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Chronic allograft vasculopathy (CAV) limits the lifespan of pediatric heart transplant recipients. We investigated blood markers of inflammation, endothelial dysfunction, and damage to both the native and transplanted vasculature in children after heart transplantation. Serum samples were taken from pediatric heart transplant recipients for markers of inflammation and endothelial activation. The systemic vasculature was investigated using brachial artery flow-mediated dilatation and carotid artery intima-medial hyperplasia. CAV was investigated using intravascular ultrasound. Mean intima-media thickness (mIMT)0.5 mm was used to define significant CAV. Forty-eight children (25 male) aged 8-18 years were enrolled in the study. Patients were a median (interquartile range) 4.1 (2.2-8.7) years after transplant. Patients had increased levels of circulating IL6 (3.86 [2.84-4.95] vs. 1.66 [1.22-2.63] p0.0001), vascular cell adhesion molecule 1 (539 [451-621] vs. 402 [342-487] p0.001), intracellular adhesion molecule 1 305 (247-346) vs. 256 (224-294) p = 0.002 and thrombomodulin (7.1 [5.5-8.1] vs. 3.57 [3.03-4.71] p0.0001) and decreased levels of tumor necrosis factor-α, E selectin, and P selectin, compared with controls. The systemic vasculature was unaffected. Patients with severe CAV had raised serum von Willebrand factor and decreased serum thrombomodulin. Posttransplant thrombomodulin levels are elevated after transplant but significantly lower in those with mIMT0.5 mm. This suggests that subclinical inflammation is present and that natural anticoagulant/thrombomodulin activity is important after transplant.

We undertook a sequential study in 29 children with steroid-sensitive nephrotic syndrome (SSNS) off treatment to seek evidence for T-cell activation in relapse. T-cell subsets and activation markers were analysed using two-colour flow cytometry. Soluble IL2 receptor (sIL2R) was measured in serum and urine by enzyme-linked immunosorbent assay (ELISA). Fifteen children were examined in remission and subsequent relapse (group A) and fourteen remained in remission (group B). In group A the proportion of CD4 + cells expressing the activation marker CD25 (alpha-chain of the IL2 receptor) increased significantly from remission to relapse : CD4 + 25 + cells rose from 5.6 to 7.0% of total lymphocytes, and from 15.8 to 19.1% of CD4 + lymphocytes (paired t test : P

Kawasaki disease is a systemic vasculitis of unknown etiology, with clinical observations suggesting a substantial genetic contribution to disease susceptibility. We conducted a genome-wide association study and replication analysis in 2,173 individuals with Kawasaki disease and 9,383 controls from five independent sample collections. Two loci exceeded the formal threshold for genome-wide significance. The first locus is a functional polymorphism in the IgG receptor gene FCGR2A (encoding an H131R substitution) (rs1801274; P = 7.35 × 10(-11), odds ratio (OR) = 1.32), with the A allele (coding for histadine) conferring elevated disease risk. The second locus is at 19q13, (P = 2.51 × 10(-9), OR = 1.42 for the rs2233152 SNP near MIA and RAB4B; P = 1.68 × 10(-12), OR = 1.52 for rs28493229 in ITPKC), which confirms previous findings(1). The involvement of the FCGR2A locus may have implications for understanding immune activation in Kawasaki disease pathogenesis and the mechanism of response to intravenous immunoglobulin, the only proven therapy for this disease.

Objective Endothelial injury is central to the pathogenesis of vasculitis. The purpose of this study was to assess how indices of endothelial injury and repair change during different stages of disease activity in children with primary systemic vasculitis (PSV). Methods Fifty children with PSV, 17 children with nonvasculitic inflammatory diseases (pediatric inflammatory disease controls), 35 healthy age- and sex-matched pediatric controls, and 27 healthy adult controls were included in the study. Biomarkers examined were endothelial microparticles (EMPs), circulating endothelial cells (CECs), angiogenic growth factors, and endothelial progenitor cells (EPCs). EMP binding to annexin V, EMPs expressing CD144 or E-selectin, and EPCs expressing vascular endothelial growth factor receptor 2 (VEGFR-2), CD133, and CD34 were examined by flow cytometry. CECs were enumerated using immunomagnetic bead extraction techniques, and VEGF and angiopoietin 2 (Ang-2) were measured by enzyme-linked immunosorbent assay. Results Levels of CD144+ EMPs, CECs, VEGF, and EPCs were all significantly elevated in children with active vasculitis as compared with healthy children, and the levels declined with remission-inducing therapy in the individual patients. Treatment-naive patients with active disease had significantly higher levels of VEGF and Ang-2 than did those with active disease who were receiving treatment, although the levels of CECs and EMPs remained high in both of these groups. Conclusion Elevation of the levels of CECs, EMPS, EPCs, VEGF, and Ang-2 occurs during active vasculitis in children. EPC responses to active vasculitis are different in children as compared with that observed in adults with vasculitis, and both CECs and EMPs can be used to monitor disease activity in children with vasculitis.

Background. Vascular calcification occurs in the majority of patients with chronic kidney disease, but a subset of patients does not develop calcification despite exposure to a similar uraemic environment. Physiological inhibitors of calcification, fetuin-A, osteoprotegerin (OPG) and undercarboxylated-matrix Gla protein (uc-MGP) may play a role in preventing the development and progression of ectopic calcification, but there are scarce and conflicting data from clinical studies.Methods. We measured fetuin-A, OPG and uc-MGP in 61 children on dialysis and studied their associations with clinical, biochemical and vascular measures.Results. Fetuin-A and OPG were higher and uc-MGP lower in dialysis patients than controls. In controls, fetuin-A and OPG increased with age. Fetuin-A showed an inverse correlation with dialysis vintage (P = 0.0013), time-averaged serum phosphate (P = 0.03) and hs-CRP (P = 0.001). Aortic pulse wave velocity (PWV) and augmentation index showed a negative correlation with fetuin-A while a positive correlation was seen with PWV and OPG. Patients with calcification had lower fetuin-A and higher OPG than those without calcification. On multiple linear regression analysis Fetuin-A independently predicted aortic PWV (P = 0.004, ss = -0.45, model R-2 = 48%) and fetuin-A and OPG predicted cardiac calcification (P = 0.02, ss = -0.29 and P = 0.014, ss = 0.33, respectively, model R-2 = 32%).Conclusions. This is the first study to define normal levels of the calcification inhibitors in children and show that fetuin-A and OPG are associated with increased vascular stiffness and calcification in children on dialysis. Higher levels of fetuin-A in children suggest a possible protective upregulation of fetuin-A in the early stages of exposure to the pro-calcific and pro-inflammatory uraemic environment.

Summary Superantigens (SAgs) are potent stimulators of T cells bearing specific Vβ T cell receptors (TCR) and may play a role in the pathogenesis of Kawasaki syndrome (KS), although despite 15 years of intense study this area remains controversial. Because SAgs can cause Vβ restricted T cell activation in the absence of Vβ skewing the aims of this study were to describe a flow cytometric protocol to study both CD4 and CD8 Vβ repertoires, and CD69 expression across the CD4 and CD8 Vβ repertoire in children with KS. Sixteen children with KS were studied. There was no significant increase in overall peripheral blood CD4 or CD8 T cell activation as determined by CD69 expression. However, Vβ restricted CD4 and/or CD8 activation was observed in eight of 11 (72%) of the KS patients, a finding not observed in healthy controls. Thirteen of 16 (81%) of the KS patients had evidence of either Vβ skewing (particularly CD4 Vβ2 and Vβ5·1) and/or Vβ restricted activation. Three patients had Vβ restricted activation in the absence of skewing. We suggest that these preliminary observations highlight the many layers of complexity when considering T cell activation in KS, which could explain some of the conflicting studies regarding peripheral blood T cell activation and Vβ skewing. It is likely that in order to move forward with this debate a combination of detailed microbiological, immunological and molecular techniques applied to individual patients will be required ultimately to prove or refute the SAg hypothesis of KS.

OBJECTIVE. Our aim was to evaluate the clinical outcomes, safety, and efficacy of percutaneous transluminal angioplasty for renovascular hypertension in children.METHODS. A retrospective review of data for all children with renovascular hypertension who underwent percutaneous transluminal angioplasty at a single center between 1984 and 2003 was performed. Patients with renal transplants and inflammatory multisystem diseases were excluded.RESULTS. Thirty-three children, 1.9 to 17.9 years of age (median: 10.3 years), underwent renal angioplasty and/or stenting. Underlying syndromes were present in 10. On angiograms, 16 had bilateral renal artery stenosis, 15 intrarenal disease, 8 aortic stenosis, and 7 cerebrovascular disease. Forty-eight percutaneous transluminal angioplasty procedures were performed, including 15 stenting procedures. There was a high rate of restenosis after stenting (7 of 19 cases, compared with 2 of 27 cases after balloon dilation). Outcomes were cured (ie, blood pressure normal without treatment) for 9 patients, improved blood pressure with same or reduced treatment for 7, blood pressure maintained in >95th percentile because of cerebrovascular disease for 2, no change in blood pressure despite technical success for 10, and technical failure for 5. Blood pressure control improved in 11 of 13 children who had main renal artery disease alone and in 6 of 20 with associated intrarenal disease or stenoses in other vascular beds. There was 1 procedure-related death and 5 minor complications.CONCLUSIONS. Angioplasty produced clinically worthwhile improvement for ∼50% of patients. High incidence rates of extrarenal involvement and intrarenal disease and a high restenosis rate after stenting accounted for poor blood pressure control in the rest.

Objective. Microparticles are released from endothelial cells in response to a variety of injurious stimuli and recently have been shown to be increased in a number of diseases associated with endothelial dysfunction. This study examined endothelial microparticle (EMP) and platelet microparticle (PMP) profiles in children with systemic vasculitis to test the hypothesis that EMPs may provide a noninvasive means of examining endothelial activation or injury. Methods. The study cohort comprised 39 children with systemic vasculitis at various stages of disease activity, 24 control children with febrile disease, and a control group of 43 healthy subjects. Plasma was ultra-centrifuged at 17,000g for 60 minutes, and the microparticle pellets were examined using flow cytometry. Results. Plasma from patients with active systemic vasculitis contained significantly higher numbers of E-selectin-positive EMPs compared with that from patients in remission, healthy controls, or febrile disease controls (P = 0.000 for each). A similar result was obtained for the numbers of EMPs expressing the marker CD105. There was also a significant increase in PMPs expressing CD42a in the active vasculitis group as compared with the other groups, but this difference was not significant for PMPs expressing P-selectin. The EMP counts correlated with the Birmingham Vasculitis Activity Score and the acute-phase reactant levels in the patients with systemic vasculitis, but there was a poor correlation overall between EMP counts and the acute-phase reactant levels in the febrile disease controls. Conclusion. EMPs may provide a window to the activated endothelium and could provide important pathophysiologic insights into the vascular injury associated with vasculitis of the young.

Urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG) and retinol-binding protein (RBP), sensitive markers of renal tubular damage and dysfunction respectively, were evaluated in paired remission and relapse urine samples from 16 patients (median age 12 years), with minimal change nephrotic syndrome (MCNS), in single samples from 5 nephrotic patients (median age 12 years) with focal segmental glomerulosclerosis (FSGS) and in 183 normal controls aged 2-16 years. The NAG and RBP data were expressed as a ratio over urinary creatinine (Cr). The NAG/Cr and RBP/Cr geometric means (ranges) for normal subjects were 11.1 (3.4-35.5) micromol 2-methoxy-4-(2'-nitrovinyl)-phenol (MNP)/h per mmol and 3.1 (0.3-38.8) microg/mmol, respectively. The NAG/Cr data revealed a weak negative correlation with age in normal children, whereas RBP/Cr was independent of age. RBP/Cr and NAG/Cr in MCNS in remission were the same as in controls. In MCNS in relapse, NAG/Cr was significantly elevated (P=0.001), while in FSGS both RBP/Cr and NAG/Cr were significantly raised (P=0.001 and P0.008, respectively). These findings suggest that elevated NAG/Cr may be an indicator of relapse in both MCNS and FSGS and elevated RBP/Cr may allow differentiation between the two.

Experimental studies have pointed to charge selectivity as an important determinant of glomerular permeability to macromolecules. Loss of glomerular basement membrane (GBM) polyanion has been proposed as a cause of the selective proteinuria in minimal change nephrotic syndrome (MCNS). However, the presence of less-anionic albumin in urine than plasma from MCNS and focal and segmental glomerulosclerosis (FSGS) patients has been interpreted both as evidence for partial maintenance of charge selectivity and for involvement of other pathogenic mechanisms. The exact role of charge selectivity in the pathogenesis of nephrotic proteinuria remains controversial. We have examined the clearance of endogenous proteins of differing size and charge in children with idiopathic nephrotic syndrome (NS). Chromatofocusing was used to determine the isoelectric points (pIs) of albumins in paired plasma and urine samples from patients with FSGS (n = 6) and MCNS (n = 6). Charge selectivity was assessed by comparing the pIs of the fractions with the highest albumin concentration (model pI) in plasma and urine. The difference between the modal pIs was defined as the delta modal pI. Charge selectivity was also assessed from the albumin/transferrin and IgG4/IgG1 clearance ratios; size selectivity from the IgG1/albumin and IgG1/transferrin as well as the IgG4/albumin and IgG4/transferrin clearances. In children with FSGS, the mean (+/-SD) delta modal pI was -0.05 +/- 0.16, and in MCNS -0.05 +/- 0.11. Neither value differed significantly from zero. The albumin/transferrin clearance ratio showed no significant difference between FSGS and MCNS, but the IgG4/IgG1 clearance ratio was significantly higher in MCNS (P < 0.05). Size selectivity was significantly reduced in FSGS compared with MCNS (for IgG1/transferrin P < 0.01 and for IgG1/albumin P < 0.05). For IgG4/transferrin and IgG4/albumin, P was < 0.05. In conclusion, there was no evidence for residual charge selectivity in idiopathic NS associated with either MCNS or FSGS during nephrotic-range proteinuria. There was a significant loss of GBM size selectivity in children with FSGS with heavy proteinuria compared with children with MCNS with heavy proteinuria.

Size and charge selectivity of capillary permeability in the salivary glands of nephrotic children were investigated by measuring salivary excretion of endogenous plasma proteins of different size and charge. We examined 10 children with steroid-sensitive nephrotic syndrome (SSNS) in relapse and subsequent remission, 11 with steroid-resistant nephrotic syndrome, and 11 healthy children (controls). Albumin [mol. wt. 66 kilodaltons (kDa), isoelectric point (pI) 4.9] was measured by radioimmunoassay, transferrin (mol. wt. 77 kDa, pI 5.9) and immunoglobulins IgG1 (mol. wt. 150 kDa, pI 7–9) and IgG4 (mol. wt. 150 kDa, pI

Mutations in SLC29A3 lead to pigmentary hypertrichosis and non-autoimmune insulin-dependent diabetes mellitus (PHID) and H syndromes, familial Rosai-Dorfman disease, and histiocytosis-lymphadenopathy plus syndrome. We report a new association of PHID syndrome with severe systemic inflammation, scleroderma-like changes, and cardiomyopathy. A 12-year-old girl with PHID syndrome presented with shortness of breath, hepatosplenomegaly, and raised erythrocyte sedimentation rate and C-reactive protein. An echocardiogram showed biventricular myocardial hypertrophy, and cardiac magnetic resonance imaging showed circumferential late gadolinium enhancement of the myocardium. No systemic amyloid deposits were observed on a whole-body serum amyloid P scintigraphy scan. Abdominal ultrasound revealed intra-abdominal fat surrounding the solid organs, suggesting a possibility of evolving lipodystrophy with visceral adiposity. PHID syndrome is a novel monogenic autoinflammatory syndrome (AIS) associated with severe elevation of serum amyloid. Lipodystrophy, cutaneous sclerodermatous changes, and cardiomyopathy were also present in this case. In contrast to other AIS, blockade of interleukin-1 and tumor necrosis-α was ineffective.

International audience; IntroductionThe aetiopathogenesis of juvenile dermatomyositis (JDM) remains poorly understood. In particular the contribution of monocytes or macrophages, which are frequently observed to be an infiltrate within muscle tissue very early in the disease process, is unknown. We hypothesised that these cells secrete the pro-inflammatory myeloid related protein (MRP) 8/14 which may then contribute to muscle pathology in JDM.MethodsIn this study of 56 JDM patients, serum MRP8/14 levels were compared with clinical measures of disease activity. Muscle biopsies taken early in disease were assessed by immunohistochemistry to determine the frequency and identity of MRP-expressing cells. The effects of MRP stimulation and endoplasmic reticulum (ER) stress on muscle were tested in vitro. Serum or supernatant levels of cytokines were analyzed by multiplex immunoassay.ResultsSerum MRP8/14 correlated with physician's global assessment of disease activity in JDM (R = 0.65, p = 0.0003) and muscle strength/endurance, childhood myositis assessment score (CMAS, R = −0.55, p = 0.004). MRP8/14 was widely expressed by CD68+ macrophages in JDM muscle tissue. When cultured with human myoblasts, MRP8 led to the secretion of MCP-1 and IL-6, which was enhanced by ER stress. Both inflammatory mediators were detected in significantly higher levels in the serum of JDM patients compared to healthy controls.ConclusionsThis study is the first to identify serum MRP8/14 as a potential biomarker for disease activity in JDM. We propose that tissue infiltrating macrophages secreting MRP8/14 may contribute to myositis, by driving the local production of cytokines directly from muscle.

Background. Fibroblast growth factor 23 (FGF23), a bone-derived phosphaturic hormone, is elevated in chronic kidney disease (CKD). There are scarce data on the levels of its essential co-receptor klotho, and longitudinal changes in FGF23 levels are also unknown. Methods. We examined FGF23 and soluble klotho (sklotho) levels over 1 year in 154 children with CKD Stages 1–5 (CKD1–5), were on dialysis or who have received a transplantation. Results. In children with CKD1–5 and who were receiving dialysis, FGF23 correlated inversely with the estimated glomerular filtration rate (eGFR) (P < 0.001), whereas a decrease in s-klotho was observed with a lower eGFR (P = 0.01). There was no correlation between FGF23 and serum phosphate (P) or parathyroid hormone (PTH) in our cohort wherein 89 and 66%, respectively, had normal levels. FGF23 increased by 6-fold over a 12month period in children with eGFR of 15–29 mL/min/ 1.73 m 2 , with an overall 5% annual increase in the CKD1–5 and dialysis cohort. High FGF23 levels were seen with high calcium (Ca) levels (P < 0.001). FGF23 levels were high when 25-hydroxyvitamin D [25(OH)D] and 1,25-dihydroxyvitamin D [1,25(OH)2D] were deficient (P = 0.05 and P < 0.001, respectively). s-klotho levels correlated positively with 25(OH)D (P < 0.001) and negatively with PTH (P = 0.04) and age (P = 0.03). Multivariate regression analysis demonstrated a strong relationship between FGF23 and eGFR, whereas the association between s-klotho and eGFR as observed in univariate analysis was lost following the adjustment of confounders. In transplanted patients, FGF23 correlated with eGFR (P = 0.02) and 25(OH)D (P = 0.05). Conclusions. This study shows increasing FGF23 and reduced s-klotho levels with progressive renal failure even in a population of children with well-controlled P levels. Novel associations between FGF23 and serum Ca as well as 25(OH)D warrant further investigation.

SUMMARY Fifty-nine children with acute Kawasaki disease (KD), a childhood vasculitis, were compared with 35 children with fever due to infection and 48 healthy children. Levels of soluble E-selectin (sE-selectin), soluble intercellular adhesion molecule-1 (sICAM-1), and soluble vascular cell adhesion molecule-1 (sVCAM-1)in the healthy children were double those found in adults. All three soluble cell adhesion molecules and von Willebrand factor (vWF) were higher in the children with KD than in the healthy children, but only sE-selectin, a marker for activated endothelial cells, and sICAM-1 were higher than in the febrile children. The high levels of vWF in KD appear to reflect the prominent acute-phase reaction. This information can help us to understand further the complex interactions between cytokines. circulating inflammatory cells and the vascular endothelium, and may lead to new therapeutic avenues in KD and other inflammatory diseases and vasculitides.

Cyclosporin A (CyA) is now commonly used in the management of children with steroid-dependent nephrotic syndrome. In order to assess nephrotoxicity related to CyA therapy, we measured glomerular filtration rate (GFR) on 123 occasions in 24 children with minimal change nephrotic syndrome receiving CyA. GFR was estimated from the plasma clearance of 51chromium-EDTA every 3 months during CyA therapy of up to 27 months duration. There was a significant reduction in GFR after 3 months of CyA therapy [118 +/- 33 (SD) to 93 +/- 24 ml/min per 1.73 m2] but no further fall thereafter, although the reduction in GFR was sustained for the duration of CyA therapy. This reduction in GFR appeared to be reversible upon cessation of CyA, but careful monitoring of renal function is necessary in such patients to prevent the development of longer term nephrotoxic sequelae.

Abnormal T lymphocyte function and reduced interleukin-2 (IL-2) production have been implicated in the pathogenesis of the nephrotic syndrome (NS). We investigated: (1) lymphocyte subpopulations and expression of IL-2 receptor (IL-2R) on T cells using two-colour flow cytometry, (2) serum IL-2 and (3) the soluble component of IL-2R (sIL-2R) in serum, using enzyme-linked immunosorbent assay, in 38 children with NS. All children, except those in remission, had marked proteinuria. They were divided into groups according to renal pathology: (1) steroid-sensitive NS (SSNS) not receiving prednisolone therapy, (2) SSNS on prednisolone, (3) focal segmental glomerulosclerosis (FSGS), (4) SSNS in remission and not receiving prednisolone therapy, (5) congenital NS (CNS). Results were compared with 26 age-matched controls. Total T lymphocytes (CD3) were reduced in groups 1 and 2; CD4 count was reduced in groups 1-4; CD8 count increased in groups 2 and 3; CD8 and CD19 (B lymphocytes) were significantly reduced in group 5. Increased IL-2R expression (CD25) on CD4 lymphocytes was noted in groups 1, 2 and 3 implying activation of these cells. In patients with SSNS, increased serum sIL-2R was recorded during relapse (1,273 +/- 497 U/l vs. 913 +/- 401 U/l in remission, P0.005) but free serum IL-2 was not detectable at any stage. The specific alterations in lymphocyte subpopulations in SSNS and FSGS would imply an involvement of the immune system distinct from that in CNS.

Monocyte chemoattractant protein-1 (MCP-1) has a pathogenic role in murine lupus nephritis (LN). We recruited 25 pediatric and adolescent systemic lupus erythematosus (SLE) patients from our lupus clinic [13 (52%) patients with LN and 12 (48%) lupus non-nephritis patients] and evaluated their urinary and plasma MCP-1 levels compared to adult and childhood controls. The median age and SLE disease duration of patients were 14.4 and 5.5 years, respectively. LN patients had a higher median renal (p = 0.01) British Isles Lupus Assessment Group (BILAG) index, with a tendency for higher total BILAG scores (p = 0.2). There were significantly increased urinary MCP-1 levels in the LN patients compared to healthy controls (p < 0.001) whose values were significantly higher than lupus non-nephritis children (p< 0.004). Urinary MCP-1 levels correlated well with total BILAG scores (r = 0.82, p = 0.04). There were no differences in plasma MCP-1 levels between SLE patient groups and pediatric controls, although the levels in the childhood controls were elevated compared to those of the adult controls (p < 0.04). These results provide evidence of increased urinary—but not plasma—MCP-1 levels in children with LN, which correlates well with SLE disease activity as measured by the BILAG index.

Interleukin-8 and polymorphoneutrophil leucocyte activation in hemolytic uremic syndrome of childhood. Polymorphoneutrophil leucocytes (PMNLs) are implicated in the pathogenesis of diarrhea-associated hemolytic uremic syndrome (D+ HUS). We investigated mechanisms of PMNL involvement by measuring tumor necrosis factor α (TNFα) and the novel cytokine, interleukin-8 (IL-8), a potent activator of neutrophils, together with α- antitrypsin-complexed elastase (α1-AT-E) as a marker of neutrophil degranulation, and anti-neutrophil cytoplasmic antibodies (ANCA). IL-8 was not detected in the 17 normal children, but was significantly elevated in 20 of 25 D+ HUS children (P < 0.005), and in three of nine children with non-diarrhea-associated (D—) HUS. Sequential data showed that IL-8 peaked transiently in the circulation, reaching a maximum just before a more protracted burst of α1-AT-E. The IL-8 levels correlated significantly with circulating al-AT-E concentrations (r = 0.50, P < 0.05). In D+ HUS IL-8 levels also correlated with the PMNL count (r = 0.63, P < 0.005), and the highest values were seen in those children who died in the acute phase of the disease. TNFα was raised in only 1 of 16 D+ HUS children and in no patients were ANCA detected. The data suggest that PMNLs in HUS are recruited by IL-8, that this cytokine plays a key role in the PMNL activation which occurs, and that agents which suppress this recruitment and activation might play a therapeutic role in this disorder.

As there is a 10% risk of hypertension developing in children with reflux nephropathy and the renin-angiotensin system has been implicated in its aetiology, a long term prospective study has been undertaken to explore the relationship between plasma renin activity (PRA) and blood pressure in such patients. In 1978, of 100 normotensive children with reflux nephropathy 8% were shown to have PRA above normal. Five years later of 85 subjects suitable for analysis 13% had increased PRA and it was shown that PRA and blood pressure SD scores significantly increased. The present study refers to the 10 year follow up in which 95 of the original group were traced but eight of these were unavailable for study and 28 others were excluded from analysis because of extraneous factors that might influence blood pressure or PRA. Results therefore on 59 have been analysed. PRA was above normal in 13/59 (20%) subjects, and PRA and blood pressure SD scores had further increased. The data continue to support the role of the renin-angiotensin system in the observed rise of blood pressure in reflux nephropathy, but individual PRA measurements do not appear so far to predict reliably the onset of hypertension in affected patients.

Background: Circulating endothelial cells (CECs) are biomarkers for endothelial cell (EC) injury and are quantified using immunomagnetic bead extraction (IBE), or flow cytometry (FC). Reports suggest that there is good agreement between these methods for CEC quantification. Objectives: We examined levels of agreement between these techniques in children with systemic vasculitis. Methods: We addedHUVECorhuman pulmonary arteryECto whole blood to optimize FC gating strategies for EC. EC-optimized FC was then compared with IBE for CEC enumeration in 25 children with vasculitis and 20 healthy controls. Results: Using Bland– Altman analysis, agreement between IBE and EC-optimized FC was poor in children with vasculitis (n = 25) and healthy controls (n = 20): IBE consistently detected higher values than the EC-optimized FC method: themean difference between the two techniques was 60 CECs mL)1, 95% CI ±374 CECs mL)1 (paired analyses of 45 individuals). Agreement was poorest for vasculitis patients:mean difference (IBE – EC-optimized FC) 120 CECs mL)1, 95% CI ±460 CECs mL)1 (P = 0.018). We identified three reasons for this discrepancy: (i) sub-optimal FC gating parameters previously used for detecting CECs; (ii) inherent lack of sensitivity of FC compared with IBE for CEC rare event detection; and (iii) use of lysis buffers required for FC causing CEC lysis. Conclusions: There was poor agreement between EC-optimized FC and IBE for the quantification of CECs from children with active vasculitis and controls.We emphasize that in this clinical setting the two techniques are not directly comparable when comparing results obtained using these different methodologies.

OBJECTIVES To determine whether vascular endothelial growth factor A (VEGF) and its receptors are expressed during bladder development in mice when capillaries are forming, and whether exogenous VEGF might enhance the growth of endothelia and other types of bladder cells, using an embryonic organ-culture model. MATERIALS AND METHODS Whole bladders from wild-type mice, at embryonic day (E) 14, were grown in serum-free organ culture in an air/5% CO2 atmosphere; some cultures were supplemented with VEGF and/or with VEGF receptor 1/Fc chimera (VEGFR1/Fc), which blocks VEGF bioactivity. Organs were harvested after 6 days and the expression of VEGF and related molecules assessed using immunohistochemistry. RESULTS VEGF, VEGFR1 and VEGFR2 positive cells were immunodetected in E14 and E18 bladders. Exogenous VEGF increased whole-organ growth, as assessed by explant areas, total cell numbers, DNA and protein content; proliferation was enhanced, and apoptosis decreased, in urothelium and surrounding tissues. VEGF also increased the proportions of cells expressing endothelial (CD31) and smooth muscle (α smooth muscle actin) markers. VEGFR1/Fc blocked the growth-enhancing effects of exogenous VEGF. CONCLUSIONS In organ culture, exogenous VEGF not only stimulated embryonic bladder endothelial cells but also strikingly enhanced the growth of the whole organ. Whether the effects of VEGF on diverse bladder cell populations are direct or indirect requires further investigation. The finding that VEGF protein is present in embryonic bladders in vivo raises the possibility that it has similar actions during normal development. The results also illuminate the pathobiology of certain bladder diseases in which VEGF levels have been shown to be increased.

We have determined levels of glutathione (GSH), ATP, mitochondrial complex activity and apoptosis rate in proximal tubular cells (PTCs) exfoliated from urine in cystinotic (n=9) and control (n=9) children. Intracellular GSH was significantly depleted in cystinotic PTCs compared with controls (6.8 nmol GSH/mg protein vs 11.8 nmol GSH/mg protein; P

To investigate the potential for endothelial cells to operate as superantigen-presenting cells for T cells and the potential for such an interaction to cause endothelial cell activation and injury.Class II major histocompatibility complex (MHC)-positive human umbilical vein endothelial cells (HUVECs) were cocultured for 4 hours with purified T cells and the superantigens staphylococcal enterotoxin B (SEB) or toxic shock syndrome toxin 1 (TSST-1). After staining with fluorescence-conjugated monoclonal antibodies, flow cytometric analysis was performed on the HUVECs and T cells to examine V(beta)-restricted T cell adherence to the endothelial cell monolayer, V(beta)-restricted T cell activation (CD69 up-regulation), surface expression of endothelial cell activation markers, and generation of endothelial microparticles (EMPs).Coculture of purified T cells with class II MHC-positive HUVECs and either TSST-1 or SEB resulted in V(beta)-restricted CD69 up-regulation by CD4 and CD8 cells (V(beta)2 activation for TSST-1; V(beta)3, V(beta)5.1, and V(beta)12 activation for SEB). Additionally, there was CD4 and CD8 T cell V(beta)-restricted adherence to the HUVEC monolayer at 4 hours. Expression of intercellular adhesion molecule 1, E-selectin, and vascular cell adhesion molecule 1 was up-regulated on the class II MHC-positive HUVECs following exposure to superantigen in the presence of T cells, and there was increased EMP release from activated HUVECs, which occurred earlier and was of greater magnitude than that observed in response to tumor necrosis factor alpha.Class II MHC-positive endothelial cells operate as competent superantigen-presenting cells for CD4 and CD8 lymphocytes in vitro. Dual signaling between endothelial cells and T cells results in V(beta)-restricted activation and adherence to endothelial monolayers and endothelial cell activation and release of EMPs expressing inducible cell adhesion molecules. It is proposed that this mechanism could account in part for the vascular injury associated with superantigen-mediated diseases including Kawasaki disease.

Renal tubular and glomerular function was studied in patients under 18 years of age with childhood-onset systemic lupus erythematosus (SLE) in relation to disease activity in two groups: patients with clinical or laboratory evidence of lupus nephritis and those without (lupus non-nephritis). We reviewed 11 patients with lupus non-nephritis and 10 patients with lupus nephritis over a 12-month period. The measured glomerular filtration rates had a tendency to be lower in the lupus nephritis group. Glomerular dysfunction was manifest in the lupus nephritis group with elevated urinary albumin/creatinine ratios (P

Summary Superantigens (SAgs) are potent stimulators of T cells bearing specific Vβ T cell receptors (TCR) and may play a role in the aetiopathogenesis of systemic vasculitis, although this remains contentious. To investigate the possible aetiological role of SAgs, this study examined peripheral blood T cell Vβ repertoires in children with systemic vasculitis. FACS analysis of 17 different peripheral blood T cell Vβ families was performed in 20 healthy control children, 27 disease control children with nonvasculitic inflammatory disease, 25 children with primary systemic vasculitis, six patients with Kawasaki disease (KD) and six patients with Henoch–Schönlein purpura (HSP). There was a significantly increased variance of CD4 Vβ12 and Vβ17, and CD8 Vβ1 in the primary systemic vasculitis group compared to control and disease controls. Moreover, 80% of the primary systemic vasculitis children had one or more CD4 Vβ expansions or deletions, compared with 30% of controls (P

The aim of this report was to describe childhood patients with Wegener granulomatosis (WG) from one centre, to analyse the variety of clinical manifestations seen and compare the data with other published paediatric and adult series. The records of 17 patients with WG who were under the care of Great Ormond Street Hospital for Children (GOSH) from 1981 to 1998 were reviewed. We analysed presenting features before admittance to GOSH and the clinical signs observed whilst the children were under the care of the hospital. Of 17 patients, 13 were females and there was a male/female ratio of 1:3.25. Among the patients there were 2 sisters. The age of the patients at disease onset varied from 2 weeks to 14 years. The median/mean age was 6/6.3 years. American College of Rheumatology criteria for diagnosing WG were fulfilled in 11 of 17 patients. The frequency of different system involvement was: respiratory 87%, kidneys 53%, sinuses 35%, joints 53%, eyes 53%, nervous system 12%, skin 53%. cANCA was positive in 10 patients (59%), but pANCA was negative in all measured sera. Kidneys were involved in 2 of 8 patients (25%) with the disease onset from 0 to 5 years and in 7 of 9 patients (78%) with the disease onset from 6 to 14 years ( P

Nephrocalcinosis (NC) is a complication of the treatment of X-linked hypophosphatemic rickets (XLHR). Some studies have found that treated patients have enteric hyperoxaluria caused by phosphate therapy and have implicated calcium oxalate, whereas others have found only calcium phosphate in renal biopsy tissue.We aimed to study the urinary supersaturation of calcium oxalate and calcium phosphate and to determine whether these measures are risk factors for NC. We collected 24-hour urine samples from 20 patients (12 girls) with XLHR, mean +/- SD age 8.2 +/- 4.7 years, and from 79 age-matched members of a healthy control group prospectively.The median 24-hour urine excretions of oxalate, phosphate, and citrate (mmol/1.73 m(2) per day) were significantly increased in patients compared with the control group (oxalate 0.38 vs 0.28, P =. 0012; phosphate 63.1 vs 25.8, P.0001; citrate 4.18 vs 2.7, P =. 0002). However, no significant differences were seen in the calcium oxalate or calcium phosphate between patients and the control group. No significant differences were seen in 24-hour urine calcium or magnesium excretion between patients and the control group; however, 8 patients had hypercalciuria. A significant higher urine volume in patients compared with the normal group (826 mL/m(2) 24-hour vs 597 mL/m(2) 24-hour; P.005) was found. Twelve patients had NC at the time of investigation, and although the oxalate excretion was significantly higher in these patients, no significant difference was seen in the relative supersaturation of calcium oxalate monohydrate (CaC(2)O(4).H(2)O) compared with the 8 without NC.Although 24-hour urine oxalate and phosphate excretion are increased in treated patients with XLHR, there is no increase in the supersaturation of either calcium oxalate or phosphate. Determination of the supersaturation of calcium oxalate or calcium phosphate does not predict the development of NC in XLHR.

OBJECTIVE To establish the role played by the circulating nitric oxide synthase inhibitors N(G)-monomethyl-L-arginine (L-NMMA), asymmetrical dimethyl arginine (ADMA) and symmetric dimethyl arginine (SDMA) and its association with hypertension of children and adolescents. DESIGN We measured plasma concentrations of L-NMMA, ADMA and SDMA in 38 hypertensives (median age 7.7 years) and in nine healthy normotensive controls (median age 8.2 years) using high-performance liquid chromatography. In addition, their plasma renin activity was determined. The subjects' glomerular filtration rates were calculated from plasma creatinine and height measurements. To determine the vasoactive potency of the arginine analogues, concentration-response curves were plotted for the responses in isolated endothelium-intact and endothelium-denuded mouse aortic rings that had been pre-contracted by administration of a threshold concentration of phenylephrine. RESULTS Plasma ADMA and SDMA concentrations in members of the hypertensive group [0.23 +/- 0.03 and 1.37 +/- 0.06 micromol/l, respectively (means +/- SEM)] were significantly higher than those in members of the control group (ADMA 0.10 +/- 0.01 micromol/l and SDMA 1.18 +/- 0.06 micromol/l). Plasma concentrations of L-NMMA were similar in members of the hypertensive (0.21 +/- 0.01 micromol/l) and control (0.18 +/- 0.02 micromol/l) groups. The glomerular filtration rate of the hypertensive group was below normal [70.4 +/- 5.4 ml/min per 1.73 m2 (mean +/- SEM)] and was significantly associated with elevated plasma concentrations of ADMA (r = -0.77, P < 0.001), SDMA (r = -0.38, P = 0.02) and L-NMMA (r = 0.35, P = 0.03). Higher plasma ADMA concentrations were associated with a lower plasma renin activity (r = -0.36, P = 0.04). The vasoactive potencies of ADMA (concentration for half-maximal effect with the endothelium intact 25.4 +/- 7.1 micromol/l) and L-NMMA (concentration for half-maximal effect with the endothelium intact 8.2 +/- 2.9 micromol/l) was significantly (P < 0.05) greater than that of SDMA. Both ADMA and L-NMMA (at 3 micromol/l concentrations) initiated a significant vasocontractile response from baseline (P = 0.03 and P < 0.001, respectively). These effects were absent after the endothelium had been removed. SDMA had no effect. CONCLUSIONS Plasma ADMA and SDMA levels are increased in hypertensive children. By inference from in-vitro data, ADMA appears to attain sufficient concentrations to produce a significant change in vascular tone and hence might play a role in the pathophysiology of childhood hypertension.

OBJECTIVES To investigate nitric oxide (NO) activity in childhood hypertension using nitrite and nitrate (NOx) concentrations in plasma as an index of nitric oxide generation. DESIGN Cross sectional study. SETTING Tertiary care paediatric centre and district general hospitals in the UK. PATIENTS Children attending the above centre for treatment of hypertension. The control subjects were normotensive healthy children attending district general hospitals for minor medical and surgical disorders. INTERVENTIONS None. MAIN OUTCOME MEASURES Plasma (P) and urinary (U) NOx concentrations, blood pressure, and glomerular filtration rate. RESULTS Sixteen normal children (mean age 6.9 years), 13 children with reno-vascular hypertension (mean age 7.8 years), and 25 children with hypertension associated with renal parenchymal disease (mean age 10.7 years) were studied. Mean (SD) P NOx values of children with hypertension with renovascular disease (15.3 (11.4) μmol/l) and renal parenchymal disease (18.3 (11.4) μmol/l) were significantly above that of normal children (11.9 (5.9) μmol/l) after accounting for age and glomerular filtration rate influences. Higher concentrations of P NOx in normal children were associated with younger age, but not in the children with hypertension. Higher P NOx concentrations were also associated with a lower glomerular filtration rate in normal children and children with hypertension with renal parenchymal disease, but not in the children with hypertension with renovascular disease. U NOx excretion expressed as a ratio against urine creatinine (U creat ) excretion was not statistically different among the study groups. CONCLUSIONS P NOx is increased in children with hypertension even after statistical elimination of the glomerular filtration rate and age influences. This suggests a normal or increased NO synthase activity in childhood hypertension in contrast with adults with hypertension in whom it is described as reduced.

Purpose Inflammation and endothelial dysfunction are involved in coronary allograft vasculopathy (CAV) after heart transplant (HT) but the mechanisms and the potential impact on the native vasculature is unknown. Methods and Materials We used IVUS to evaluate CAV in children after transplant and studied native, systemic vascular structure and function with carotid intima-medial thickness (cIMT) and brachial artery flow mediated dilatation (FMD). In 54 children (28 male) age 9 to 18 years, we undertook IVUS, cIMT and FMD median 58 months (2.2 to 151) after HT. Findings were compared to 16 age, sex matched, healthy controls. Circulating markers of inflammation and endothelial activation were also measured. Results 10 patients had evidence of CAV with mean intima-media thickening > 0.5 mm analysed over 26 mm (SD 9) of the LAD coronary. This represents patients in the upper quartile. No relation to time post transplant and donor age was detected. HT patients had evidence of endothelial activation with an increase in soluble e-selectin, VCAM1 and thrombomodulin in the absence of raised inflammatory cytokines. CAV was related to low levels of thrombomodulin™, tissue factor (TF) and increased von Willebrand Factor (vWF) in peripheral blood suggesting a relationship to coagulation homeostasis. In contrast there were no abnormalities of systemic vascular structure and function. Conclusions After heart transplant there was evidence of significant CAV but not systemic vasculopathy. TF, TM and vWF were related to coronary IMT suggesting involvement in pathogenesis of CAV and novel treatment opportunities. Patient Control Median Max Min Median Max Min p value IL1B 0.6 0.001 4.2 0.001 0.001 0.9 IL8 3.5 1.6 9.0 4.3 2.0 9.1 0.06 sVCAM_1 538 244 758 442 318 676 0.03* sE selectin 15 7.6 27.7 11.4 7.5 19.6 0.005* Thrombomodulin 7.0 4.4 11.3 5.2 4.4 9.1 hsCRP 0.3 0.01 8.7 0.2 0.05 3.4 0.9 IL6 3.9 1.4 20.7 3.1 1.7 13.3 0.3 TNF alpha 5.0 2.7 10.9 5.3 3.6 8.0 0.3 Mean IMT ng/ml > 0.5 mm p value Thrombomodulin 6.0 7.2 0.046 TF 27.8 35.3 0.023 vWF 0.79 0.54 0.013

We studied urine protein excretion in 55 adults with reflux nephropathy (median age 26.9 years) who had had normal blood pressure, renal function and ureteric reimplantation in childhood. Urine retinol binding protein (RBP), N-acetyl-beta-D-glucosaminidase (NAG), albumin, bacteriuria, systolic blood pressure, glomerular filtration rate (GFR), peripheral plasma renin activity (PRA) and the degree of renal scarring were measured in each subject; 20 had bilateral and 35 unilateral renal scarring; 5 were hypertensive and none were in renal failure. Urinary NAG and RBP excretions were significantly greater in the study group than in 34 healthy controls (median age 29.7 years). Within the study group, NAG excretion significantly correlated with PRA (P = 0.02). RBP excretion correlated with PRA, systolic blood pressure and the laterality (bilateral vs. unilateral) of scarring (P0.01). Urinary albumin excretion correlated with systolic blood pressure (P = 0.03). We conclude that increased urinary protein, especially NAG and RBP excretion, occur late after ureteric re-implantation in reflux nephropathy independent of GFR. Its association with PRA supports the concept of segmental perfusion and filtration as an important mechanism that may explain the above findings.

SUMMARY sE-selectin, sICAM-1, sVCAM-1 and von Willebrand factor (vWF) were assayed in 238 samples in a longitudinal study of 81 normal children from 9.5 to 15.5 years old. Multilevel modelling was used to quantify changes with age. sE-selectin, sICAM-1 and sVCAM-1 all fell significantly over the age range (by 17%, 16%, and 10%, respectively). In contrast, levels of vWF were not age-dependent. Our findings highlight the need for age-matched controls when studying cell surface adhesion molecules in disease groups, and may imply developmental changes in expression of these molecules and their shedding from the cell surface.

There is evidence of neutrophil involvement in the pathogenesis of the haemolytic uraemic syndrome (HUS), and neutrophil release products are thought to cause endothelial cell damage. Elastase is the major lysosomal proteinase liberated by activated neutrophils. In this study we measured both free and complexed elastase. No free elastase activity could be detected in the plasma of patients with diarrhoea-associated (D+) HUS using a specific substrate. However, there was a marked increase in alpha 1-antitrypsin (alpha 1-AT) complexed elastase as measured by a newly developed enzyme-linked immunosorbent assay not only in D+ HUS, but also in non-diarrhoea-associated (D-) HUS. This finding is independent of either a high polymorphonuclear leucocyte count or renal failure. This increase in bound elastase together with our sequential data which demonstrate raised alpha 1-AT complexed elastase levels early in the disease process further support the theory that neutrophil activation is one of the key events in the pathophysiology of this disorder.

Introduction: Despite conflicting evidence and much debate, superantigenic stimulation of the immune system in Kawasaki disease (KD) remains an attractive hypothesis since there is considerable overlap between the clinical and immunological phenotypes of KD and classical superantigen-mediated diseases such as the toxic shock syndrome. Moreover, although there are limited data in adults suggesting that SAgs may be involved in the initiation of other primary systemic vasculitides, no such data exists for children. Methods: To investigate the possible aetiological role of SAgs, this study examined peripheral blood TCR Vb repertoires in children with KD (n=6), polyarteritis nodosa (PAN, n=23), Wegener's granulomatosis (WG, n=1), and microscopic polyangiitis (MPA, n=1). 20 normal children and 30 children with non-vasculitic inflammatory disease, or recipients of renal allografts served as controls and disease controls respectively. 3 colour FACS analysis of peripheral blood mononuclear cells stained with conjugated monoclonal antibodies to CD3, CD4, CD8, and 17 different Vb families was performed. Results: The mean % of CD4+ T cells bearing Vb2 was significantly increased in the KD group versus controls and disease controls (p=0.03 and p=0.01 respectively). Individual KD patients were also noted to have CD4+ T cell Vb expansions other than Vb2 (Vb5.1 n=2; Vb12 n=1). 60% of the primary systemic vasculitis patients had one or more TCR Vb expansions in the CD4+ lymphocyte population, compared with 30% of the controls (p=0.02-0.05), and 36% of the disease controls (p=0.05-0.1). Unlike KD, however, the pattern of Vb families expanded in individual patients was more diverse, perhaps indicative of the involvement of several different SAgs. Follow-up of 7 primary systemic vasculitis patients demonstrated a normalization of the CD4+ T cell Vb repertoire following induction of remission. Conclusion: Our preliminary data provide indirect evidence for an aetio-pathogenetic role for SAgs in KD and primary systemic vasculitides affecting children.

Renal venous PRA was measured in 49 normotensive children without renal disease undergoing routine cardiac catheterization. PRA levels did not differ significantly between both renal veins and were significantly higher in the renal veins than in the IVC. There was a constant mean ratio of 1.21 between the renal veins and the IVC at low, intermediate, and high absolute PRA levels. Three patients had a renal venous PRA ratio greater than 1.4 and the highest ratio observed was 1.55. This fidning supports 1.5 as an acceptable upper limit of normality for the interpretation of renal vein PRA ratios in the investigation of patients with suspected renal hypertension. In four patients, PRA in the renal veins was significantly lower than in the IVC. The possibility of renin removal by these kidneys is discussed.

The urinary extraction of albumin, retinol binding protein, and N-acetyl-beta-D-glucosaminidase were studied in 60 children with insulin dependent diabetes mellitus and in 45 normal children to find out whether the renal tubules played a part in causing the early increase in urinary excretion of albumin that occurs in diabetes mellitus. Two overnight urine samples were collected and the protein excretion measured and expressed as the geometric mean of the protein to creatinine ratio (urinary albumin:creatinine ratio, urinary retinol binding protein:creatinine ratio, and urinary N-acetyl-beta-D-glucosaminidase:creatinine ratio, respectively). The excretion of all three proteins was significantly higher in the diabetic children with 15 (25%) of urinary albumin:creatinine ratio, 16 (27%) of urinary retinol binding protein:creatinine ratio, and 43 (72%) of urinary N-acetyl-beta-D-glucosaminidase:creatinine ratio values being above the normal range. Significant correlations were observed between urinary albumin:creatinine ratio and urinary retinol binding protein:creatinine ratio, urinary albumin:creatinine ratio and urinary N-acetyl-beta-D-glucosaminidase:creatinine ratio, and urinary retinol binding protein:creatinine ratio and urinary N-acetyl-beta-D-glucosaminidase:creatinine ratio. There were also significant correlations between glycated haemoglobin 1c (HbA1c) and these proteins, especially N-acetyl-beta-D-glucosaminidase. No correlations were observed with the fractional excretion of sodium, flow rate of urine, glomerular filtration rate, or blood pressure. These data show that tubular abnormalities are present early in the course of insulin dependent diabetes mellitus and suggest that the early increase in urinary excretion of albumin may be at least partly tubular in origin, and that glycaemic control may influence this aspect of proximal tubular function.

Plasma-renin-activity (P.R.A.) was raised in 9 of 15 hypertensive children with pyelonephritic scarring secondary to urinary-tract infection and vesicoureteric reflux and also in 8 of 100 normotensive children with such scars. P.R.A. was much less likely to fall with age in normotensive children with renal scarring than in normal children. The identification of hyperreninaemic normotensive children with renal scarring is important, since P.R.A. may prove to be of value in early identification of children at risk of developing hypertension. A longitudinal follow-up is proposed to establish this hypothesis.

The variability of urine albumin excretion (UAE) was studied in normal and diabetic children and, in addition, the best method of expressing the data was investigated. In 39 timed overnight urine samples from diabetic children, the urine albumin creatinine clearance ratio (CA/CC) was compared with the urine albumin creatinine concentration ratio (UA/UC), the urine albumin excretion rate (UAER) and the urine albumin concentration (UA). UA/UC predicted CA/CC (r = 0.95) better than either UAER (r = 0.83, P less than 0.02) or UA (r = 0.90), 0.1 greater than P greater than 0.05). The within-individual and the between-individual variability in overnight UA/UC in 171 urine samples from 73 normal children was compared with that of 406 urine samples from 119 diabetic children, using a "random effects type 2 nested analysis of variance" model. Geometric mean (range) UA/UC (mg/mmol) in diabetic children, 0.55 (0.04-6.90), was greater than in normal children, 0.33 (0.05-2.10, P less than 0.01), and 18% of diabetics had a value of UA/UC above the normal range. Within-individual variance was the same in normals (0.12) and diabetics (0.12), but between-individual variance in diabetics (0.18) was much greater than in normals (0.03). These data show that within-individual observations for both normals and diabetics are highly but equally variable. Furthermore, from these data, it is possible to infer that a minimum of five estimations are necessary per individual to estimate the true mean value of urine albumin excretion with reasonable confidence.

The clinical features of 55 cases of autosomal recessive polycystic kidney disease (ARPCKD) have been reviewed. Each had evidence of ARPCKD. The outcomes of 87% were known; 24 had died. Twenty-four of 31 were seen between 1980 and 1986; 7 could not be traced. Forty-five percent presented under 1 month; 38% between 1 month and 1 year; and 9 cases over 1 year. Hyponatraemia occurred in 15 out of 19 aged less than 3 months; hypertension occurred in 65%; splenomegaly in 47% of those surviving more than 3 months. Portocaval shunts were done in 5 aged 2-12 years. Thirteen died of renal failure, 6 under 1 year, and 7 between 1 year and 13 years. Life-table survival rates calculated from birth revealed that 86% were alive at 3 months, 79% at 1 year, 51% at 10 years, and 46% at 15 years. Calculations based on patients who survived to 1 year of age showed that 82% were alive at 10 years and 79% at 15 years. These results reveal an improved prognosis for a condition once assumed to be fatal.

Eight of 100 normotensive children who had pyelonephritic scarring secondary to urinary infection and vesicoureteric reflux were found in an earlier study to have increased plasma renin activity (PRA). Because the risk of these patients becoming hypertensive is between 10% and 20% and because renin activity may play a part in the pathogenesis of the hypertension, PRA and blood pressure were studied in 98 of the original group after five years of follow up. Two patients could not be traced, and other factors that might influence blood pressure or PRA led us to exclude 13 others, 10 of whom were girls taking oral hormonal contraceptives. Increased PRA was found in 11 of the remaining 85 patients but not in five of the eight patients with increased PRA in the first study. Of eight children identified as hypertensive in the follow up study, only three had had increased PRA five years previously. In normal children PRA decreases with age. In the initial study this tendency was less pronounced in children with renal scars, and in the follow up study it was reversed. This was also confirmed by PRA standard deviation scores, which showed a significant increase in PRA during the five years. PRA tends to rise in patients with pyelonephritic scars as they grow older. There was no direct correlation between blood pressure and PRA, plasma creatinine concentration, or degree of scarring. Analysis of blood pressure standard deviation scores, however, suggested an excessive rise in blood pressure during the five years.