Urine IgM excretion predicts outcome in ANCA-associated renal vasculitis

Urinary isomorphic red blood cells for the prediction of disease severity and renal outcomes in MPO-ANCA-associated vasculitis: a retrospective cohort study

BACKGROUND

Hematuria is common in myeloperoxidase anti-neutrophil cytoplasmic antibody associated vasculitis (ANCA-MPO). Previous studies have mainly focused on urinary dysmorphic red blood cells and few have reported the clinical significance of isomorphic urinary red blood cells. Therefore, the main aim of this study was to assess the predictive yield  of urinary isomorphic red blood cells for disease severity and renal outcomes in patients with ANCA-MPO associated vasculitis.

METHODS

A total of 191 patients with ANCA-MPO associated vasculitis with hematuria were retrospectively selected and were divided into two groups (with isomorphic red blood cells versus dysmorphic red blood cells) according to the percentage of isomorphic red blood cells on urinary sediment analysis. Clinical, biological and pathological data at diagnosis were compared. Patients were followed up for a median of 25 months and progression to end-stage kidney disease and death were regarded as main outcome events. Additionally, univariate and multivariate Cox regression models were used to estimate the risk factors for end-stage kidney disease.

RESULTS

Out of 191 patients, 115 (60%) had ≥ 70% and 76 (40%) had < 30% urine isomorphic red blood cells. Compared with patients in the dysmorphic red blood cell group, patients in the isomorphic red blood cell group had a significantly lower estimated glomerular filtration rate (eGFR) [10.41 mL/min (IQR 5.84-17.06) versus 12.53 (6.81-29.26); P = 0.026], higher Birmingham Vasculitis Activity Score [16 (IQR 12-18) versus 14 (10-18); P = 0.005] and more often received plasma exchange [40.0% versus 23.7% (P = 0.019)] at diagnosis. Kidney biopsies revealed a higher proportion of patients with glomerular basement membrane fracture in the isomorphic red blood cell group [46.3% versus 22.9% (P = 0.033)]. Furthermore, patients with predominant urinary isomorphic red blood cells were more likely to progress to end-stage kidney disease [63.5% versus 47.4% (P = 0.028)] and had a higher risk of death [31.3% versus 19.7% (P = 0.077)]. The end-stage kidney disease-free survival was lower in patients in the isomorphic red blood cell group (P = 0.024). However, urine isomorphic red blood cells ≥ 70% could not predict the presence of end-stage kidney disease in multivariate Cox analysis.

CONCLUSION

Myeloperoxidase-anti-neutrophil cytoplasmic antibody associated vasculitis patients with predominant urinary isomorphic red blood cells at diagnosis had more severe clinical manifestations and a higher risk of poor renal outcomes. In this respect, urinary isomorphic red blood cells could be viewed as a promising biomarker of ANCA_MPO vasculitis severity and progression.

Analysis of the risk factors for end‑stage renal disease and mortality in ANCA-associated vasculitis: a study from a single center of the Chinese Rheumatism Data Center

OBJECTIVE

The purpose of this study was to describe the clinical features of AAV and identify possible risk factors for end-stage renal disease (ESRD) and mortality in AAV based on the experience of a single center in China.

METHODS

A prospective cohort study of AAV was conducted based on data acquired by the Chinese Rheumatism Data Center (CRDC). The cohort involved 140 patients diagnosed with AAV in the Second Affiliated Hospital of Nanchang University from January 2013 to April 2022. Clinical characteristics and prognostic data were prospectively collected. The patients were divided into an ESRD group and a non-ESRD group, a death group and a survival group, Then, univariate and multivariate COX regression models were used to determine the risk factors associated with ESRD and mortality by AAV.

RESULTS

Multivariate Cox regression results showed that high initial serum creatinine (hazard ratio (HR) = 1.001, 95% confidence interval (CI): 1.000-1.002, P = 0.024), high initial Birmingham vasculitis activity score (BVAS) (HR = 1.081, 95% CI: 1.027-1.138, P = 0.003), and the need for dialysis treatment (HR = 4.918, 95% CI: 1.727-14.000, P = 0.003) were independent risk factors for the progression of ESRD in AAV patients. Multivariate Cox regression results showed that alveolar hemorrhage (HR = 3.846, 95% CI: 1.235-11.973, P = 0.020), interstitial lung disease (HR = 4.818, 95% CI: 1.788-12.982, P = 0.002), and low initial estimated glomerular filtration rate (EGFR) (HR = 0.981, 95% CI: 0.968-0.995, P = 0.009) were independent risk factors for the prediction of death in AAV patients.

CONCLUSION

These findings suggest that high initial serum creatinine, a high initial BVAS score, and the need for dialysis were independent risk factors for the progression of ESRD in AAV patients. Alveolar hemorrhage, interstitial lung disease, and low initial EGFR were independent risk factors for death. Key Points • The risk factors for ESRD in AAV determined in this study are high initial serum creatinine, a high initial BVAS score, and the need for dialysis. • The risk factors for mortality in AAV are alveolar hemorrhage, interstitial lung disease, and low initial EGFR.

Consideration of Therapeutic Plasma Exchange in Association With Inflammatory Lesions in ANCA-Associated Glomerulonephritis: A Real-World Retrospective Study From a Single Center

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a systemic vasculitis, most frequently presenting as microscopic polyangiitis (MPA) or granulomatosis with polyangiitis (GPA). Pathogenic ANCAs trigger a deleterious immune response resulting in pauci-immune necrotizing and crescentic glomerulonephritis (GN). Standard therapeutical regimens include aggressive immunosuppressive therapy. Since some patients require renal replacement therapy (RRT) despite intensive immunosuppressive therapy, additional therapeutic plasma exchange (PEX) to deplete pathogenic ANCAs has been recommended but its value has recently been questioned. Because therapeutic decision making is crucial in these critically ill patients, we here aimed to identify inflammatory lesions in association with PEX consideration in a retrospective study from a single center tertiary hospital in a real-world population of 46 patients with severe AAV requiring intensive care treatment. The decision to consider PEX was more likely in patients with need for intensive care treatment and severe renal dysfunction. In contrast, short-term outcomes did not depend on clinical, or laboratory characteristics assessed at admission. Histopathological analysis confirmed active disease reflected by increased glomerular necrosis and crescents, but these histopathological findings did not associate with short-term outcome either. Interestingly, only increased global glomerular sclerosis in renal biopsies associated with a detrimental short-term outcome. In conclusion, our study investigated determinants for the consideration of therapeutic PEX in patients with severe AAV requiring intensive care treatment. This aspect underscores the need for renal biopsy and requires further investigation in a prospective controlled setting for therapeutic decision making especially in patients with severe AAV requiring intensive care treatment, especially important for treating intensivists.

The risk factors for early mortality and end-stage renal disease in anti-neutrophil cytoplasmic antibody-associated glomerulonephritis: experiences from a single center

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a common disease with high mortality. Kidney involvement in AAV commonly performances as ANCA-associated glomerulonephritis (AAGN). We aimed to identify the risk factors for mortality and end-stage renal disease(ESRD) within 6 months since diagnosis in AAGN patients. A total of 350 AAGN patients were enrolled in our center between 2004 and 2017 retrospectively. We analyzed the demographic, clinical and follow-up data. Factors for mortality and ESRD were investigated with univariate and multivariate Cox regression models. The median follow-up time was 60.8 (IQR 31.2, 84.5) months and 40 (11.4%) patients died within the first 6 months. In the multivariate analysis, age ≥ 65 years (HR = 2.245, 95%CI 1.085-4.645, P = 0.029), high leukocyte counts (HR = 1.089, 95%CI 1.015-1.168, P = 0.018), high Birmingham Vasculitis Activity Score (BVAS) (HR = 1.089, 95%CI 1.017-1.165, P = 0.014), infection (HR = 2.023, 95%CI 1.013-4.042, P = 0.046) and low serum albumin (HR = 0.916, 95%CI 0.845-0.992, P = 0.030) were independent risk factors for all-cause mortality in the first 6 months. A total of 95 patients reached ESRD within the first 6 months. The renal survival rate was 72.9% at 6 months. Multivariate analysis showed that high BVAS (HR = 1.198, 95%CI 1.043-1.376, P = 0.011), high daily urine protein (HR = 1.316, 95%CI 1.046-1.656, P = 0.019) and low eGFR (HR = 0.877, 95%CI 0.804-0.957, P = 0.003) were independent risk factors for ESRD. The mortality and ESRD rates were high in the first 6 months for AAGN patients. High disease activity evaluated by BVAS impacted both on patients' survival and renal survival, while over 65 years of age and infection were risk factors for mortality.

Mass spectrometry-based proteomic exploration of the small urinary extracellular vesicles in ANCA-associated vasculitis in comparison with total urine

ANCA-associated vasculitis (AAV) is a rare, but potentially severe autoimmune disease, even nowadays displaying increased mortality and morbidity. Finding early biomarkers of activity and prognosis is thus very important. Small extracellular vesicles (EVs) isolated from urine can be considered as a non-invasive source of biomarkers. We evaluated several protocols for urinary EV isolation. To eliminate contaminating non-vesicular proteins due to AAV associated proteinuria we used proteinase K treatment. We investigated the differences in proteomes of small EVs of patients with AAV compared to healthy controls by label-free LC-MS/MS. In parallel, we performed an analogous proteomic analysis of urine samples from identical patients. The study results showed significant differences and similarities in both EV and urine proteome, the latter one being highly affected by proteinuria. Using bioinformatics tools we explored differentially changed proteins and their related pathways with a focus on the pathophysiology of AAV. Our findings indicate significant regulation of Golgi enzymes, such as MAN1A1, which can be involved in T cell activation by N-glycans glycosylation and may thus play a key role in pathogenesis and diagnosis of AAV. SIGNIFICANCE: The present study explores for the first time the changes in proteomes of small extracellular vesicles and urine of patients with renal ANCA-associated vasculitis compared to healthy controls by label-free LC-MS/MS. Isolation of vesicles from proteinuric urine samples has been modified to minimize contamination by plasma proteins and to reduce co-isolation of extraluminal proteins. Differentially changed proteins and their related pathways with a role in the pathophysiology of AAV were described and discussed. The results could be helpful for the research of potential biomarkers in renal vasculitis associated with ANCA.

Patterns of urinary albumin and IgM associate with markers of vascular ageing in young to middle-aged individuals in the Malmö offspring study

BACKGROUND

Increased urinary excretion of IgM and low-grade albuminuria are associated with increased risk of cardiovascular morbidity and mortality. The objective of this study was to investigate the association between urinary IgM, albuminuria, and vascular parameters reflecting arterial structure and function.

METHODS

Subjects of the present study were from the Malmö Offspring study (MOS) cohort, and included 1531 offspring (children and grand-children) to first-generation subjects that participated in the Malmö Diet Cancer-Cardiovascular Arm study cohort. At baseline, technical measurements of arterial stiffness (carotid-femoral pulse wave velocity; c-f PWV), carotid arterial morphology, 24-h ambulatory blood pressure recordings, ankle-brachial-index (ABI), and evaluation of endothelial function (reactive hyperemia index, RHI) were performed. Urinary (U) IgM, U-albumin, and U-creatinine were measured. Multivariate adjusted logistic regression was used to test whether U-IgM excretion and increasing urinary albumin excretion were related to vascular parameters.

RESULTS

Detectable U-IgM was independently associated with higher systolic blood pressure, odds ratio (OR) 1.021, 95% confidence interval (CI, 1.003-1.039), p = 0.025 and lower ABI; ABI dx: OR 0.026, 95% CI (0.002-0.381), p = 0.008, ABI sin: OR 0.040, 95% CI (0.003-0.496), p = 0.012. Low-grade albuminuria was independently associated with systolic and diastolic blood pressure, aortic blood pressure, the c-f PWV and the number of carotid intima plaques (p < 0.05).

CONCLUSIONS

In young to middle-aged, mostly healthy individuals, increased U-IgM excretion and low-grade albuminuria are associated with adverse vascular parameters. Increased U-IgM excretion may reflect subclinical peripheral atherosclerosis, whereas increased U-albumin excretion is associated with a wide range of cardiovascular abnormalities. This may reflect different pathophysiological mechanisms.

Urinary IgM excretion: a reliable marker for adverse pregnancy outcomes in women with chronic kidney disease

Objective

Chronic kidney disease (CKD) pregnancies are at high risk of developing adverse outcomes. In non-pregnant subjects with CKD, higher urinary IgM levels are associated with poor renal survival and higher rates of cardiovascular deaths. In this study, we assessed whether urinary IgM levels are associated with an increased risk of adverse pregnancy outcomes (APO) in CKD pregnancies.

Methods

We performed a nested case–control study within a cohort of CKD patients with singleton pregnancies attended at a tertiary care hospital. The study included 90 CKD patients who eventually developed one or more APO and 77 CKD patients who did not. Urinary IgM excretion was determined from the 24-h urine samples at enrollment by an ultrasensitive enzyme immunoassay.

Results

The risk for combined APO and for preeclampsia (PE) was higher among women with urinary IgM and proteinuria levels values in the highest quartile or with CKD stages 4–5 (odds ratios, OR ≥ 2.9), compared with the lowest quartile or with CKD stage 1. Urinary IgM levels were more closely associated with the risk of either combined or specific APO (PE, preterm birth, and for having a small-for-gestational-age infant; OR ≥ 5.9) than either the degree of total proteinuria or CKD stages. Among patients with CKD stage 1, the risk of combined APO, PE, and preterm birth was higher in women with urinary IgM levels values in the highest quartile (OR ≥ 4.8), compared with the three lower quartiles, independently of proteinuria.

Conclusion

In CKD pregnancies, at the time of initial evaluation, proteinuria and CKD stage are associated with increased risk of combined APO. However, urinary IgM concentrations appear to be better predictors of an adverse outcome and may be useful for risk stratification in CKD pregnancies.

Urinary N-acetyl-β-glucosaminidase and estimated Glomerular filtration rate may identify patients to be treated with immuno-suppression at diagnosis in idiopathic membranous nephropathy

AIM

The clinical course of idiopathic membranous nephropathy (IMN) varies from spontaneous remission of nephrotic syndrome (NS) to end-stage renal disease (ESRD). The aim of the study was baseline identification of patients with high risk of progression for which immunosuppressive therapy is mandatory.

METHODS

Eighty-six IMN subjects were followed for a median of 69 months (range 6-253). Receiver operating characteristic curve and Cox proportional hazards model were used to evaluate prognostic factors for progression, defined as ESRD or estimated glomerular filtration rate (eGFR) reduction ≥50% of baseline.

RESULTS

Among all, 24 subjects had progression. Area under the ROC curve of N-acetyl-β-glucosaminidase/creatinine ratio (NAG/C) were significantly higher than proteinuria/24 h (0.770 and 0.637 respectively, P = 0.018). In Cox proportional hazards regression analysis, NAG/C and eGFR were independent predictors of progression. Compared to lowest tertile of NAG/C (<9.4 UI/gC) or highest tertile of eGFR (≥88 mL/min per 1.73m² ), the multivariable-adjusted hazard ratio of highest tertile of NAG/C (≥19.2) was 18.97 (95%CI, 1.70-211.86) and lowest tertile of eGFR (<59) was 11.58 (95%CI, 2.02-66.29). Subjects with high NAG/C or low eGFR (high-risk, n = 43) had greater progression rate compared to moderate to low NAG/C and high eGFR (low-risk, n = 43) with or without NS at baseline (Log-rank test P = 0.001 and 0.006, respectively). In NS subjects (n = 65), high-risk group progression rate was significantly higher (91% vs. 29%, P = 0.003) and remission rate significantly lower (0% vs. 42%, p < 0.001) in non-immunosuppressed compared to steroids and cyclophosphamide treated patients; no significant differences were observed in low-risk group.

CONCLUSION

Idiopathic membranous nephropathy subjects with high NAG/C and low eGFR have greater risk of progression, and immunosuppressive treatment is suggested at diagnosis.

Monocyte Chemoattractant Protein-1 in Antineutrophil Cytoplasmic Autoantibody-Associated Vasculitis: Biomarker Potential and Association with Polymorphisms in the MCP-1 and the CC Chemokine Receptor-2 Gene

Antineutrophil cytoplasmic autoantibody- (ANCA-) associated vasculitis (AAV) are relapsing-remitting disorders with unpredictable prognosis. There is a need of biomarkers for distinguishing which patients will have a more severe outcome and also for predicting relapses in disease activity. This study confirms the previous results of urinary MCP-1 (uMCP-1) as a prognostic marker and explores its potential as a marker of disease activity. Method. 114 patients with AAV were followed regularly between 2002 and 2011 at Skåne University Hospital. Urine samples, blood samples, and clinical status were registered. The urine samples were analyzed in an in-house-developed ELISA. PCR-RLFP was used to analyze the MCP-1 and CCR2 genes. Results. Patients with severe prognosis had significantly higher levels of uMCP-1 compared to patients with nonsevere prognosis and healthy controls. Patients with renal damage had higher levels compared to patients who did not have renal damage. There was also a tendency of higher uMCP-1 levels in active disease as compared to remission. AA in the -2518 position in the MCP-1 gene was associated with a more severe outcome compared to the A/G or the G/G genotype. The A/A genotype were also associated with higher levels of uMCP-1. No significant associations were seen for the CCR2-V64I. Conclusion. This study confirmed the connection between high uMCP-1 levels and poor prognosis and also disease activity. It also suggests an association of the A/A genotype at position -2518 in the MCP-1 gene and poor prognosis in AAV. uMCP-1 is clearly a candidate biomarker of potential clinical value. The A/A genotype association needs further evaluation.

Simple, readily available clinical indices predict early and late mortality among patients with ANCA-associated vasculitis

Background

The early identification of patients with ANCA-associated vasculitis (AAV) who are at increased risk for inferior clinical outcome at the time of diagnosis might help to optimize the immunosuppressive therapy. In this study we wanted to determine the predictive value of simple clinical characteristics, which may be applicable for early risk-stratification of patients with AAV.

Methods

We retrospectively analyzed the outcome of 101 consecutive patients with AAV receiving a protocolized immunosuppressive therapy. Baseline Birmingham Vasculitis Activity Score (BVAS) and non-vasculitic comorbidities were computed, then predictors of early (<90 days) and late (>90 days) mortality, infectious death, relapse and end stage kidney disease (ESKD) were evaluated.

Results

The baseline comorbidity score independently predicted early mortality (HR 1.622, CI 1.006–2.614), and showed association with infectious mortality (HR 2.056, CI 1.247–3.392). Patients with BVAS at or above median (=21) had worse early mortality in univariable analysis (HR 3.57, CI 1.039–12.243) (p = 0.031), and had more frequent relapses (p = 0.01) compared to patients with BVAS below median.

Conclusions

Assessing baseline comorbidities, beside clinical indices characterizing the severity and extension of AAV, might help clinicians in risk-stratification of patients. Future prospective studies are needed to investigate whether therapies based on risk-stratification could improve both short term and long term survival.

Plasma pro-inflammatory cytokines, IgM-uria and cardiovascular events in patients with chest pain: A comparative study

BACKGROUND

Risk stratification of patients presenting with acute chest pain is crucial for immediate and long-term management. Traditional predictors are suboptimal; therefore inflammatory biomarkers are studied for clinical assessment of patients at risk. Recently, we reported the association of IgM-uria with worse cardiovascular outcome in patients with acute chest pain. In this study, in the same cohort of patients with chest pain, we compared the value of IgM-uria to pro-inflammatory cytokines in predicting the occurrence of subsequent cardiovascular events.

METHODS

A total of 178 consecutive patients presenting with acute chest pain to the emergency department at the University Hospital of Lund, were recruited. Twenty-seven of 57 patients with acute coronary syndrome (ACS), and 18 of 118 patients with non-specific chest pain at baseline developed a subsequent major cardiovascular event during the 18 months follow-up. Urinary proteins (IgM-uria and Microalbuminuria) and plasma inflammatory markers (IL-6, Il-8, IL-10, IFN-γ and TNF-α) were measured at time of admission.

RESULTS

Using the receiver operating characteristic curves, the area under the curve for predicting cardiovascular events was 0.71 (95%CI 0.61-0.81) for IgM-uria, 0.61 (95%CI 0.51-0.71) for IL-6, 0.63 (95%CI 0.53-0.72) for IL-8, 0.65 (95%CI 0.56-0.74) for IL-10, and 0.64 (95% CI 0.54-0.74) for TNF-α. In multivariate Cox-regression analysis adjusted for age, microalbuminuria, IgM-uria, IL-10, TNF-α, troponin T, hsCRP and ACS at baseline; IgM-uria was the only biomarker that remained an independent predictor of outcome (HR = 4.2, 95%CI 2.2-7.8, p < 0.001).

CONCLUSION

In patients with chest pain with or without acute coronary syndrome, IgM-uria could better predict the occurrence of cardiovascular events than plasma pro-inflammatory cytokines.

ANCA positive crescentic glomerulonephritis outcome in a Central East European cohort: a retrospective study

BACKGROUND

The recently suggested distinct pathogenic pathways for myeloperoxidase (MPO) and proteinase 3 (PR3) anti-neutrophilic cytoplasmic antibodies (ANCA) associated vasculitis could result in different modes of presentation and outcome. Moreover, kidney outcome was related to a new histopathologic classification of pauci-immune glomerulonephritis. As reports were not always concordant, possible because differences in severity of organ lesions and ethnicity, we evaluated the outcome of a cohort of Central-East European patients with crescentic glomerulonephritis in relation with ANCA specificity and histopathological classification.

METHODS

Seventy-five patients were consecutively diagnosed by kidney biopsy (76 % MPO-ANCA specificity, 52 % crescentic) and followed for a median period of 3.2 years. Study end-points were response to therapy, end stage renal disease (ESRD) and death.

RESULTS

PR3-ANCA patients were younger, in higher proportion male and had higher Birmingham Vasculitis Activity Scores (BVAS). The kidney disease was severe at presentation (median creatinine 5 mg/dL; 27 % required temporary dialysis) and worst in PR3-ANCA positive patients (50 % patients needed temporary dialysis vs. 19 %). The lung was the second most affected organ (31 % severe lung hemorrhage). Lung and kidney damage were related; the odds of hemorrhagic alveolitis in patients needing dialysis at presentation were 4 (95 % CI 1-13; p = 0.006) times higher than in those who did not. The rate of response to therapy (without signs of active vasculitis and stable or declining serum creatinine) was 60 % and was associated with dialysis independency, older age and higher platelet number at presentation. The probabilities to survival 1 and 5 years for kidney and patient were 93 and 64 %, and respectively 88 and 67 %. Kidney survival was predicted by response to therapy and dialysis independency at presentation. Patients with BVAS < 15 and responding to induction therapy had better chances of survival. Neither response to therapy nor outcome was influenced by ANCA specificity or by the histopathological class.

CONCLUSIONS

When kidney damage is severe in ANCA vasculitis, the need of dialysis at presentation and the response to induction therapy overcome the prognostic utility of both ANCA specificity and histopathological class.

Tubular reabsorption of high, middle and low molecular weight proteins according to the tubulo-interstitial damage marker N-acetyl-β-D-glucosaminidase in glomerulonephritis

BACKGROUND

Proteinuria, the hallmark of glomerular diseases, is an independent predictor of end-stage renal disease (ESRD) progression. Proteinuria is a mixture of proteins of different molecular weight (MW) dependent on alterations of glomerular filtration barrier (GFB) and reabsorption impairment by proximal tubular epithelial cells (PTECs). We aimed to evaluate the excretion of different-MW proteins according to the tubulo-interstitial damage marker N-acetyl-β-D-glucosaminidase (NAG) in glomerulonephritides (GNs).

METHODS

In 189 patients [idiopathic membranous nephropathy (IMN) n = 84, primary focal segmental glomerulosclerosis (FSGS) n = 48, crescentic IgA nephropathy (CIgAN) n = 37, minimal change disease (MCD) n = 20] several urinary proteins were measured at biopsy: α2-macroglobulin/creatinine ratio; fractional excretion of IgG, transferrin, albumin and α1-microglobulin, and the NAG/creatinine ratio divided by estimated glomerular filtration rate (eGFR) (NAG/C/eGFR), as NAG excretion is dependent on functioning nephron mass. Protein excretion was compared between 4th vs. 1st quartile of NAG/C/eGFR.

RESULTS

In IMN, FSGS and CIgAN high-MW proteins excretion (α2-macroglobulin, IgG) was greater than that of middle- (transferrin, albumin) and low-MW proteins (α1-microglobulin) in 4th vs. 1st quartile of NAG/C/eGFR; the mean fold excretion increase of high-MW proteins in 3 GNs was 74.9, higher than that of middle- (34.8) and low-MW proteins (12.0). Higher excretion of high-MW proteins may be dependent on lower reabsorption by PTECs. By contrast, in MCD the difference in excretion of different-MW proteins is probably due to high GFB selectivity.

CONCLUSION

High-MW protein excretion is dependent on GFB alteration and reduced reabsorption; its prognostic significance is ominous because in several glomerular diseases progression is associated with high-MW protein excretion.

Urinary Smad1 is a new biomarker for diagnosis and evaluating the severity of diabetic nephropathy

The aim of this study was to analyze urinary Smad1 level in patients with type 2 diabetes, explore the possibility of Smad1 being a biomarker for early diagnosis and evaluation of severity of diabetic nephropathy, and explore the impact factors affecting urinary Smad1 concentration. In this study, 132 subjects with type 2 diabetes and 50 healthy volunteers were enrolled. Subjects were grouped according to urine albumin to creatinine ratio (ACR) into: normal albumin in urine (NAU), low albumin in urine (LAU), high albumin in urine (HAU), and very high albumin in urine (VHAU). Among those, LAU, HAU, and VHAU were regarded as the diabetic nephropathy group (DN group), NAU was regarded as nondiabetic nephropathy (non-DN group), and the healthy volunteers were the controls. Enzyme-linked immunosorbent assay was used to detect the urinary Smad1 concentration, urinary Smad1 to creatinine ratio (SCR) was used as the standard reference. Compared with non-DN group, SCR of DN group was higher (P < 0.05), while there was no difference between the non-DN group and controls (P > 0.05). There was no significant difference for SCR between LAU and NAU groups (P > 0.05). The SCR was higher in VHAU group than those in HAU and LAU groups, and higher in HAU than that in LAU group (P < 0.05). Pearson correlation analysis showed that SCR measures were positively correlated to ACR, duration and diabetic retinopathy of the disease (r = 0.285, 0.230, 0.202; P = 0.001, 0.008, 0.019, respectively). Multiple linear regression analysis showed that ACR and duration were independent impact factors for SCR (P < 0.05). This is the first known study examining the correlation of Smad1 and DN in clinical practice. It suggested that the urinary Smad1 may be a potential diagnostic parameter for DN and may be used to evaluate the severity of DN. However, it cannot predict those in patients with the earliest DN and low urine albumin concentration. Furthermore, ACR and duration may be independent impact factors for urinary Smad1.

Urinary immunoglobulin G to albumin ratio and N-Acetyl-Beta-D-Glucosaminidase as early predictors of therapeutic response in ANCA-associated glomerulonephritis

Background

The aim of our study was to evaluate the prognostic value of glomerular and tubular proteinuria and tubular enzymuria as early indicators of therapeutic response to induction therapy with i.v. pulse cyclophosphamide (CyC) and methylprednisolone (MP) in patients with antineutrophil cytoplasmic antibody (ANCA) associated glomerulonephritis.

Methods and Findings

An observational single-center study was conducted in 30 patients with ANCA-associated glomerulonephritis. Patients were divided into subgroups with good or poor response to CyC therapy according to clinical and laboratory parameters. The diagnosis of ANCA-associated glomerulonephritis was based on the Chapel-Hill disease definitions. Good response to induction therapy was significantly associated with higher absolute values of urine N-acetyl-beta-D-glucosaminidase (NAG) to creatinine ratio (above 14.83 microcat/mol) and urine immunoglobulin G (IgG) to albumin ratio (above 0.09) at the time of diagnosis, while albuminuria or proteinuria did not have any early predictive value. The remission of renal disease was anticipated as early as 3 months after introduction of induction therapy in patients with reduction of urine NAG to creatinine ratio below the baseline value and in patients with at least 24% rise in eGFR.

Conclusions

Urine IgG to albumin and urine NAG to creatinine ratio are better early predictors of treatment response in patients with ANCA-associated glomerulonephritis than proteinuria or albuminuria.

Increased urinary IgM excretion in patients with chest pain due to coronary artery disease

BACKGROUND

Micro-albuminuria is a recognized predictor of cardiovascular morbidity and mortality in patients with coronary artery disease. We have previously reported, in diabetic and non-diabetic patients, that an increased urinary excretion of IgM is associated with higher cardiovascular mortality. The purpose of this study was to investigate the pattern of urinary IgM excretion in patients with acute coronary syndrome (ACS) and its correlation to cardiovascular outcome.

METHODS

Urine albumin, and IgM to creatinine concentration ratios were determined in 178 consecutive patients presenting with chest pain to the Department of Emergency Medicine (ED) at the University Hospital of Lund. Fifty eight (23 female) patients had ACS, 55 (19 female) patients had stable angina (SA), and 65 (35 female) patients were diagnosed as non-specific chest pain (NS).

RESULTS

Urine albumin and IgM excretions were significantly higher in patients with ACS (p = 0.001, and p = 0.029, respectively) compared to patients with NS-chest pain. During the 2 years follow-up time, 40 (19 female) patients suffered a new major cardiovascular event (ACS, acute heart failure, stroke) and 5 (4 male/1 female) patients died of cardiovascular cause. A high degree of albuminuria and IgM-uria significantly predicted cardiovascular mortality and morbidity (HR = 2.89, 95% CI: 1.48 - 5.66, p = 0.002). Microalbuminuric patients (≥3 mg/mmol) with high IgM-uria (≥0.005 mg/mmol) had a 3-fold higher risk for cardiovascular new events compared to patients with low IgM-uria (RR = 3.3, 95% CI: 1.1 - 9.9, p = 0.001).

CONCLUSION

In patients with chest pain, an increased urine IgM excretion, is associated with coronary artery disease and long-term cardiovascular complications. Measuring urine IgM concentration could have a clinical value in risk stratification of patients with ACS.

Urinary IgG and α2-macroglobulin are powerful predictors of outcome and responsiveness to steroids and cyclophosphamide in idiopathic focal segmental glomerulosclerosis with nephrotic syndrome

Objective. To assess whether high-molecular-weight proteins excretion predicts outcome and therapy-responsiveness in patients with FSGS and nephrotic syndrome. Research Design and Methods. Thirty-eight patients measured at biopsy fractional excretion of IgG (FEIgG) and urinary α2-macroglobulin/creatinine ratio (α2m/C). Low and high risk groups were defined by cutoffs assessed by ROC analysis. In all patients first-line therapy was with steroids alone or in combination with cyclophosphamide. Results. α2m/C and FEIgG were correlated with segmental sclerosis (r = 0.546; r = 0.522). Twenty-three patients (61%) entered Remission and 9 (24%) progressed to ESRD. Comparing low and high risk groups, by univariate analysis remission was predicted by FEIgG (77% versus 25%, P = 0.016) and α2m/C (81% versus 17%, P = 0.007) and ESRD at best by FEIgG (0% versus 75%, P < 0.0001) and α2m/C (4% versus 67%, P < 0.0001). By multivariate analysis FEIgG was the only independent predictor of remission and α2m/C the most powerful predictor of ESRD. Low and high risk groups of FEIgG and α2m/C in combination had very high predictive value of sustained remission and ESRD in response to therapy. Conclusions. FEIgG and α2m/C are powerful predictors of outcome and responsiveness to steroids and cyclophosphamide; their predictive value, if validated in prospective studies, may be useful in clinical practice suggesting first-line alternative treatments in high risk patients.

Urine high and low molecular weight proteins one-year post-kidney transplant: relationship to histology and graft survival

Increased urinary protein excretion is common after renal transplantation and portends worse outcome. In this study we assessed the prognostic contribution of several urinary proteins. Urinary total protein, albumin, retinol binding protein (RBP), α-1-microglobulin, IgG and IgM were measured in banked urine samples from 221 individuals 1 year after renal transplantation (age 52 ± 13 years, 55% male, 93% Caucasian and 82% living donor). Levels of all proteins measured were higher than in normal nontransplant populations. Patients with glomerular lesions had higher urinary albumin than those with normal histology, while those with interstitial fibrosis and tubular atrophy plus inflammation (ci>0, cg = 0, i>0) had higher levels of IgG, IgM, α-1-microglobulin and RBP. Concomitant normal levels of urinary albumin, IgM and RBP identified normal histology (specificity 91%, sensitivity 15%,). Urinary levels of the specific proteins were highly correlated, could not differentiate among the histologic groups, and appeared to result from tubulointerstitial damage. Increased urinary excretion of the low molecular weight protein RBP was a sensitive marker of allografts at risk, predicting long-term graft loss independent of histology and urinary albumin. This study highlights the prognostic importance of tubulointerstitial disease for long-term graft loss.

Urinary markers of glomerular injury in diabetic nephropathy

Diabetic nephropathy, the leading cause of renal failure worldwide, affects approximately one-third of all people with diabetes. Microalbuminuria is considered the first sign and the best predictor of progression to renal failure and cardiovascular events. However, albuminuria has several limitations. Therefore, earlier, more sensitive and specific biomarkers with greater predictability are needed. The aim of this paper is to discuss the current literature on biomarkers of glomerular injury that have been implicated in diabetic kidney disease.

Urine IgM-excretion as a prognostic marker for progression of type 2 diabetic nephropathy

Although the clinical manifestations of type 2 diabetic nephropathy and decline in kidney function are similar to those in type 1, the clinical course and the renal structural changes are more heterogeneous in type 2 diabetic patients. Previous studies have shown that an increased urine IgM excretion in patients with type 1 diabetic nephropathy was associated with poor outcome. In the present follow-up study we examine the prognostic value of baseline urine IgM excretion in patients with type 2 diabetes mellitus.

METHODS

A cohort of 106 (74 male and 32 female) patients with type 2 diabetes regularly attending our diabetes out-patient clinic at Skane University Hospital in Lund. They were recruited prospectively under the period between 1992 and 2004. Patients were followed-up until January 2009. The end point was cardiovascular (CV) death or end-stage renal disease (ESRD). The median follow-up time was 5 years (0.5-13 years). Participants were divided according to degree of albuminuria and IgM-uria.

RESULTS

During follow-up time, 28 (19 male and 9 female) patients died of CV events and 41 (26 male and 15 female) developed ESRD. The risk of CV mortality was 2.4 fold, and the risk of renal failure 4.9 fold higher in patients with increased urine IgM excretion compared to patients with low urine IgM excretion. Stratified analysis showed that an increased urine IgM excretion was an independent predictor of renal and cardiovascular death irrespective of the degree of albuminuria (HR=3.6, 95% CI: 2.1-6.0, P<0.001). In conclusion, type 2 diabetic nephropathy patients with high urine IgM excretion rates carry an increased risk of renal and cardiovascular death.

Clinical features and outcome of microscopic polyangiitis under a new consensus algorithm of ANCA-associated vasculitides in Korea

The classification system for antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis and polyarteritis nodosa had its limitations due to numerous overlapping features of these disease entities. The aim of this study is to investigate the clinical features and outcome of patients diagnosed with microscopic polyangiitis (MPA) according to the newly proposed consensus algorithm of ANCA-associated vasculitides and polyarteritis nodosa. Fifty-five cases of MPA, comprised of 33 men and 22 women, diagnosed according to a new consensus algorithm at a single tertiary hospital were identified for analysis. The main clinical features were constitutional symptoms (78.2%), followed by renal involvement (74.5%), musculoskeletal symptoms (67.3%), skin manifestations (50.9%), neurologic involvement (43.6%), and lung involvement (41.8%). P-ANCA and/or anti-myeloperoxidase antibody were present in 69.1%. Five Factor Score and Birmingham Vasculitis Activity Score (BVAS) at diagnosis were 1.1 ± 0.9 and 10.9 ± 4.9, respectively. Forty-four patients were available for a long-term follow-up, and six patients (13.6%) resulted in death. Mortality was associated with BVAS > 9 at the time of diagnosis, age > 60 years, and presence of cardiomyopathy and interstitial lung disease. The survival rate at 1 and 3 years was 93.9 and 89.2%, respectively. Eight patients (14.5%) required dialysis at the time of diagnosis. This is the first study to demonstrate the clinical features in patients with MPA using a new consensus algorithm. Survival rate was higher than previously reported, and interstitial lung disease was a new risk factor for death in patients with MPA.

Overall survival, renal survival and relapse in patients with microscopic polyangiitis: a systematic review of current evidence

OBJECTIVE

There are limited data on the long-term prognosis of microscopic polyangiitis (MPA). A systematic review was performed to estimate the survival, renal survival and relapse rates in patients with MPA.

METHODS

Articles included in MEDLINE and EMBASE databases were reviewed. Randomized or non-randomized trials, cohort, case-control and cases-series studies of patients with MPA diagnosed according to Chapel Hill Consensus Conference definitions, a high rate of biopsy-confirmed diagnosis, follow-up >1 year and follow-up losses <10%. Two independent authors using a predefined questionnaire for evaluating the quality and risk of bias for each study extracted data.

RESULTS

Eighteen studies for MPA prognosis (n = 940) and six for MPA outcomes after transplantation (n = 65) were included. Survival rates were 77-100% at 1 year, 46-80% at 5 years and 60-80% at 10 years. Higher mortality density occurred within the first months after diagnosis. Vasculitis was the cause of death in 32-50% of patients. Relapses were detected in 19-39% of cases (median time to relapse 15-43 months). Renal graft survival was 85-94% at 1 year and 51-87% at 5 years. Age, renal involvement and immunosuppressive treatment were related to mortality. Lower relapse rate was achieved with 12 vs 6 CYC pulses.

CONCLUSION

Evidence regarding MPA prognosis is weak. MPA mortality is mainly concentrated in the first months after diagnosis. Fewer than 50% of deaths are related to MPA activity. MPA long-term prognosis is less severe, although relapses are frequent. End-stage renal failure is a frequent complication of MPA, and renal transplantation could be an effective therapy in these patients. Early diagnosis, early initiation of a tailored therapy according to risk factors and a longer follow-up of the patients are needed.

Review: Serum and urine biomarkers of kidney disease: A pathophysiological perspective

The use of reliable biomarkers is becoming increasingly important for the improved management of patients with acute and chronic kidney diseases. Recent developments have identified a number of novel biomarkers in serum or urine that can determine the potential risk of kidney damage, distinguish different types of renal injury, predict the progression of disease and have the potential to assess the efficacy of therapeutic intervention. Some of these biomarkers can be used independently while others are more beneficial when used in combination with knowledge of other clinical risk factors. Advances in gene expression analysis, chromatography, mass spectrometry and the development of sensitive enzyme-linked immunosorbent assays have facilitated accurate quantification of many biomarkers. This review primarily focuses on describing new and established biomarkers, which identify and measure the various pathophysiological processes that promote kidney disease. It provides an overview of some of the different classes of renal biomarkers that can be assessed in serum/plasma and urine, including markers of renal function, oxidative stress, structural and cellular injury, immune responses and fibrosis. However, it does not explore the current status of these biomarkers in terms of their clinical validation.

The value of IgG-uria in predicting renal failure in idiopathic glomerular diseases. A long-term follow-up study

BACKGROUND

Proteinuria is the hallmark of glomerular disease and non-selective proteinuria is often associated with progression to renal failure. The predictive value of urine IgG excretion was studied comprehensively in patients with nephrotic syndrome. In the present follow-up study, we examine the predictive value of IgG-uria in patients with idiopathic glomerular diseases with a wide range of proteinuia.

METHODS

A total of 189 (113 males and 76 females) patients with idiopathic glomerulonephritis and serum creatinine of less than 150 μmol/L diagnosed between 1993 and 2004 were followed up to their last visit in 2009. Measurement of urine excretion of albumin, IgG, and protein HC were performed in the early morning of spot urine samples collected at the time of the diagnostic renal biopsy. Patients were stratified according to urine protein concentrations and the progression rate to end-stage renal disease (ESRD) calculated using Kaplan-Meier survival analysis. ESRD was defined as the start of renal replacement therapy.

RESULTS

During the study follow-up time of 1429 person-years; 26 (13.8%) patients reached ESRD. The overall mean kidney survival time of studied patients with serum creatinine less than 150 were 13.4 years. The incidence rate of ESRD was ∼18 per 1000 person-years. Stratified analysis identified urinary excretion of IgG, but not albuminuria, as predictor of ESRD. The progression rate to ESRD was 36 per 1000 person-years in patients with urine IgG concentration exceeding 5 mg/mmol urine creatinine, compared to a progression rate of 6/1000 person-years for patients with lower levels of urine IgG.

CONCLUSION

The findings of the study suggest that at early stages, the level of IgG-uria is useful to be used in risk stratification of patients with proteinuric glomerular diseases.

Long-term follow-up of microscopic polyangiitis, 17-year experience at a single center

BACKGROUND

Long-term prognoses of Wegener granulomatosis (WG) and Churg-Strauss syndrome (CSS) are known; however, few data exist on long-term prognoses for microscopic polyangiitis (MPA). Our aim was to analyse the prognoses of MPA.

METHODS

Cohort study with retrospective selection of patients. Twenty-two patients admitted to our Hospital (1990-2006) with biopsy-proven MPA were studied. The start date for entry into the study was the date of diagnosis. Statistical analysis was performed to look for prognostic factors for survival.

RESULTS

MPA patients were followed-up for a median of 78 (5-131) months. MPA patients were treated with cyclophosphamide (Cy) plus corticosteroid (Cs) (59%) or Cs alone (41%). Seven MPA patients died. Cumulative MPA patient survival at 1, 5, and 10 years were 85% (75-95%), 85% (75-95%), and 74% (60-88%) in those treated with Cy plus Cs and 50% (32-68%), 36% (14-58%), and 0% (0-30%) in those treated with Cs alone, respectively (P=0.04). Disease extent index <5 (P=0.02) and age <65 years (P=0.02) were associated with improved survival rates in MPA patients treated with Cy. Five MPA (23%) patients relapsed after a median of 54 months (35-93). No variables were related to relapses. Despite treatment, 11MPA (50%) patients developed end-stage renal disease after a median of 9 months (0-53).

CONCLUSIONS

Most MPA patients had life-threatening renal or lung involvement at diagnosis. Patients not treated with immunosuppressants had a poorer prognosis. The long-term prognosis of MPA patients who survived 6 months post diagnosis was good, although renal survival rates are low.

Serum and Urinary Biomarkers Determination and Their Significance in Diagnosis of Kidney Diseases

Chronic kidney disease (CKD) is becoming a major public health problem worldwide due to the epidemic increase of patients on renal replacement therapy and their high cardiovascular morbidity and mortality. The only effective approach to this problem is prevention and early detection of CKD. In addition, despite significant improvements in therapeutics, the mortality and morbidity associated with acute kidney injury (AKI) remain high. A major reason for this is the lack of early markers for AKI, and hence an unacceptable delay in initiating therapy. Therefore, there is a pressing need to develop biomarkers (proteins and other molecules in the blood or urine) for renal disease, which might assist in diagnosis and prognosis and might provide endpoints for clinical trials of drugs designed to slow the progression of renal insufficiency. Besides serum creatinine, promising novel biomarkers for AKI include a plasma panel (neutrophil gelatinase-associated lipocalin-NGAL and cystatin C) and a urine panel (NGAL, kidney injury molecule-1, interleukin-18, cystatin C, alpha 1-microglobulin, Fetuin-A, Gro-alpha, and meprin). For CKD, these include a similar plasma panel and a urine panel (NGAL, asymmetric dimethylarginine, and liver-type fatty acid-binding protein). Increased plasma and urinary TGF-β1 levels might contribute to the development of chronic tubulointerstitial disease, indicating the possible therapeutic implications. Furthermore, to differentiate lower urinary tract infection and pyelonephritis interleukin-6 and serum procalcitonin levels were introduced. It will be important in future studies to validate the sensitivity and specificity of these biomarker panels in clinical samples from large cohorts and in multiple clinical situations.

Immune response biomarker profiling application on ProtoArray protein microarrays

The development of autoantibodies is observed in autoimmune disorders and numerous cancers. Consequently, autoantibodies form the basis of potential diagnostic and prognostic assays, as well as approaches for monitoring disease progression and treatment response. The effective use of autoantigen biomarkers for these applications, however, is contingent upon the identification of not one but multiple biomarkers. This is a consequence of the observation that the development of autoantibodies to any given protein is typically seen only in a fraction of patients. We have previously demonstrated the utility of functional protein microarrays containing thousands of different human proteins (ProtoArrays) for discovering novel autoimmune biomarkers in serum and plasma. Here, we describe a protocol for detecting autoantibodies in urine.

Incidence and survival rates in Wegener's granulomatosis, microscopic polyangiitis, Churg-Strauss syndrome and polyarteritis nodosa

OBJECTIVE

To estimate the incidence of and survival rates for WG, microscopic polyangiitis (MPA), Churg-Strauss syndrome (CSS) and PAN within a defined population in southern Sweden.

METHODS

Cases were retrieved using hospital records and a serology database. All new cases of WG, MPA, CSS and PAN between 1997 and 2006 were included, provided they met pre-defined criteria, and were followed until 30 June 2008. The study area comprised two health care districts with a total population of 641 000. The standardized mortality ratio (SMR) was estimated using Swedish population data as a reference.

RESULTS

A total of 140 (WG, 63; MPA 65; CSS 6; and PAN 6) cases (52% women) with a median age of 67.6 (range 20-96) years fulfilled the inclusion criteria. The annual incidence per million of the population (95% CI) was estimated to be 9.8 (7.4-12.2) for WG, 10.1 (7.7-12.6) for MPA and 0.9 (0-1.7) for both CSS and PAN. The highest incidence was found in patients aged >or=75 years (79.1/million). The 1- and 5-year survival rates were 87.8 and 71.6% for all patients, but lower for MPA (80 and 55%) compared with WG (95 and 83%; P = 0.001), although the difference was not significant in the multivariate analysis. The SMR was 2.77 (95% CI 2.02, 3.71) for all patients.

CONCLUSIONS

The incidence of WG and MPA was equal in our district, but there was a difference in survival rates related to age and renal function. A progressive increase in age-specific incidence rates was observed.

Increased urine IgM excretion predicts cardiovascular events in patients with type 1 diabetes nephropathy

BACKGROUND

Diabetic nephropathy, a major complication of diabetes, is characterized by progressive renal injury and increased cardiovascular mortality. An increased urinary albumin excretion due dysfunction of the glomerular barrier is an early sign of diabetic nephropathy. An increased urinary excretion of higher molecular weight proteins such as IgM appears with progression of glomerular injury. We aim here to study the prognostic significance of urine IgM excretion in patients with type 1 diabetes mellitus (type 1 diabetic nephropathy).

METHODS

This is an observational study of 139 patients with type 1 diabetes mellitus (79 males and 60 females) under routine care at the diabetic outpatient clinic at the Lund University Hospital. The median follow-up time was 18 years (1 to 22) years. Urine albumin and urine IgM concentration were measured at time of recruitment.

RESULTS

Overall 32 (14 male and 18 female) patients died in a cardiovascular event and 20 (11 male and 9 female) patients reached end-stage renal disease. Univariate analysis indicated that patient survival and renal survival were inversely associated with urine albumin excretion (RR = 2.9 and 5.8, respectively) and urine IgM excretion (RR = 4.6 and 5.7, respectively). Stratified analysis demonstrated that in patients with different degrees of albuminuria, the cardiovascular mortality rate and the incidence of end-stage renal disease was approximately three times higher in patients with increased urine IgM excretion.

CONCLUSION

An increase in urinary IgM excretion in patients with type 1 diabetes is associated with an increased risk for cardiovascular mortality and renal failure, regardless of the degree of albuminuria.

Monocyte chemoattractant protein 1 is a prognostic marker in ANCA-associated small vessel vasculitis

BACKGROUND

The (anti neutrophil cytoplasmatic autoantibody ANCA), associated small vessel vasculitides (ASVV) are relapsing-remitting inflammatory disorders, involving various organs, such as the kidneys. (Monocyte chemoattractant protein 1 MCP-1) has been shown to be locally up regulated in glomerulonephritis and recent studies have pointed out MCP-1 as a promising marker of renal inflammation. Here we measure urinary cytokine levels in different phases of disease, exploring the possible prognostic value of MCP-1, together with (interleukin 6 IL-6), (interleukin 8 IL-8) and (immunoglobulin M IgM).

METHODS

MCP-1, IL-6 and IL-8 were measured using commercially available ELISA kits, whereas IgM in the urine was measured by an in-house ELISA.

RESULTS

The MCP-1 levels in urine were significantly higher in patients in stable phase of the disease, compared with healthy controls. Patients in stable phase, with subsequent adverse events; had significantly higher MCP-1 values than patients who did not. MCP-1 and IgM both tended to be higher in patients relapsing within three months, an observation, however, not reaching statistical significance. Urinary levels of IL-6 correlated with relapse tendency, and IL-8 was associated with disease outcome.

CONCLUSIONS

Patients with ASVV have raised cytokine levels in the urine compared to healthy controls, even during remission. Raised MCP-1 levels are associated with poor prognosis and possibly also with relapse tendency. The association with poor prognosis was stronger for U-MCP-1 than for conventional markers of disease like CRP, BVAS, and ANCA, as well as compared to candidate markers like U-IgM and U-IL-8. We thus consider U-MCP-1 to have promising potential as a prognostic marker in ASVV.

Improved outcome in Wegener's granulomatosis and microscopic polyangiitis? A retrospective analysis of 95 cases in two cohorts

OBJECTIVES

Mortality rates for Wegener's granulomatosis (WG) and microscopic polyangiitis (MPA) have decreased after the introduction of cyclophosphamide. Standardized mortality ratio (SMR) expresses the overall mortality of patients compared with the general population. The aims of this study were to compare survival in an old and a recent cohort of patients with WG and MPA using SMR and to determine predictors for death in both groups combined.

DESIGN

Survival analyses were performed by Kaplan-Meier survival curves, SMR and proportional hazards regression models.

SETTING

The nephrology and rheumatology clinics at Linköping University Hospital, Sweden.

SUBJECTS

All patients diagnosed with WG or MPA in the catchment area during 1978-2005 were divided into two cohorts; patients diagnosed before (n=32, old cohort) and after (n=63, recent cohort) December 31, 1996.

RESULTS

The two cohorts differed regarding the proportion of WG (75% vs. 56%, P=0.03) and a tendency for more pronounced kidney involvement in the old cohort: 266 micromol L(-1) (16% dialysis-dependent) vs. 192 micromol L(-1) (5% dialysis-dependent), but were comparable regarding disease severity. SMR at 1 and 5 years were 2.1 (95% CI: 0.43-6.09) and 1.6 (95% CI: 0.6-3.2) in the recent cohort and 5.2 (95% CI: 1.07-15.14) and 2.5 (95% CI: 0.93-5.52) in the old cohort. Five-year survival was 87% and 81%. Serum creatinine, age, end-stage renal disease, diagnosis before 1997 and first relapse were independent predictors for death.

CONCLUSION

Patient survival in WG and MPA analysed with SMR may be better than previously believed. Severe renal disease and disease relapse were the major predictors of reduced survival.

Local immune response to upper urinary tract infections in children

Vaccines are needed against urinary tract infections (UTIs) in children, as episodes of pyelonephritis (PN) may cause renal scarring. Local immune mechanisms are regarded to confer protection, yet they have been poorly characterized for children. This study explores the local immune response in children by looking for newly activated pathogen-specific antibody-secreting cells (ASC), expected to appear transiently in the circulation as a response to UTI. Urinary tract-originating ASC specific to each patient's own pathogen or P fimbria were studied in 37 children with PN. The children were examined for recidivism and renal scarring in a 6-month follow-up study. Pathogen-specific ASC were found in 33/37 children, with the magnitude increasing with age. In contrast to the case for adults, with immunoglobulin A (IgA) dominance, in 18/33 cases IgM dominated the response, and this occurred more frequently in infants (63%) than in older children (30%). The most vigorous response was found to whole Escherichia coli bacteria (geometric mean, 63 +/- 2,135 ASC/10(6) peripheral blood mononuclear cells [PBMC]), yet responses were found to P fimbriae (13 +/- 33 ASC/10(6) PBMC), too. The response peaked at 1 to 2 weeks and was low/negligible 3 to 7 weeks after the beginning of symptoms. Recidivism was seen in seven patients, and renal scarring was seen in nine patients. In conclusion, a response of circulating ASC was found in children with UTIs, with the magnitude increasing with age. Since IgM is not present in urine, the IgM dominance of the response suggests that systemic immune mechanisms are more important in the immune defense in children than in adults. In 81% of patients, no recidivism was seen, suggesting a successful immune defense.