What is the difference between IgA nephropathy and Henoch-Schönlein purpura nephritis?

Relationship between immune parameters and organ involvement in children with Henoch-Schonlein purpura

Henoch-Schonlein purpura (HSP) is the most common type of connective tissue diseases which increasingly occurs in children in recent years and its pathogenesis remains unclear. In order to explore the immune parameters and underlying pathogenesis mechanism of children with HSP, the study involved 1232 patients with HSP having different clinical symptoms and their laboratory indicators were evaluated. Th1/Th2 imbalance and overactivity of Th2 cells can cause increase in the synthesis and release of immunoglobulins in children with HSP. The number of red blood cells and white blood cells in urine was directly proportional to the level of IgA and inversely proportional to the level of serum complements (C3 and C4). Activation of these complements caused by immunoglobulin in patients with HSP plays an important role in renal injury. The urinary protein content in children with HSP along with proteinuria was positively correlated with IgE level, and IgE mediated type 1 hypersensitivity can cause increase in capillary permeability and weakened the charge barrier; hence, it could be considered as one of the causes of proteinuria in HSP. Additionally, the NK cells percentage was reduced and impaired immune function of NK cells were related to the immune injury of the digestive tract and kidney.

Toll-like receptors, immunoproteasome and regulatory T cells in children with Henoch-Schönlein purpura and primary IgA nephropathy

BACKGROUND

Henoch-Schönlein purpura (HSP) nephritis and primary IgA nephropathy (pIgAN) present with glomerular IgA deposits, but differ with regard to clinical features. The suspected involvement of different immune system pathways is largely unknown.

METHODS

This study was aimed at investigating some of the immunological features including Toll-like receptors (TLR), proteasome (PS)/immunoproteasome (iPS) switch, and the regulatory T cell system (Treg/Th17 cells) in 63 children with HSP with/without renal involvement and in 25 with pIgAN. Real-time PRC (Taqman) was used to quantify mRNA levels in peripheral blood mononuclear cells (PBMC).

RESULTS

The expression of mRNAs encoding for TLR4 in both HSP and pIgAN was higher than in controls (HC) and in both diseases FoxP3mRNA and TGF-β1mRNA expression was significantly lower than in HC. A switch from PS to iPS (LMP2/β1) was detected only in PBMC of HSP and it correlated with the level of TLR2mRNA, which was selectively increased only in children with HSP.

CONCLUSION

Children with HSP and pIgAN present with similar signs of engagement of the innate immunity and regulatory T cell depression. The increased immunoproteasome switch, which correlated with TLR2 activation, may suggest an innate immunity pathway peculiar to HSP vasculitic presentation. This research area also deserves further investigation for possible therapeutic applications.

Henoch-Schönlein purpura nephritis in children

Henoch-Schönlein purpura (HSP) is the most common vasculitis in children, in whom prognosis is mostly dependent upon the severity of renal involvement. Nephritis is observed in about 30% of children with HSP. Renal damage eventually leads to chronic kidney disease in up to 20% of children with HSP nephritis in tertiary care centres, but in less than 5% of unselected patients with HSP, by 20 years after diagnosis. HSP nephritis and IgA nephropathy are related diseases resulting from glomerular deposition of aberrantly glycosylated IgA1. Although both nephritides present with similar histological findings and IgA abnormalities, they display pathophysiological differences with important therapeutic implications. HSP nephritis is mainly characterized by acute episodes of glomerular inflammation with endocapillary and mesangial proliferation, fibrin deposits and epithelial crescents that can heal spontaneously or lead to chronic lesions. By contrast, IgA nephropathy normally presents with slowly progressive mesangial lesions resulting from continuous low-grade deposition of macromolecular IgA1. This Review highlights the variable evolution of similar clinical and histological presentations among paediatric patients with HSP nephritis, which constitutes a challenge for their management, and discusses the treatment of these patients in light of current guidelines based on clinical evidence from adults with IgA 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.

Using the Oxford classification of IgA nephropathy to predict long-term outcomes of Henoch-Schönlein purpura nephritis in adults

Recently, there has been emerging concern that crescents, the main histologic feature of Henoch-Schönlein purpura nephritis, merely reflect active inflammation, and may not be useful in predicting long-term outcomes. We therefore conducted a single-center retrospective study to evaluate whether the new Oxford classification of immunoglobulin A nephropathy can be used to predict long-term outcome in patients with Henoch-Schönlein purpura nephritis. We included 61 biopsy-proven patients with Henoch-Schönlein purpura nephritis between January 1991 and August 2010. In addition to the International Study of Kidney Disease in Children classification, pathologic findings were also evaluated by the Oxford classification. Primary outcomes were defined as either the onset of estimated glomerular filtration rate <60 ml/min per 1.73 m(2) with ≥30% decrease in estimated glomerular filtration rate from baseline or end-stage renal disease. During a median follow-up of 49.3 months, 13 (21%) patients reached the primary end point. A Kaplan-Meier plot showed that renal event-free survival was significantly longer in patients with <50% crescents than in those with crescents in ≥50% of glomeruli (P=0.003). Among the components of the Oxford classification, patients with endocapillary hypercellularity (E1; P=0.016) and tubular atrophy/interstitial fibrosis (T1/T2; P=0.018) had lower renal survival rates than those with E0 and T0. In a multivariate Cox model adjusted for clinical and pathologic factors, E1 (hazard ratio=8.91; 95% confidence interval=1.47-53.88; P=0.017) and T1/T2 (hazard ratio=8.74; 95% confidence interval=1.40-54.38; P=0.020) were independently associated with reaching a primary outcome, whereas the extent of crescentic lesions was not. Our findings suggest that the Oxford classification can be used in predicting long-term outcomes of Henoch-Schönlein purpura nephritis.

Central venous catheter infection-induced Henoch-Schönlein purpura in a patient on hemodialysis

A 69-year-old man, who had been dialyzed using a permanent central venous catheter for 2 years, presented with Henoch-Schönlein purpura and positive perinuclear anti-neutrophil cytoplasmic antibody (p-ANCA). He was diagnosed with catheter-related infection by Staphylococcus aureus. After administration of antibiotic and steroid therapy, purpura disappeared and p-ANCA gradually became negative. This case supports the conclusion that infection can be pathogenesis of the vasculitis, including ANCA-positive HSP. Additionally, impregnation of catheters with antibiotics can be an effective treatment for catheter infections.

Assessment of the effect of mesangial hypercellularity in childhood nephropathies to the clinical and laboratory findings

AIM

To assess the relationship between mesangial hypercellularity in various childhood nephropathies and clinical and laboratory parameters.

METHODS AND PATIENTS

The reports of the renal biopsies were evaluated retrospectively. The patients with diagnosis of IgA nephropathy (isolated and Henoch-Schönlein nephritis), IgM nephropathy, or isolated mesangial proliferative glomerulonephritis were included. Each nephropathy group was divided into two subgroups according to the severity of mesangial hypercellularity as mild and severe. The biochemical data and histopathological findings of the patients were recorded.

RESULTS

When the groups were compared, it was found that the patients with IgA nephropathy had hematuria (p = 0.043) and the patients with IgM nephropathy had nephrotic syndrome more frequently than the other patients (p = 0.01). No difference was detected between the groups regarding the severity of mesangial hypercellularity. On the other hand, when the groups were evaluated within themselves, no significant association was detected between the severity of mesangial hypercellularity and clinical and laboratory parameters. It was determined that the renal biopsy was performed earlier in patients with Henoch-Schönlein nephritis compared to the other cases (p = 0.004). Compared to the isolated IgA nephropathy group, it was found that the number of cases with severe mesangial hypercellularity was higher and the level of proteinuria was more prominent in patients with Henoch-Schönlein nephritis. Additionally, when the patients with Henoch-Schönlein nephritis were evaluated, the degree of proteinuria was found to be higher in patients with severe mesangial hypercellularity compared to those of showing mild mesangial hypercellularity (p = 0.002).

CONCLUSION

It was observed that there is no direct relation between the severity of mesangial hypercellularity and clinical and laboratory findings in various childhood nephropathies. However, when Henoch-Schönlein nephritis is compared with IgA nephropathy, it was found that the severity of mesangial hypercellularity was higher in cases with Henoch-Schönlein nephritis and the level of proteinuria was more prominent in those cases. However, no difference was detected in glomerular filtration rates and biochemical data with regard to the level of mesangial hypercellularity.

Henoch-Schönlein purpura in a renal transplant recipient with prior IgA nephropathy following influenza vaccination

Henoch-Schönlein purpura (HSP) is a systemic small-vessel leucocytoclastic vasculitis with deposition of immune complexes containing Immunoglobulin A (IgA). IgA Nephropathy (IgAN) is a glomerulonephritis caused by mesangial deposition of IgA. The onset of HSP, but not IgAN, has been linked to influenza vaccination. We report the first case of HSP with glomerular involvement, in a renal transplant recipient following influenza vaccination. The patient had prior end-stage renal failure (ESRF) secondary to IgAN, without clinical evidence of IgAN recurrence after transplantation. This is of clinical relevance as influenza vaccination is regarded safe, effective, and recommended after renal transplantation. Nephrologists should be aware of the potential for influenza vaccination to have adverse effects in renal transplant recipients, especially if the primary renal disease is HSP or IgAN.

A case report of the anti-glomerular basement membrane glomerulonephritis with mesangial IgA deposition

A 46-year-old Japanese male with a past medical history of microscopic hematuria presented with nausea, vomiting, and abdominal pain for which he had been diagnosed with rapidly progressive glomerulonephritis with a peak serum creatinine of 6.6 mg/dL and anti-glomerular basement membrane antibody of 214 EU. Light microscopy showed cellular crescent formation, and immunofluorescence illustrated both linear staining of IgG along the glomerular basement membrane and granular staining of IgA and C3 in the mesangial area; however, the PAS staining of mesangial expansions and mesangial proliferations were not observed. Clinical and histological findings suggested anti-glomerular basement membrane glomerulonephritis with mesangial IgA deposition, suggesting IgA nephropathy, a rare condition.

Clinical outcomes, when matched at presentation, do not vary between adult-onset Henöch-Schönlein purpura nephritis and IgA nephropathy

Henöch-Schönlein purpura nephritis (HSPN) is considered a systemic form of immunoglobulin A nephropathy (IgAN). Although these are different pictures of a single disease, there are no studies directly comparing long-term outcomes of these two clinical entities. To clarify this, we studied 120 patients with biopsy-proven HSPN and 1070 patients with IgAN. The primary outcome was the composite of a doubling of baseline serum creatinine, end-stage renal disease, or death. Secondary outcomes included the individual renal outcomes or the rate of decline in estimated glomerular filtration rate. In the unmatched cohort, patients with HSPN had more vasculitic symptoms, more favorable histologic features, and were more commonly treated with steroids than patients with IgAN. The risk of reaching the primary outcome was significantly lower in HSPN patients than patients with IgAN (hazard ratio, 0.67). The 1:2 propensity score matching gave matched pairs of 89 patients with HSPN and 178 patients with IgAN, resulting in no differences in baseline conditions. In this matched cohort, there were no significant differences in reaching the primary and secondary outcomes between the two groups. Thus, after adjustment by propensity score matching, clinical outcomes did not differ between HSPN and IgAN, suggesting the two forms of the same disease have a similar prognosis.

A case of elderly-onset Crescentic Henoch-Schönlein purpura nephritis with hypocomplementemia and positive MPO-ANCA

Henoch-Schönlein purpura (HSP) is common in childhood and often self-limiting. There have been limited studies on elderly-onset HSP nephritis (HSPN). A 76-yr-old man was transferred to our hospital with a 1-month history of oliguria, abdominal pain, edema and palpable purpura in the legs. Three months ago, he was admitted to another hospital with jaundice, and consequently diagnosed with early common bile duct cancer. The patient underwent a Whipple's operation. Antibiotics were administrated because of leakage in the suture from the surgery. However, he showed progressive renal failure with edema and purpura in the legs. Laboratory investigations showed serum creatinine 6.4 mg/dL, 24-hr urine protein 8,141 mg/day, myeloperoxidase anti-neutrophil cytoplasmic antibodies (MPO-ANCA) 1:40 and C(3) below 64.89 mg/dL. Renal biopsy showed crescentic glomerulonephritis, as well as mesangial and extracapillary Ig A deposition. We started steroid therapy and hemodialysis, but he progressed to end-stage renal failure and he has been under maintenance hemodialysis. We describe elderly onset HSPN with MPO-ANCA can be crescentic glomerulonephritis rapidly progressed to end stage renal failure.

[Therapy in IgA nephropathy--when and how to do it]

IgA nephropathy is the most common primary glomerulonephritis worldwide. The clinical spectrum covers a wide range of features from minor urinary abnormalities (asymptomatic hematuria and mild proteinuria with normal renal function) to acute and chronic renal insufficiency. Ideally, the goal of treatment would be to correct any defects in IgA1 glycosylation and to modify mesangial deposition or removal of IgA1 deposits. There are only a few randomized controlled trials in IgA nephropathy; for this reason most treatment options are largely based on expert opinion. Authors discuss therapeutic options of different clinical pictures and the optimized renoprotective treatment of all IgA nephropathy patients.

Early treatment with methylprednisolone pulse therapy combined with tonsillectomy for heavy proteinuric henoch-schönlein purpura nephritis in children

Background

There is no clear consensus as to which patients with Henoch-Schönlein purpura nephritis (HSPN) at risk of a poor outcome should be treated and what therapeutic regimen should be used.

Methods

Nine children with heavy proteinuric HSPN received prompt initiation of methylprednisolone pulse therapy (MPT) combined with tonsillectomy in a prospective study.

Results

At presentation, the mean values for the patients’ urine protein excretion (early-morning urinary protein/creatinine ratio), serum IgA, activity index (AI), and chronicity index (CI) were 5.0 ± 5.6 g/g Cr, 135.6 ± 56.5 mg/dl, 4.0 ± 0.7, and 1.7 ± 1.3, respectively. At the second biopsy, conducted approximately 24 months after initiation of therapy, the patients’ serum albumin had significantly increased (4.4 ± 0.2, p < 0.01), and the serum IgA and AI had significantly decreased (88.1 ± 30.8 mg/dl, p < 0.05; 2.0 ± 1.2, p < 0.01, respectively), whereas the CI remained unchanged. Proteinuria disappeared within 24 months in all but 1 patient, and hematuria disappeared within 38 months in all patients. No patient showed renal impairment or experienced a recurrence and/or exacerbation of HSP/HSPN.

Conclusions

Early treatment with MPT combined with tonsillectomy is effective in ameliorating the histopathological progression and improving the clinical course of children with heavy proteinuric HSPN.

Soluble interleukin-2 receptor alfa predicts renal outcome in IgA nephropathy

BACKGROUND

Both systemic and mucosal IgA production are controlled by T lymphocytes and infiltrating T lymphocytes are involved in the progression of interstitial fibrosis in chronic kidney disease (CKD). Since the concentration of soluble interleukin-2 receptor alfa (sIL-2Ra) reflects the degree of T cell activation over time, we studied the impact of interleukin-2 receptor alfa levels on disease progression in patients with biopsy-proven IgA nephropathy (IgAN), a disease in which 20-30% of the patients progress to end-stage renal failure.

METHODS

sIL-2Ra plasma levels were measured in 194 patients (median age 39 years, 70% men) and 84 matched controls. One hundred and seventy-nine of the patients, with an estimated glomerular filtration rate (GFR) of ≥15 mL/min/1.73m(2) at baseline (CKD Stages 1-4), were followed for up to 15 years (median 52 months; range 12-188). sIL-2Ra was evaluated as a risk marker for severe renal progression, here defined by the development of CKD Stage 5 (GFR <15 mL/min/1.73m(2)), a 50% decline in GFR during the follow-up period or a 30% GFR decline within 5 years of follow-up. In 51 patients, upon whom a renal biopsy had been performed within 2 years of IL2-Ra measurement, the biopsies were scored according to the Oxford classification. The correlations between the histopathological findings and the sIL-2Ra levels were examined.

RESULTS

sIL2-Ra levels were significantly higher in patients than in controls (P < 0.001). sIL-2Ra levels in the upper third tertile predicted a severe renal outcome, even after adjustment for the main clinical risk factors: time average albuminuria and GFR at baseline (Relative risk 5.35, P < 0.001). sIL-2Ra levels also correlated significantly to the yearly GFR slope (β = -0.24, P = 0.01). According to the Oxford classification, the presence of >25% tubular atrophy/interstitial fibrosis (T1-2) was associated with higher sIL-2Ra levels, after adjustment for serum creatinine levels, if analysed within 4 months [n = 24, odds ratio (OR) 1.0, P = 0.044] or within 2 years from the kidney biopsy (n = 51, OR 1.0, P = 0.017).

CONCLUSIONS

The plasma levels of sIL-2Ra were predictive of long-term renal disease progression in a large cohort of patients with biopsy-proven IgAN. Further studies are warranted to evaluate if sIL-2Ra levels can feasibly contribute in the monitoring of effects of treatment, aimed to prevent the progression of interstitial fibrosis and progressive glomerulosclerosis in IgAN.

Immune complexes in acute adult-onset Henoch-Schonlein nephritis

BACKGROUND

Adult-onset Henoch-Schönlein purpura nephritis (HSPN) and primary IgA (IgAN) nephropathy have been considered indistinguishable immunohistopathologically and are often considered as two extremes of one disease entity. We postulate that adult-onset Henoch-Schönlein can be distinguished histologically from primary IgAN and that both diseases differ in their immunopathological mechanisms.

METHODS

Twenty consecutive patients with adult-onset HSPN were studied. Serum was analysed for circulating IgA immune complexes; renal biopsies were analysed by light and electron microscopy (EM). As disease controls, 40 IgAN patients were studied.

RESULTS

Intracapillary leukocyte margination was seen in 15 of the 20 patients and cellular crescent formation in all renal biopsies of the HSPN patients. IgAN biopsies showed a few small crescents without intracapillary leukocytes. In 16 HSPN patients, EM was performed and in 10, no dense deposits were found. In all biopsies of IgAN patients, typical 'humps' were found. In 6 of 9 analysed HSPN patients, intermediate to large circulating immune complexes were found, whereas in 4 of 28 analysed patients with primary IgAN small circulating immune complexes were found.

CONCLUSIONS

We consider adult-onset HSPN distinguishable in histology and ultrastructure from primary IgAN. We believe adult-onset Henoch-Schönlein to be a circulating immune complex disease.

Henoch-Schonlein purpura nephritis: pathophysiology, treatment, and future strategy

Henoch-Schönlein purpura nephritis is a rare kidney disease leading to chronic kidney disease in a non-negligible percentage of patients. Although retrospective studies suggest beneficial effects of some therapies, prospective randomized clinical trials proving treatment efficacy are still lacking. The dilemma of spontaneous recovery even in patients with severe clinical and histologic presentation and of late evolution to chronic kidney disease in patients with mild initial symptoms renders it difficult for clinicians to expose patients to treatment protocols that are not evidence-based. A better understanding of the pathophysiology of progression to chronic kidney disease in Henoch-Schönlein purpura patients could be achieved by designing prospective international multicenter studies looking at determinants of clinical and histopathological evolution as well as possible circulating and urinary markers of progression. Such studies should be supported by a database available on the web and a new histologic classification of kidney lesions. This paper reports clinical, pathologic, and experimental data to be used for this strategy and to assist clinicians and clinical trial designers to reach therapeutic decisions.

Clinical remission of Henoch-Schönlein purpura nephritis after a monotherapeutic tonsillectomy

We herein describe an adult male patient who presented with tonsillitis, purpura, hematuria, and proteinuria. The serological analyses revealed elevated serum antistreptolysin, and the throat culture yielded Lancefield group A β-hemolytic streptococci. A renal biopsy revealed mild mesangial proliferation associated with granular mesangial depositions of IgA and C3, consistent with Henoch-Schönlein purpura nephritis (HSPN). Initially, the patient was treated with dipyridamole, which was followed by limited improvements in the proteinuria and hematuria. Nine months later, the tonsillitis relapsed due to GAS infection and deteriorated urinary abnormalities were noticed, which finally disappeared after monotherapeutic tonsillectomy. Although the impact of tonsillectomy on the treatment of HSPN remains to be characterized, our observations suggest that tonsillectomy in the present patient played a pivotal role in facilitating the recovery of the renal injuries. Because the arbitrary application of a tonsillectomy appears to be accompanied by ethical concerns, the evaluation of the clinical benefits of this procedure should be addressed more directly in the future.

Idiopathic immunoglobulin A nephropathy in children and adolescents

Immunoglobulin A nephropathy is now recognized as the glomerular disease most often associated with progressive renal failure in patients around the world. In many cases it is not known when the disease starts to inflict glomerular injury, but recent studies that have shown genetically determined abnormalities in glycosylation of the IgA molecule suggest that this may begin in early life. This review focuses on recent advances in our understanding of IgA nephropathy, with special emphasis on clinical aspects of the disease when it presents in children and adolescents. In addition, the sections dealing with therapeutic options for patients with IgA nephropathy concentrate on studies that have been carried out on children. Whenever possible, data from randomized controlled clinical trials have formed the basis for recommendations. Unfortunately, this is not always possible, because of the lack of such trials in patients with IgA nephropathy.

Outcome of renal allograft in patients with Henoch-Schönlein nephritis: single-center experience and systematic review

BACKGROUND

Henoch-Schönlein nephritis (HSN) is a rare condition resulting in end-stage renal disease. Therefore, graft outcomes and recurrence rates after transplantation are not well studied. Also, the effect of donor type on graft outcome has not been evaluated thoroughly.

METHODS

The graft outcome and recurrence rate in 20 kidney recipients with HSN were compared with age-, sex-, and donor source-matched controls (control A, primary immunoglobulin A nephropathy; control B, other causes; 40 recipients per group). To assess the effect of donor type, we pooled our data with two previous cohort studies where donor type had been described in detail.

RESULTS

Overall graft survival rates were 87.7% at 10 years. The overall recurrence rate of HSN was 15.4% over 10 years. Graft survival and recurrence rates in the HSN group were similar to those of control A and control B. The pooled data showed a 29.4% incidence rate for recurrent HSN. Living related donor transplantation showed a trend of higher recurrence compared with recipients with nonrelated grafts, although it was marginally significant (P=0.059). However, the graft survival rate in related-donor recipients was not inferior to that in the unrelated-donor recipients.

CONCLUSIONS

Long-term graft survival and recurrence rates in kidney recipients with HSN were comparable to those of recipients with primary immunoglobulin A nephropathy. The type of donor did not significantly affect long-term graft survival.

CD81 gene defect in humans disrupts CD19 complex formation and leads to antibody deficiency

Antibody deficiencies constitute the largest group of symptomatic primary immunodeficiency diseases. In several patients, mutations in CD19 have been found to underlie disease, demonstrating the critical role for the protein encoded by this gene in antibody responses; CD19 functions in a complex with CD21, CD81, and CD225 to signal with the B cell receptor upon antigen recognition. We report here a patient with severe nephropathy and profound hypogammaglobulinemia. The immunodeficiency was characterized by decreased memory B cell numbers, impaired specific antibody responses, and an absence of CD19 expression on B cells. The patient had normal CD19 alleles but carried a homozygous CD81 mutation resulting in a complete lack of CD81 expression on blood leukocytes. Retroviral transduction and glycosylation experiments on EBV-transformed B cells from the patient revealed that CD19 membrane expression critically depended on CD81. Similar to CD19-deficient patients, CD81-deficient patients had B cells that showed impaired activation upon stimulation via the B cell antigen receptor but no overt T cell subset or function defects. In this study, we present what we believe to be the first antibody deficiency syndrome caused by a mutation in the CD81 gene and consequent disruption of the CD19 complex on B cells. These findings may contribute to unraveling the genetic basis of antibody deficiency syndromes and the nonredundant functions of CD81 in humans.

Pathogenesis of Henoch-Schönlein purpura nephritis

The severity of renal involvement is the major factor determining the long-term outcome of children with Henoch-Schönlein purpura (HSP) nephritis (HSPN). Approximately 40% children with HSP develop nephritis, usually within 4 to 6 weeks after the initial onset of the typical purpuric rashes. Although the pathogenetic mechanisms are still not fully delineated, several studies suggest that galactose-deficient IgA1 (Gd-IgA1) is recognized by anti-glycan antibodies, leading to the formation of the circulating immune complexes and their mesangial deposition that induce renal injury in HSPN.

Henoch-Schönlein purpura associated with Helicobacter pylori infection in a child

Henoch-Schönlein purpura is an acute leukocytoclastic vasculitis that primarily affects children. Henoch-Schönlein purpura is often associated with an infection, and a wide variety of infectious agents have been implicated in the pathogenesis. We report a child with Henoch-Schönlein purpura associated with Helicobacter pylori infection. Treatment of the Helicobacter pylori infection was accompanied by prompt resolution of the Henoch-Schönlein purpura.

Efficacy of early dental and ENT therapy in preventing nephropathy in pediatric Henoch-Schönlein purpura

In a previous study, we demonstrated the benefit of tonsillectomy for early recovery from Henoch-Schönlein purpura (HSP) nephritis (HSPN), suggesting the pathological role of tonsils in HSP (Inoue et al., Clin Nephrol 67:298-305, 2007). In this study, we evaluated the efficacy of extensive eradication of infectious foci directly connected to the tonsils, including those involved in oral as well as ear, nose, and throat (ENT) diseases, in reducing the nephropathy in HSP. For this purpose, we examined the focal points of infection in 40 newly diagnosed HSP patients. After these focal points of infection had been identified, they were extensively eradicated; when the clinical course was intractable, we also considered tonsillectomy. After administering such therapy to HSP patients, we prospectively followed them up for 0.6 to 8 years. The identified focal infections included dental caries in 28 (70%), apical periodontitis in 21 (53%), rhinosinusitis in 19 (48%), tonsillitis in five (13%), and otitis media in four (10%) of the 40 patients. Seventeen patients (43%) had more than two simultaneous infectious foci, whereas, in five (13%), no infectious focus was found. In 32 patients, antimicrobial treatment with concurrent dental and/or ENT therapy resulted in a complete cure without development of HSPN or recurrent attacks. In eight patients, we performed tonsillectomy-adenotonsillectomy to treat their clinical symptoms, including aggravated purpura and recurrent attacks of HSP or HSPN. All patients were completely cured. The overall incidence of HSPN was only three out of the 40 patients (8%). Oral and ENT diseases were found with high percentages in HSP patients. Early and extensive treatment for these lesions and tonsillectomy-adenotonsillectomy for intractable cases may prevent the complication of HSPN, contributing to the early curing of HSP.

High mobility group box chromosomal protein 1 in patients with renal diseases

BACKGROUND/AIM

The high mobility group box chromosomal protein 1 (HMGB1), a nuclear DNA-binding protein, has recently been recognized as a new proinflammatory cytokine. The purpose of this study was to examine the significance of HMGB1 in patients with renal diseases.

METHODS

HMGB1 concentrations in sera were measured by enzyme-linked immunosorbent assay, and antibodies against HMGB1 were examined by Western blotting in patients who underwent renal biopsies and in healthy controls. Immunohistochemistry for HMGB1 was also performed.

RESULTS

Serum HMGB1 was more likely to be positive in patients who underwent renal biopsies as compared with the controls. Patients with anti-neutrophil cytoplasmic antibody-related glomerulonephritis (ANCA-GN) and those with Henoch-Schonlein purpura nephritis showed a significantly higher tendency to be HMGB1 positive. The presence of anti-HMGB1 antibody was not associated with the presence of serum HMGB1. Immunohistochemistry revealed that HMGB1 was expressed in mononuclear cells in the interstitium or in the glomeruli of some patients with ANCA-GN or IgA nephropathy (IgAN). Subanalysis demonstrated that among patients with IgAN, those who had crescent formation showed a higher tendency to be HMGB1 positive than those who did not.

CONCLUSIONS

HMGB1 was expressed in the sera of patients with renal diseases who underwent renal biopsies, especially among those who had vasculitis including ANCA-GN, Henoch-Schonlein purpura nephritis, and IgAN with glomerular crescents.

Electrophoretic methods for analysis of urinary polypeptides in IgA-associated renal diseases

We evaluated the utility of SDS-PAGE/Western blot and CE coupled with MS (CE-MS) for detection of urinary polypeptide biomarkers of renal disease in patients with IgA-associated glomerulonephritides. In a reference cohort of 402 patients with various renal disorders and 207 healthy controls, we defined CE-MS patterns of renal damage and IgA nephropathy (IgAN). In a blinded analysis of a separate cohort of patients with IgAN (n = 10), Henoch-Schoenlein purpura (HSP) with nephritis (n = 10), and IgA-associated glomerulonephritis due to hepatitis C virus (HCV)-induced cirrhosis (n = 9), and healthy controls (n = 12), we compared SDS-PAGE/Western blot and CE-MS against clinical urinalysis for detection of urinary proteins/polypeptides. Urinalysis indicated proteinuria for 50, 90, and 33% of patients, respectively, and for none of the healthy controls. SDS-PAGE/Western blot showed urinary polypeptides abnormality for 90, 80, and 67% of patients, respectively, and for none of the healthy controls. CE-MS indicated a Renal Damage Pattern in 80, 80, and 100 of patients, respectively, and in 17% of healthy controls, with the more specific IgAN Pattern in 90, 90, and 1%, respectively, and in none of the healthy controls. Based on differences in CE-MS patterns, the disease mechanisms may differ among various IgA-associated glomerulonephritides. These exploratory findings should be evaluated in a prospective study with contemporaneous renal biopsy and urinary testing. If validated, it may be feasible to adapt the CE-MS methodology to develop novel tests to detect renal injury at earlier stages, assess clinical manifestations, and monitor responses to therapy in patients with IgA-associated renal diseases.

Splenic peliosis in the course of IgA nephropathy

The immunoglobulin A (IgA) immunoregulation disorders lie at the basis of Henoch-Schönlein purpura nephritis and IgA nephropathy. Peliosis is the condition characterized by cystic formations within the parenchyma of solid organs filled with blood. The authors report a case of a girl presenting with hematuria occurring during the course of respiratory infections since her fifth year. Pathohistological examination was not performed at that time. At the age of 13, the girl was hospitalized for abdominal pain. Computed tomography examination showed the presence of multiple, relatively well-defined nodular formations located in the spleen parenchyma. Splenectomy was performed. Morphological finding completely corresponded to peliosis of the spleen, with the deposits of IgA in the lesions within it. A year and a half following the splenectomy, a typical clinical picture of Henoch-Schönlein purpura nephritis developed. Biopsy findings of the skin and kidneys detected deposits of IgA. This is the first case of a patient suffering from associated IgA and Henoch-Schönlein purpura nephritis complicated by splenic peliosis to be described in the world's literature.

Immunopathogenesis of IgAN

The defining hallmark of IgA nephropathy (IgAN) is deposition of polymeric IgA1 in the glomerular mesangium accompanied by a mesangial proliferative glomerulonephritis. The mechanisms involved in mesangial polymeric IgA1 deposition and the initiation of inflammatory glomerular injury remain unclear. This lack of a complete understanding of the pathogenesis of IgAN has meant that there is still no treatment known to modify mesangial deposition of IgA. Increasing evidence, however, supports the importance of IgA-containing immune complex formation as a pivotal factor driving mesangial IgA deposition and triggering of glomerular injury. A number of potentially important changes to the IgA1 molecule have been identified in IgAN, which may contribute to immune complex formation. These changes suggest that the polymeric IgA1 that deposits in IgA nephropathy is derived from mucosally primed plasma cells. The presence of this IgA in the circulation reflects displacement of mucosal B lineage cells to systemic sites and may be the result of mishoming of lymphocytes trafficking along the mucosa-bone marrow axis.

Urinary biomarkers of IgA nephropathy and other IgA-associated renal diseases

IgA nephropathy is the most common primary glomerulonephritis and is a frequent cause for chronic kidney disease in children and young adults. Glomerular deposition of IgA also characterizes other renal disorders, including Henoch-Schoenlein purpura nephritis and immune-complex glomerulonephritis afflicting patients with liver disease due to chronic infection with the hepatitis C virus. Several treatment options are often considered, with the goal to prevent end-stage renal failure. Unfortunately, the diagnosis currently requires an invasive procedure, a renal biopsy. Because of the inherent risks, repetitive renal biopsy is frequently foregone as a means to monitor the clinical course or response to treatment. Recent advances in the analysis of the urinary proteome suggest that the excreted polypeptides include disease-specific patterns. We review recent studies of the various techniques for the identification and validation of such urinary biomarkers of IgA-associated glomerulonephritides. Currently, capillary electrophoresis coupled with mass spectrometry (MS) offers the greatest promise. To date, it seems more likely that disease-specific urinary polypeptide biomarkers are comprised of a panel of several distinct and well-defined peptides rather than a single molecule. Even most patients in clinical remission with normal clinical testing (dipstick urinalysis and quantitative proteinuria) were correctly classified by the pattern of polypeptides identified by capillary electrophoresis coupled with MS. With confirmation and refinement, such urinary testing may provide a tool for the diagnosis and monitoring of patients with IgA-associated renal diseases that is more sensitive than current standard clinical testing and far less risky than renal biopsy.

Henoch Schonlein purpura in children: an epidemiological study among Dutch paediatricians on incidence and diagnostic criteria

BACKGROUND

The aim of the present study on the occurrence of Henoch-Schönlein Purpura (HSP) in Dutch children is to give some insight into the epidemiology of HSP in the Netherlands, to record the diagnostic criteria used by Dutch paediatricians and to evaluate the accuracy of the latter using the presence of IgA in the skin when biopsies are available.

METHODS

Each month in 2004, all Dutch paediatricians received an electronic card asking them to mention new diagnosed HSP. Paediatricians reporting one or more new patients with HSP were sent a list of questions concerning various parameters.

RESULTS

232 patients from 0 to 18 years of age (6.1/10(5)) were reported as having contracted HSP in 2004. 29% presented renal symptoms. In accordance with the classification criteria of the American College of Rheumatology, 80% of paediatricians consider that isolated purpura (without haematological abnormalities) is sufficient to allow the diagnosis of HSP in children. From the 17 skin biopsies performed, only 9 (53%) presented IgA deposits. The follow-up duration, considered as necessary, was longer in case of renal symptoms at presentation. However, 45% of patients without renal symptoms would be followed for more than 1 year.

CONCLUSION

Considering the recent (2006) EULAR/PReS endorsed consensus criteria for the classification of childhood vasculitides, HSP should have been diagnosed in only 160 of the 179 patients of our study. The use of isolated non-thrombocytopenic purpura as the only criterion to diagnose HSP in children might therefore lead to over diagnosis and unnecessary follow-up.

The role of chemokines in Henoch Schonlein Purpura

BACKGROUND

The pathogenesis of Henoch Schonlein Purpura is incompletely understood and the role of chemokines is unknown.

OBJECTIVE

To investigate the levels of CC chemokines, eotaxin, TARC, and CXC chemokine IP-10 in Henoch Schonlein Purpura.

METHODS

Three groups of children were enrolled in the study: Henoch Schonlein Purpura in active stage (n = 26), Henoch Schonlein Purpura in remission phase (n = 26) and healthy children (n = 18). Levels of eotaxin, TARC, and IP-10 were determined in plasma using ELISA.

RESULTS

No significant difference was observed in the plasma level of eotaxin and TARC levels between the HSP and healthy children (>0.05). We could not find any significant difference between acute phase of the disease and convalescent phase in eotaxin and TARC levels (P > 0.05). We have suggested significant decreases in plasma IP-10 in the acute phase of the disease compared with the convalescent phase (P < 0.05). There was a significant difference in IP-10 levels between active stage and healthy controls, too (<0.05). We could not find any significant correlation between chemokine levels and system involvement (>0.05).

CONCLUSION

Our study shows that plasma level of eotaxin and TARC levels do not differ between the HSP and healthy children. But, decreasing the release of the Th1 chemokine IP-10 in HSP active stage may show that in HSP, there is no shift to Th1 lymphocytes in children with HSP. Further investigations are warranted to more fully explore and understand the production of and potential role of these chemokines in HSP.

Glomérulonéphrites extracapillaires

Crescentic glomerulonephritis are characterised by a crescent shaped cellular proliferation that may lead to glomerular destruction. Over 50% of at least 10 analysed glomeruli should be affected. The search for immune deposits by immunofluorescence is an important diagnostic step. Patients present with rapidly progressive glomerulonephritis (RPGN): renal failure, proteinuria and haematuria. Extra-renal symptoms may help diagnosis. Diseases are classified in three groups according to immunofluorescence studies. Group I is characterised by linear deposits along the glomerular basement membrane (GBM) with anti-GBM auto-antibodies responsible for Goodpasture's disease. Group II put together various diseases with immune complex deposits. In group III, no significant immune deposits are found. Those "pauci-immune" glomerulonephritis are secondary to anti-neutrophil cytoplasmic antibodies (ANCA) positive systemic vasculitis, mainly Wegener's granulomatosis and microscopic polyangiitis. Primary glomerulonephritis may also be associated with crescent formation. Treatment is urgently required. Diagnosis is suspected in the context of extra-renal symptoms or immunological abnormalities, and confirmed by a kidney biopsy, that also helps to define prognosis. Apart from some group II glomerulonephritis, the induction treatment is often an association of steroids and cyclophosphamide, with plasma exchange in case of Goodpasture's disease. After remission, a maintenance treatment is required for ANCA-positive vasculitis to prevent relapses. The high rate of opportunistic infections and cancer give the rational for searching less aggressive therapeutic options.

Role of mesangial fibrinogen deposition in the pathogenesis of crescentic Henoch-Schonlein nephritis in children

AIMS

To clarify the role of mesangial fibrinogen deposition in crescentic Henoch-Schönlein nephritis (HSN).

METHODS

A retrospective analysis of 21 children with HSN treated with immunosuppressants. Serial renal biopsies were performed before and after treatment. They were divided into two groups according to the immunofluorescent course of fibrinogen deposition: group I (n = 9), no or decreased deposition; group II (n = 12), persistent or increased deposition.

RESULTS

There were no differences between the two groups in renal manifestations or laboratory and histological findings at presentation. However, the activity index after immunosuppressive treatment was significantly decreased in group I (mean, 7.9 (SEM, 0.7) v 2.9 (0.4); p = 0.008) and unchanged in group II (mean, 6.8 (SEM, 0.3) v 6.0 (2.1)). The chronicity index was unchanged in group I, but increased in group II (mean, 0.8 (SEM, 0.3) v 1.8 (0.3); p = 0.02). Univariate analysis revealed that the only factor significantly related to persistent or increased fibrinogen deposition was age more than 9 years (p = 0.03). Furthermore, the intensity of fibrinogen deposition at the second biopsy correlated positively with the age at onset (R2= 0.306; p = 0.009) and changes in the percentage of crescents (post-treatment crescents (%) minus pretreatment crescents (%)) correlated positively with the intensity of fibrinogen deposition at the second biopsy (R2= 0.193; p = 0.046).

CONCLUSIONS

This study indicates that fibrinogen deposition has an important role to play in renal injury of crescentic HSN and reflects persistent severe histological activity.

Activation of tubular epithelial cells by mesangial-derived TNF-alpha: glomerulotubular communication in IgA nephropathy

BACKGROUND

IgA nephropathy (IgAN), characterized by mesangial IgA deposition, runs a variable clinical course with tubulointerstitial damage and renal failure in no less than 30% of patients. Histologically, IgA is rarely detected in renal tubules. The direct toxicity by IgA on renal tubules remains uncertain. We hypothesize that mediators released from human mesangial cells (HMC) triggered by IgA deposition may lead to activation of proximal tubular epithelial cells (PTEC).

METHODS

The binding of IgA to PTEC or HMC was assessed by flow cytometry. IgA-HMC medium was prepared by collecting the spent medium in which growth arrested HMC were incubated with IgA isolated from patients with IgAN, healthy control subjects, or other nephritic control patients. PTEC was cultured with the IgA-HMC medium in the presence or absence of neutralizing antibodies to TNF-alpha, IL-1beta, TGF-beta, or PDGF. Gene expression and protein synthesis of TNF-alpha, MIF, or ICAM-1 by PTEC were determined by RT-PCR and ELISA, respectively.

RESULTS

The binding of IgA isolated from patients with IgAN to PTEC was increased when compared to binding of IgA from healthy control subjects (P < 0.005). However, the binding to PTEC was less than one tenth that of HMC in IgAN. The binding to PTEC was not mediated through known IgA receptors, as shown by competitive binding assays and gene expression of the receptors. Despite the in vitro binding, PTEC cultured with isolated IgA exhibited no increased cell proliferation or enhanced synthesis of TNF-alpha, MIF, or sICAM-1. However, when PTEC were cultured with IgA-HMC medium prepared from IgAN patients, there was enhanced proliferation of PTEC (P < 0.001) and increased synthesis of TNF-alpha, MIF, and sICAM-1 when compared with PTEC cultured with IgA-HMC medium from control subjects (P < 0.001). The synthesis of MIF and sICAM-1 by PTEC cultured with IgA-HMC medium was reduced by neutralizing antibodies to TNF-alpha (P < 0.001) but not by neutralizing antibodies to IL-1beta, TGF-beta, or PDGF.

CONCLUSION

Our finding implicates that TNF-alpha released from the mesangium after IgA deposition activates renal tubular cells. The glomerulotubular communication could play an important role in the pathogenesis of tubulointerstitial damage in IgAN.

Serum IgA/C3 Ratio May Be a Useful Marker of Disease Activity in Severe Henoch-Schönlein Nephritis

BACKGROUND/AIMS

This study was designed to investigate whether the serum IgA/C3 ratio can be a serologic marker of disease activity in children with severe Henoch-Schönlein nephritis (HSN).

METHODS

Twelve HSN patients who were treated with steroids and cyclosporine were examined. The levels of serum IgA and C3 were measured using an international reference preparation (IFCC/CRM470) and a renal biopsy was performed in all patients before and after therapy. After therapy, patients were divided into 3 groups: complete remission (n = 6, group I), mild urinary abnormalities (n = 3, group II), and active renal disease (n = 3, group III).

RESULTS

The serum IgA/C3 ratio decreased significantly in groups I and II after therapy (2.62 +/- 0.82 vs. 2.02 +/- 0.52, p = 0.02), whereas the ratio in group III increased, although it was not statistically significant (2.13 +/- 0.93 vs. 4.67 +/- 1.71, p = 0.25). A follow-up renal biopsy revealed that the activity index was reduced in groups I and II (7.0 +/- 2.4 vs. 3.6 +/- 1.6, p = 0.016), and not changed in group III (7.3 +/- 2.1 vs. 9.3 +/- 2.5, p = 0.25). The activity index at a follow-up renal biopsy correlated positively with the changes of the serum IgA/C3 ratio: posttherapy activity index = 1.20 x DeltaIgA/C3 + 4.78 (r = 0.635, p = 0.027); where DeltaIgA/C3 is posttherapy IgA/C3--pretherapy IgA/C3.

CONCLUSION

These findings suggest that the serum IgA/C3 ratio may be a useful marker to predict disease activity and histologic severity in HSN.