Insight into the Interplay of Gd-IgA1, HMGB1, RAGE and PCDH1 in IgA Vasculitis (IgAV).

The pathogenesis of IgAV, the most common systemic vasculitis in childhood, appears to be complex and requires further elucidation. We aimed to investigate the potential role of galactose-deficient immunoglobulin A1 (Gd-IgA1), high-mobility group box 1 (HMGB1), receptor for advanced glycation end products (RAGE) and protocadherin 1 (PCDH1) in the pathogenesis of IgAV. Our prospective study enrolled 86 patients with IgAV and 70 controls. HMGB1, RAGE, Gd-IgA1 and PCDH1 in serum and urine were determined by the enzyme-linked immunosorbent assay (ELISA) method at the onset of the disease and after a six-month interval in patients and once in the control group. Serum concentrations of HMGB1, RAGE and PCDH1 and urinary concentrations of HMGB1, RAGE, Gd-IgA1 and PCDH1 were significantly higher in patients with IgAV than in the control group (p < 0.001). Concentrations of HMGB1 (5573 pg/mL vs. 3477 pg/mL vs. 1088 pg/mL, p < 0.001) and RAGE (309 pg/mL vs. 302.4 pg/mL vs. 201.3 pg/mL, p = 0.012) in the serum of patients remained significantly elevated when the disease onset was compared with the six-month follow-up interval, and thus could be a potential marker of disease activity. Urinary concentration of HMGB1 measured in the follow-up period was higher in patients with nephritis compared to IgAV without nephritis (270.9 (146.7-542.7) ng/mmol vs. 133.2 (85.9-318.6) ng/mmol, p = 0.049) and significantly positively correlated with the urine albumine to creatinine ratio (τ = 0.184, p < 0.05), the number of erythrocytes in urine samples (τ = 0.193, p < 0.05) and with the outcome of nephritis (τ = 0.287, p < 0.05); therefore, HMGB1 could be a potential tool for monitoring patients with IgAV who develop nephritis. Taken together, our results imply a possible interplay of Gd-IgA1, HMGB1, RAGE and PCDH1 in the development of IgAV. The identification of sensitive biomarkers in IgAV may provide disease prevention and future therapeutics.

Analysis of the association between kidney injury biomarkers concentration and nephritis in immunoglobulin A vasculitis: A pediatric cohort study.

OBJECTIVE: The aim of this study was to investigate the clinical course, selected biochemical parameters and concentrations of renal injury biomarkers such as neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1) and liver-fatty acid binding protein (L-FABP) in patients with immunoglobulin A vasculitis (IgAV) to identify the markers associated with nephritis in the course of the disease (IgAVN). METHODS: The study involved 29 children with IgAV and 34 healthy controls. Eleven (38%) patients had renal involvement (IgAV-N) and 18 (62%) did not exhibit nephritis (IgAV-noN). Initial laboratory tests, determining the concentrations of NGAL, KIM-1 and L-FABP in serum and urine, were conducted on children from the study group in an acute phase of IgAV as well as after an average of 6 months, during a follow-up visit. The interconnection between renal involvement, anthropometric measurements, epidemiological data, laboratory parameters and levels of examined biomarkers have been thoroughly evaluated. RESULTS: The serum and urine levels of NGAL, KIM-1 and L-FABP were significantly higher in children with an acute phase of IgAV as compared to the control group (P < .001) and markedly lower during follow-up retesting in comparison with the values obtained at inclusion (P < .001). However, the concentration of none of the evaluated biomarkers correlated with nephrological indices. Among all examined parameters, only male subjects were associated with nephritis (P = .017). CONCLUSIONS: We have established no evident association between the concentrations of NGAL, KIM-1 and L-FABP and nephritis in the course of IgAV in children. Additionally, we confirmed a significant male predominance in patients with nephritis.

Prognostic implications of normal or minimal urinary findings on long-term renal impairment in adults with Henoch-Schönlein purpura.

BACKGROUND: Renal involvement in adult Henoch-Schönlein purpura is a major cause of morbidity and can lead to significant long-term renal impairment. The prognostic significance of normal or minimal urinary abnormalities at diagnosis is unknown. OBJECTIVE: To assess the risk of long-term renal impairment in patients with Henoch-Schönlein purpura who present with normal or minimal urinary abnormalities. METHODS: Retrospective cohort study of adult Henoch-Schönlein purpura patients presenting with normal urinalysis results, microscopic hematuria, or low-grade proteinuria. Patients were followed for development of long-term renal impairment, with adjusting for comorbidities. RESULTS: Forty-seven patients were included, with median follow-up 73.9 months (interquartile range 35 to 98 months). Thirty-nine patients (83.0%) had abnormal urinalysis results, of whom 15 (38.5%) progressed to long-term renal impairment. In contrast, 8 patients (17%) had normal urinalysis results, of whom only 1 (12.5%) developed long-term renal impairment (adjusted hazard ratio 10.58; 95% confidence interval 1.18-94.73). Renal events occurred at a median 36.1 months (interquartile range 17.1 to 61 months) from diagnosis, earlier in patients with comorbidities compared with those with none, and in a constant event rate over time. LIMITATIONS: Small sample size. CONCLUSIONS: Microscopic hematuria and low-grade proteinuria at Henoch-Schönlein purpura diagnosis is a poor prognostic sign for the development of long-term renal impairment. This population should be targeted for prolonged surveillance.

Urinalysis monitoring in children with Henoch-Schönlein purpura: Is it time to revise?

OBJECTIVES: To describe the natural history and risk factors of renal involvement in our Henoch-Schönlein purpura (HSP) inception cohort. METHODS: HSP patients followed at our center for at least 6 months between 1/2009-4/2017 were included. A 2-year urinalysis (UA) monitoring protocol was adopted (6 monthly and another 6 of 3 monthly UA). Renal involvement included minimal renal involvement defined as isolated hematuria (urine red blood cells >5/high-power field or 10/µL) and/or proteinuria (urine protein >1+), and renal impairment defined as nephritic, nephrotic symptoms, or renal insufficiency. Recurrent HSP were excluded. Kaplan-Meier estimates and log-rank test were used to analyze the duration to onset and resolution of abnormal UA. Relationships between demographic and clinical features and renal involvement were studied using logistic regression analyses. RESULTS: Two hundred and thirty-eight patients (52.9% male) were analyzed. Median duration of follow up was 20.6 (interquartile range 11.3-24.4) months. Eighty-nine children (37.4%) developed abnormal UA either at diagnosis (n = 43), or during follow up (n = 46), mostly (91.0%) within 6 months. Seventeen patients (7.1%) developed renal impairment. Among patients without renal impairment, an earlier subsidence (P = 0.008) was noted in those with normal UA at diagnosis and most abnormal UA resolved by 18 months in this subgroup. Older age at diagnosis was a risk factor of renal involvement (P < 0.001). Prednisolone therapy for non-renal indications did not affect the onset or duration of renal involvement. CONCLUSIONS: Normal UA at diagnosis indicated a shorter duration of renal involvement. We propose a curtailed duration of follow up for those with normal and abnormal UA at diagnosis.

Elevated urinary monocyte chemoattractant protein-1 levels in children with Henoch-Schonlein purpura nephritis.

BACKGROUND: Chemokine monocyte chemoattractant protein-1 (MCP-1) has been proved as a potential urinary biomarker in nephropathies. The aim of this study was to investigate the urinary monocyte chemoattractant protein-1 (MCP-1) levels and clinical significance in Henoch-Schonlein purpura (HSP) children with and without nephritis and determine the association of MCP-1 with proteinuria. METHODS: A total of 261 HSP children-with or without nephritis-and 84 healthy control children were enrolled in this study. Of these, 126 HSP nephritis (HSPN) children were subdivided into three groups according to total urine protein in 24 h (TUP): Group A, mild proteinuria group with TUP <25 mg/kg; Group B, moderate proteinuria group with TUP ≥25 mg/kg and <50 mg/kg; Group C, severe proteinuria group with TUP ≥50 mg/kg. Urinary MCP-1 levels were determined by ELISA. Levels of serum creatinine (Cr), blood urea nitrogen (BUN), urinary α1-micro globulin (α1-MG), micro-albumin (mAlb), immunoglobulin G (IgG), transferrin (TRF) and TUP were performed to determine their associations with MCP-1. RESULTS: Urinary MCP-1 was significantly higher in HSPN group in comparison with HSP group and controls (P < 0.05), but no significant difference was found between the HSP group and the healthy group (P > 0.05). The levels of urinary MCP-1 increased in parallel to the enhancement of total urine protein in 24 h in HSPN patients. There were statistically significant differences among these three groups of HSPN children (p < 0.05). Urinary MCP-1 correlated positively with urinary α1-MG, mAlb, IgG, TRF and TUP in HSPN, whereas no correlation was observed with serum Cr and BUN. CONCLUSIONS: MCP-1 was elevated in children with HSPN and correlated with proteinuria. Urinary MCP-1 could be used as a suitable, non-invasive biomarker to provide valuable information not only for the diagnosis of HSPN, but also for evaluation of severity of renal damage.

Efficacy of mizoribine and prednisolone combination therapy in adult patients with IgA vasculitis.

Immunoglobulin (Ig)A vasculitis (IgAV), formerly known as Henoch-Schönlein purpura, is one of the most common vasculitis caused by an IgA-mediated immune complex. It occurs most frequently in childhood and less commonly in adulthood. As for the treatment of IgAV in adults, there are few studies dealing with the administration and efficacy of intravenous pulse steroid therapy or combination therapy using prednisolone (PSL) and immunosuppressive drugs. Mizoribine (MZB) is a newly developed immunosuppressive drug with few adverse effects; however, there are currently few studies using MZB in adult patients with IgAV. In this study, we evaluated the efficacy of MZB combined with a course of PSL in adult patients with IgAV. Five patients with adult onset IgAV were enrolled in the study. All patients received oral PSL (initial dose 30-50 mg/day), and MZB was administered orally at a single morning dose of 150 mg. We investigated the clinical manifestations and prognosis of these patients receiving the combination therapy of MZB and PSL retrospectively. All patients showed complete or partial remission of proteinuria and microscopic hematuria with the combination therapy of MZB and PSL. Furthermore, no significant adverse effects were observed. Although this study had an uncontrolled small group, our results indicate that the combination of MZB with PSL could be a possible new treatment for adult patients with IgAV.

The ISKDC classification and a new semiquantitative classification for predicting outcomes of Henoch-Schönlein purpura nephritis.

BACKGROUND: Histological findings from primary kidney biopsies were correlated with patient outcomes in a national cohort of paediatric Henoch-Schönlein nephritis (HSN) patients. METHODS: Primary kidney biopsies from 53 HSN patients were re-evaluated using the ISKDC (International Study of Kidney Disease in Children) classification and a modified semiquantitative classification (SQC) that scores renal findings and also takes into account activity, chronicity and tubulointerstitial indices. The ISKDC and SQC classifications were evaluated comparatively in four outcome groups: no signs of renal disease (outcome A, n = 27), minor urinary abnormalities (outcome B, n = 18), active renal disease (outcome C, n = 3) and renal insufficiency, end-stage renal disease or succumbed due to HSN (outcome D, n = 5). For the receiver operating characteristic and logistic regression analyses, outcomes A and B were considered to be favourable and outcomes C and D to be unfavourable. The median follow-up time was 7.3 years. RESULTS: The patients with an unfavourable outcome (C and D), considered together due to low patient numbers, had significantly higher total biopsy SQC scores and activity indices than those who had a favourable one (groups A and B). The chronicity and tubulointerstitial indices differed significantly only between group C + D and group A. The difference in areas under the curve between the total biopsy SQC scores and ISKDC findings was 0.15 [p = 0.04, normal-based 95% confidence interval (CI) 0.007-0.29, bias-controlled 95% CI -0.004 to 0.28]. CONCLUSIONS: Our results suggest that the modified SQC is more sensitive than ISKDC classification for predicting the outcome in HSN cases.

Clinical outcomes in children with Henoch-Schönlein purpura nephritis without crescents.

BACKGROUND: Henoch-Schönlein purpura is the most common vasculitis in children. Its long-term prognosis depends on renal involvement. The management of Henoch-Schönlein purpura nephritis (HSPN) remains controversial. This study reports the prognosis of children with HSPN presenting with class 2 International Study of Kidney Disease in Children (ISKDC) nephritis. METHODS: All children with HSPN class 2 diagnosed between 1995 and 2015 in four pediatric nephrology centers were included, and clinical and biological data were collected from the medical files. The primary endpoint was proteinuria remission defined as a proteinuria <200 mg/L. RESULTS: Ninety-two children were included in the study with a median follow-up of 36 (6-120) months; 28% had nephrotic syndrome, 31% proteinuria >3 g/L, 52% proteinuria between 1 and 3 g/L, and 18% proteinuria <1 g/L. Forty-seven percent of patients received orally treatment with steroids alone, 37% received methylprednisolone pulses followed by steroids orally, 18% received no steroids. Although 85% reached remission during follow-up, 12% did not maintain complete remission over time so that only 75% remained in complete remission by the end of the follow-up. Univariate analysis found a higher likelihood of remission in patients with higher proteinuria at disease onset (p = 0.009). This trend was not found in the multivariate analysis after adjusting for treatments, as patients with higher proteinuria were most often treated with steroids. CONCLUSION: Our study shows that one fourth of patients with HSPN class 2 remain proteinuric and thus carry the risk of developing chronic kidney disease over the long term. This finding, together with the better outcome of patients treated with steroids, is in favor of using high-dose steroids orally or IV in these patients.

Differences in pathological characteristics and laboratory indicators in adult and pediatric patients with Henoch-Schönlein purpura nephritis.

We aimed to investigate the differences in renal histopathological changes and laboratory parameters between adult and pediatric patients with Henoch-Schönlein purpura nephritis (HSPN), and to analyze the correlation between laboratory parameters and renal histopathological grading. A total of 139 patients diagnosed with HSPN between September 2010 and December 2014 at the First Hospital of Jilin University, China, were retrospectively reviewed. The clinical and pathological characteristics were examined and compared between the adult and the pediatric patients. A majority of adult (75.0%) and pediatric (66.2%) patients were categorized as pathological grade III HSPN. Adults having crescent lesions, interstitial fibrosis and renal artery involvement significantly outnumbered child counterparts (all P<0.05). Pathological grading showed a positive correlation with 24-h urine protein (r=0.307, P=0.009), microalbuminuria (r=0.266, P=0.000) and serum globulin (r=0.307, P=0.014), and a negative correlation with serum albumin (r=0.249, P=0.037) in pediatric patients with HSPN. Among adult patients with HSPN, histopathological grading showed a positive correlation with 24-h urine protein (r=0.294, P=0.015), microalbuminuria (r=0.352, P=0.006), α1-microglobulin (r=0.311, P=0.019) and immunoglobulin G (r=0.301, P=0.023) in urine, and serum creatinine (r=0.292, P=0.018). Further, a negative correlation between serum albumin and pathological grading was also observed (r=0.291, P=0.018). In conclusion, the severity of renal pathological lesions in HSPN patients is well reflected by the levels of proteinuria. Adult patients have more severe renal histopathological changes than pediatric patients.

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.

Urinary neopterin: an immune activation marker in mesangial proliferative glomerulonephritis.

BACKGROUND: To clarify in vivo neopterin expression within the human kidney and its clinical role as a biomarker for immune complex-mediated mesangial proliferative glomerulonephritis (mesPGN) in children. METHODS: We examined neopterin expression within the kidneys of 14 patients with mesPGN and five patients with minimal changes. We also measured the serum and urinary neopterin levels in fourteen patients with mesPGN and sixteen age-matched healthy controls and correlated the histological findings and clinical features. RESULTS: Neopterin expression was observed within the distal tubular epithelial cells. It was induced within the glomerular endothelial cells and infiltrated CD68-positive macrophages in the glomeruli and interstitial areas. Furthermore, urinary neopterin levels were significantly elevated and positively correlated with histopathological findings and the degree of proteinuria. CONCLUSIONS: These findings indicate that increased urinary neopterin may reflect macrophage activation and active inflammation within the kidney in immune complex-mediated glomerulonephritis. Neopterin may thus represent a useful biomarker of immune complex-mediated glomerulonephritis in the clinical setting.

Elevated urinary levels of cystatin C and neutrophil gelatinase-associated lipocalin in Henoch-Schönlein purpura patients with renal involvement.

Henoch-Schönlein purpura (HSP) is a commonest systemic vasculitis in childhood. The long-term prognosis of HSP is determined by the degree of renal involvement. The aim of this study is to search novel clinically applicable biomarkers to evaluate renal involvement in HSP patients. 20 bio-indexes in urine samples were simultaneously screened by antibody array assay. We indicated that urinary levels of cystatin C (Cys C) and neutrophil gelatinase-associated lipocalin (NGAL) in HSP patients with renal involvement were significantly higher than those without renal involvement and healthy controls. Furthermore, ELISA was used to analyze urinary Cys C and NGAL levels in HSP patients with or without renal involvement, atopic dermatitis (AD) patients and healthy controls. Our results demonstrated that urinary Cys C and NGAL levels in HSP patients with renal involvement were significantly elevated, when compared with those without renal involvement, AD patients and control subjects. In addition, by receiver operating characteristic (ROC) curve analysis, we demonstrated that the area under the ROC curve of NGAL (0.789) was larger than that of Cys C (0.692). Taken together, we show firstly that urinary Cys C and NGAL levels is abnormally elevated in HSP patients with renal involvement. We suggest that urinary Cys C and NGAL are novel useful biomarkers of renal involvement in HSP patients.

Urinary MCP-1/creatinine in Henoch-Schönlein purpura and its relationship with nephritis.

BACKGROUND: Monocyte chemotactic protein-1 (MCP-1) plays a direct role in the infiltration of macrophages and monocytes during the early stages of Henoch-Schönlein purpura (HSP) nephritis. The aim of this study was to compare the urinary MCP-1/creatinine levels in children with and without HSP nephritis and determine if they are associated with the severity of renal lesions. METHODS: We included 77 patients with HSP and 25 healthy control children. Levels of serum creatinine, urinalysis, and 12-h proteinuria assessments were performed. Urinary MCP-1 levels were determined by ELISA. RESULTS: Fifty-seven patients had nephritis (74 %). Urinary MCP-1/creatinine levels were significantly higher in patients with HSP nephritis (median, 653 pg/mg) compared to those with HSP without nephritis (median, 269 pg/mg) or healthy children (191 pg/mg). In addition, higher MCP-1/creatinine levels were observed in HSP patients who had renal biopsy (median, 1,412 pg/mg) in comparison to HSP patients without renal biopsy (median, 302 pg/mg). The urinary MCP-1 cut-off value of 530 pg/mg could be used to distinguish patients who undergo renal biopsy with a sensitivity of 81 % and specificity of 77 %. CONCLUSIONS: Urinary MCP-1/creatinine levels are elevated in the early stages of severe HSP nephritis and can be used as a biomarker for HSP nephritis.

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.

Henoch schonlein purpura--a 5-year review and proposed pathway.

Henoch Schonlein Purpura (HSP) is the commonest systemic vasculitis of childhood typically presenting with a palpable purpuric rash and frequently involving the renal system. We are the first group to clinically assess, critically analyse and subsequently revise a nurse led monitoring pathway for this condition.A cohort of 102 children presenting with HSP to a secondary/tertiary level UK paediatric hospital over a five year period, were monitored using a nurse led care pathway. Using this cohort, the incidence (6.21 cases per 100,000 children per year) and natural disease course of HSP nephritis (46% initial renal inflammation; 9% subsequent renal referral; 1% renal biopsy and immunosuppression) was determined. Older patients were at higher risk of requiring a renal referral (renal referral 12.3 (8.4-13.5) years vs. normal outcome 6.0 (3.7-8.5) years; p<0.01). A normal urinalysis on day 7 had a 97% (confidence interval 90 to 99%) negative predictive value in predicting a normal renal outcome.Using this data and existing literature base, The Alder Hey Henoch Schonlein Purpura Pathway was developed, a revised pathway for the screening of poor renal outcome in HSP. This is based on a six-month monitoring period for all patients presenting with HSP, which importantly prioritises patients according to the urine findings on day 7 and thus intensively monitors those at higher risk of developing nephritis. The pathway could be easily adapted for use in different settings and resources.The introduction of a standardised pathway for the monitoring of HSP will facilitate the implementation of disease registries to further our understanding of the condition and permit future clinical trials.

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.

Cut-off values for serum matrix metalloproteinase-9: is there a threshold to predict renal involvement for Henoch-Schonlein purpura in children?

AIM: To clarify whether the level of matrix metalloproteinase-9 (MMP-9), tissue inhibitor matrix metalloproteinase-1 (TIMP-1) or the ratio of MMP-9/TIMP-1 was associated with the renal involvement in Henoch-Schonlein purpura (HSP); and to explore whether there existed early diagnostic measure for HSP nephritis (HSPN). METHODS: Sixty-six patients with HSPN, 68 patients with HSP and 60 healthy children (control group) were enrolled into our study. Serum and urine samples before treatment were collected for detection. RESULTS: Compared with the HSP group and control group, serum MMP-9, TIMP-1 and ratio of MMP-9/TIMP-1 in the HSPN group were significantly higher (P<0.05 and P<0.01, respectively). Urine MMP-9, TIMP-1 and ratio of MMP-9/TIMP-1 in the HSPN group were obviously higher than those of the control group (P<0.05) and the HSP group (P<0.05). Receiver-operator curve (ROC) analysis was performed to obtain the area under the curve (AUC) and the AUC and its 95% confidence interval (CI) of serum MMP-9 were 0.97 and 0.95-0.99, respectively. The optimal cut-off point (sensitivity; specificity) of serum MMP-9 for diagnosing HSPN was 179.79 mg/L (0.96; 0.88). CONCLUSION: Levels of MMP-9, TIMP-1 and ratio of MMP-9/TIMP-1 in serum and urine were remarkably high in the patients with HSPN, but the serum MMP-9 was more sensitive. Serum MMP-9 may be associated with the occurrence and development of renal involvement in HSPN and become an important indicator for early diagnosis of HSPN.