rendered contradictory findings. The objective of the present study is to shed light on these inconclusive results and clarify the role of TNF-α and any possible contribution of this factor in the development and progression of sporadic IgAN. Therefore, a meta-analysis of all available genetic association studies relating the TNF-α G-308A polymorphism to the risk for development and/or progression of IgAN was conducted. Seven studies were included in the meta-analysis. Three of them included populations of European descent (Caucasians) and four involved Asians. The generalized odds ratio (OR_G) was used to estimate the risk for the development and/or progression of the disease. Overall, the meta-analysis did not detect any significant association between the G-308A variant and both the risk of developing IgAN and the risk for progression of IgAN. In conclusion, these results suggest that TNF-α does not constitute a key component in the genetic architecture of sporadic IgAN. However, further evidence deciphering the influence of TNF-α on IgAN is still needed.

Deciphering prognostic value of CD22 and its contribution to suppression of proinflammatory cytokines production in patients with IgA nephropathy

BACKGROUND

CD22, mainly expressed in mature B cells, could negatively regulate the function of B cells by binding to sialic acid-positive IgG (SA-IgG). Soluble CD22 (sCD22) is generated by the cleavage of the extracellular domain of CD22 on the membrane surface. However, the role of CD22 in IgA nephropathy (IgAN) remains unknown.

METHODS

A total of 170 IgAN patients with a mean follow-up of 18 months were included in this study. The sCD22, TGF-β, IL-6 and TNF-α were detected using commercial ELISA kits. SA-IgG were purified to stimulate peripheral blood mononuclear cells (PBMCs) from IgAN patients.

RESULTS

The plasma levels of sCD22 were lower in IgAN patients in comparison with healthy control. Furthermore, CD22 mRNA levels in PBMCs from patients with IgAN were significantly lower than those of healthy controls. The plasma levels of sCD22 were positively correlated to the mRNA levels of CD22. We found that patients with higher sCD22 levels had a lower level of serum creatinine and a higher level of eGFR on the time of renal biopsy and a higher remission rate of proteinuria and a lower risk of kidney events at the end of follow-up. The logistic regression analysis showed sCD22 was associated with an increased odd of proteinuria remission after being adjusted for eGFR, proteinuria, and SBP. After adjusting for confounding variables, sCD22 was a borderline significant predictor of less kidney composite endpoint. In addition, the sCD22 levels were positively associated with SA-IgG in plasma. The experimental results in vitro showed that addition of SA-IgG enhanced the release of sCD22 in cell supernatant and the phosphorylation of CD22 in PBMCs, further inhibiting the production of IL-6, TNF-α, and TGF-β in cell supernatant in a dose-dependent manner. Pretreatment with CD22-antibody significantly increased the expression of cytokines in PBMCs.

CONCLUSIONS

This is the first study to demonstrate that lower plasma soluble CD22 in IgAN patients and high soluble CD22 levels are associated with an increased odd of proteinuria remission and a decreased odd of kidney endpoint. The interaction between CD22 and SA-IgG can inhibit proliferation and inflammation release in PBMCs from IgAN patients.

Clinical phenotype and cytokine profile of adult IgA vasculitis with joint involvement

OBJECTIVE

Joint involvement can be observed during the course of adult IgA vasculitis (IgAV). However, clinical picture, prognosis, or pathophysiological data associated with this condition have been overlooked. We aimed to describe the clinical characteristics and outcome of IgAV patients with joint involvement and look to a specific cytokine profile.

METHODS

We analyzed clinical and biological data from a nationwide study that included adult IgAV patients. Presentation and outcomes of patients with or without joint involvement were compared at baseline and during follow-up. Plasma cytokine measurements of IgAV patients included in a prospective study were also analyzed using multiplex assays.

RESULTS

Among 260 patients, 62% had joint involvement. Among them, rheumatological manifestations included arthralgia (100%) or arthritis (16%), mostly involving the knees and ankles. In multivariate analysis, patients with joint involvement, compared to those without, were younger (p = 0.002; OR 0.87; 95% CI 0.80-0.95) and showed more frequent gastrointestinal tract involvement (p = 0.012; OR = 2.08; 95% CI 1.18-3.67). However, no difference in terms of clinical response, relapse, end-stage renal disease, or death was observed between groups. Among 13 cytokines measured, plasma interleukin (IL)-1β level was higher in patients with joint involvement compared to those without (mean ± SEM IL-1β, 3.5 ± 1.2 vs. 0.47 ± 0.1 pg/ml; p = 0.024) or healthy controls (vs. 1.2 ± 0.5 pg/ml; p = 0.076).

CONCLUSION

Joint involvement is frequent in adult IgAV and is associated with more frequent gastrointestinal involvement. Increased plasma IL-1β levels raise the question of targeting this cytokine in patients with chronic and/or refractory joint involvement. Key Points • Joint involvement in adult IgAV is a frequent manifestation. • Joint involvement is associated with more frequent gastrointestinal manifestations. • Interleukin-1β (IL-1β) might orchestrate joint inflammation in adult IgAV. • IL-1β might be a therapeutic target in patients with chronic and/or refractory joint involvement.

Meta-analysis of the neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios in Henoch-Schonlein purpura and its complications

OBJECTIVE

The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are associated with the severity of Henoch-Schonlein purpura (HSP). Therefore, we conducted a meta-analysis to evaluate the clinical significance of NLR and PLR in HSP and its complications.

METHODS

A comprehensive literature search was conducted by searching the PubMed, EMBASE, Web of Science, Cochrane Library, China National Knowledge Infrastructure, Wanfang, VIP, and SinoMed databases from their inception to September 31, 2020. We used the standard mean difference (SMD) with a 95% confidence interval (CI) to estimate the pooled effect and used subgroup analysis to investigate heterogeneity.

RESULTS

A total of 1,691 HSP patients and 563 healthy controls (HCs) from 15 studies were included in the analysis. The NLR value was significantly higher in 431 HSP patients with gastrointestinal complications (HSP-GCs) than that in 833 HSP patients without GCs (SMD = 1.09, 95% CI: 0.62-1.57, P < 0.001); in 83 HSP adult patients with renal involvement (HSP-RI) than that in 131 adult HSP patients without RI (SMD = 0.33, 95% CI: 0.05-0.60, P = 0.021); and in 831 HSP patients than that in 563 HCs (SMD = 0.70, 95% CI: 0.51-0.89, P < 0.001). The PLR was significantly higher in 417 HSP patients than that in 264 HCs (SMD = 0.39, 95% CI: 0.06-0.71, P = 0.02).

CONCLUSIONS

NLR could serve as a useful biomarker to predict GCs and RI in patients with HSP. However, further well-designed and large cohort studies are warranted to confirm these findings.

Serum TNF-α Level Is Associated with Disease Severity in Adult Patients with Immunoglobulin A Vasculitis Nephritis

Background

Tumor necrosis factor-α (TNF-α) is a proinflammatory factor involved in the pathogenesis of immunoglobulin A vasculitis (IgAV). The association between serum TNF-α and disease severity in adult patients with IgAV nephritis (IgAV-N) has been inadequately evaluated.

Methods

Serum TNF-α was measured by chemiluminescence immunoassay in 53 renal biopsy-proved IgAV-N patients, 53 healthy controls, and 53 IgA nephropathy (IgAN) patients. The correlations of clinicopathologic parameters of IgAV-N patients with serum TNF-α were analyzed.

Results

In this cross-sectional study, the median age of IgAV-N patients was 29 (25-37) years, and 67.9% were female. Serum TNF-α was significantly higher in the IgAV-N group than in the healthy group [7.4 (5.7-9.4) pg/mL vs. 5.9 (5.0, 7.1) pg/mL, P = 0.001], but comparable with sex, age, and estimated glomerular filtration rate (eGFR) grade-matched IgAN patients. Serum creatinine (P = 0.006) and serum cystatin C (P = 0.001) were positively correlated with serum TNF-α level, while albumin (P = 0.014) and eGFR (P = 0.021) were negatively correlated with serum TNF-α level. Multivariate linear regression analysis revealed that eGFR (P = 0.007) was an independent clinical predictor of serum TNF-α. Patients with higher pathological classification grade also had higher serum TNF-α.

Conclusions

Serum TNF-α is associated with renal function and the pathological classification of adult patients with IgAV-N. TNF-α is a potential biomarker for the assessment of IgAV-N severity.

Monitoring Immune Responses in IgA Nephropathy: Biomarkers to Guide Management

IgA nephropathy (IgAN) is the commonest biopsy-reported primary glomerulonephritis worldwide. It has an incidence which peaks among young adults, and 30 to 40% of patients' progress to end stage kidney disease within twenty years of diagnosis. Ten-year kidney survival rates have been reported to be as low as 35% in some parts of the world. The successful management of IgAN is limited by an incomplete understanding of the pathophysiology of IgAN and a poor understanding of how pathophysiology may vary both from patient to patient and between patient groups, particularly across races. This is compounded by a lack of rigorously designed and delivered clinical trials in IgAN. This is slowly changing, with a number of Phase 2 and 3 clinical trials of novel therapies targeting a number of different putative pathogenic pathways in IgAN due to report in the next 5 years. From our current, albeit limited, understanding of the pathophysiology of IgAN it is unlikely a single therapy will be effective in all patients with IgAN. The successful management of IgAN in the future is, therefore, likely to be reliant on targeted therapies, carefully selected based on an individualized understanding of a patient's risk of progression and underlying pathophysiology. The potential role of biomarkers to facilitate personalization of prognostication and treatment of IgAN is immense. Here we review the progress made over the past decade in identifying and validating new biomarkers, with a particular focus on those that reflect immunological responses in IgAN.

YB-1 Interferes with TNFα-TNFR Binding and Modulates Progranulin-Mediated Inhibition of TNFα Signaling

Inflammation and an influx of macrophages are common elements in many diseases. Among pro-inflammatory cytokines, tumor necrosis factor α (TNFα) plays a central role by amplifying the cytokine network. Progranulin (PGRN) is a growth factor that binds to TNF receptors and interferes with TNFα-mediated signaling. Extracellular PGRN is processed into granulins by proteases released from immune cells. PGRN exerts anti-inflammatory effects, whereas granulins are pro-inflammatory. The factors coordinating these ambivalent functions remain unclear. In our study, we identify Y-box binding protein-1 (YB-1) as a candidate for this immune-modulating activity. Using a yeast-2-hybrid assay with YB-1 protein as bait, clones encoding for progranulin were selected using stringent criteria for strong interaction. We demonstrate that at physiological concentrations, YB-1 interferes with the binding of TNFα to its receptors in a dose-dependent manner using a flow cytometry-based binding assay. We show that YB-1 in combination with progranulin interferes with TNFα-mediated signaling, supporting the functionality with an NF-κB luciferase reporter assay. Together, we show that YB-1 displays immunomodulating functions by affecting the binding of TNFα to its receptors and influencing TNFα-mediated signaling via its interaction with progranulin.

Serum levels of tumor necrosis factor alpha in patients with IgA nephropathy are closely associated with disease severity

Background

Tumor necrosis factor alpha (TNF-α) is considered to play an important role in the pathogenesis in IgA nephropathy (IgAN). The correlations between serum TNF-α and disease severity in patients with IgAN remain controversial.

Methods

Concentrations of serum TNF-α of 147 patients with IgAN and 126 healthy subjects were measured by chemiluminescence immunoassay. Correlations with clinicopathological features of patients with IgAN were evaluated.

Results

Serum levels of TNF-α [9.20 (7.70–10.60) pg/mL vs. 6.04 (5.11–7.23) pg/mL, P < 0.0001] were higher in patients with IgAN than that in healthy subjects. Receiver operating characteristic curve analysis revealed that TNF-α had better discrimination between patients with IgAN and healthy controls than estimated glomerular filtration rate [TNF-α: (AUC, 0.87; 95% CI, 0.83–0.91; P < 0.0001) vs. estimated glomerular filtration rate: (AUC, 0.76; 95% CI, 0.71–0.82; P < 0.0001), P = 0.007]. Multivariate linear regression analyses showed that serum levels of TNF-α were positively correlated with 24-h urine protein excretion (r = 0.33, P = 0.04), urinary protein to serum creatinine ratio (r = 0.33, P = 0.03), serum creatinine (r = 0.46, P < 0.0001) and Cystatin C (r = 0.59, P < 0.0001) in IgAN and negatively correlated with estimated glomerular filtration rate (r = − 0.49, P < 0.0001) after adjustment for sex, systolic blood pressure and diastolic blood pressure. Patients with higher mesangial hypercellularity or tubular atrophy/interstitial fibrosis score according to Oxford classification showed higher serum levels of TNF-α.

Conclusions

Our data showed that serum levels of TNF-α detected by chemiluminescence immunoassay was a potential biomarker for evaluating the disease severity in IgAN.

Electronic supplementary material

The online version of this article (10.1186/s12882-018-1069-0) contains supplementary material, which is available to authorized users.

Effects of Periostracum Cicadae on Cytokines and Apoptosis Regulatory Proteins in an IgA Nephropathy Rat Model

Periostracum cicadae, the cast-off shell of the cicada Cryptotympana pustulata Fabricius, is used in traditional Chinese medicine for its diaphoretic, anticonvulsive, sedative, antipyretic, and antiallergic effects. However, the exact pathogenesis of immunoglobulin A nephropathy (IgAN) remains unclear, thereby hindering investigations to identify novel therapeutic agents. A rat IgAN model was established by administration of bovine serum albumin, lipopolysaccharide, and carbon tetrachloride, which simultaneously established blood stasis and a heat syndrome model. The animals were sacrificed to detect changes in protein levels in urine and blood. Immunofluorescence was performed to assess IgA deposition in the glomeruli. Tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin 6 (IL-6) levels were measured in bronchoalveolar lavage fluid (BALF) by enzyme-linked immunosorbent assay. Hematology and eosin, periodic acid-Schiff, TUNEL (TdT-mediated dUTP Nick-End Labeling), and immunohistochemical staining were performed to evaluate histopathological changes in kidney tissues. Additionally, target-related proteins were measured by Western blotting. Periostracum cicadae resulted in a reduction in blood and urine protein levels. Serum TNF-α, IL-1β, and IL-6 levels significantly decreased in the periostracum cicadae-treated groups compared to the IgAN group. Furthermore, a reduction in MCP-1 (Monocyte Chemotactic Protein-1), TLR4 ((Toll-Like Receptor 4)), and IgA expression levels and a dose-dependent increase in caspase 3 expression were observed in response to periostracum cicadae treatment. TGF-β1(Transforming Growth Factor-β) levels decreased, whereas that of Fas increased in the kidney tissues of the periostracum cicadae-treated groups. The findings of the present study indicate that periostracum cicadae induces apoptosis and improves kidney inflammation and fibrosis in IgA nephropathy rat models.

Correlation between serum inflammatory factors TNF-α, IL-8, IL-10 and Henoch-Schonlein purpura with renal function impairment

The changes of tumor necrosis factor-α (TNF-α), interleukin-8 (IL-8), interleukin-10 (IL-10) in the serum of Henoch-Schonlein purpura nephritis (HSPN) patients were analyzed to explore the correlation between the above inflammatory factors and progression of the disease. The present study used the double antibody sandwich enzyme-linked immunosorbent assay (ELISA) method to detect the serum levels of TNF-α, IL-8, IL-10 and urine protein in 112 cases of patients with Henoch-Schonlein purpura (HSP), including 54 cases of HSP combined with renal function impairment (group HSPN), and 58 cases not combined with renal function impairment (NHSPN), as well as 50 healthy patients who were selected as the control group. The concentration of TNF-α, IL-8, and IL-10 in the serum of HSP patients were higher than that of the control group, and the difference was statistically significant (P<0.05). There was no significant difference in the levels of IL-10, and IL-8 between the HSPN group and the NHSPN group (P>0.05), but the level of TNF-α in the serum of HSPN group was significantly higher than that of NHSPN group (P<0.05). TNF-α, IL-8 and IL-10 levels of the acute nephritis, chronic nephritis and nephrotic syndrome groups were all higher than the simple proteinuria group. In addition, the levels of the three factors of the acute nephritis group were all higher than those of the chronic nephritis and nephrotic syndrome groups (P<0.05). IL-8, IL-10, and TNF-α were positively correlated with the urinary protein levels. The results indicated that the levels of serum TNF-α, IL-8 and IL-10 are correlated with HSPN, and serum TNF-α concentration can be used as an indicator of the severity 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.

Macrophage-derived tumor necrosis factor-α mediates diabetic renal injury

Monocyte/macrophage recruitment correlates strongly with the progression of diabetic nephropathy. Tumor necrosis factor-alpha (TNF-α) is produced by monocytes/macrophages but the direct role of TNF-α and/or macrophage-derived TNF-α in the progression of diabetic nephropathy remains unclear. Here we tested whether inhibition of TNF-α confers kidney protection in diabetic nephropathy via a macrophage-derived TNF-α dependent pathway. Compared to vehicle-treated mice, blockade of TNF-α with a murine anti-TNF-α antibody conferred kidney protection in Ins2Akita mice as indicated by reductions in albuminuria, plasma creatinine, histopathologic changes, kidney macrophage recruitment and plasma inflammatory cytokine levels at 18 weeks of age. To assess the direct role of macrophage-derived TNF-α in diabetic nephropathy, we generated macrophage specific TNF-α deficient mice (CD11bCre/TNF-α^Flox/Flox). Conditional ablation of TNF-α in macrophages significantly reduced albuminuria, the increase in plasma creatinine and BUN, histopathologic changes and kidney macrophage recruitment compared to diabetic TNF-α^Flox/Flox control mice after 12 weeks of streptozotocin-induced diabetes. Thus, production of TNF-α by macrophages plays a major role in diabetic renal injury. Hence, blocking TNF-α could be a novel therapeutic approach for treatment of diabetic nephropathy.

Advances in our understanding of the pathogenesis of Henoch-Schönlein purpura and the implications for improving its diagnosis

Henoch-Schönlein purpura (HSP) is a leukocytoclastic vasculitis classically characterized by palpable purpura, arthritis, abdominal pain and renal disease. In this article, we summarize our current understanding of the pathogenesis of HSP and the implications for improving its diagnosis. Although the pathogenesis of HSP is not fully understood yet, exciting new information has emerged in recent years, leading to a better understanding of its pathogenesis. Here, we discuss genetic predisposition, immunoglobulins with a particular emphasis on IgA1, activated complements, cytokines and chemokines, abnormal coagulation and autoantibodies in the underlying pathogenic mechanisms. Finally, diagnostic criteria for HSP developed by institutions such as the American College of Rheumatology and the European League against Rheumatism/Paediatric Rheumatology European Society were proposed to improve early detection and diagnosis.

Glomerular angiotensin-converting enzyme 2 in pediatric IgA nephropathy

BACKGROUND

Angiotensin-converting enzyme (ACE) 2 is a homolog of ACE and is thought to be a potent counter-regulator against ACE activity. However, the role of ACE2 has not been investigated in pediatric patients with IgA nephropathy (IgAN). This study was performed to examine the relationship between ACE2 expression and the development of pediatric IgAN.

METHODS

We performed immunohistochemical analysis of ACE2 and ACE in 39 patients with pediatric IgAN and 14 patients with minor glomerular abnormalities, and elucidated the effects of various cytokines on ACE2 expression in cultured human mesangial cells.

RESULTS

ACE2 expression levels in glomeruli and tubules were positively correlated with the mesangial hypercellularity score, while ACE expression levels in glomeruli and tubules are not. Multiple regression analysis showed that the mesangial hypercellularity score correlated with the ACE2 expression level in glomeruli and the urinary protein-creatinine ratio. In IgAN patients not treated with a renin-angiotensin system blocker, ACE2 expression levels in glomeruli were significantly increased compared to patients with minor glomerular abnormalities. IgAN patients treated with a renin-angiotensin system blocker did not show this increase in ACE2 expression. Furthermore, cultured human MC showed increased ACE2 mRNA and protein after treatment with IL-1β, a pro-inflammatory cytokine in IgAN. In fact, glomerular expressions of IL-1β were remarkably increased in patients with IgAN.

CONCLUSION

These data indicate that ACE2 expression in glomeruli is associated with mesangial hypercellularity in early lesions of pediatric IgAN.

The association of cytokine gene polymorphism with reflux nephropathy

OBJECTIVE

To identify genetic risk factors for the progression of vesicoureteral reflux (VUR) to reflux nephropathy, we examined polymorphisms of multiple cytokine genes among VUR patients with or without renal scarring.

METHODS

A total of 238 VUR patients aged between 1 and 18 years with (n = 113) or without renal scarring (n = 125) were included. The presence of renal scarring was demonstrated by renal parenchymal examination using Technetium-99m dimercaptosuccinate scintigraphy. Sera of the patients were examined for tumor necrosis factor-alpha (TNF-α, -308), transforming growth factor-beta1 (TGF-β1, +869, +915), interleukin-6 (IL-6, -174), interleukin-10 (IL-10, -1082, -819, -592) and interferon-gamma (IFN-γ, +874) gene polymorphisms using the polymerase chain reaction sequence-specific primer method.

RESULTS

Among patients with renal scarring, frequencies for the T/T G/C and C/C G/C genotypes of TGF-β1 gene (p = 0.003), GCC/GCC genotype of IL-10 gene (p = 0.015), GC phenotype of IL-6 gene (p = 0.001) and T/T genotype of IFN-γ gene (p = 0.001) were higher compared to patients without renal scarring. Regarding the TNF-α gene, among patients with low grade VUR only, the G/G genotype was associated with an increased risk.

CONCLUSIONS

Certain genotypes of cytokine gene polymorphisms seem to be associated with an increased or decreased susceptibility to reflux nephropathy, which may explain why only a proportion of VUR patients progress to reflux nephropathy. This information may aid in prediction of prognosis and implementing more aggressive management strategies at earlier stages. Further immunogenetic studies may identify novel targets for the management and prevention of the condition.

Effects of hemoperfusion in the treatment of childhood Henoch-Schönlein purpura nephritis

PURPOSE

Immune mediators play a role in the pathogenesis of Henoch-Schönlein purpura (HSP) nephritis. Since hemoperfusion (HP) is able to eliminate the immune mediators in many diseases, we investigated the effects of HP in the treatment of HSP nephritis.

METHODS

90 children with HSP nephritis were enrolled and followed up for 12 months. They were assigned to the HP group or the control group, respectively. Both groups were treated with corticosteroids and other supportive therapy. Patients in the HP group received HP for 3 consecutive days. The major outcomes included the percentage of patients with HSP nephritis, extrarenal symptoms, and recurrences and changes in serum levels of immune mediators.

RESULTS

The percentage of patients with nephritis in the HP group was less than that in the control group at each visit; the differences for prortions at 1, 3, 6, 12 months were 16.7% (p = 0.133), 31.3% (p = 0.004), 10.8% (p = 0.283), and 20.6% (p = 0.003), respectively. The severity and duration of abdominal and joint pains in the acute phase were significantly improved in the HP group compared to those in the control group. Hemoperfusion also significantly reduced patients' serum levels of immune mediators including IgA, TNF-α, IL-6, and LTB4. However, recurrences between the two groups were not significantly different.

CONCLUSIONS

Hemoperfusion in combination with corticosteroid was more effective than corticosteroid alone in treating HSP nephritis. The effects may be achieved by eliminating immune mediators.

Lack of association between macrophage migration inhibitory factor gene promoter (-173 G/C) polymorphism and childhood Henoch-Schönlein purpura in Turkish patients

Henoch-Schönlein purpura (HSP) is a small-vessel vasculitis of autoimmune hypersensitivity with rash, arthritis, abdominal pain and renal involvements. Macrophage migration inhibitory factor (MIF) is a immunoregulatory proinflammatory cytokine, and a major mediator at the inflammatory sites. The pathogenesis of HSP has not been fully elucidated. Here we aimed to assess the influence of macrophage migration inhibitory factor gene (-173 G/C) polymorphism in the susceptibility and clinical expression of patients with Henoch-Schönlein purpura (HSP). HSP patients (n:139) and ethnically matched healthy controls (n:100) were genotyped by PCR-RFLP. Genotype analysis of both polymorphisms did not reveal a significant deviation from Hardy-Weinberg equilibrium in any group (p > 0.05). No significant difference was obtained in genotype distribution (p > 0.05) and allele frequencies (p > 0.05) between patients and controls. A statistically significant genotype-phenotype correlation was not obtained when HSP patients were stratified by the presence of certain systemic complications and the macrophage migration inhibitory factor gene (-173 G/C) polymorphism (p > 0.05). A significant risk was not observed in the subjects both with the GC+CC genotype (p = 0.06, OR: 0.5538, 95% CI: 0.2985-1.0274) and C allele (odds ratio: C vs. G: 1.799, 95% CI: 1.002-3.23, p = 0.05). Our findings suggest that MIF gene -173 G/C polymorphism is not associated with HSP in the present Turkish population.

Inverse temporal changes of lipoxin A4 and leukotrienes in children with Henoch-Schönlein purpura

The pathogenesis of Henoch-Schönlein purpura (HSP) is not clearly understood. It remains unclear how changes of lipoxin A(4) (LXA(4)) that acts as a "braking signal" in inflammatory process occur in patients with HSP. In this study, we determined the temporal changes of blood and urinary LXA(4), Leukotriene (LT)B(4) and urinary LTE(4) in 49 children with HSP. Inverse temporal changes between gradually increased blood and urinary LXA(4) and gradually decreased blood and urinary LTB(4) and urinary LTE(4) were found in patients with HSP. Furthermore, both 15-S-hydroxyeicosatetraenoic acid and LXA(4) inhibited the LTB(4)-induced chemotaxis of leukocytes and release of LTB(4) from leukocytes obtained from the patients in the active phase of HSP. In 22 children with HSP nephritis, concordant with the gradually increased severity of mesangial proliferation and proteinuria, the glomerular expressions of 15-lipoxygenase and the levels of urinary LXA(4) gradually decreased and the glomerular expressions of LTC(4) synthase and the urinary LTE(4) and LTB(4) gradually increased. The levels of blood and urinary LXA(4) in patients with HSP nephritis were lower than those in patients with purpura alone in early resolution of HSP. The levels of blood and urinary LTB(4) and urinary LTE(4) in the patients with HSP nephritis were higher than those in patients with purpura alone in early resolution of HSP. There was positive correlation between blood LTB(4) and serum C-reactive protein in 49 children with HSP. These data suggest that LTs may play a proinflammatory and profibrotic role in the pathogenesis of HSP, and insufficiency of LXA(4) may be responsible for the patients with HSP whose illness become more serious.

Endothelin 1 levels in relation to clinical presentation and outcome of Henoch Schonlein purpura

Background

Henoch Schonlein purpura (HSP) is a common vasculitis of small vessels whereas endothelin-1 (ET-1) is usually reported elevated in vasculities and systematic inflammation. The aim of the present study was to investigate whether ET-1 levels are correlated with the clinical presentation and the outcome of HSP.

Methods

The study sample consisted of thirty consecutive patients with HSP. An equal number of healthy patients of similar age and the same gender were served as controls. The patients' age range was 2–12.6 years with a mean ± SD = 6.3 ± 3 years. All patients had a physical examination with a renal, and an overall clinical score. Blood and urinary biochemistry, immunology investigation, a skin biopsy and ET-1 measurements in blood and urine samples were made at presentation, 1 month later and 1 year after the appearance of HSP. The controls underwent the same investigation with the exception of skin biopsy.

Results

ET-1 levels in plasma and urine did not differ between patients and controls at three distinct time points. Furthermore the ET-1 were not correlated with the clinical score and renal involvement was independent from the ET-1 measurements. However, the urinary ET-1 levels were a significant predictor of the duration of the acute phase of HSP (HR = 0.98, p = 0.032, CI0.96–0.99). The ET-1 levels did not correlate with the duration of renal involvement.

Conclusion

Urinary ET-1 levels are a useful marker for the duration of the acute phase of HSP but not for the length of renal involvement.

Urinary kallikrein excretion is related to renal function change and inflammatory status in chronic kidney disease patients receiving angiotensin II receptor blocker treatment

AIM

This study was to evaluate the correlation of urinary kallikrein to renal function, proteinuria and urinary cytokines in chronic kidney disease patients in a longitudinal follow up.

METHOD

We measured urinary kallikrein and cytokines in 50 patients who were followed up for 12 months.

RESULTS

Using regression model we found that the kallikrein excretion (estimated by log kallikrein/creatinine) was positively correlated to log estimated glomerular filtration rate in the beginning and the end of follow up (P = 0.049 and 0.006, respectively). No correlation existed between kallikrein excretion and proteinuria. The kallikrein excretion decreased after 12 months of follow up, which was also associated with the decrease of log estimated glomerular filtration rate. There was a significant positive correlation between the log urinary kallikrein and monocyte chemoattractant protein-1 (MCP-1) concentration (correlation coefficient = 0.277; P = 0.049). Urinary kallikrein excretion was also positively correlated with serum MCP-1 level (correlation coefficient = 0.431; P = 0.002). No correlation existed between urinary kallikrein and transforming growth factor beta-1 or tumour necrosis factor-alpha concentration.

CONCLUSION

Urinary kallikrein excretion is positively correlated to renal function, serum and urinary inflammatory mediator MCP-1 in chronic kidney disease patients. These findings indicate that urinary kallikrein excretion may reflect the change of renal function and kidney inflammatory status.

Henoch-Schönlein purpura after etanercept therapy for psoriasis

Etanercept is a recombinant dimeric fusion protein consisting of a tumor necrosis factor-alpha receptor ligand-binding region linked to the Fc portion of human IgG. It is approved for use in the treatment of rheumatoid arthritis, ankylosing spondylitis, juvenile rheumatoid arthritis, psoriasis, and psoriatic arthritis. Since 1998, there have been reports of vasculitic adverse events, including necrotizing vasculitis and leukocytoclastic vasculitis. In addition, the adverse events reporting system of the U.S. Food and Drug Administration has recorded 35 cases of leukocytoclastic vasculitis, 20 after etanercept therapy and 15 after infliximab. Most cases of cutaneous vasculitis describe development of symptoms within 3 months of etanercept use. In only one case report was direct immunofluorescence performed on tissue and no specific immunoreactivity found. We describe the first case of Henoch-Schönlein purpura with acute renal failure associated with increase in etanercept dose after 11 months of use for treatment of psoriasis. Discontinuation of the drug and treatment with a course of systemic steroids led to the complete resolution of the vasculitis and improvement of renal function. Vasculitis occurring even during chronic use of antitumor necrosis factor agents must be considered as possibly related to the therapy.

Leptin levels in Henoch–Schönlein purpura

The objective of this paper is to assess the possible role of nitric oxide (NO) and leptin in Henoch-Schönlein purpura (HSP). We investigated the serum leptin and total nitrite levels in 22 children with HSP in the acute phase and after remission and in 20 age- and sex-matched healthy control. Serum leptin levels (nanograms per milliliter; median, min-max) were statistically higher in the acute phase (12.9, 9.1-19.5) than those in the remission phase (6.1, 3.7-10.5, p<0.001) and in the control group (4.9, 3.8-7.5, p<0.001). Also, serum nitrite levels (micromole per liter; median, min-max) were higher in children in the acute phase (45.0, 32.0-60.0) compared to those in remission phase (30.5, 23.0-48.0) and in the control group (29.5, 18.0-38.0) (p<0.001, p<0.001, respectively). There was a positive correlation between serum leptin and total nitrite levels (r=0.65, p<0.001). We have demonstrated that serum leptin and NO levels were increased during the acute phase in children with HSP, and returned to normal levels in remission. We suggest that leptin and NO may have a role in the immunoinflammatory process of HSP, especially in the acute phase. Further studies are needed to clearly establish the roles of leptin and NO in the pathogenesis of HSP.

Pentoxifylline ameliorates proteinuria through suppression of renal monocyte chemoattractant protein-1 in patients with proteinuric primary glomerular diseases

Proteinuria (albuminuria) reflects dysfunction of the glomerular permeability barrier in which inflammatory cytokines play a key role. Pentoxifylline (PTX) is a phosphodiesterase inhibitor that possesses potent anti-inflammatory and immunomudulatory effects. This study evaluated the effectiveness of PTX to reduce proteinuria and inflammatory mediators in patients with proteinuric primary glomerular diseases. Seventeen patients with primary glomerular diseases, a persistent spot proteinuria exceeding 1.5 g/g creatinine (Cr) and a glomerular filtration rate between 24 and 115 ml/min/1.73 m(2) were treated with PTX 400 mg twice daily for 6 months. Before and after the treatment, serum Cr, plasma renin activity and aldosterone concentrations, plasma and urinary tumor necrosis factor (TNF)-alpha, interleukin-1beta and monocyte chemoattractant protein (MCP)-1, as well as urinary protein and Cr were measured. PTX significantly reduced urinary protein excretion, along with an increase of serum albumin. A significant correlation existed between the basal urinary protein/Cr and the basal urinary MCP-1/Cr ratios. PTX lowered the urinary MCP-1/Cr ratio, and the percent reduction of urinary protein/Cr ratio correlated directly with the precent decrease of urinary MCP-1/Cr ratio after PTX treatment. There was no significant change in blood pressure, renal function, biochemical parameters, plasma renin activity and aldosterone concentrations, or plasma TNF-alpha and MCP-1 levels during the study. In conclusion, administration of PTX 800 mg per day is safe and effective for reducing proteinuria in patients with proteinuric primary glomerular diseases. This beneficial effect occurs in close association with a reduction of urinary MCP-1 excretion.

C-peptide signals via Galpha i to protect against TNF-alpha-mediated apoptosis of opossum kidney proximal tubular cells

Cell loss by apoptosis occurs in renal injury such as diabetic nephropathy. TNF-alpha is a cytokine that induces apoptosis and has been implicated in the pathogenesis of diabetic nephropathy. The aim was to investigate whether C-peptide or insulin could modulate TNF-alpha-mediated cell death in opossum kidney proximal tubular cells and to examine the mechanism(s) of any effects observed. C-peptide and insulin protect against TNF-alpha-induced proximal tubular cell toxicity and apoptosis. Cell viability was analyzed by methylthiazoletetrazolium assay; cell viability was reduced to 60.8 +/- 2.7% of control after stimulation with 300 ng/ml TNF-alpha. Compromised cell viability was reversed by pretreatment with 5 nM C-peptide or 100 nM insulin. TNF-alpha-induced apoptosis was detected by DNA nick-end labeling and by measuring histone associated DNA fragments using ELISA. By ELISA assay, 300 ng/ml TNF-alpha increased apoptosis by 145.8 +/- 4.9% compared with controls, whereas 5 nM C-peptide and 100 nM insulin reduced apoptosis to 81.6 +/- 4.8 and 77.4 +/- 3.1% of control, respectively. The protective effects of C-peptide and insulin were associated with activation of NF-kappaB. Activation of NF-kappaB by C-peptide was pertussis toxin sensitive and dependent on activation of Galpha(i). Phosphatidylinositol 3-kinase but not extracellular signal regulated mitogen-activated protein kinase mediated C-peptide and insulin activation of NF-kappaB. The cytoprotective effects of both C-peptide and insulin were related to increased expression of TNF receptor-associated factor 2, the product of an NF-kappaB-dependent survival gene. These data suggest that C-peptide and/or insulin activation of NF-kappaB-regulated survival genes protects against TNF-alpha-induced renal tubular injury in diabetes. The data further support the concept of C-peptide as a peptide hormone in its own right and suggest a potential therapeutic role for C-peptide.

Effect of tumor necrosis factor alpha and vascular permeability growth factor on albuminuria in rats

The purposes of this study were to measure the serum levels of vascular permeability growth factor (VPGF) and tumor necrosis factor alpha (TNFalpha) in minimal lesion nephrotic syndrome (MLNS) patients and to assess their effect on albuminuria in rats. Serum for VPGF and TNFalpha was obtained during relapse and remission from 18 MLNS patients. Tumor necrosis factor alpha was infused at the rate of 10 and 20 ng/h and VPGF at the rate of 20 and 40 ng/h for 5 days into the left renal artery of rats. Urinary albumin (24-h collection) was measured prior to infusion and on days 2, 4 and 5. Rats infused with 1% bovine serum albumin served as controls. Serum VPGF and TNFalpha levels in MLNS patients in relapse were not different from those seen during remission. A significant increase in albuminuria was observed on day 4 and 5 only when rats were infused with TNFalpha at the rate of 20 ng/h as compared to the excretion seen in same animals prior to the infusion of cytokine and on days 4 and 5 of normal controls. Neither VPGF nor TNFalpha seems to be the circulating pathogenic cytokine for proteinuria in MLNS. However, TNFalpha may contribute to the increased albuminuria via a paracrine effect at the glomerulus.

Macrophages and progressive tubulointerstitial disease

Macrophages and progressive tubulointerstitial disease. In chronic renal disease, tubulointerstitial inflammation and injury is associated with infiltrating macrophages. As a consequence of primary injury, proteinuria, chronic hypoxia, and glomerular-derived cytokines may all differentially modulate the expression of factors that promote macrophage recruitment. In addition to adhesion molecules and chemokines, products of complement system and renin-angiotensin system activation may direct this process. Once present at interstitial sites, macrophages interact with resident cells and extracellular matrix to generate a proinflammatory microenvironment that amplifies tissues injury and promotes scarring. There is now increasing evidence for the efficacy of interventions directed against factors that recruit, activate, or are produced by macrophages. A detailed understanding of the biology of this area may lead to the further development of therapies that will improve the outcome of renal disease.

The role of tumor necrosis factor-alpha in Henoch-Schonlein purpura

Henoch-Schonlein purpura (HSP) is one of the most common types of vasculitis disorders in childhood and is characterized by a rash, arthritis, abdominal pain, and renal involvement. The factors that determine and mediate the severity of HSP and its renal involvement remain poorly understood, although it is likely that pro-inflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha), are involved in the pathogenesis. Serum and urine levels of TNF-alpha were measured in children with HSP in the acute and convalescent phases by ELISA. Serum TNF-alpha levels were significantly higher in proteinuric HSP in the acute phase (36.6+/-8.5 pg/ml) compared with those with HSP without renal involvement and those with hematuric HSP (25.4+/-4.5 and 27.1+/-3.9 pg/ml) (P<0.005). However, these significantly higher levels disappeared in the convalescent phase. Using matched serum samples from the same patients, serum TNF-alpha levels of proteinuric HSP patients were significantly lower in the convalescent phase (29.9+/-4.6 pg/ml, P <0.05) than in the acute phase (39.1+/-8.2 pg/ml). Although urine TNF-alpha levels were higher in proteinuric HSP in the acute phase and reduced in the convalescent phase, there were no significantly high or low levels. These results suggest that increased TNF-alpha levels in the serum induce a series of functional and morphological changes in the glomerular cells in the acute phase and may be used as markers for monitoring the disease activity of HSP with severe renal involvement.

Production of chemokines in Kawasaki disease, Henoch-Schönlein purpura and acute febrile illness

We compared the production of three chemokines; interferon-gamma-inducible protein-10 (IP-10), monocyte chemoattractant protein-1 (MCP-1) and growth-related onco-gene-alpha(Gro-alpha) that attracts monocytes or neutrophils, or both, in peripheral blood at acute stage of Kawasaki disease (n=29), Henoch-Schönlein purpura (n=15) and acute febrile illnesses (n=12). The production of the chemokines was assayed by ELISA. The plasma levels of IP-10 were markedly elevated in Kawasaki disease (538.6+/-336.4 pg/mL) and acute febrile illnesses (417.1 +/-262.2 pg/mL) compared with in Henoch-Schönlein purpura (58.7 +/-95.7 pg/mL) (p<0.05). The MCP-1 levels were elevated in Kawasaki disease (443.0 +/-473.1 pg/mL) and acute febrile illnesses (328.6 +/-261.1 pg/mL) compared with in Henoch-Schönlein purpura (82.9 +/-79.0 pg/mL) (p<0.05). The Gro-alpha levels were elevated only in acute febrile illnesses (134.3 +/-153.6 pg/mL) compared with in Kawasaki disease (31.8 +/-22.1 pg/mL) or Henoch-Schönlein purpura (29.4 +/-53.3 pg/mL) (p<0.05). According to these results, monocytes may play an important role in Kawasaki disease. In acute febrile illnesses, both monocytes and neutrophils may play an important role. By contrast, Henoch-Schönlein purpura may not be associated with the role of monocytes and neutrophils. Further studies using a larger number of cases are needed.

TUMOR NECROSIS FACTOR-α GENE POLYMORPHISM IN REFLUX NEPHROPATHY

PURPOSE

Interstitial scarring contributes to the progression of renal failure in reflux nephropathy. The proinflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) has been implicated in the disease susceptibility and pathogenesis of several inflammatory diseases promoting interstitial infiltration of inflammatory cells. We evaluate the frequency of TNF-alpha gene polymorphism in patients with reflux nephropathy.

MATERIAL AND METHODS

Renal scarring was evaluated with technetium dimercapto-succinic acid renal scan. Genotyping was performed on 104 patients with reflux nephropathy and 30 controls for the TNF-alpha gene polymorphisms using polymerase chain reaction and restriction digest. This polymorphism involved a guanidine to adenosine transition at position -308 and was designated as TNF1 (-308G) and TNF2 (-308A).

RESULTS

The allele frequencies of TNF1 and TNF2 were 18.8% and 81.2% in patients with reflux nephropathy and 76.7% and 23.3% in controls, respectively. The genotype distribution of TNF-alpha-AA was significantly higher (66.4% vs 10%, p <0.05), while the TNF-alpha-GG was lower (13.4% vs 60%, p <0.05) in patients with reflux nephropathy compared to controls.

CONCLUSIONS

This study demonstrates for the first time the association of the cytokine TNF-alpha gene polymorphism in patients with reflux nephropathy. Our data suggest that patients with vesicoureteral reflux and TNF-alpha AA genotype may have increased susceptibility to reflux nephropathy.

The role of fish oil/omega-3 fatty acids in the treatment of IgA nephropathy

Beneficial effects of omega-3 polyunsaturated fatty acids (n-3 PUFA) have been reported in recent epidemiologic studies and randomized clinical trials in a variety of cardiovascular and autoimmune diseases. Fish and marine oils are the most abundant and convenient sources of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the two major n-3 fatty acids that serve as substrates for cyclooxygenase and lipoxygenase pathways leading to less potent inflammatory mediators than those produced through the n-6 PUFA substrate, arachidonic acid. N-3 PUFA can also suppress inflammatory and/or immunologic responses through eicosanoid-independent mechanisms. Although the pathophysiology of IgA nephropathy is incompletely understood, it is likely that n-3 PUFA prevents renal disease progression by interfering with a number of effector pathways triggered by mesangial immune-complex deposition. In addition, potential targets of n-3 PUFA relevant to renal disease progression could be similar to those involved in preventing the development and progression of cardiovascular disease by lowering blood pressure, reducing serum lipid levels, decreasing vascular resistance, or preventing thrombosis. In IgA nephropathy, efficacy of n-3 PUFA contained in fish oil supplements has been tested with varying results. The largest randomized clinical trial performed by our collaborative group provided strong evidence that treatment for 2 years with a daily dose of 1.8 g of EPA and 1.2 g of DHA slowed the progression of renal disease in high-risk patients. These benefits persisted after 6.4 years of follow up. With safety, composition, and dosing convenience in mind, we can recommend two products that are available as pharmaceutical-grade fish-oil concentrates, Omacor (Pronova Biocare, Oslo, Norway) and Coromega (European Reference Botanical Laboratories, Carlsbad, CA).

Urinary and renal interstitial concentrations of TNF-alpha increase prior to the rise in albuminuria in diabetic rats

BACKGROUND

The development of diabetic nephropathy has been linked to the release of vasoactive hormones and growth factors. Currently the role of inflammatory cytokines in this pathogenic process is not clear.

METHODS

We utilized the microdialysis technique to monitor early changes in tumor necrosis-alpha (TNF-alpha) levels in the renal interstitial fluid and urine of conscious Sprague-Dawley rats (N = 8) before and after induction of diabetes with streptozotocin (STZ). Measurement of the urinary albumin excretion (UAE) was utilized to monitor the development and progression of diabetic nephropathy.

RESULTS

UAE increased from 0.56 +/- 0.20 microg/min to 8.14 +/- 2.98 microg/min 17 days after induction of diabetes (P = 0.01). Renal interstitial fluid TNF-alpha increased from 11.96 +/- 5.32 pg/mL at baseline to 45.02 +/- 11.69 pg/mL 5 days after induction of diabetes (P = 0.03). Renal interstitial fluid TNF-alpha levels remained elevated throughout the remainder of the study period. Urinary TNF-alpha also increased significantly compared to baseline 3 days after induction of diabetes (294.18 +/- 36.94 pg/mL vs. 16.05 +/- 6.07 pg/mL, P < 0.002). There was a second significant rise in urinary TNF-alpha concentration to 638.16 +/- 36.94 pg/mL 21 days after induction of diabetes (P < 0.001). Serum TNF-alpha levels were undetectable before STZ injection and remained undetectable by the end of the study. Urinary and renal interstitial fluid TNF-alpha in the control rats (N = 5) did not change throughout the study.

CONCLUSION

We found an early rise in renal TNF-alpha levels after induction of diabetes with STZ, which precedes the rise in UAE by about 2 weeks. These findings suggest a possible contribution of TNF-alpha in the complicated pathogenic process resulting in microalbuminuria in diabetes.

Polymorphisms of the tumour necrosis factor alpha gene at position -308 and TNFd microsatellite in primary IgA nephropathy

BACKGROUND

The development of glomerular inflammation in immunoglobulin A nephropathy (IgAN) has been associated with various cytokines, including tumour necrosis factor alpha (TNFalpha). A biallelic polymorphism in the promoter region of the TNFalpha gene (TNFA), at position -308, has been described (TNFA-1 and TNFA-2) and is associated with increased TNFalpha production for the TNFA-2 allele. Another microsatellite polymorphism has been described for TNFd, which is functional and associated with increased production of TNFalpha for the d3 allele.

METHODS

We have studied these two polymorphisms in 242 Caucasian patients with biopsy-proven IgAN (169 male, 73 female), who were followed from 1990 to 1999, and in 210 appropriate local Caucasian controls (133 male, 77 female) for comparison of genotypes and allelic distribution.

RESULTS

The respective frequencies of A1/A1, A1/A2 and A2/A2 TNFA genotypes were 76.4, 22.3 and 1.3% in IgAN vs 78.1, 19.5 and 2.4% in controls (P=NS). For TNFd, the frequencies of the respective genotypes d3/d3, d3/non-d3 and non-d3/non-d3 were significantly different (chi(2)=12.30, P=0.002, Pc=0.013) with an increased frequency of the low-producer genotype non-d3/non-d3 in IgAN patients (24 vs 12%). The combination of TNFA and TNFd polymorphisms demonstrated that compared with controls, patients with non-A2 and non-d3 alleles (low producers) were more common (18 vs 9%; P=0.006). In the genotype/clinical phenotype correlations, we could not demonstrate significant differences between the different subgroups of patients. However, high-producer TNFalpha patients (A2 and d3 alleles) had more chronic renal failure than others (36.6 vs 22.9%) at last follow-up and their survival without chronic renal failure (Kaplan-Meier) was lower. Nevertheless, TNFalpha polymorphisms were not an independent risk factor for the progression of the disease.

CONCLUSIONS

TNFA and TNFd polymorphisms seem to influence the occurrence or initiation of the disease, but do not play a significant role, if any, in the progression of IgA nephritis.

Schönlein-henoch purpura in children and adults: diagnosis, pathophysiology and management

Schönlein-Henoch syndrome is a form of systemic small-vessel vasculitis, characterised by vascular and/or mesangial immunoglobulin A1 deposits. The main clinical manifestations are vascular purpura, predominating on the lower limbs, and articular, gastrointestinal and renal symptoms. Pulmonary, cardiac, genital and neurological symptoms have also be observed. The syndrome usually affects children, whereas it is rare in adults. The frequency of renal involvement varies between individual studies (from 20 to 100%). Renal manifestations are usually mild and transient, although chronic nephropathies may occur. Overall, an estimated 2% of children with Schönlein-Henoch purpura progress to renal failure and up to 20% of children with nephritis treated in specialised centres require haemodialysis. The renal prognosis appears to be worse in adults. Aetiological investigations are required, as a triggering factor is found in approximately half the patients (e.g. viral, bacterial and parasitic infections, drugs, toxins, systemic diseases and cancer). Dapsone has beneficial effects on cutaneous, gastrointestinal and articular manifestations in adults, especially those with chronic forms. Corticosteroids may be useful for refractory abdominal pain. Methylprednisolone pulse therapy, immunosuppressive drugs (e.g. cyclophosphamide and azathioprine), plasma exchange and polyclonal immunoglobulin therapy are beneficial in very rare life-threatening forms of the disease and in rare instances where renal function is compromised.

Impact of interleukin-1 receptor antagonist and tumor necrosis factor-alpha gene polymorphism on IgA nephropathy

BACKGROUND

It is evident that cytokines play an important role in the pathogenesis as well as disease progression in IgA nephropathy (IgAN). The level of cytokine production is influenced by different genotypes that reflect gene polymorphism of the pertinent cytokine. Interleukin-1 receptor antagonist (IL-1ra) and tumor necrosis factor-alpha (TNF-alpha) gene polymorphism have been found to affect disease susceptibility and activity in several inflammatory diseases. However, the impact of these polymorphisms in IgAN patients has not previously been thoroughly studied.

METHODS

We investigated 111 cases of biopsy-proven IgAN and 100 healthy, normal controls for their IL-1ra and TNF-alpha gene polymorphism. IL-1ra gene polymorphism was characterized as a variable number of tandem repeats of a 86 bp sequence within intron 2. Five alleles were identified and were designated as IL1RN*1, IL1RN*2, IL1RN*3, IL1RN*4, and IL1RN*5, corresponding to 4, 2, 5, 3, 6 repeats, respectively. A polymorphism in the promoter region of the TNF-alpha gene was also studied. This polymorphism involved a guanidine to adenosine transition at position -308 and was designated as TNF1 (-308G) and TNF2 (-308A).

RESULTS

There were 54 male and 57 female patients with a mean age of 30.3 +/- 12.5 years and a disease duration of 66. 8 +/- 47.2 months. The mean duration of the follow-up period was 47. 3 +/- 32.6 months. In the patient group, the allele frequencies of IL1RN*1, IL1RN*2, IL1RN*3, IL1RN*4, and IL1RN*5 were 89.6%, 9.9%, 0%, 0.5%, and 0%, respectively, whereas the corresponding carriage rates were 100%, 19.8%, 0%, 0.9%, and 0%, respectively. An excessive carriage of IL2RN*2 was found in the patients when compared with normal controls (allele frequency, 9.9 vs. 2.5%, P < 0.0001). The allele frequencies of TNF1 and TNF2 were 94.1 and 5.9%, respectively, and the carriage rates were 99.1 and 10.8%, respectively, in the patients, which was not significantly different from those of normal controls. When the patients were stratified into mild and severe groups according to their initial presentation, none of the studied alleles correlated with the severity. However, patients with gross hematuria were associated with a higher carriage rate of TNF2 when compared with patients without gross hematuria (allele frequency, 15. 4 vs. 4.6%, P = 0.0552; carriage rate, 30.8% vs. 8.2%, P = 0.0272). Renal survival analysis revealed that the TNF2 carrier had a renal survival comparable with TNF2 (-) patients. However, the carriage of the IL1RN*2 allele was associated with a significantly poorer long-term outcome with a median survival time of 72 months, as compared with those without IL1RN*2 (134 months, P < 0.01).

CONCLUSION

IL-1ra and TNF-alpha gene polymorphism may affect disease susceptibility as well as disease activity and long-term outcome in human IgAN. Treatment with an IL-1ra or IL-1 blocking agent may be relevant in those carrying the IL1RN*2 allele.

Henoch-Schönlein purpura in children. Report of 100 patients and review of the literature

Henoch-Schönlein purpura (HSP) is an acute leukocytoclastic vasculitis that primarily affects children. In the current report, the author presents the clinical features of 100 children with HSP and reviews the literature, placing particular emphasis on new information concerning the etiology, immunopathogenesis, and treatment of HSP. The dominant clinical features of HSP are cutaneous purpura (100%), arthritis (82%), abdominal pain (63%), gastrointestinal bleeding (33%), and nephritis (40%). The etiology of HSP remains unknown, but it is clear that IgA plays a critical role in the immunopathogenesis of HSP, as evidenced by increased serum IgA concentrations, IgA-containing circulating immune complexes, and IgA deposition in vessel walls and renal mesangium. There are 2 subclasses of IgA, but HSP is associated with abnormalities involving IgA1 exclusively, and not IgA2. This finding may be a consequence of abnormal glycosylation of O-linked oligosaccharides unique to the hinge region of IgA1 molecules. Although several lines of evidence suggest a genetic susceptibility to HSP, the fundamental basis for the abnormalities involving IgA remain unclear. In general, HSP is an acute, self-limited illness, but one-third of patients will have 1 or more recurrences of symptoms. Corticosteroid therapy may hasten the resolution of arthritis and abdominal pain, but does not prevent recurrences. To date, no form of therapy has been shown to shorten appreciably the duration of HSP. The long-term prognosis of HSP is directly dependent on the severity of renal involvement. Corticosteroids in usual doses have no effect on established nephritis. Evidence is emerging that treatment with high-dose intravenous pulse methylprednisolone coupled with azathioprine or cyclophosphamide may be beneficial in patients with severe nephritis.

Imbalances in serum proinflammatory cytokines and their soluble receptors: a putative role in the progression of idiopathic IgA nephropathy (IgAN) and Henoch-Schönlein purpura nephritis, and a potential target of immunoglobulin therapy?

Following recent experimental data suggesting an aggravating effect of circulating proinflammatory cytokines on the histological lesions of IgAN, we studied changes in serum proinflammatory cytokines and their soluble receptors and antagonists in patients treated with polyvalent immunoglobulins (15 with severe nephropathy who had indicators of poor prognosis: heavy proteinuria, hypertension, altered renal function and Lee's histological grade III or IV; and 14 with moderate forms of IgAN who had permanent albuminuria > 300 mg/day and < 2000 mg/day, Lee's histological grade II and a glomerular filtration rate > 70 ml/min) in comparison with healthy controls (n = 20) and patients with non-IgA nephritides (n = 50). These were measured by means of specific immunometric assays before and after 9 months of immunoglobulin therapy. Total tumour necrosis factor (TNF) serum and IL-6 levels were elevated in IgAN patients before therapy, relative to controls, and normalized after immunoglobulin therapy. Levels of soluble TNF receptor of type I (sR55) and type II (sR75) increased on immunoglobulin therapy. TNF index alpha-55,75 used to assess biologically available TNF-alpha (ratio of total TNF-alpha divided by levels of soluble TNF receptors sR55 and sR75) was elevated before therapy and was below healthy control values after 9 months of immunoglobulin administration. Levels of serum IL-1 receptor antagonist were low prior to immunoglobulin administration in patients with severe forms of IgAN, and normalized on therapy. Serum interferon-gamma was unmodified. The histological activity index correlated with serum total TNF-alpha, TNF index alpha-55,75 and serum IL-6 levels, whereas proteinuria correlated with serum total TNF-alpha and TNF index alpha-55,75 but not with serum IL-6. These data suggest that the overproduction of proinflammatory cytokine is unbalanced by their natural antagonists in IgAN and Henoch-Schönlein syndrome. This process may play a role in the progression of the disease and be one of the targets of immunoglobulin therapy.

Adhesion molecules and urinary tumor necrosis factor-alpha in idiopathic membranous glomerulonephritis

Adhesion molecules are required in several physiological processes, but their altered function/expression is associated with the pathogenesis of inflammatory diseases. In the present study on idiopathic membranous glomerulonephritis (MGN) the expression of adhesion molecules (ICAM-1, VCAM-1, PECAM-1, E-selectin, LFA-1, Mac-1) was analyzed in different cellular compartments of the kidney using an indirect immunoperoxidase technique and monoclonal antibodies. Relationships between the expression of these molecules and the clinical and morphological activity of the disease and the urinary excretion of tumor necrosis factor alpha (TNF-alpha) were studied in 20 patients. The results were compared with the findings in ten normal kidneys and urinary TNF-alpha in 17 healthy subjects. The expression of adhesion molecules in glomeruli and tubules was unchanged apart from a diminished expression of VCAM-1 (P = 0.014) in glomerular parietal epithelial cells and PECAM-1 in glomerular endothelial cells (P < 0.01). Interstitial peritubular capillaries expressed significantly (P = 0.009) more E-selectin compared with the controls. The interstitial compartment had a highly increased number of cells expressing ICAM-1 in MGN (32.4 +/- 4.6 cells/high power field) compared with the controls (9.4 +/- 1.2; P < 0.001). Also, cells expressing VCAM-1 (10.2 +/- 1.6 vs. 2.8 +/- 1.9; P = 0.005). PECAM-1 (25.9 +/- 5.3 vs. 7.4 +/- 2.1; P = 0.006), and LFA-1 (20.4 +/- 3.6 vs. 8.3 +/- 1.5; P = 0.041) were increased in the interstitium. Proteinuria correlated particularly with the expression of E-selectin in peritubular capillaries (r = 0.63, P = 0.004). The number of LFA-1 expressing inflammatory cells in the interstitium correlated with peritubular capillary E-selectin (r = 0.8, P < 0.001) and interstitial ICAM-1 (r = 0.61, P = 0.009) expression, but histological alterations did not correlate with the expression of adhesion molecules. Tumor necrosis factor-alpha excretion was significantly increased in MGN (41 +/- 8 pg/mg creatinine) compared with the controls (13 +/- 2; P = 0.001), and in particular, it correlated with the interstitial expression of LFA-1 (r = 0.71, P = 0.002). This study suggests that active MGN leads not only to proteinuria but also to increased urinary TNF-alpha excretion. These may serve as triggers for the up-regulation of adhesion molecules in the peritubular capillaries and interstitial cells thus enhancing the development of the interstitial injury.

The balance of pro- and anti-inflammatory cytokines in cardiac surgery

Homeostatic control of the balance of pro- and anti-inflammatory cytokines is important for the maintenance of health. Cardiac surgery, with its intense pro-inflammatory stimulus, constitutes a major challenge to the patient's ability to maintain this balance. Pre- and intraoperative factors influencing the maintenance of cytokine balance are discussed.

Interleukin-1 receptor antagonist allele: is it a genetic link between Henoch-Schönlein nephritis and IgA nephropathy?

Henoch-Schönlein purpura nephritis (HSPN) is a multi-organ systemic vasculitis, which shares many clinical, histological and immunological features with IgA nephropathy (IgAN). To address whether these two diseases have a common genetic background, the polymorphism of the variable number tandem repeat (VNTR) of IL-1 receptor antagonist (IL-1ra) gene has been analyzed using PCR in patients diagnosed with HSPN (N = 43) and IgAN (N = 97), together with normal controls (N = 98) and patients with acute post-infectious glomerulonephritis (APGN), under the concept that IL-1 might play an important role in mediating pathogenesis of vasculitis and glomerulonephritis. It was found that the allele frequency and carriage rate of the interleukin-1 receptor antagonist allele (IL1RN*2) of the IL-1ra gene increased significantly in HSPN patients as compared to IgAN (P < 0.01), APGN (P < 0.05) and normal subjects (P < 0.01). Interestingly, varied carriage rates of IL1RN*2 were found among various groups of IgAN patients presenting with different clinical manifestations. The carriage rate of IL1RN*2 was significantly higher in patients with recurrent gross hematuria than other groups of IgAN patients (P < 0.01). Furthermore, although the carriage rate of IL1RN*2 was higher in HSPN (46.5%) than average IgAN patients (26.8%; P < 0.01), there was no significant difference in the carriage rate of IL1RN*2 between HSPN and those IgAN patients with recurrent gross hematuria (42.8%l P > 0.05). It suggested that the IL1RN*2 allele might be a genetic marker shared by HSPN and a special group of IgAN patients with recurrent gross hematuria. Our preliminary observation provided a genetic evidence to support the hypothesis that HSPN and certain subgroup of IgAN are closely related diseases. Such an association of the gene polymorphism of IL-1ra between HSPN and IgAN with recurrent gross hematuria might serve as a key to explore their pathogenesis and eventually a specific intervention.