Pathogenesis of Henoch-Schönlein purpura nephritis

Potential of Serum and Urinary Matrix Metalloproteinase-9 Levels for the Early Detection of Renal Involvement in Children With Henoch-Schönlein Purpura

Background

Matrix metalloproteinase-9 (MMP-9) is an enzyme implicated in the pathogenesis of renal diseases. Renal involvement is the principal cause of morbidity and mortality in children with Henoch-Schönlein purpura (HSP).

Objectives

The aim of this study was to evaluate whether serum and urinary MMP-9 levels are associated with renal involvement in HSP

Patients and Methods

We evaluated 40 children with HSP (patient group) and 27 healthy volunteer children (control group). The patient group was divided into two subgroups based on the presence or absence of nephritis. Nephritis was defined as the existence of hematuria and/or proteinuria. All anthropometric data, physical examination findings, blood pressure, and laboratory parameters were recorded. The serum and urine samples were analyzed to determine the MMP-9 levels three days after the initial phase of the disease.

Results

The mean age was 7.65 ± 3.41 (range 2 - 16) years in the patient group and 9.52 ± 3.91 (range 2 - 16) years in the control group. Henoch-Schonlein purpura nephritis (HSPN) was identified in eight patients. There was no significant difference in the serum MMP-9 levels between the HSPN subgroup and the controls (P > 0.05). However, there were significant differences in the urinary MMP-9 levels between the HSP subgroup and the control group (P < 0.05), with the urinary MMP-9 levels being significantly higher in patients in the HSP subgroup (P = 0.001). Further, the urinary MMP-9 levels were significantly higher in the patients with nephritis than in the patients without nephritis (P = 0.001) and the controls (P = 0.001). The optimal cut-off point (sensitivity; specificity) of the urinary MMP-9 level for the diagnosis of HSPN was 94.7 pg/mL.

Conclusions

The levels of MMP-9 in the urine were remarkably high in patients with HSPN. This non-invasive marker may therefore be an important indicator for the early diagnosis of nephritis in children with HSP.

Mycoplasma pneumoniae as a trigger for Henoch-Schönlein purpura in children

Mycoplasma pneumoniae is one of the most common causes of respiratory tract infections in children. Extrapulmonary manifestations are seen in up to 25% of infected patients. Extrapulmonary complications are associated with the central nervous system, gastrointestinal tract, skin changes, myocarditis, pericarditis, hemolytic anemia, thrombocytopenia and thrombosis. The majority of extrapulmonary symptoms are associated with skin changes such as exanthematous skin eruptions, erythema nodosum, urticaria, Stevens-Jonson syndrome. M. pneumoniae stimulates production of the interleukins and tumor necrosis factor (TNF) α and can cause vasculitis. Henoch-Schönlein purpura (HSP) is a leucoclastic vasculitis that affects small vessels. Clinical manifestations of HSP include typical rash, arthritis, gastrointestinal and sometimes renal involvement. The main feature in HSP is abnormal IgA deposits in vessel walls. Circulating abnormal glycosylated IgA 1 and IgG antibodies form immune complexes: IgA1-IgG and anti-IgA 1. Immune complexes activate cytokines, parts of complement and influence directly the endothelium. We report cases of three children with Henoch-Schönlein purpura with prolonged and recurrent skin and joint changes. The serological analysis (positive serum IgM) confirmed Mycoplasma pneumoniae infection. Treatment with clarithromycin caused complete regression of disease. We suggest that in the case of prolonged symptoms of vasculitis due to Henoch-Schönlein purpura, Mycoplasma pneumonia infection may be a potential cause of exacerbation of the disease.

A higher frequency of CD4(+)CXCR5(+) T follicular helper cells in patients with newly diagnosed Henoch-Schönlein purpura nephritis

T follicular helper (TFH) cells play an important role in the humoral immune responses. The aim of this study was to examine the frequency of different subsets of CD4(+)CXCR5(+) TFH cells and B cells in patients with new-onset Henoch-Schönlein purpura nephritis (HSPN). The numbers of different subsets of CD4(+)CXCR5(+) TFH cells, B cells and the constituents of serum cytokines were detected in a total of 25 patients with newly diagnosed HSPN before and after treatment, and in 14 healthy controls (HC). The potential connection of these cells with the clinical characteristics in HSPN patients was analyzed. The numbers of circulating CD4(+)CXCR5(+), CD4(+)CXCR5(+)ICOS(+) and CD4(+)CXCR5(+)PD-1(+) TFH cells, CD86(+)CD19(+), CD38(+)CD19(+) B cells and serum IL-2, IL-4, IL-17A, IL-21 and IFN-γ were significantly higher in HSPN patients (p<0.05) than in HC. Before and after treatment the numbers of CD4(+)CXCR5(+) TFH cells were negatively correlated with the values of eGFR (r=-0.7162, p<0.05; r=-0.732, p<0.05, respectively). Similarly the numbers of CD4(+)CXCR5(+)PD-1(+) TFH cells were negatively correlated with 24-h urinary proteins (r=-0.4013, p<0.05; r=-0.7857, p<0.05, respectively), and the numbers of CD4(+)CXCR5(+)ICOS(+) TFH cells were positively correlated with the levels of serum IL-21 (r=0.5186, p<0.05; r=0.8503, p<0.05, respectively) and 24-h urinary protein (r=0.6045, p<0.05; r=0.833, p<0.05, respectively) in these patients, regardless of treatment. Following treatment the numbers of CD4(+)CXCR5(+), CD4(+)CXCR5(+)PD-1(+), and CD4(+)CXCR5(+)ICOS(+) TFH cells, as well as serum levels of IL-21 were significantly reduced, however IL-4 levels were noticeably increased (p<0.05). A higher frequency of circulating CD4(+)CXCR5(+) TFH cells existed in patients with HSPN and may be a viable therapeutic target.

Long-Term Therapeutic Plasma Exchange to Prevent End-Stage Kidney Disease in Adult Severe Resistant Henoch-Schonlein Purpura Nephritis

A 27-year-old man presented with a palpable purpuric skin rash and joint and abdominal pain in April 2010. He had acute kidney injury and his creatinine quickly deteriorated to 687 μmol/L, with associated nephrotic range proteinuria. Kidney biopsy showed crescentic Henoch-Schonlein nephritis. He was treated with intravenous cyclophosphamide and prednisolone despite which his renal function deteriorated; he required haemodialysis for a short duration and seven sessions of therapeutic plasma exchange (TPE). Renal function improved, but after discharge from hospital he suffered 2 further relapses, each with AKI, in 4 months. Cyclophosphamide was not effective and therefore Rituximab was introduced. He initially had a partial response but his renal function deteriorated despite continued therapy. TPE was the only treatment that prevented rapid renal functional deterioration. A novel long-term treatment strategy involving regular TPE every one to two weeks was initiated. This helped to slow his progression to end-stage kidney disease over a 3-year period and to prolong the need for renal replacement therapy over this time.

Correlation of TLR2 and TLR4 expressions in peripheral blood mononuclear cells to Th1- and Th2-type immune responses in children with henoch-schönlein purpura

We discussed the correlation of TLR2 (Toll-like receptor) and TLR4 expressions in peripheral blood mononuclear cells (PBMCs) to Th1- and Th2-type immune responses in children with Henoch-Schönlein Purpura (HSP). The role of TLR2 and TLR4 in the pathogenesis of HSP was analyzed. Sixty-four HSP children treated at our hospital from October 2011 to November 2012 were enrolled and divided into NHSPN group (complicated by renal impairment, 36 cases) and HSPN group (not complicated by renal impairment, 28 cases). In the meantime, 30 normal children receiving physical examination at our hospital were recruited as controls. Peripheral blood T cell subgroups and TLR2 and TLR4 expressions in PBMCs were detected by using flow cytometry; relative expression levels of TLR2 and TLR4 mRNA in PBMCs by real-time quantitative fluorescence PCR, and plasma levels of IFN-γ, IL-4 and IL-6 by ELISA method. Relative expression levels of TLR2 and TLR4 mRNAs in PBMCs and TLR2 and TLR4 protein expressions in children with HSP were significantly higher than those of the controls (P<0.01). The relative expression levels of TLR2 and TLR4 mRNAs in PBMCs and TLR2 and TLR4 protein expressions in HSPN group were obviously higher than those in NHSPN group (P<0.05; P<0.01; P<0.01; P<0.01); CD3(+) T cells and CD3(+)CD4(+) T cells in HSP group were significantly decreased, while CD3(+)CD8(+) T cells and CD3(+)HLADR(+) T activated cells were considerably increased (P<0.01); The plasma levels of IL-4 and IL-6 in HSP group were significantly higher than those of the normal controls (P<0.01, P<0.01); IFN-γ level in the former was much lower than in the control group (P<0.05); IFN-γ/IL-4 ratio in the former was also lower than that in the control (P<0.01); TLR2 and TLR4 expressions in HSP group showed significantly positive correlation with the plasma levels of IL-4 and IL-6 (P<0.01, P<0.05; P<0.01, P<0.01) and significantly negative correlation with IFN-γ/IL-4 ratio (P<0.01; P<0.01). TLR2 and TLR4 activation may be involved in the pathogenesis of HSP. TLR2 and TLR4 overactivation may induce HSP-related renal impairment; Children with HSP showed T-cell disorders and Th1/Th2 imbalance. Activated TLR2 and TLR4 possibly mediate the pathogenesis of HSP by upregulating Th2-type immune responses.

Even mild cases of paediatric Henoch-Schönlein purpura nephritis show significant long-term proteinuria

AIM

Henoch-Schonlein purpura (HSP) is a common cause of paediatric renal disease in children, representing 10-15% of paediatric glomerulonephritis. This study examined the long-term outcome of biopsy-proven HSP nephritis to identify correlations between disease development and treatment.

METHODS

Patients from three French centres were retrospectively analysed.

RESULTS

We followed up 142 patients aged from 2 to 10.5 years with HSP nephritis, graded according to the International Study Group of Kidney Disease in Childhood classification. Mean (±SD) age at presentation was 7.6 ± 2.8 years. Nephrotic range proteinuria was present in 28% of patients with Grade II lesions, 60% with Grade III and 90% with Grade IV. Significant proteinuria (>0.5 g/L) was found in nine of 48 patients 3 years after renal biopsy, eight of 25 patients after 5 years and three of 14 patients after 10 years. There was no correlation between the proteinuria risk at 3, 5 or 10 years and the initial histological lesion or treatment modality. Treatment with angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (ACEi/ARB) was linked to lower proteinuria, especially if it was started precociously.

CONCLUSION

Even mild forms of HSP nephritis risk significant long-term proteinuria. Very early introduction of ACEi/ARB may improve the long-term outcome independent of histological lesions.

Higher Serum Angiotensinogen Is an Indicator of IgA Vasculitis with Nephritis Revealed by Comparative Proteomes Analysis

IgA vasculitis (IgAV), previously named as Henoch–Schönlein purpura, is the most common systematic vasculitis with unknown etiology. Lack of appropriate study system and/or animal model limits the understanding of its molecular pathogenesis and hinders the identification of targets for rational therapy, especially for its long-term complication, IgAV nephritis (IgAVN). In this study, we applied comparative analysis of serum proteomes to obtain an insight about disease pathogenesis. This study has utilized high sensitivity nanoscale ultra performance liquid chromatography-mass spectrometry (nanoLC-MS/MS) to investigate the alterations in serum proteomic profiles in patients with IgAV (n=6), IgAVN (n=6) and healthy subjects (n=7). The differentially expressed proteins were subjected to functional pathway analysis by PANTHER and DAVID software. We identified 107 differentially expressed proteins among three different groups, and functional analysis suggested that, in addition to earlier reported pathways, such as acute phase response, immune response, complement and blood coagulation pathways, hemostasis and Wnt signaling pathway were probably involved in pathogenesis of IgAV. A few differentially abundant proteins identified, such as C4a, serum amyloid A, angiotensinogen, and kininogen 1, were further validated by ELISA. More importantly, we found that angiotensinogen concentration is correlated with IgAVN and could be used as a potential marker for the progression of IgAV. This is the first report of analyzing the proteomic alterations in IgAV patients and the differentially proteins identified in this study may enhance understanding of the pathology of IgAV and a few of them may be used to monitor disease progression.

24h Urinary Protein Levels and Urine Protein/Creatinine Ratios Could Probably Forecast the Pathological Classification of HSPN

This study aimed to assess the relevance of laboratory tests in Henoch-Schönlein purpura nephritis (HSPN) classification, and determine accurate classification factors. This prospective study included 694 HSPN patients who underwent ultrasound-guided percutaneous renal biopsy (PRB). Renal specimens were scored according to International Study of Kidney Disease in Children (ISKDC) classification. Meanwhile, blood samples were immediately collected for laboratory examination. The associations between laboratory parameters and HSPN classification were assessed. Significant differences in levels of serum Th1/Th2 cytokines, immunoglobulins, T-lymphocyte subsets, complement, and coagulation markers were obtained between HSPN patients and healthy children. Interestingly, 24h urinary protein (24h-UPRO) levels and urine protein/urine creatinine ratios could determine HPSN grade IIb, IIIa, and IIIb incidences, with areas under ROC curve of 0.767 and 0.731, respectively. At 24h-UPRO >580.35mg/L, prediction sensitivity and specificity were 75.2% and 70.0%, respectively. These values became 53.0% and 82.3%, respectively, with 24h-UPRO exceeding 1006.25mg/L. At urine protein/urine creatinine > 0.97, prediction sensitivity and specificity were 65.5% and 67.2%, respectively, values that became 57.4% and 80.0%, respectively, at ratios exceeding 1.2. Cell and humoral immunity, coagulation and fibrinolytic systems are all involved in the pathogenesis of HSPN, and type I hypersensitivity may be the disease trigger of HSPN. 24h-UPRO levels and urine protein/creatinine ratios could probably forecast the pathological classification of HSPN.

Hematologic and immunological characteristics of Henoch-Schönlein purpura in rat and rabbit models induced with ovalbumin based on type III hypersensitivity

Henoch-Schönlein purpura (HSP) is a common systemic vasculitis in children. Animal models of HSP are needed to better understand the mechanism of HSP. Here, we investigated hematologic and immunologic profiles in HSP rat and rabbit models. Models were established with ovalbumin (OVA) based on type III hypersensitivity. During the acute phase, the models exhibited varying degrees of cutaneous purpura, joint inflammatory response, gastrointestinal bleeding, glomerular capsule protein exudation, vascular dilatation, and increased IgA expression and immune complex deposition. Twenty four hours after antigen challenge, compared with the controls, the models showed a significantly increased white blood cell count and granulocytes count and percentage, decreased number and percentage of lymphocytes, no change in platelet concentration, significantly increased serum IL-4 and TNF-α levels, and decreased CD4⁺ T cell, CD4/CD8 ratio, and C3 and C4 levels. Compared with the hematologic and immunologic profiles in pediatric HSP patients, the rat and rabbit HSP models can mimic pediatric HSP characteristics. Our studies provide two useful animal models for further investigations of the pathogenesis, diagnosis, drug screening and treatment of HSP.

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.

Developments in large and midsize vasculitis

Childhood vasculitis is a complex and fascinating area in pediatric rheumatology that has experienced an unprecedented surge in research, leading to new knowledge over the past several years. Vasculitis is defined as the presence of inflammatory cell infiltration in blood vessel walls, usually with multisystemic involvement. The most frequent forms of vasculitis in childhood are the small-size vasculitides, of which Henoch-Schoenlein Purpura and other leucocytoclastic vasculitis are the best examples, followed by Kawasaki disease, a midsize vasculitis, and Takayasu arteritis, a large-size vasculitis, both of which are topics in this article.

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.

Add-on therapy with montelukast in the treatment of Henoch-Schönlein purpura

BACKGROUND

Previous studies suggested that leukotrienes (LT) were involved in the pathogenesis of Henoch-Schönlein purpura (HSP). This study investigated the efficacy of an add-on therapy with montelukast in the treatment of HSP.

METHODS

In this four-center, double-blind, placebo-controlled, parallel paired comparative study, 130 children with HSP were divided into two large groups: 84 patients without nephritis and 46 patients with nephritis. For each pair of patients with the same severity of disease, one subject was randomly allocated to one subgroup and the other allocated to the other subbroup; one subgroup received routine treatment plus placebo treatment, while the other subgroup received routine treatment plus montelukast treatment for 3 months. The efficacy was determined using Severity Scale Score (SSS). Blood eosinophil count, eosinophil cationic protein (ECP), IgE, interleukin (IL)-4, IL-5, IL-6, IL-8, IL-17, LTB4 , and urinary LTE4 were measured.

RESULTS

Add-on therapy with montelukast alleviated the symptoms of HSP including purpura, abdominal pain, stool occult blood, arthritis, proteinuria and hematuria, and, accordingly, shortened the length of hospital stay, and lowered blood eosinophil count, ECP, IgE, IL-4, IL-5, IL-6, IL-8, IL-17, LTB4 , and urinary LTE4 production, and also lowered the HSP relapse rate during the 3 months of treatment, but did not alter the outcome of nephritis at the end of follow up.

CONCLUSIONS

Add-on therapy with montelukast alleviated the symptoms of HSP. HSP may be improved by add-on therapy with a leukotriene receptor antagonist.

Successful outcome of a corticodependent henoch-schönlein purpura adult with rituximab

Henoch-Schönlein purpura (HSP) is a systemic vasculitis involving small vessels with deposition of immunoglobulin A (IgA) complexes, usually affecting children. Compared with children, HSP in adults is more severe and frequently associated with cancer. We report the case of a 49-year-old woman with medical history of kidney transplantation for segmental glomerular hyalinosis. Eight years after the transplantation, while taking combined immunosuppressive therapy with tacrolimus and azathioprine indicated for the prevention against transplant rejection, she developed a Henoch-Schönlein purpura. Vasculitis involves skin and sciatic peroneal nerve and she received systemic corticosteroid treatment. Because of four relapses and corticosteroid dependence, the patient was treated with rituximab (two intravenous infusions of 1000 mg given two weeks apart). Successful outcome was observed along two years of follow-up. This new case of successful use of rituximab in HSP promotes more investigations of this treatment in clinical trials.

Clinical significance of TLR3 and TLR4 in peripheral blood mononuclear cells from children with Henoch-Schönlein purpura nephritis

The aim of the present study was to investigate the expression levels and clinical significance of Toll-like receptor (TLR) 3 and 4 in peripheral blood mononuclear cells (PBMCs) collected from children with Henoch-Schönlein purpura (HSP) nephritis. The randomized controlled trial was conducted between August 2011 and March 2013, and 105 children with a clinical diagnosis of HSP were enrolled in the study. According to the 24-h urinary protein measurements and the presence of renal damage, the 105 cases were divided into groups A, B and C as follows: Group A, children with HSP but without renal damage; group B, children with HSP nephritis but without proteinuria; group C, children with HSP nephritis and proteinuria. A total of 30 healthy children were enrolled in the normal control group (group N). The primary endpoints were the detection of TLR3 and 4 mRNA and protein expression levels in PBMCs by flow cytometry and quantitative polymerase chain reaction. The mRNA and protein expression levels of TLR4 in the PBMCs were significantly higher in groups A, B and C when compared with group N. In addition, the mRNA and protein expression levels of TLR4 in group C were much higher when compared with groups A and B. A positive correlation was identified between TLR4 protein expression and 24-h urinary protein levels in group C. The expression levels of TLR3 did not significantly differ among the groups. Protein and mRNA expression levels of TLR4 in PBMCs significantly increased and exhibited a positive correlation with urinary protein excretion. These results indicate that aberrant activation of TLR4 may be relevant to the development of HSP nephritis.

Renal neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 expression in children with acute kidney injury and Henoch-Schönlein purpura nephritis

The aim of this study was to investigate the expression of neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) in the serum, urine and renal tissues of children with acute kidney injury (AKI) and Henoch-Schönlein purpura nephritis (A-on-C). A prospective single-center evaluation of the serum, urine and renal NGAL and KIM-1 levels was performed in a cohort of children. Blood and 5-ml urine samples were collected from each patient for the analysis of NGAL and KIM-1 levels using an ELISA. In addition, the expression of NGAL and KIM-1 in the kidney was examined using immunohistochemistry in patients with A-on-C and HSPN. The expression of serum cystatin C, β2-macroglobulin and serum creatinine (SCr), as well as urinary β2-MG and SCr, in the patients with A-on-C was significantly higher than that of HSPN patients, and the expression of NGAL and KIM-1 in the serum and urine in the A-on-C patients was also significantly higher than that of HSPN patients. However, there were no significant differences in the urine protein levels between the two groups. NGAL and KIM-1 were expressed in renal tubular epithelial cells, and the expression of NGAL and KIM-1 in the A-on-C patients was significantly higher than that in HSPN patients. In addition, the urine NGAL and KIM-1 levels were negatively correlated with glomerular filtration rate, but there was no significant correlation between the urine NGAL/KIM-1 and urine protein levels. The changes in serum and urine NGAL and KIM-1 levels may be applied to the diagnosis of A-on-C.

Pentraxin 3 as a novel early biomarker for the prediction of Henoch-Schönlein purpura nephritis in children

We investigated the potential role of pentraxin 3 (PTX3) in Henoch-Schönlein purpura (HSP), a common multisystemic vasculitis affecting children, as a predictor of Henoch-Schönlein purpura nephritis (HSPN). A total of 108 cases consisting of 34 children with HSP, 37 children with HSPN, and 37 healthy control children were enrolled in this prospective study from March 2010 to February 2013. Blood and urine samples were collected to measure plasma PTX3, C-reactive protein (CRP), serum creatinine, blood urea nitrogen (BUN), urine microalbumin (MALB), and β2-microglobulin (β2-MG). Median plasma PTX3 concentrations were significantly higher in children with HSPN and HSP than in control subjects before treatment (6.99, 4.18-9.78 ng/ml; 3.19, 1.13-4.27 ng/ml; 1.24, 0.87-2.08 ng/ml, respectively; all p < 0.05). Median plasma PTX3 concentrations were also significantly higher in children with HSPN than in children with HSP before treatment (6.99, 4.18-9.78 vs. 3.19, 1.13-4.27 ng/ml; p < 0.05). After treatment, median plasma PTX3 concentrations significantly decreased in children with HSP (from 3.19, 1.13-4.27 to 1.08, 0.65-2.19 ng/ml; p < 0.05) and HSPN (from 6.99, 4.18-9.78 to 1.29, 1.01-2.26 ng/ml; p < 0.05). Plasma PTX3 concentration was positively correlated with CRP (rho = 0.532, p = 0.001), MALB (rho = 0.606, p < 0.001), β2-MG (rho = 0.490, p = 0.002), and 24-h urinary protein quantity (rho = 0.650, p < 0.001) in children with HSPN. Considering vasculitis, we found that PTX3 could be used as a more efficient potential predictor of HSPN than CRP as indicated by the area under the receiver operating characteristic (ROC) curve (AUCROC) of PTX3 (AUCROC = 0.837; p < 0.001) and CRP (AUCROC = 0.514; p = 0.845). The threshold PTX3 concentration with optimal sensitivity and specificity was 4.30 ng/ml (sensitivity 73.0 %, specificity 79.6 %).

CONCLUSION

PTX3 seems to have an important role in multisystemic vasculitis of HSP, may be involved in the development of HSPN, and used as an early biomarker to predict HSPN.

Age of onset as a risk factor of renal involvement in Henoch-Schönlein purpura

Background

Henoch-Schönlein purpura (HSP) is the most common vasculitis in children, characterized by triad of symptoms; palpable purpura without thrombocytopenia, abdominal pain, and arthritis. Renal involvement often occur in children with HSP. No data on the renal involvement of children with HSP in Indonesia, especially West Java.

Objective

To evaluate renal involvement in children with HSP.

Methods

Retrospective study was conducted in children with HSP in Department of Child Health, Hasan Sadikin Hospital, from 2006 to 2011. Characteristics and clinical manifestations was reviewed from medical record. HSP was diagnosed by American College of Rheumatology 1990 criteria or European League Against Rheumatism/Pediatric Rheumatology International Trials Organization/Pediatric Rheumatology European Society 2008.

Results

There were 128 patients, consisting of 82 male (64.9%) and 46 female (35.1%) with ratio 1.8:1. Mean age was 7.9 ± 2.9 years old which range from 6 month to 15 years. Peak morbidity was between 5-10 years old. Prevalence of HSP in Hasan Sadikin Hospital tend to raise from 2.7/100,000 in 2008 to 5.2/100,000 in 2010. In most patients (71%) purpura was the first symptom. Seventy-one patients (44.5%) had arthritis and 89 patients (69.5%) had abdominal pain, while renal involvement was in 28 patients (21.8%). Gastrointestinal manifestations tend to manifest in patients less than 5 years old (p = 0.267), while renal involvement tend to manifest in age group 11-15 years old (p = 0.015) with odds ratio 3.1 (95% confidence interval, 1.2-8.1).

Conclusion

Renal involvement in children with HSP is more common in age group 11 to 15 years old.

Validation of the absolute renal risk of dialysis/death in adults with IgA nephropathy secondary to Henoch-Schönlein purpura: a monocentric cohort study

Background

We established earlier the absolute renal risk (ARR) of dialysis/death (D/D) in primary IgA nephropathy (IgAN) which permitted accurate prospective prediction of final prognosis. This ARR was based on the potential presence at initial diagnosis of three major, independent, and equipotent risk factors such as hypertension, quantitative proteinuria ≥ 1 g per day, and severe pathological lesions appreciated by our local classification scoring ≥ 8 (range 0–20). We studied the validity of this ARR concept in secondary IgAN to predict future outcome and focused on Henoch-Schönlein purpura (HSP) nephritis.

Methods

Our cohort of adults IgAN concerned 1064 patients with 101 secondary IgAN and was focused on 74 HSP (59 men) with a mean age of 38.6 at initial diagnosis and a mean follow-up of 11.8 years. Three major risk factors: hypertension, proteinuria ≥1 g/d, and severe pathological lesions appreciated by our global optical score ≥8 (GOS integrated all elementary histological lesions), were studied at biopsy-proven diagnosis and their presence defined the ARR scoring: 0 for none present, 3 for all present, 1 or 2 for the presence of any 1 or 2 risk factors. The primary end-point was composite with occurrence of dialysis or death before (D/D). We used classical statistics and both time-dependent Cox regression and Kaplan-Meier survival curve methods.

Results

The cumulative rate of D/D at 10 and 20 years post-onset was respectively 0 and 14% for ARR = 0 (23 patients); 10 and 23% for ARR = 1 (N = 19); 27 and 33% for ARR = 2 (N = 24); and 81 and 100% (before 20 y) in the 8 patients with ARR = 3 (P = 0.0007). Prediction at time of diagnosis (time zero) of 10y cumulative rate of D/D event was 0% for ARR = 0, 10% for ARR = 1, 33% for ARR = 2, and 100% by 8.5y for ARR = 3 (P = 0.0003) in this adequately treated cohort.

Conclusion

This study clearly validates the Absolute Renal Risk of Dialysis/Death concept in a new cohort of HSP-IgAN with utility to individual management and in future clinical trials.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Soluble transferrin receptor in urine, a new biomarker for IgA nephropathy and Henoch-Schönlein purpura nephritis

OBJECTIVES

IgA nephropathy (IgAN) and Henoch-Schönlein purpura nephritis (HSPN) might represent different ends of a continuous spectrum of glomerular disease. In both conditions, upregulated soluble transferrin receptor (sTfR) might be excreted in urine, which could be a potential biomarker to monitor disease activity and therapeutic response.

METHODS

In this pilot study, 132 Caucasian patients consulting the Nephrology Department at the Ghent University Hospital because of a glomerulopathy and 50 normal controls were included. Urinary sTfR concentrations were determined in concentrated urine using a newly developed latex-enhanced immunonephelometric assay.

RESULTS

Median urinary sTfR concentration was higher in patients with a primary glomerulopathy than in healthy subjects (p<0.0001). More importantly, absolute median levels of urinary sTfR were markedly higher in patients with active IgAN or HSPN [10μg/L, 95% confidence interval (CI): 6-18μg/L] in comparison with those with other morphological types of glomerulopathy (2μg/L, 95%CI: 1-4μg/L) (p<0.0001). A statistically significant difference in urinary sTfR concentration was observed between patients with active IgAN or HSPN and patients who had achieved partial or complete remission (p<0.0001). Multiple regression analysis with urinary sTfR as dependent variable revealed that proteinuria was the main predictor of urinary sTfR concentration (r(2)=0.52, p<0.001).

CONCLUSION

Determination of sTfR in urine is a new and sensitive method for a potential biomarker of IgAN and HSPN.

Aberrant histone modifications in peripheral blood mononuclear cells from patients with Henoch-Schönlein purpura

Henoch-Schönlein purpura (HSP), the most common type of leukocytoclastic vasculitis, is caused by T cell-mediated autoimmune reactions. In this study, we analyze histone modification patterns in peripheral blood mononuclear cells (PBMCs) of HSP patients, and investigate the expression levels of inflammatory cytokines (IFN-γ, IL-2, IL-4, IL-6 and IL-13), transcription factors (T-bet, GATA-3 and TIM-1) and chemokines (CXCL4 and CXCL10) in HSP patients. Our results show that histone H3 acetylation and methylation are significantly enhanced in PBMCs from HSP patients. We also demonstrate specifically that marked increases in histone H3 acetylation and H3 lysine 4 trimethylation occur at the IL-4 loci in these patients. In addition, the expression levels of IL-4, IL-6, IL-13, GATA-3, TIM-1 and CXCL4 are also increased. These findings suggest that abnormal histone modifications are present in the PBMCs of patients with HSP, possibly contributing to the activation of pathological immune responses associated with HSP.

Serum levels of alpha-smooth muscle actin and c-Met as biomarkers of the degree of severity of Henoch-Schonlein purpura nephritis

Approximately 40% of patients with Henoch-Schonlein purpura (HSP) develop Henoch-Schonlein purpura nephritis (HSPN) after 4 to 6 weeks of subcutaneous hemorrhaging. Immunoglobulin-A nephropathy (IgAN) and HSPN have numerous similarities, which can cause difficulty in correctly diagnosing the disorder during a differential diagnosis. The pathogenesis of the 2 diseases is not clear. We enrolled 137 patients with HSPN, 107 patients with IgAN, and 28 healthy (control) patients in our study. The levels of alpha-smooth muscle actin (α-SMA), c-Met, and Gal-deficient IgA1 (Gd-IgA1) in the 3 patient groups were determined and compared. The α-SMA, c-Met, and Gd-IgA1 levels and the clinical data from the patients with HSPN were analyzed for any correlations. The α-SMA and c-Met levels of the HSPN group were significantly higher than those of the IgAN and healthy control groups (P < 0.01). The Gd-IgA1 levels of the HSPN and IgAN groups were significantly different from the Gd-IgA1 level of the healthy control group (P < 0.01). The α-SMA levels of the HSPN group were positively correlated with blood urea nitrogen levels, serum creatinine levels, hematuria index, and proteinuria levels (P < 0.01). The c-Met levels of the HSPN group were positively correlated with the blood urea nitrogen and serum creatinine levels (P < 0.01). There were no significant differences among the α-SMA, c-Met, and Gd-IgA1 levels or the clinical data for the child and adult patients with HSPN. The serum levels of α-SMA and c-Met in patients with HSPN may be associated with the degree of disease severity. Gd-IgA1 is involved in the common immunologic pathogenesis of HSPN and IgAN.

CTLA-4 exon 1 +49A/G polymorphism is associated with renal involvement in pediatric Henoch-Schönlein purpura

BACKGROUND

Henoch-Schönlein purpura (HSP) is a multisystemic vasculitis of unknown etiology. Cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) and CD28 have been reported to be important candidate genes for conferring susceptibility to autoimmunity. In this study, we investigated the correlation of CTLA-4 and CD28 gene polymorphisms with HSP in children with and without renal involvement.

METHODS

The CTLA-4 exon 1 +49A/G, promoter -318C/T and CD28 IVS3 +17T/C single nucleotide polymorphisms (SNPs) were genotyped in 110 children with HSP and 90 ethnically matched healthy controls through restriction fragment-length polymorphism (RFLP).

RESULTS

The CTLA-4 (+49) GG genotype and G allele (GG + AG genotype) were more common in HSP patients with renal involvement (n = 52) than in HSP patients without renal involvement (n = 58) (P = 0.019 and 0.001, respectively). There were no significant differences in the prevalence of CTLA-4 (+49 A/G), (-318C/T) and CD28 IVS3 (+17 /T/C) polymorphisms between HSP patients and controls.

CONCLUSIONS

Our findings suggest that the CTLA-4 +49 GG genotype and G allele may contribute to increased risk for the development of renal damage in HSP patients.

C1GALT1 polymorphisms are associated with Henoch-Schönlein purpura nephritis

BACKGROUND

Henoch-Schönlein purpura nephritis (HSPN) is the most serious long-term complication of Henoch-Schönlein purpura and aberrant galactosylation of IgA1 plays a role in its development. However, the precise role of genetic factors contributing to the abnormal IgA1 galactosylation remains unknown.

METHODS

In order to examine the effects of C1GALT1 gene encoding core 1 β1,3-galactosyltransferase, an important role in the β1,3 glycosylation of IgA1, on HSPN susceptibility, we conducted a case-control association genetic study in 269 HSP and 61 HSPN in China. Five tagging SNPs, SNP1(-734 C/T), SNP4(-465A/G), SNP6(-330 G/T), SNP7(-292 C/-), and SNP8(1365 G/A) in C1GALT1 were studied using single-locus and haplotype-based multilocus analysis.

RESULTS

Our results demonstrated that 1365 G allele frequency was significantly higher in HSPN patients than in HSP patients without nephritis (0.459 vs 0.331, p = 0.0008, adjusted p' = 0.004) with an odds ratio (OR) = 1.716, 95%CI 1.151-2.560). The GG genotype of 1,365 G/A was significantly different in HSP without nephritis and HSPN (p = 0.008, adjusted p'' = 0.04). We did not observe statistically significant differences in haplotype frequencies between HSPN and HSP patients.

CONCLUSIONS

In conclusion, our study suggested that the 1365 G/A polymorphism of the C1GALT1 gene may contribute to HSPN development.

Outcome of Henoch-Schönlein purpura 8 years after treatment with a placebo or prednisone at disease onset

BACKGROUND

Corticosteroids have been shown not to prevent the development of Henoch-Schönlein nephritis. However, long-term follow-up data are scarce.

METHODS

The long-term outcome of patients in a randomized placebo-controlled prednisone study was evaluated 8 years later with a health questionnaire completed by 160/171 (94%) patients and by urine and blood pressure screening (138/171, 81%).

RESULTS

Twelve patients had hematuria and/or proteinuria and seven had hypertension. The patients with nephritis at onset of Henoch-Schönlein purpura (HSP) had an increased risk of hypertension and/or urine abnormalities (odds ratio 3.6, p = 0.022, 95% confidence interval 1.3-10.0). There were no differences between the prednisone and placebo groups. Recurrences of purpura were reported by 15 patients, with some recurrences continuing for 10 years. All five reported pregnancies were complicated by proteinuria. Four patients presented with hematuria and/or proteinuria at the control visit, and four had hypertension. Of these, two had a decreased estimated glomerular filtration rate.

CONCLUSIONS

HSP has a good long-term prognosis in unselected patients, although skin relapses with/without late-onset nephritis may occur, even a decade after the initial disease. Urine and blood pressure abnormalities 8 years after HSP are associated with nephritis at its onset. Early prednisone treatment does not affect the outcome and should not be routinely used.

Urinary angiotensinogen levels in relation to renal involvement of Henoch-Schonlein purpura in children

AIM

To investigate whether urinary angiotensinogen (UAGT) levels are correlated with renal involvement of Henoch-Schonlein purpura (HSP) in children, and to explore whether UAGT has any relation to the severity of HSP.

METHODS

The study sample consisted of 107 patients (50 boys and 57 girls, 6.68±2.41 years) with clinical diagnosis of HSP. A 24 h urine sample was collected before treatment. UAGT levels were measured in patients with HSP in the acute and convalescent phases by enzyme linked immunosorbent assay.

RESULTS

Urinary angiotensinogen/urinary concentration of creatinine levels were significantly higher in proteinuric HSP in the acute phase and the convalescent phase (32.02±3.95 and 25.31±4.11 µg/g) compared with those with HSP without renal involvement (17.26±2.60 and 15.14±3.81 µg/g) and those with hematuric HSP (19.70±2.21 and 17.28±3.62 µg/g) (P<0.0001 and P<0.01, respectively). Using matched urine samples from the same patients, UAGT/urinary concentration of creatinine (UCr) levels of proteinuric HSP patients were significantly lower in the convalescent phase (25.31 ± 4.11 µg/g, P<0.01) than in the acute phase (32.02±3.95 µg/g). UAGT/UCr levels showed positive correlation with 24 h urine protein or serum creatinine in both hematuric HSP and proteinuric HSP groups during the acute phase (P<0.05).

CONCLUSIONS

Urinary angiotensinogen levels were remarkably high in the acute phase in the patients with proteinuric HSP, suggesting increased UAGT may indicate a series of functional changes in the kidney and it may be used as a potential biomarker of severity of HSP to monitor the progression of HSP with renal involvement.

Henoch-Schönlein purpura with hypocomplementemia

BACKGROUND

Abnormalities of the complement system in Henoch-Schönlein purpura (HSP) have been reported, but how this abnormality in the complement system impacts on the prognosis of HSP remains unknown.

METHODS

We retrospectively studied patients hospitalized for HSP in the Children's Hospital Affiliated to Soochow University between October 2010 and May 2011. Patients with HSP and hypocomplementemia were the cases, and those without hypocomplementemia were the HSP controls. Another group of children (n = 50) with upper respiratory tract infections, but without HSP acted as negative controls.

RESULTS

A total number of 338 HSP patients were included in this study (n = 53 cases, n = 285 controls). In the cases, C3 and C4 levels decreased in 29 patients, C3 was low in 6, and C4 in 18. Complement levels returned to normal within 3 months in all HSP patients except one. Case group patients had higher levels of serum IgG and arthralgia, as well as positive titers of antistreptolysin-O. Rates of abdominal pain, gastrointestinal bleeding, Henoch-Schönlein purpura nephritis (HSPN), and serum IgA and IgM levels were similar in the two HSP groups.

CONCLUSION

Hypocomplementemia associated with HSP is a transient phenomenon. The incidence of significant sequelae such as HSPN between patients with and without hypocomplementemia does not differ.

Treatment of children with Henoch-Schönlein purpura nephritis with mycophenolate mofetil

BACKGROUND

Henoch-Schönlein purpura (HSP) can progress to Henoch-Schönlein purpura nephritis (HSPN), and the most effective management remains unclear. Our aim was to evaluate the efficacy of mycophenolate mofetil (MMF) for treating pediatric patients with HSPN and nephrotic-range proteinuria.

METHODS

Twelve children, seven boys and five girls, mean age 8.33 (range 6-12) years at the time of HSPN diagnosis with nephrotic-range proteinuria, were treated with MMF. All patients failed steroid treatment, and mean proteinuria at the time of MMF initiation was 5.6 g/d. MMF dosage ranged from 20 to 25 mg/kg per day. Patients also received an angiotensin-converting enzyme inhibitor (cliazapril) at MMF initiation. Mean follow-up was 3.9 (range 2.3-5.5) years.

RESULTS

All patients responded to MMF at a mean of 2.5 (range 1-4 months). Among the 12 patients, MMF was administered for 10 months in five, 12 months in six, and 15 months in one. At last follow-up, all patients had negative proteinuria and normal renal function, and no relapses were noted. No serious adverse effects of MMF were noted in any patient.

CONCLUSION

MMF is useful for treating pediatric patients with HSPN and nephrotic-range proteinuria.

Improved outcome of Henoch-Schonlein purpura nephritis by early intensive treatment

OBJECTIVE

To evaluate the different therapies used to treat mild, moderate and severe Henoch-Schonlein purpura nephritis (HSPN) patients and to identify the most effective treatment.

METHODS

One hundred and eighty six children were evaluated retrospectively. They were divided into mild, moderate and severe condition groups. Different therapeutic protocols of non-steroid therapy, hydrocortisone sodium succinate (HCSS) therapy, methylprednisolone (MP) pulse therapy, and MP in combination with tripterygium glycoside (TG) therapy were used to treat the different groups.

RESULTS

After 4 wk, in the mild group, patients were more likely to respond to HCSS therapy than non-steroid therapy (P < 0.05). Moderate HSPN patients were more likely to respond to MP therapy than HCSS therapy (P < 0.05). Severe HSPN patients were more likely to respond to MP in combination with TG than single MP therapy (P < 0.05). At last follow-up, all children had normal urinalysis, blood pressure and serum urea and creatinine. In the mild group, the mean duration of proteinuria was shorter in HCSS therapy group than in non-steroid therapy group (P < 0.05). In the moderate group, the mean duration of proteinuria was shorter in MP pulse therapy group than in HCSS therapy group (P < 0.05).

CONCLUSIONS

The present study has demonstrated a superior effect of HCSS therapy in patients with mild HSPN disease, of MP therapy in patients with moderate disease, and of MP in combination with TG therapy in patients with severe disease. Intensive therapy administered initially reduces the duration of urinary protein abnormality.

[Cutaneous vasculitis]

Vasculitis is a term that refers to damage and inflammation of the walls of blood vessels of any size. The classification of types of cutaneous vasculitis continues to be a challenge, probably because of our lack of understanding of the etiology and pathogenesis of this condition. Changes in the vessel wall will be visible on microscopy and will enable the different clinical forms to be distinguished according to the caliber of affected vessels, the type of cell that predominates in the inflammatory infiltrate, or the presence of such key findings as extravascular granulomas. Skin manifestations (macules, papules, nodules, livedo reticularis, etc) correlate with the size of the vessel affected. The prognosis in cases of vasculitis with skin involvement will be determined by the presence or absence of extracutaneous disease. Systemic vasculitis shows a predilection for certain organs, such as the kidney or lung. The introduction of immunosuppressant drug treatments has led to evident improvement in survival rates for patients with vasculitis. This review covers practical aspects of the pathophysiology, histopathology, treatment, and differential diagnosis of the main clinical presentations of vasculitis with cutaneous involvement.

Kinin system activation in vasculitis

Vasculitis is a systemic autoimmune inflammatory disease, characterized by inflammation in and around vessel walls leading to perturbed vessel patency and tissue damage. Many different organs may be involved. In this review, pathogenetic mechanisms of vasculitis are discussed, with special reference to activation of the kinin system. Mechanisms of kinin system activation are described, ultimately leading to release of kinins from high molecular weight kininogen. These vasoactive peptides promote inflammation.

CONCLUSION

  Kinin system activation during vasculitis promotes inflammation.

Successful outcome using rituximab as the only immunomodulation in Henoch-Schonlein purpura: case report

In the current report, we describe a patient with moderate nephritis and severe skin Henoch Schönlein purpura (HSP) who has been treated with rituximab. Complete and sustained skin and renal remission resulted from the treatment. Thus, further studies are required to confirm the efficacy of rituximab as first-line treatment in HSP, and it might be an interesting new therapeutic option.

Analysis of the urinary peptidome associated with Helicobacter pylori infection

AIM: To investigate the relationship between urinary peptide changes and Helicobacter pylori (H. pylori) infection using urinary peptidome profiling.

METHODS: The study was performed in volunteers (n = 137) who gave informed consent. Urinary peptides were enriched by magnetic beads based weak cation exchange chromatography and spectrums acquired by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS). ClinProTools bioinformatics software was used for statistical analysis and the recognition of peptide patterns. The marker peptides were identified by LTQ Obitrap XL tandem MS.

RESULTS: Approximately 50 proteins or peptides which loaded onto the magnetic beads were detected by MALDI-TOF MS. By optimizing the parameters of the model, the Genetic Algorithm model had good recognition capability (97%) and positive predictive value (94%). Based on the model, 2 markers with molecular masses of 6788 and 1912 Da were found that differentiated between H. pylori positive and negative volunteers. The m/z 1912 sequence was parsed as SKQFTSSTSYNRGDSTF. The peptide was identified as isoform 1 of the fibrinogen α chain precursor, whose concentration in urine was markedly higher in H. pylori infected volunteers than in H. pylori non-infected ones.

CONCLUSION: The appearance of urinary fibrinogen degradation products is caused by an active H. pylori-induced process.

Henoch-Schönlein purpura

PURPOSE OF REVIEW

To provide an update on recent advances in the genetic susceptibility, pathogenesis and treatment of Henoch-Schönlein purpura.

RECENT FINDINGS

Recent work has advanced our understanding of the genetic susceptibility and pathogenesis of Henoch-Schönlein purpura, but there are still significant gaps in our knowledge. Information concerning the most effective treatment of Henoch-Schönlein purpura has begun to emerge. Corticosteroid therapy reduces the duration and severity of abdominal and joint pain, but corticosteroids do not prevent the development of nephritis, or alter the natural history of Henoch-Schönlein purpura. The most effective treatment for severe nephritis remains unclear despite multiple, mostly retrospective reports investigating a variety of drugs.

SUMMARY

Despite recent progress, our understanding of the genetic susceptibility, pathogenesis and treatment of Henoch-Schönlein purpura remains incomplete. Further research is necessary in order to clearly define the genetic susceptibility and the pathogenesis of Henoch-Schönlein purpura. Multicenter clinical trials are needed to determine the most effective treatment of Henoch-Schönlein purpura, particularly for patients with severe nephritis.

Tissue deposits of IgA-binding streptococcal M proteins in IgA nephropathy and Henoch-Schonlein purpura

IgA nephropathy (IgAN) and Henoch-Schönlein purpura (HSP) are diseases characterized by IgA deposits in the kidney and/or skin. Both may arise after upper respiratory tract infections, but the pathogenic mechanisms governing these diseases remain unclear. Patients with IgAN (n = 16) and HSP (n = 17) were included in this study aimed at examining whether IgA-binding M proteins of group A streptococci could be involved. As M proteins vary in sequence, the study focused on the IgA-binding-region (IgA-BR) of three different M proteins: M4, M22, and M60. Renal tissue from IgAN and HSP patients and skin from HSP patients were examined for deposits of streptococcal IgA-BR by immunohistochemistry and electron microscopy using specific antibodies, and a skin sample from a HSP patient was examined by mass spectrometry. IgA-BR deposits were detected in 10/16 IgAN kidneys and 7/13 HSP kidneys. Electron microscopy demonstrated deposits of IgA-BRs in the mesangial matrix and glomerular basement membrane, which colocalized with IgA. Skin samples exhibited IgA-BR deposits in 4/5 biopsies, a result confirmed by mass spectrometry in one patient. IgA-BR deposits were not detected in normal kidney and skin samples. Taken together, these results demonstrate IgA-BR from streptococcal M proteins in patient tissues. IgA-BR, would on gaining access to the circulation, encounter circulatory IgA and form a complex with IgA-Fc that could deposit in tissues and contribute to the pathogenesis of IgAN and HSP.