Oxidative damage of erythrocyte membrane in nephrotic syndrome

 Erythrocytes are target cells for peroxidative damage. Abnormal susceptibility of erythrocyte lipids to peroxidation is believed to reflect a similar abnormality in other organs and tissues. The changes in erythrocyte lipid peroxidation [measured by malonyldialdehyde (MDA) concentration] and erythrocyte membrane cholesterol (EMC) and their correlation with plasma lipid changes were studied in 36 children with steroid-responsive minimal change nephrotic syndrome (MCNS) (16 in relapse, 20 in remission) and 30 matched healthy controls. Erythrocyte MDA levels were significantly higher in relapse [126.3±40.6 nmol/g hemoglobin (Hb)] compared with remission (101.2±21.3 nmol/g Hb, P<0.02) and in controls (95.4±20.4 nmol/g Hb, P<0.001). Plasma MDA levels in relapse were also higher than in remission (4.26±1.19 nmol/ml vs. 3.16±1.18 nmol/ml, P<0.01), and in controls (2.49±0.86 nmol/ml, P<0.001). The EMC content changed significantly during remission (1.22±0.15 mg/10¹⁰ cells in relapse, 1.09±0.19 mg/10¹⁰ cells in remission, P<0.04). These results show an increased sensitivity of red cells to lipid peroxidation in patients with steroid-sensitive nephrotic syndrome without the development of renal failure and anemia. Lipid peroxidation of plasma lipids and erythrocyte membrane may be a primary phenomenon, but this should be confirmed by investigation of peroxidation of renal lipids. Received: 7 January 1998 / Revised: 4 May 1998 / Accepted: 13 August 1998     

Implication of serum IgE in childhood nephrotic syndrome

Elevated serum IgE levels have been related to glomerular diseases. We investigated the relationship between serum total and specific IgE levels and their modulating factors [interleukin-4 (IL-4) and sCD23] and the outcome of childhood nephrotic syndrome (NS) after steroid treatment. We found that children with NS had significantly higher serum IgE levels than age-matched allergic patients and normal controls. Patients with steroid-resistant nephrotic syndrome (SRNS) had higher serum IgE levels than patients with steroid-sensitive nephrotic syndrome (SSNS) both pre and post treatment. Elevated initial serum IgE levels appeared to be associated with poor outcome. Although one-half of nephrotic children had detectable specific IgE to common allergens (dust mites or milk), the presence of specific IgE was not correlated with disease outcome. Serum IL-4 levels were not different among normal controls and patients with SRNS or SSNS. However, serum sCD23 levels in NS patients were significantly higher than in normal controls both pre and post treatment. Serum sCD23, but not IL-4, levels were correlated with serum total IgE levels. Our results suggest that regulation of total IgE production correlates with the disease activity and outcome of NS, although the presence of common specific IgE may not be linked to the pathogenesis.     

High serum adiponectin levels during steroid-responsive nephrotic syndrome relapse

Adiponectin (ADPN), exclusively expressed and secreted from adipocytes, is a recently discovered protein hormone with anti-atherogenic and anti-inflammatory properties in contrast to other well-known adipocytokines. It has independent negative associations with obesity and hyperinsulinemia/insulin resistance. Apart from chronic renal failure, nephrotic syndrome was suggested as the only renal disease condition associated with raised plasma ADPN levels in adults. We aimed to evaluate the effect of nephrotic state on serum adiponectin (ADPN) levels in pediatric patients with steroid-responsive nephrotic syndrome (SRNS) by comparing the levels in relapse and remission as well as in control subjects and documenting possible relationships between ADPN and proteinuria as well as serum protein/lipid parameters. 34 patients with SRNS and 22 healthy age, sex and BMI-matched control subjects were enrolled into the study. 15 of the 34 SRNS patients had active diseases, and these were known as the SRNS-relapse group (ten relapsed and five newly-diagnosed patients), while the remaining 19 were in complete remission (the SRNS-remission group). Serum ADPN levels, blood chemistry (protein/albumin, triglyceride (TG), cholesterol (Cho) and lipoprotein levels) and 24-hour proteinuria were studied. ADPN levels were determined by ELISA. As expectedly, there were significant alterations in serum protein-lipid parameters and 24-hour proteinuria levels in SRNS patients consistent with their disease activity. SRNS-relapse patients had substantially higher ADPN levels (36.77±15.06 (5.61–59.41, median 39.84) g/ml), compared to those in SRNS-remission and control groups (14.17±6.02 (3.28–29.40, median 12.80) g/ml and 11.84±7.53 (2.81–31.46, median 10.85) g/ml, respectively, p=0.001). There were strong positive correlations between serum ADPN levels and Cho (r=0.637, p=0.000), TG (r=0.516, p=0.002), low density lipoprotein (r=0.614, p=0.000) levels and 24-hour proteinuria (r=0.828, p=0.000) levels, whereas protein (r=–0.695, p=0.000) and albumin (r=0.732, p=0.000) levels were inversely correlated with ADPN levels. Regression analysis showed a significant correlation between ADPN and proteinuria (p=0.000). In conclusion, remarkably increased serum ADPN levels were detected in SRNS-relapse compared to those in SRNS-remission. This phenomenon might be the reflection of a compensatory response to nephrotic state characterized by massive proteinuria, hypoalbuminemia and hyperlipidemia.     

Follow-up of steroid-resistant nephrotic syndrome: tubular proteinuria and enzymuria

The aim of this study was to examine the compromise of proximal tubule cells in steroid-resistant nephrotic syndrome patients with a histologic diagnosis of focal segmental glomerulosclerosis (FSGS) through assessment of the urinary levels of β₂-microglobulin (β₂M) and N-acetyl-β-d-glucosaminidase (NAG) during active disease and remission over a follow-up period of 3 years. We studied 34 children with nephrotic syndrome: 12 with steroid-resistant nephrotic syndrome (SRNS) and massive proteinuria, 7 with steroid-dependent nephrotic syndrome (SDNS) and 15 with steroid-sensitive nephrotic syndrome (SSNS). Of the SSNS patients, 8 children were in remission (RM) and 7 were in relapse (RL). Seven healthy children were included as controls. Urinary β₂M, measured by enzyme-linked immunosorbent assay, was significantly increased in the SRNS group as compared to the SDNS group (P<0.01), SSNS in remission (P<0.01), and controls (P<0.01). There were no differences between the SRNS group and SSNS in relapse. Analysis of urinary N-acetyl-β-d-glucosaminidase (U-NAG) by colorimetric assay showed significantly higher values in the SRNS group of patients than in SDNS, SSNS, and control groups. A positive correlation between U-NAG and proteinuria was demonstrated (r=0. 73, P<0.01). The SRNS group of patients (n=12, 11 with a histologic diagnosis of FSGS and one with diffuse mesangial proliferation) was treated with the same protocol of i.v. methylprednisone and oral cyclophosphamide. Long-term follow-up showed a progressive decrease in U-β₂M and U-NAG excretion to control values in the 3rd year, except in one patient who did not respond to the treatment. In the FSGS patients, evaluation of the contribution of structural interstitial histological abnormalities, including each of the histological parameters considered in interstitial scarring to the functional tubule abnormalities assessed by β₂M and NAG excretion, was performed by multiple regression analysis. The r ² values for β₂M and NAG were 53.99%, P=0.19, and 57.90%, P=0.14, respectively; neither was significant. We conclude that: (1) proximal tubule cell dysfunction, partially affected by massive albuminuria, may account for the higher values of β₂M and NAG excretion in the SRNS patients and (2) urine β₂M and NAG levels are not helpful in identifying histological evidence of structural tubulointerstitial damage in children with steroid-resistant nephrotic syndrome. Received: 28 December 1999 / Revised: 20 July 2000 / Accepted: 21 July 2000     

Serum IgE in primary glomerular diseases and its clinical significance

Total serum IgE was measured in 119 cases of primary glomerular diseases and 33 normal healthy persons. Statistically significant higher levels were noted in minimal change disease (MCD; median: 630 U/ml), IgM nephropathy (IgMN; 618 U/ml), focal glomerulosclerosis (FGS; 373 U/ml) and membranous glomerulonephritis (MGN; 144 U/ml). A higher level of serum IgE was noted in association with more frequent relapse or steroid resistance in MCD and IgMN and in FGS with nephrotic syndrome. A small group of IgA nephropathy with nephrotic range proteinuria was also noted to have extraordinarily high serum IgE. These findings suggest that IgE may play an important role in the pathogenesis of MCD, IgMN, and FGS and may serve as a prognostic indicator in terms of steroid responsiveness in MCD and IgMN.     

Urinary <Emphasis Type="Italic">N</Emphasis>-acetyl-beta-<Emphasis Type="SmallCaps">D</Emphasis> glucosaminidase (NAG) level in idiopathic nephrotic syndrome

Urinary N-acetyl-beta-D glucosaminidase (NAG) is a sensitive biomarker of renal parenchymal disease. The aim of this study was to investigate variations in the levels of NAG excretion among different sub-groups of nephrotic syndrome (first episode, relapsers, and resistant) and its prediction based on proteinuria. Thirty-five patients with idiopathic nephrotic syndrome, aged 1–12 years, as well as 15 age- and gender-matched normal children (controls) were enrolled in the study. Among the 35 patients, ten were classified with first episode nephrotic syndrome (FENS), 17 with relapsing nephrotic syndrome (RNS), and eight with steroid-resistant nephrotic syndrome (SRNS). Urinary NAG/creatinine levels were significantly increased in SRNS patients as compared to FENS and RNS patients (p < 0.001); the FENS and RNS groups had comparable levels. A urinary NAG/creatinine value of ≤108.9 U/g was found to identify steroid-sensitive patients with a sensitivity, specificity, positive predictive value, and negative predictive value of 78.8, 100, 100 and 77.7%, respectively. Significant correlations were found between experimental and predicted values of urinary NAG/creatinine in steroid sensitive nephrotic syndrome (SSNS) (R ² = 0.9643) and SRNS patients (R ² = 0.9823). Urinary NAG/creatinine values were found to be higher in SRNS than SSNS patients and have moderate predictive value for steroid responsiveness. This level can be obtained based on urinary protein/creatinine ratio or 24 h urinary protein levels.     

Hearing status in children with frequently relapsing and steroid resistant nephrotic syndrome

Background

Children with idiopathic nephrotic syndrome (INS) are at risk of hearing impairment due to nephrotoxic drugs and biochemical impairments.

Methods

Forty children with INS aged 5–16 years [20 patients with frequently relapsing nephrotic syndrome (FRNS)/steroid dependent nephrotic syndrome (SDNS) and 20 with steroid resistant nephrotic syndrome (SRNS)] and 20 normal healthy controls were enrolled in this study. Pure tone audiometry was done using the ALPS AD 2000 audiometer. Sensorineural hearing loss was diagnosed when the bone conduction level was >20 dB and the difference in air to bone gap was ≤15 dB. Based on the air conduction (AC) threshold, deafness was graded into the following categories: mild (26–40 dB), moderate (41–55 dB), moderately severe (56-70 dB), severe (71–91 dB) and profound (>91 dB).

Results

Children with FRNS/SDNS had a higher threshold for hearing at frequencies of 250 and 500 Hz, respectively, than the controls. Of the children in the FRNS/SDNS category, three (15 %) had mild sensorineural hearing impairment. These children had a low serum calcium level (P?<?0.03) and received higher cumulative doses of furosemide (P?<?0.04). Children with SRNS had a higher threshold for hearing at frequencies of 250, 500, 1,000, and 2,000 Hz, respectively, than the controls. Of the 20 children with SRNS, ten (50 %) had sensoineural hearing impairment (8 mild, 2 moderate). Children with SRNS with a hearing defect had received a higher cumulative dose of furosemide (P?<?0.03).

Conclusions

Children with FRNS/SDNS and SRNS are at risk of sensorineural hearing impairment. The risk factors associated with this impairment were higher cumulative doses of furosemide and hypocalcemia. Larger prospective cohort studies are required to evaluate this association.     

Serum and urine soluble interleukin-2 receptor in idiopathic nephrotic syndrome

Although a cellular immune pathogenesis is suspected in idiopathic nephrotic syndrome of childhood (INS), there is scant direct evidence of in vivo immune activation. In order to investigate cytokine cascade activation in INS, soluble interleukin-2 receptor (sIL-2R) in plasma and urine was characterized and its levels measured in INS patients during relapse. Immunochemically detectable sIL-2R had a molecular mass of 35–46 kDa in both serum and urine and the molecule appears to be excreted intact; the pI was 5.05. INS patients had elevated serum sIL-2R levels compared with adult normal controls (845±97 vs. 373±47 U/ml,P=0.001) and were significantly higher than previously published age-matched controls. Urinary excretion of sIL-2R was 47.2±13 U/mg creatinine in patients. Both the sIL-2R excretion rate and the fractional excretion of sIL-2R were positively correlated with the excretion of albumin (P=0.02 and 0.002, respectively). These increased serum and urine levels occurred whether relapse was or was not associated with an intercurrent illness. We conclude that: (1) despite increased sIL-2R excretion during INS relapse, serum levels are significantly elevated; (2) while the elevated urinary levels could result from enhanced intrarenal production, they more likely reflect the increased serum levels; (3) the elevated sIL-2R levels support an immune pathogenesis in INS.     

Serum insulin-like growth factor binding protein (IGFBP)-4 and IGFBP-5 in children with chronic renal failure: relationship to growth and glomerular filtration rate

Growth retardation in children with chronic renal failure (CRF) is partly due to an inhibition of insulin-like growth factor (IGF) activity by an excess of high-affinity IGF-binding proteins (IGFBPs). The aim of this study was to analyze the serum levels and forms of IGFBP-4 and IGFBP-5 in CRF patients using specific, recently developed radioimmunoassays (RIAs) and immunoblot analysis. We examined 89 children [age 11.5 (2.8–19.0) years] with CRF [glomerular filtration rate 26.6 (7.0–67.4) ml/min per 1.73 m²], nine of them with end-stage renal disease undergoing peritoneal dialysis. Serum-immunoreactive IGFBP-4 levels were fourfold increased in CRF (prepubertal 1080±268 ng/ml; pubertal 989±299 ng/ml) compared to healthy prepubertal controls (265±73 ng/ml). In contrast, serum IGFBP-5 levels were not significantly increased neither in prepubertal (361±120 ng/ml vs 282±75 ng/ml in controls) nor pubertal CRF children (478±165 ng/ml vs 491±80 ng/ml in controls). Immunoblot analysis showed the presence of intact as well as fragmented IGFBP-4 and IGFBP-5. Serum IGFBP-4, but not IGFBP-5, levels were inversely correlated with GFR (r=–0.39, P<0.001). In prepuber- tal children, IGFBP-4 levels were inversely correlated with standardized height (r=–0.40; P<0.005). In contrast, IGFBP-5 levels were positively correlated both with standardized height (r=0.32, P<0.02) and baseline height velocity (r=0.45, P<0.005). A 3-month therapy with rhGH stimulated serum IGFBP-5 levels by 43% (P<0.01); there was no consistent effect on IGFBP-4 levels. There was a positive correlation between IGFBP-4 and IGFBP-2 (r=0.46, P<0.001); IGFBP-5 was positively correlated with IGF-I (r=0.59, P<0.001), IGF-II (r=0.42, P<0.001) and IGFBP-3 (r=0.47, P<0.001) and inversely correlated with IGFBP-1 (r=–0.41, P<0.001). In summary, serum IGFBP-4 is fourfold elevated in children with CRF in relation to the degree of renal dysfunction and contributes to the marked increase in IGF-binding capacity in CRF serum. The inverse correlation of serum IGFBP-4 with standardized height is consistent with its role as another inhibitor of the biological action of the IGFs on growth plate cartilage. In contrast, serum IGFBP-5 is not elevated in CRF serum and circulates mainly as proteolysed fragments. The positive correlation of serum IGFBP-5 with growth and its increase during GH therapy indicate that IGFBP-5 is a stimulatory IGFBP in patients with CRF, either by enhancing IGF activity through better presentation of IGF to its receptor or by an IGF-independent effect through activation of a specific, recently described putative IGFBP-5-receptor. Received: 24 September 1999 / Revised: 6 January 2000 / Accepted: 13 January 2000 / Accepted: 13 January 2000     

Subclinical non-autoimmune hypothyroidism in children with steroid resistant nephrotic syndrome

Background

Thyroid status has not been studied well in children with steroid resistant nephrotic syndrome (SRNS).

Methods

In this cross sectional study we recruited 20 children aged 1–16 years with SRNS and similar number of controls. Serum levels of FT3, FT4 and TSH were measured in all the subjects. Overt hypothyroidism was defined as low FT4 (normal values: 0.7–2.0 ng/mL) and elevated serum TSH above reference values (0.45–4.5 mIU/L). Subclinical hypothyroidism (SH) was defined as an elevation in serum TSH with a normal serum FT4 concentration. The primary outcome measure was serum levels of FT3, FT4 and TSH in children with SRNS.

Results

Thirty per cent of the children (n = 6) with SRNS had non-autoimmune subclinical hypothyroidism (2 children each with grade I, II and III). Children with SRNS had a median TSH value [3.9 mIU/L (0.5–13)] within normal range, but levels were high as compared to controls. Out of 6 children with SH, 3 were in partial remission, 3 were in complete remission. The TSH levels normalized on thyroxine supplementation in grades II and III subclinical hypothyroidism.

Conclusion

Subclinical non-autoimmune hypothyroidism is present in a significant proportion of children with SRNS despite partial or complete remission. Thyroid profile should be evaluated routinely in this subset of patients.     

Mutational analysis of <Emphasis Type="Italic">NPHS2</Emphasis> and <Emphasis Type="Italic">WT1</Emphasis> in frequently relapsing and steroid-dependent nephrotic syndrome

Idiopathic nephrotic syndrome is a common pediatric kidney disease, 80% of all cases are steroid sensitive (SSNS). A significant proportion of children with SSNS will have a frequently relapsing or steroid-dependent course (FRNS/SDNS) that is associated with significant treatment-related morbidity. Mutations in NPHS2 account for more than 28% of all cases of steroid-resistant nephrotic syndrome (SRNS) and dominant mutations in WT1 for 5%; while mutations are absent from children with uncomplicated SSNS. Since FRNS/SDNS is phenotypically positioned within a spectrum between SSNS and SRNS, we hypothesized that heterozygous mutations of NPHS2 may be causing FRNS/SDNS. Mutational analysis of NPHS2 and WT1 was carried out in a single-center cohort of 20 children with FRNS/SDNS, ten children with uncomplicated SSNS (control), and 22 children with SRNS (control). Renal biopsy findings were available in 15/20 children with FRNS/SDNS and revealed IgM nephropathy, MCNS, and FSGS in six, five, and four children, respectively. Children with FRNS/SDNS were significantly younger at first presentation than those with SSNS and SRNS (median age: 3.0 years in FRNS/SDNS patients, 7.0 years in SSNS patients, and 5.0 in SRNS patients; p < 0.001). No NPHS2 or WT1 mutations were found in patients with FRNS/SDNS and uncomplicated SSNS. The hypothesis that FRNS/SDNS may be associated with heterozygous mutations in NPHS2 or WT1 was not confirmed.     

Long-term effects of levamisole treatment in childhood nephrotic syndrome

The effects of levamisole treatment on long-term outcome were evaluated in a retrospective study of frequently-relapsing (FRNS, n =15), steroid-dependent (SDNS, n =13), and steroid-resistant (SRNS, n =6) nephrotic syndrome in 34 children (21 boys, 13 girls, mean age 5.0±3.4 years) during a 60-month follow-up period. The definition of frequent relapses was 4 relapses per year. The current relapse was treated with prednisolone 60 mg/m² per day for 4 weeks, then with 40 mg/m² every other day for 4 weeks, after which the dose was tapered by 10 mg weekly. From the beginning of the 5th week, levamisole was introduced at a dose of 2 mg/kg per day. The duration of levamisole treatment was 17±7 months. Before starting levamisole treatment the mean level of proteinuria was 2.17±1.34 g/day and the relapse rate was 4.41/year. By the end of levamisole therapy, proteinuria had fallen to 0.142±0.211 g/day and the relapse rate to 0.41/year. No relapse occurred in 23 of the 34 patients during levamisole treatment. In the 24-month follow-up period after the discontinuation of levamisole, 28 children remained in total remission, while 6 had relapses. The cumulative steroid dose before levamisole therapy was 7,564.4±3,497.1 mg/year and following the introduction of levamisole 1,472.9±1,729.9 mg/year ( P <0.0001). We observed reversible neutropenia in 5 patients, but no other side effects were seen. Our findings suggest that in FRNS and SDNS levamisole significantly reduces both the relapse rate and the cumulative steroid dose; therefore, it could be recommended for these patients. In SRNS patients it has also some benefit because proteinuria and the cumulative steroid dose could be reduced significantly.     

Glycosaminoglycan excretion in children with nephrotic syndrome

Although most childhood nephrotic syndromes respond to steroid treatment, steroid resistant nephrotic syndrome (SRNS) is also common and is particularly difficult to treat. This study investigated the role of glycosaminoglycans (GAG) in the pathogenesis and clinical course of nephrotic syndrome in children. Thirty-four children (21 males and 13 females, mean age 3.7±1.6 years) with steroid-sensitive nephrotic syndrome and 20 children with steroid-resistant nephrotic syndrome (12 males and 8 females, mean age 10.9±3.8 years; of the twenty, four had primary SRNS (FSGS) and the others had secondary SRNS) were included the study. Mean urine levels of GAG relative to creatinine (U_GAG/U_Cr) in patients with SRNS (n=20, 113.01±78.46 mg g^–1 Cr) and in patients experiencing the nephrotic period of steroid-sensitive nephrotic syndrome (n=34, 132.15±101.55 mg g^–1 Cr) were both significantly higher than mean U_GAG/U_Cr for control subjects (n=30, 51.83±47.66 mg g^–1 Cr) (P<0.01 for both). Patients excreted significantly more GAG during the nephrotic period of steroid-sensitive nephrotic syndrome than during remission (132.15±101.55 vs 39.11±42.73 mg g^–1 Cr, respectively; P<0.01). There was, however, no significant difference between U_GAG/U_Cr for patients with steroid-resistant nephrotic syndrome and U_GAG/U_Cr in the nephrotic period of steroid-sensitive nephrotic syndrome. Urine GAG excretion correlated significantly with the severity of proteinuria. The results suggest that GAG play a significant role in the pathogenesis of nephrotic syndrome but that GAG excretion is not a marker for response to steroid treatment in pediatric patients with this condition.     

Tacrolimus is an alternative therapy option for the treatment of adult steroid-resistant nephrotic syndrome: a prospective, multicenter clinical trial

Background

The optimal therapy for adult steroid-resistant nephrotic syndrome (SRNS) remains a therapeutic challenge. We investigated the efficacy and safety of tacrolimus as a promising regimen in Chinese adult patients.

Methods

A prospective, multicenter trial was conducted in 9 nephrology centers from 2006 to 2008, in patients with SRNS (defined as failure to respond to 1 mg/kg/day of prednisone for 8, and 16 weeks, in focal segmental glomerulosclerosis). Patients were treated with tacrolimus (TAC) plus prednisone for 12 months. TAC dose was titrated to achieve a target trough blood concentration of 5–10 ng/ml for the first 6 months and 4–6 ng/ml for the subsequent 6 months. The primary outcomes included complete or partial remission [complete remission (CR): proteinuria <0.3 g/24 h, with serum albumin ≥3.5 g/dl and stable renal function; partial remission (PR): proteinuria between 0.3 and 3.5 g/24 h and a decrease of at least 50 % from the baseline level, with serum albumin ≥3.0 g/dl and stable renal function]. Secondary end-points included relapse rate, changes of clinical parameters (proteinuria, serum albumin, and lipid profile) and adverse events.

Results

Twenty-four patients with SRNS were enrolled. After 6 months of therapy, CR was achieved in 58.3 % of patients and PR in 16.7 %, yielding a final response rate of 75.0 %. The decrease in proteinuria was 43.1 ± 17.5 % after the first month of treatment (P < 0.001). Complete or PR was achieved in 6 of 8 patients with minimal change disease, 4 of 6 patients with mesangioproliferative glomerulonephritis (MsPGN), 6 of 7 patients with focal segmental glomerulosclerosis (FSGS), and all 2 patients with IgA nephropathy. Two patients (1 with MsPGN and 1 with FSGS) experienced relapses during the subsequent 6 months of follow-up. Adverse events included infection, hand tremor, diarrhea, acute reversible or persistent nephrotoxicity.

Conclusions

In conjunction with prednisone, TAC may be an alternative therapeutic regimen for adult SRNS patients. However, adverse events in these patients should be carefully monitored, especially at the beginning of treatment. Randomized controlled trials with longer follow-up are warranted.     

T-lymphocyte activation in steroid-sensitive nephrotic syndrome in childhood

We undertook a sequential study in 29 children with steroid-sensitivenephrotic syndrome (SSNS) off treatment to seek evidence forT-cell activation in relapse. T-cell subsets and activationmarkers were analysed using two-colour flow cytometry. SolubleIL2 receptor (sIL2R) was measured in serum and urine by enzyme-linkedimmunosorbent assay (ELISA). Fifteen children were examinedin remission and subsequent relapse (group A) and fourteen remainedin remission (group B). In group A the proportion of CD4⁺ cellsexpressing the activation marker CD25 (alpha-chain of the IL2receptor) increased significantly from remission to relapse:CD4⁺25⁺ cells rose from 5.6 to 7.0% of total lymphocytes, andfrom 15.8 to 19.1% of CD4⁺ lymphocytes (paired t test: P<0.0005and <0.001 respectively). No correlations were found betweenCD4⁺25⁺ cells and plasma albumin or cholesterol concentrations.SIL2R concentration in serum did not change in relapse, butincreased significantly in urine from 272 to 592 U/mg creatinine(P<0.01). No significant difference was found in remissionbetween groups A and B. We conclude that early relapse in SSNSis associated with activation of CD4⁺ (T-helper) cells whichis not secondary due to the nephrotic state itself.     

NGAL distinguishes steroid sensitivity in idiopathic nephrotic syndrome

Background

Idiopathic nephrotic syndrome (NS) is the most common glomerular disorder of childhood. Invasive biopsy remains the diagnostic method of choice for NS. Prognosis correlates with steroid responsiveness, from sensitive (SSNS) to resistant (SRNS). Neutrophil gelatinase-associated lipocalin (NGAL) has been demonstrated to be a powerful risk marker of chronic kidney disease progression. We set out to determine if urine NGAL can distinguish between patients with SRNS, SSNS, and healthy controls.

Methods

Urine and clinical data were collected from patients at Cincinnati Children's Hospital who were recently diagnosed with active nephrotic syndrome as well as healthy controls. Participants included SRNS (n?=?15), SSNS (n?=?14), and healthy controls (n?=?10). Urinary NGAL was measured by ELISA and normalized to creatinine.

Results

Median NGAL was significantly (p?p?r?=??0.5, p?

Conclusions

NGAL levels differentiate SSNS from SRNS and correlate with disease severity in SRNS.

     

Oxidant stress in primary nephrotic syndrome: does it modulate the response to corticosteroids?

In order to assess the oxidative stress in newly diagnosed children with primary nephrotic syndrome (PNS), we serially measured serum total antioxidant capacity (TAC) and malondialdehyde (MDA) in 33 children with PNS and ten healthy matched controls. Patients were classified into two groups: those who had steroid-sensitive nephrotic syndrome (SSNS; n = 26) and those who had steroid-resistant nephrotic syndrome (SRNS; n = 7). Of the patients with SSNS, 15 were non-relapsers and 11 were relapsers. At the proteinuric phase, all patients had significantly higher MDA levels and lower TAC than the controls. These changes were more marked in patients with SRNS than in those with SSNS. During remission and still on corticosteroids, patients had higher TAC and similar MDA levels as in the proteinuric phase, but the TAC and MDA levels still significantly differed from those of the controls. More improvement in TAC and MDA levels occurred in patients following the weaning of corticosteroids, but TAC was still lower in the patients than in the controls. Moreover, TAC was higher in non-relapsers than in relapsers. Using a receiver operating characteristic curve, the initial response to corticosteroids could be predicted at serum TAC level ≥0.73 mM/L (sensitivity 89%, specificity 86%), while serum TAC levels ≤ 1.14 mM/L after the weaning of corticosteroids could predict that the patient would not relapse (sensitivity 91%, specificity 80%). In conclusion, based on our results, PNS can be considered to be associated with oxidative stress even during remission. This stress may modulate the response to corticosteroids. Further prospective studies using larger numbers of patients are needed to validate these results.     

Interleukin-6 and interleukin-8 in the urine of children with acute pyelonephritis

Interleukin-6 (IL-6) and interleukin-8 (IL-8) are important mediators of the inflammatory response in serious bacterial infections. We studied the levels of these two cytokines (standardised for urinary creatinine) in the urine of infants and children during and 6 weeks after acute pyelonephritis and in non-renal febrile controls and healthy children without apparent infection. IL-6 was detected in the urine of 52% of children with pyelonephritis compared with 15% of other children (P<0.001). The median urinary IL-6 level in acute pyelonephritis was 4 pg/mol compared with undetectable levels in the control group (P<0.001). IL-8 was detected in 98% of children with pyelonephritis and 42% of other children (P<0.001). The median concentration of IL-8 was 188 pg/mol in pyelonephritis; it was undetectable in controls (P<0.001). IL-8 levels were higher in children less than 1 year of age (P<0.001).     

Implications of blood soluble and cell surface tumor necrosis factor receptors in childhood nephrotic syndrome

We investigated whether leukocyte cell surface TNF receptors (cTNFR) and plasma soluble TNF receptors (sTNFR) could serve as predictors of childhood steroid-resistant nephrotic syndrome (SRNS) during the early stage of diagnosis. We recruited 39 nephrotic children for studies correlating plasma sTNFR and leukocyte cTNFR with disease activity and therapeutic response. We found that patients with idiopathic childhood nephrotic syndrome (NS) had higher pre-treatment plasma sTNFR1 ( P<0.001) and sTNFR2 levels ( P<0.001) than controls without NS. In contrast, cTNFR1 ( P<0.001) and cTNFR2 ( P=0.014) expression on granulocytes but not lymphocytes was lower in patients than controls. Patients with SRNS, similar to steroid-sensitive nephrotic syndrome (SSNS), had higher sTNFR1 and sTNFR2 levels pre treatment. However, patients with SRNS revealed higher expression of cTNFR1 ( P<0.001) and cTNFR2 ( P=0.023) than those with SSNS. After 4 weeks of steroid treatment, plasma sTNFR1 and sTNFR2 levels returned to normal in both patients with SRNS and SSNS. Post treatment, the decreased cTNFR1 and cTNFR2 expression on granulocytes in patients with SSNS returned to normal, while patients with SRNS revealed no change before and after treatment. This study suggests that a higher plasma sTNFR level associated with lower cTNFR expression reflects NS disease activity, whereas a higher initial granulocyte cTNFR expression tends to predict steroid resistance. TNFR may play a pathophysiological role in childhood NS.