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?

Gut-kidney axis in IgA nephropathy: Role on mesangial cell metabolism and inflammation

IgA Nephropathy (IgAN) is the commonest primary glomerular disease around the world and represents a significant cause of end-stage renal disease. IgAN is characterized by mesangial deposition of IgA-immune complexes and mesangial expansion. The pathophysiological process includes an abnormally glycosylated IgA1, which is an antigenic target. Autoantibodies specifically recognize galactose-deficient IgA1 forming immune complexes that are amplified in size by the soluble IgA Fc receptor CD89 leading to deposition in the mesangium through interaction with non-classical IgA receptors. The local production of cytokines promotes local inflammation and complement system activation, besides the stimulation of mesangial proliferation. The spectrum of clinical manifestations is quite variable from asymptomatic microscopic hematuria to rapidly progressive glomerulonephritis. Despite all the advances, the pathophysiology of the disease is still not fully elucidated. The mucosal immune system is quoted to be a factor in triggering IgAN and a "gut-kidney axis" is proposed in its development. Furthermore, many recent studies have demonstrated that food intake interferes directly with disease prognosis. In this review, we will discuss how mucosal immunity, microbiota, and nutritional status could be interfering directly with the activation of intrinsic pathways of the mesangial cells, directly resulting in changes in their function, inflammation and development of IgAN.

Cytokines and Production of Aberrantly O-Glycosylated IgA1, the Main Autoantigen in IgA Nephropathy

Immunoglobulin A (IgA) nephropathy is the most common primary glomerulonephritis worldwide, with no disease-specific treatment and up to 40% of patients progressing to kidney failure. IgA nephropathy (IgAN), characterized by IgA1-containing immunodeposits in the glomeruli, is considered to be an autoimmune disease in which the kidneys are injured as innocent bystanders. Glomerular immunodeposits are thought to originate from the circulating immune complexes that contain aberrantly O-glycosylated IgA1, the main autoantigen in IgAN, bound by IgG autoantibodies. A common clinical manifestation associated with IgAN includes synpharyngitic hematuria at disease onset or during disease activity. This observation suggests a connection of disease pathogenesis with an activated mucosal immune system of the upper-respiratory and/or gastrointestinal tract and IgA1 glycosylation. In fact, some cytokines can enhance production of aberrantly O-glycosylated IgA1. This process involves abnormal cytokine signaling in IgA1-producing cells from patients with IgAN. In this article, we present our view of pathogenesis of IgAN and review how some cytokines can contribute to the disease process by enhancing production of aberrantly glycosylated IgA1. We also review current clinical trials of IgAN based on cytokine-targeting therapeutic approaches.

IgA Vasculitis: Etiology, Treatment, Biomarkers and Epigenetic Changes

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

Sialoglyco-Conjugate Abnormalities, IL-6 Trans-Signaling and Anti-Ganglioside Immune Response-Potential Interferences in Lupus Nephritis Pathogenesis

We have investigated glycoconjugates sialization profile, endogen synthesis rate of antiganglioside antibodies (AGA), IL-6 signaling pathways correlated with activity disease in systemic lupus erythematous (SLE) and lupus nephritis (LN). Material and methods. A case-control study was developed and included 109 patients with SLE with or without renal impairment, 32 patients with IgA nephropathy and 60 healthy volunteers, clinically and paraclinically monitored. The following parameters were evaluated in volunteers serum: total sialic acid (TSA), orosomucoids, lipid bound sialic acid (LSA), interleukin-6 (IL-6), soluble factors IL-6R, gp130, anti –GM1, -GM2, -GM3, -GD1a, -GD1b, -GT1b, -GQ1b antigangliosides antibodies of IgG and IgM type. Results. Experimental data analysis showed: increase in synthesis rhythm of sialoglyco-conjugated in SLE (TSA increased in SLE and LN compared to control), accelerated catabolism of LSA in LN (LSA/TSA ratio was higher in SLE and LN than in control group), overexpression of IL-6 mediated trans-signaling (sIL-6R/sgp 130 ratio was subunit in SLE and IgA nephropathy and superunit in LN), large AGA profile synthesis of IgM isotype (over 45.1% in SLE and over 20.7% in LN). Conclusions. Hypersialization, accelerated glycosphingolipids degradation, IL-6 trans-signaling amplify and AGA pattern could represent essential mechanisms in LN pathogenesis.

TLR9 activation induces aberrant IgA glycosylation via APRIL- and IL-6-mediated pathways in IgA nephropathy

Galactose-deficient IgA1 (Gd-IgA1) plays a crucial role in the development of IgA nephropathy (IgAN). However, the pathogenic mechanisms driving Gd-IgA1 production have not been fully elucidated. Innate-immune activation via Toll-like receptor 9 (TLR9) is known to be involved in Gd-IgA1 production. A proliferation inducing ligand (APRIL) and IL-6 are also known to enhance Gd-IgA1 synthesis in IgAN. With this as background, we investigated how TLR9 activation in IgA secreting cells results in overproduction of nephritogenic IgA in the IgAN-prone ddY mouse and in human IgA1-secreting cells. Injection of the TLR9 ligand CpG-oligonucleotides increased production of aberrantly glycosylated IgA and IgG-IgA immune complexes in ddY mice that, in turn, exacerbated kidney injury. CpG-oligonucleotide-stimulated mice had elevated serum levels of APRIL that correlated with those of aberrantly glycosylated IgA and IgG-IgA immune complexes. In vitro, TLR9 activation enhanced production of the nephritogenic IgA as well as APRIL and IL-6 in splenocytes of ddY mice and in human IgA1-secreting cells. However, siRNA knock-down of APRIL completely suppressed overproduction of Gd-IgA1 induced by IL-6. Neutralization of IL-6 decreased CpG-oligonucleotide-induced overproduction of Gd-IgA1. Furthermore, APRIL and IL-6 pathways each independently mediated TLR9-induced overproduction of Gd-IgA1. Thus, TLR9 activation enhanced synthesis of aberrantly glycosylated IgA that, in a mouse model of IgAN, further enhanced kidney injury. Hence, APRIL and IL-6 synergistically, as well as independently, enhance synthesis of Gd-IgA1.

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.

Assay for galactose-deficient IgA1 enables mechanistic studies with primary cells from IgA nephropathy patients

AIMS

IgA nephropathy, the most common primary glomerulonephritis worldwide, is characterized by glomerular deposition of galactose-deficient IgA1 and elevated serum levels of this IgA1 glycoform. Current ELISA methods lack sensitivity to assess galactose deficiency using small amounts of IgA1, which limits studies in primary cells due to modest IgA1 production in isolated peripheral-blood lymphocytes.

METHODS

Lectin from Helix pomatia was conjugated to biotin or acridinium ester and used in ELISA to detect galactose deficiency of IgA1 using small amounts of IgA1.

RESULTS

Lectin conjugated to acridinium had an approximately a log-fold increased sensitivity compared with biotin-labeled lectin.

CONCLUSIONS

The new method of using lectin from Helix pomatia conjugated to acridinium increased assay sensitivity, allowing future mechanistic studies with cultured primary cells.

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.

Effects of Hydroxychloroquine on Proteinuria in Immunoglobulin A Nephropathy

BACKGROUND

Hydroxychloroquine (HCQ) is a well-known immunomodulator that is useful as in the treatment for lupus because of its inhibitory effect on toll-like receptors and cytokines, which are speculated to play a role in the pathogenesis of Immunoglobulin A (IgA) nephropathy (IgAN). However, there was only one study that investigated the effect of HCQ on proteinuria in patients with IgAN.

METHODS

Ninety patients with IgAN who received HCQ in addition to optimized dosage of renin-angiotensin-aldosterone system inhibitors (RAASi) were recruited for this study, and 90 matched historical controls who received RAASi alone were selected from our registry by the propensity score matching method. Their clinical data were compared at baseline and during follow-up till the termination of HCQ or addition of immunosuppressive agents.

RESULTS

The median baseline proteinuria level of the 90 patients who received HCQ was comparable with the RAASi-alone group (1.5 [1.2, 2.1] vs. 1.5 [1.2, 1.9] g/day, p = 0.74). At 6 months post-study initiation, the median proteinuria level in the HCQ group was lower than that in the RAASi-alone group (0.8 [0.7, 1.2] vs. 1.2 [0.8, 1.8] g/day, p = 0.02). The percentage by which proteinuria was reduced in the HCQ group was significantly higher than that in the RAASi-alone group (-43% [-57, -12] vs. -19% [-46, 17], p = 0.01). No serious adverse effects were documented during treatment with HCQ.

CONCLUSION

The addition of HCQ to RAASi resulted in a significant and safe reduction in proteinuria in patients with IgAN.

Inhibition of STAT3 Signaling Reduces IgA1 Autoantigen Production in IgA Nephropathy

Introduction

IgA nephropathy is a chronic renal disease characterized by mesangial immunodeposits that contain autoantigen, which is aberrantly glycosylated IgA1 with some hinge-region O-glycans deficient in galactose. Macroscopic hematuria during an upper respiratory tract infection is common among patients with IgA nephropathy, which suggests a connection between inflammation and disease activity. Interleukin-6 (IL-6) is an inflammatory cytokine involved in IgA immune response. We previously showed that IL-6 selectively increases production of galactose-deficient IgA1 in IgA1-secreting cells from patients with IgA nephropathy.

Methods

We characterized IL-6 signaling pathways involved in the overproduction of galactose-deficient IgA1. To understand molecular mechanisms, IL-6 signaling was analyzed by kinomic activity profiling and Western blotting, followed by confirmation assays using siRNA knock-down and small-molecule inhibitors.

Results

STAT3 was differentially activated by IL-6 in IgA1-secreting cells from patients with IgA nephropathy compared with those from healthy control subjects. Specifically, IL-6 induced enhanced and prolonged phosphorylation of STAT3 in the cells from patients with IgA nephropathy, which resulted in overproduction of galactose-deficient IgA1. This IL-6−mediated overproduction of galactose-deficient IgA1 could be blocked by small molecule inhibitors of JAK/STAT signaling.

Discussion

Our results revealed that IL-6−induced aberrant activation of STAT3-mediated overproduction of galactose-deficient IgA1. STAT3 signaling pathway may thus represent a new target for disease-specific therapy of IgA nephropathy.

What Genetics Tells Us About the Pathogenesis of IgA Nephropathy: The Role of Immune Factors and Infection

Immunoglobulin A nephropathy (IgAN) is the most common type of primary glomerulonephritis, which is characterized by IgA1-containing immune-deposits in the glomerular mesangium. The epidemiologic observations of familial clustering as well as ethnic and regional discrepancies indicate a genetic component to IgAN. Large, international, genome-wide association studies have identified several susceptibility genes and loci for IgAN, many of which have been implicated in immune regulation and are shared with other autoimmune diseases. Notably, increasing numbers of genes involved in mucosal immunity have been detected; such genes may impact the susceptibility and progression of IgAN through interaction with environmental stimuli (especially infection). Here, we discuss the innate and adaptive immune mechanisms that drive protective immunity against pathogens. Our goal is to provide a representative overview of the synergistic roles between genetic predisposition and infection in IgAN pathogenesis. We anticipate that these results will provide potential therapeutic agents and advances in precision medicine.

The Origin and Activities of IgA1-Containing Immune Complexes in IgA Nephropathy

IgA nephropathy (IgAN) is the most common primary glomerulonephritis, frequently leading to end-stage renal disease, as there is no disease-specific therapy. IgAN is diagnosed from pathological assessment of a renal biopsy specimen based on predominant or codominant IgA-containing immunodeposits, usually with complement C3 co-deposits and with variable presence of IgG and/or IgM. The IgA in these renal deposits is galactose-deficient IgA1, with less than a full complement of galactose residues on the O-glycans in the hinge region of the heavy chains. Research from the past decade led to the definition of IgAN as an autoimmune disease with a multi-hit pathogenetic process with contributing genetic and environmental components. In this process, circulating galactose-deficient IgA1 (autoantigen) is bound by antiglycan IgG or IgA (autoantibodies) to form immune complexes. Some of these circulating complexes deposit in glomeruli, and thereby activate mesangial cells and induce renal injury through cellular proliferation and overproduction of extracellular matrix components and cytokines/chemokines. Glycosylation pathways associated with production of the autoantigen and the unique characteristics of the corresponding autoantibodies in patients with IgAN have been uncovered. Complement likely plays a significant role in the formation and the nephritogenic activities of these complexes. Complement activation is mediated through the alternative and lectin pathways and probably occurs systemically on IgA1-containing circulating immune complexes as well as locally in glomeruli. Incidence of IgAN varies greatly by geographical location; the disease is rare in central Africa but accounts for up to 40% of native-kidney biopsies in eastern Asia. Some of this variation may be explained by genetically determined influences on the pathogenesis of the disease. Genome-wide association studies to date have identified several loci associated with IgAN. Some of these loci are associated with the increased prevalence of IgAN, whereas others, such as deletion of complement factor H-related genes 1 and 3, are protective against the disease. Understanding the molecular mechanisms and genetic and biochemical factors involved in formation and activities of pathogenic IgA1-containing immune complexes will enable the development of future disease-specific therapies as well as identification of non-invasive disease-specific biomarkers.

Pathogenesis and gastrointestinal manifestations of IgA vasculitis

Immunoglobulin A (IgA) vasculitis is a form of leukocytoclastic vasculitis of small vessels, clinically characterized by purpuric skin lesions unrelated to any underlying coagulopathy, gastrointestinal manifestations, arthritis and/or arthralgia and renal involvement. The etiology remains unknown, but various triggers including infections, vaccination, drugs and malignancy have been hypothesized to be associated with the development of IgA vasculitis. Although the pathogenesis has not been completely figured out, genetic predisposition, aberrant glycosylation of the hinge region of IgA1, activated complements, cytokines and chemokines were put out to play important roles in the immunopathogenesis of IgA vasculitis. Histologically, the infiltration of small blood vessels with polymorphonuclear leukocytes and the presence of leukocytoclasia are typical pathologic findings in IgA vasculitis. The treatment is usually supportive, and advanced treatments include immunosuppressive drugs (glucocorticoids and immunosuppressive agents), hemopurification and surgery. The prognosis depends on the age at the disease onset and the renal involvement or not.

Cellular signaling and production of galactose-deficient IgA1 in IgA nephropathy, an autoimmune disease

Immunoglobulin A (IgA) nephropathy (IgAN), the leading cause of primary glomerulonephritis, is characterized by IgA1-containing immunodeposits in the glomeruli. IgAN is a chronic disease, with up to 40% of patients progressing to end-stage renal disease, with no disease-specific treatment. Multiple studies of the origin of the glomerular immunodeposits have linked elevated circulating levels of aberrantly glycosylated IgA1 (galactose-deficient in some O-glycans; Gd-IgA1) with formation of nephritogenic Gd-IgA1-containing immune complexes. Gd-IgA1 is recognized as an autoantigen in susceptible individuals by anti-glycan autoantibodies, resulting in immune complexes that may ultimately deposit in the kidney and induce glomerular injury. Genetic studies have revealed that an elevated level of Gd-IgA1 in the circulation of IgAN patients is a hereditable trait. Moreover, recent genome-wide association studies have identified several immunity-related loci that associated with IgAN. Production of Gd-IgA1 by IgA1-secreting cells of IgAN patients has been attributed to abnormal expression and activity of several key glycosyltransferases. Substantial evidence is emerging that abnormal signaling in IgA1-producing cells is related to the production of Gd-IgA1. As Gd-IgA1 is the key autoantigen in IgAN, understanding the genetic, biochemical, and environmental aspects of the abnormal signaling in IgA1-producing cells will provide insight into possible targets for future disease-specific therapy.

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.

Adjuvant treatments for Henoch-Schönlein purpura nephritis in children: A systematic review

BACKGROUND

The management of Henoch-Schönlein purpura nephritis (HSPN) in childhood is controversial. Adjuvant therapies such as immunoglobulin, anticoagulants, and vitamins have been used with conventional treatments despite a lack of evidence of their efficacy.

OBJECTIVE

The aim of this study was to review the scientific literature regarding adjuvant treatments administered with conventional drugs in the treatment of childhood HSPN.

METHODS

Published articles were identified from the MEDLINE and EMBASE databases (1988-December 2008; key words: Henoch-Schönlein nephritis and Henoch-Schönlein purpura). The search was limited to published English-language studies on therapeutic options for HSPN in children.

RESULTS

A total of 12 studies were identified and included in this review; most (n = 8) were case series or retrospective studies. Studies of conventional therapy combined with adjuvant treatment should be interpreted with caution. In particular, factor XIII administration was reported to improve kidney symptoms in 1 study. Based on the results from 9 studies, no convincing evidence on intravenous immunoglobu-lin, urokinase, or anticoagulants was identified. No substantial information was available on the benefit of antiplatelet agents or heparin in treating HSPN. Integrating treatment with vitamin E was not recommended based on the results from 1 randomized controlled trial. Fish oil was reported to be effective in 1 case series.

CONCLUSIONS

Studies concerning the treatment of HSPN in children with adjuvant therapies were retrospective and recommendations were drawn from level IV evidence. One randomized controlled trial on the use of tocopherol as adjuvant treatment was identified; however, no clinical utility was reported. At present, there is no strong evidence supporting benefits with the use of adjuvant treatments.

Cytokines alter IgA1 O-glycosylation by dysregulating C1GalT1 and ST6GalNAc-II enzymes

IgA nephropathy (IgAN), the most common primary glomerulonephritis, is characterized by renal immunodeposits containing IgA1 with galactose-deficient O-glycans (Gd-IgA1). These immunodeposits originate from circulating immune complexes consisting of anti-glycan antibodies bound to Gd-IgA1. As clinical disease onset and activity of IgAN often coincide with mucosal infections and dysregulation of cytokines, we hypothesized that cytokines may affect IgA1 O-glycosylation. We used IgA1-secreting cells derived from the circulation of IgAN patients and healthy controls and assessed whether IgA1 O-glycosylation is altered by cytokines. Of the eight cytokines tested, only IL-6 and, to a lesser degree, IL-4 significantly increased galactose deficiency of IgA1; changes in IgA1 O-glycosylation were robust for the cells from IgAN patients. These cytokines reduced galactosylation of the O-glycan substrate directly via decreased expression of the galactosyltransferase C1GalT1 and, indirectly, via increased expression of the sialyltransferase ST6GalNAc-II, which prevents galactosylation by C1GalT1. These findings were confirmed by siRNA knockdown of the corresponding genes and by in vitro enzyme reactions. In summary, IL-6 and IL-4 accentuated galactose deficiency of IgA1 via coordinated modulation of key glycosyltransferases. These data provide a mechanism explaining increased immune-complex formation and disease exacerbation during mucosal infections in IgAN patients.

Serum Interleukin-18 in Children with Henoch-Schönlein Purpura: A Promising Marker of Disease Activity?

Henoch-Schönlein purpura (HSp) is the most common systemic vasculitis of childhood with typical skin involvement and concurrent signs involving joints, gastrointestinal tract, and kidney. HSp pathogenesis is still far from being completely understood, though a knotty cytokine complex is believed to contribute to its intimate processes. The aim of our evaluation is to establish the relationship between serum levels of interleukin (IL)-18 and disease outcome and establish its feasibility to provide a marker of disease activity or even a prognostic tool in clinical practice. We examined clinical/laboratory variables and serum IL-18 in 17 children hospitalized during a year for HSp, diagnosed by EULAR/PRINTO/PRES criteria; the same patients were re-evaluated after 6 months. All results were compared with 25 age-matched healthy controls. IL-12 and IL-6 were also evaluated in a cohort of the same patients and compared with controls. General and clinical variables (sex, edema of the extremities, gastrointestinal or renal complications, relapses and renal involvement at 6 months) had no relationship with cytokine levels. Serum IL-18 and IL-6 levels were found significantly increased at diagnosis in HSp patients when compared with healthy controls. After 6 months, serum IL-18 and IL-12 levels were significantly decreased in patients, while IL-12 and IL-6 levels were significantly increased compared to healthy controls. Though preliminary and expecting further confirmation on a larger sample, our data support the conclusion that serum IL-18 levels reflect HSp activity.

Cytokine pattern and endothelium damage markers in Henoch-Schönlein purpura

In a longitudinal cohort study our aim was to evaluate the cytokine pattern of children affected by Henoch-Schonlein purpura (HSP) and to correlate this pattern to vascular endothelium damage and to nephropathy. The following parameters were monitored at the onset of the disease (T0) and after 6 months of follow-up (T1): clinical scores, serum levels of tumor necrosis factor alpha (TNF-alpha), interleukin 2 (IL-2), soluble IL-2 receptor (IL-2sRalpha), fibrinogen, von Willebrand factor antigen (vWf:Ag) and soluble thrombomodulin (TMD) levels. A total of 24 children (9 M, 15 F), affected by HSP, aged between 3-14 years (median 6 years), were enrolled into the study. IL-2 serum levels were significantly increased at the onset of the disease compared to control group and T1. The same pattern was observed for IL-2sRalpha and TNF-alpha. Fibrinogen and vWf:Ag concentrations were significantly higher at the onset of disease than t1 and in control group. TMD levels resulted constantly within the normal range. Concerning the analyzed parameters, no significant difference resulted to be in subjects with and without renal involvement (hematuria and/or proteinuria). Finally, raised serum TNF-alpha concentration, related to vascular endothelium damage as shown by increased vWf:Ag levels, occurred invariably in children affected by HSP both with and without renal involvement.

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.

Neutrophil activation, protein oxidation and ceruloplasmin levels in children with Henoch-Schönlein purpura

The aim of this study was to investigate the role of neutrophil activation, protein oxidation and ceruloplasmin (CLP) in the pathogenesis of Henoch-Schönlein purpura (HSP), which has not been investigated previously. Serum activities of myeloperoxidase (MPO) and arylesterase (ARYL) and levels of free thiol groups, CLP and total oxidant status (TOS) were measured in 29 children with HSP at the onset of the disease and during remission in comparison with 30 healthy subjects. Patients at active stage had significantly higher MPO activity (391+/-277 vs. 155+/-154 U/l, P<0.001), higher CLP (832+/-120 vs. 682+/-114 mg/dl, P<0.001) and TOS values (20.7+/-11.8 vs. 7.5+/-2.8 micromol H2O2/l, P<0.001) than the controls, respectively. Patients had significantly lower ARYL activity (158x10(3)+/-39x10(3) vs. 187x10(3)+/-46x10(3) U/l, P<0.001) and lower free thiol levels (234+/-48 vs. 279+/-26 micromol/l, P<0.001) than the controls, respectively. Significantly positive correlations were found between TOS and MPO (r=0.437, P=0.018) and TOS and CLP (r=0.409, P=0.028) at disease onset, whereas a negative correlation was found between MPO and thiol (r=-0.597, P=0.001) during remission. In conclusion, protein oxidation and neutrophil activation may play important roles in the pathogenesis of HSP. Further research is required to understand the potential linkage between oxidant stress and complications and to develop therapeutic strategies in HSP.

Cerebral vasculitis in a child with Henoch–Schönlein purpura and familial Mediterranean fever

In this case report, a 10-year-old girl with Henoch-Schönlein purpura (HSP) with severe central nervous system involvement and also having familial Mediterranean fever (FMF) is presented.

High-dose intravenous immunoglobulin pulse therapy in patients with progressive immunoglobulin A nephropathy: a long-term follow-up

In progressive immunoglobulin A nephropathy (IgAN), intravenous immunoglobulin (IVIg) treatment has been used to delay disease progression, but the long-term efficacy is largely unknown. We report the clinical outcomes after IVIg therapy in six male patients with progressive IgAN [median glomerular filtration rate (GFR) 31 ml/min per 1.73 m(2)] followed for a median observation period of 8 years. In this single-arm, non-randomized study, IVIg was given monthly at a dose of 2 g/kg body weight for 6 months. The course of renal function was assessed by linear regression analysis of GFR and proteinuria, and was compared to eight patients with IgAN (median GFR 29 ml/min per 1.73 m(2)) without IVIg as a contemporaneous control group. IgAN disease progression was delayed after IVIg therapy on average for 3 years. The mean loss of renal function decreased from -1.05 ml/min per month to -0.15 ml/min per month (P = 0.024) and proteinuria decreased from 2.4 g/l to 1.0 g/l (P = 0.015). The primary end-point (GFR < 10 ml/min or relapse) occurred 5.2 years (median; range 0.4-8.8) after the first IVIg pulse, and after 1.3 years (median; range 0.8-2.4) in the control group (P = 0.043). In Kaplan-Meier analysis, the median renal survival time with IVIg was prolonged by 3.5 years (IVIg 4.7 years versus control 1.2 years; P = 0.006). IVIg pulse therapy may be considered as a treatment option to reduce the loss of renal function and improve proteinuria in patients with progressive IgAN.

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.

A case of Henoch-Schonlein purpura temporarily improved by hemodialysis

We report a case of Henoch-Schonlein purpura that occurred in an adult patient with end-stage renal disease on continuous ambulatory peritoneal dialysis (CAPD) and hemodialysis (HD). The patient's skin lesions clearly decreased in number during HD, but not during CAPD. This finding has not been previously reported.

Mycophenolate mofetil alleviates persistent proteinuria in IgA nephropathy

BACKGROUND

Mycophenolate mofetil (MMF) is increasingly used to treat primary glomerulopathies. Its effectiveness in IgA nephropathy (IgAN) remains unclear.

METHODS

Forty IgAN patients with persistent proteinuria (>1 g/24 hours) despite conventional treatment with blockers of the renin-angiotensin system were randomized to receive MMF for 24 weeks (group 1) or continue conventional therapy (group 2), and followed for 72 weeks. The primary end point was reduction of proteinuria by 50% or more over entry level.

RESULTS

Sixteen patients (80%) in group 1 versus six patients (30%) in group 2 reached the primary end point (P= 0.0019). Time-averaged change in proteinuria showed a significant decline in group 1, while control subjects displayed a modest rise (P= 0.003). By 72 weeks, the mean proteinuria was 62.0 +/- 7.7% (P= 0.003) and 120.5 +/- 14.1% (P= 0.351) that of the corresponding baseline value in group 1 and group 2, respectively. There was concomitant increase in serum albumin and decrease in serum IgA levels in group 1 but not group 2 patients. Baseline histologic grades, blood pressure control, and the rates of change in serum creatinine and creatinine clearance were not different between the two groups. Normalization in binding of polymeric IgA to cultured mesangial cells and serum interleukin-6 (IL-6) levels, which sustained to study end, was observed in group 1 but not group 2 subjects.

CONCLUSION

In selected patients with IgAN, MMF is effective in lowering proteinuria and ameliorating some of the putative pathogenetic abnormalities.

Multisystemic leukocytoclastic vasculitis affecting the central nervous system

Leukocytoclastic vasculitis is a self-limiting disease with rare systemic complications in the majority of patients. This report describes a 10-year-old male with leukocytoclastic vasculitis caused by an insect bite who presented with central nervous system, lung, kidney, and gastrointestinal involvement in addition to cutaneous findings. The diagnosis was confirmed by histopathologic examination of cerebral hematoma material. Initially, his symptoms improved with a treatment protocol including steroid, cyclophosphamide, intravenous immunoglobulin, and plasmapheresis, but the patient succumbed because of nosocomial sepsis.

Pathogénie des vascularites systémiques primitives (II): vascularites ANCA-négatives

The pathogenesis of different types of systemic vasculitis negative for antineutrophil cytoplasm antibodies (ANCA) and involving small or medium-sized vessels is not very well documented. During polyarteritis nodosa (PAN), which is related to hepatitis B virus (HBV) infection, as well as during cryoglobulinemic vasculitides, associated with hepatitis C virus (HCV), and probably during Henoch Schönlein purpura, histological lesions may result from the deposition of immune complexes formed from viral antigens and from antibodies responsible for the activation of the classic complement pathway and for recruitment of polymorphonuclear neutrophils. Two other mechanisms are discussed for other types of ANCA-negative systemic vasculitis: immune complex deposition and sheer stress at arterial bifurcation points. A bacterial superantigen is suspected in Kawasaki disease but remains unproved.

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.

Pathogenesis of IgA nephropathy

Immunoglobulin A (IgA) nephropathy is an immune-complex-mediated glomerulonephritis characterized by the presence of immunoglobulin A deposits in mesangial and paramesangial regions. The patients with IgA nephropathy present with varying clinical symptoms (eg, microhematuria with preserved renal function or progressive deterioration of renal functions resulting in end-stage renal disease). The factors involved in the pathogenetic mechanisms of IgA nephropathy include (1). environmental factors, (2). genetic factors, (3). abnormality of the IgA1 molecule, and (4). various inflammatory mediators. The gene polymorphism studies for human leukocyte antigen (HLA), renin-angiotensin-aldosterone system, and selectin gene clusters, suggest a certain degree of genetic predisposition in patients for IgA nephropathy. Also, the genome-wide screening in familial IgA nephropathy showed linkage of IgA nephropathy to the 6q22-23 chromosome. Besides genetic influence in its pathogenesis, aberrant galactosylation in serum IgA and IgA1 eluted from kidneys with IgA nephropathy has been observed, and conceivably such abnormalities induce the expression of various cytokines, interleukin (IL)-6, platelet-derived growth factor (PDGF), tumor necrosis factor (TNF)-alpha, and transforming growth factor (TGF)-beta1 in the renal cells, which contributes to further glomerular injury. Despite an enormous amount of information available in the literature, further studies are needed to delineate the precise pathogenetic mechanisms involved in primary IgA nephropathy and also to facilitate the development of newer therapeutic interventions.

Tumor necrosis factor (TNF)alpha and its soluble receptor (sTNFR) p75 during acute human parvovirus B19 infection in children

Human parvovirus B19 (HPV) has been shown to be involved in the pathogenesis of various connective tissue and autoimmune diseases. In order to gain more information on HPV possible role in these diseases, we have investigated some immune responses in patients with acute HPV infection, mainly the secretion of the proinflammatory cytokine tumor necrosis factor (TNF)alpha and it's antagonist--the soluble TNF receptor (sTNFR) p75. Thirteen children with acute HPV infection and 13 healthy volunteers were investigated for the presence of autoantibodies, lymphocyte subpopulation counts, levels of total immunoglobulins, IgG subclasses and complement. The levels of TNFalpha and sTNFR p75 were determined in serum and conditioned medium (CM) from unstimulated and LPS stimulated peripheral blood mononuclear cell (PBMC) cultures. There was no difference between patients and controls regarding autoantibodies, lymphocytes, immunoglobulins, IgG subclasses and complement. A significant imbalance between TNFalpha and sTNFR p75 was found in the patients group. TNFalpha concentrations were significantly higher both in sera and in CM from the patients as compared with the controls. The levels of sTNFR concentrations were either similar (in sera) or significantly lower (in CM) in the patients compared with the controls. The TNF index, representing the biologically available TNFalpha, was significantly higher in patient's sera and CMs. In view of these results, it is conceivable that infection with human HPV in otherwise healthy children may lead to a proinflammatory state. The presence of high levels of biologically available TNFalpha, in susceptible individuals, may in turn play a role in the pathogenesis of systemic autoimmune diseases in HPV infected individuals.

The role of anti-endothelial cell antibodies in Kawasaki disease - in vitro and in vivo studies

Kawasaki disease (KD) is a systemic vasculitis with cardiac and noncardiac complications. Anti--endothelial cell antibodies (AECA) are found among many patients with KD. The aim of this study was to investigate the pathogenic role of AECA in KD using in vitro and in vivo experimental models. F(ab)2 fragments of IgG-AECA and IgM-AECA were affinity purified from a patient with active KD. Their endothelial binding and ability to induce a pro-adhesive and a pro-inflammatory phenotype were evaluated in vitro. Twenty Balb/C mice were immunized with KD-AECA or with control Ig (N-Ig) to induce AECA in a murine model by the idiotypic manipulation method. Both KD-AECA isotypes bind significantly to human umbilical vein endothelial cell (HUVEC) compared to N-Ig. The in vitro activity was demonstrated by the antibodies ability to activate endothelial cells resulting in increased IL-6 secretion, adhesion molecule expression and monocytic cell line (U937) adherence to HUVEC. Five of the mice that received KD-AECA developed murine AECA after 3 months. None of the mice that received N-Ig produced AECA. The murine AECA increased monocyte adhesion to EC in vitro, similarly to the AECA used for immunization. Furthermore, all the mice that developed AECA had proteinuria and IgG deposition in the renal mesangium. No histological or immunofluorescence evidence of cardiac vasculitis could be detected. AECA might play a role in the emergence of some of KD manifestations.

The balance between IL-1 and IL-1Ra in disease

IL-1 is an important mediator of inflammation and tissue damage in multiple organs, both in experimental animal models of disease and in human diseases. The IL-1 family consists of two agonists, IL-1alpha and IL-1beta, two receptors, biologically active IL-1RI and inert IL-1RII, and a specific receptor antagonist, IL-1Ra. The balance between IL-1 and IL-1Ra in local tissues plays an important role in the susceptibility to and severity of many diseases. An allelic polymorphism in the IL-1Ra gene has been associated with a variety of human diseases primarily of epithelial and endothelial cell origin. This association may be secondary to an imbalance in the IL-1 system with enhanced production of IL-1beta and reduced production of the major intracellular isoform of IL-1Ra. Treatment of RA with daily subcutaneous injections of recombinant IL-1Ra protein has been shown to be efficacious. Gene therapy approaches with IL-1Ra are being evaluated for the treatment of RA and other human diseases.

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.

Critical role of CD14 for production of proinflammatory cytokines and cytokine inhibitors during sepsis with failure to alter morbidity or mortality

We investigated the immunopathophysiologic responses during sepsis induced by cecal ligation and puncture (CLP) in CD4-deficient (CD14 knockout [CD14KO]) mice. Our studies were designed to specifically test the role of CD14 in the inflammatory response to sepsis and to ascertain if alterations would improve morbidity or mortality. Sepsis was induced using the CLP model with appropriate antibiotic treatment. The severity of sepsis increased in the CD14KO mice with increasing puncture size (18 gauge [18G], 21G, and 25G). Following CLP, body temperature (at 12 h) and gross motor activity levels of the sham and 25G CLP groups recovered to normal, while the 21G and 18G CLP groups exhibited severe hypothermia coupled with decreased gross motor activity and body weight. There were no significant differences in survival, temperature, body weight, or activity levels between CD14KO and control mice after 21G CLP. However, CD14KO mice expressed two- to fourfold less pro-inflammatory (interleukin-1beta [IL-1beta], tumor necrosis factor [TNF], and IL-6) and anti-inflammatory (IL-10, IL-1 receptor antagonist, and TNF receptors I and II) cytokines in the blood after 21G CLP. Plasma levels of the chemokines macrophage inflammatory protein 2alpha and KC were similarly reduced in CD14KO mice. A similar trend of decreased cytokine and cytokine inhibitor levels was observed in the peritoneal cavity of CD14KO mice. Our results indicate that the CD14 pathway of activation plays a critical role in the production of both pro-inflammatory cytokines and cytokine inhibitors but has minimal impact on the morbidity or mortality induced by the CLP model of sepsis.

Monoamine oxidase inhibitors for IgA nephropathy

IgA nephropathy (IgAN), characterized by renal mesangial deposits of antibodies (of the IgA subtype), is the most common glomerulonephritis worldwide. The cause of IgAN is not known. IgAN can often lead to end stage renal disease (ESRD), and there is no known treatment proven to prevent ESRD in IgAN. Long term use of steroids or other immunosuppressant drugs carry severe toxicities and other risks. IgAN patients have high serum levels of tumor necrosis factor-alpha (TNF). Increased monoamine levels, via increased cellular cyclic AMP, can decrease TNF elaboration. Monoamine oxidase inhibitors (MAO-Is) have been found effective in case studies for a number of diseases, e.g. rheumatoid arthritis and Crohn's disease, characterized by high TNF levels. Here I suggest that MAO-Is might be of utility in IgAN by decreasing TNF levels.

Vasculopathy, Behçet's syndrome, and familial Mediterranean fever

Within the past year information has accumulated on the role of infections in the pathogenesis of vasculitis. Superantigens play an important role in the stimulation of the immune system. Behçet's syndrome is a vasculitis that affects children as well as adults. Recently published childhood studies highlight the importance of family history and geographic differences in this disease. Familial Mediterranean fever is a genetic disease manifesting frequently in children. Studies on the function of the mutated protein pyrin in this disease are in progress. Some researchers have proposed that pyrin is an anti-inflammatory protein. Understanding its mode of action will help us understand more of the general inflammatory pathway.