Complement activation patterns in atypical haemolytic uraemic syndrome during acute phase and in remission.

Atypical haemolytic uraemic syndrome (aHUS) is associated with (genetic) alterations in alternative complement pathway. Nevertheless, comprehensive evidence that the complement system in aHUS patients is more prone to activation is still lacking. Therefore, we performed a thorough analysis of complement activation in acute phase and in remission of this disease. Complement activation patterns of the aHUS patients in acute phase and in remission were compared to those of healthy controls. Background levels of complement activation products C3b/c, C3bBbP and terminal complement complex (TCC) were measured using enzyme-linked immunosorbent assay (ELISA) in ethylenediamine tetraacetic acid (EDTA) plasma. In vitro-triggered complement activation in serum samples was studied using zymosan-coating and pathway-specific assay. Furthermore, efficiencies of the C3b/c, C3bBbP and TCC generation in fluid phase during spontaneous activation were analysed. Patients with acute aHUS showed elevated levels of C3b/c (P < 0·01), C3bBbP (P < 0·0001) and TCC (P < 0·0001) in EDTA plasma, while values of patients in remission were normal, compared to those of healthy controls. Using data from a single aHUS patient with complement factor B mutation we illustrated normalization of complement activation during aHUS recovery. Serum samples from patients in remission showed normal in vitro patterns of complement activation and demonstrated normal kinetics of complement activation in the fluid phase. Our data indicate that while aHUS patients have clearly activated complement in acute phase of the disease, this is not the case in remission of aHUS. This knowledge provides important insight into complement regulation in aHUS and may have an impact on monitoring of these patients, particularly when using complement inhibition therapy.

Rituximab in minimal change nephropathy and focal segmental glomerulosclerosis: report of four cases and review of the literature.

Minimal change nephropathy (MCNS) and focal segmental glomerulosclerosis (FSGS) are the main causes of the idiopathic nephrotic syndrome. MCNS usually responds to steroids and the long-term prognosis is generally good. However, some patients require prolonged treatment with immunosuppressive agents. FSGS generally follows a less favourable course: patients do not always respond to steroids and may progress to end-stage renal disease. Recurrence of FSGS after renal transplantation is frequently observed and may result in graft loss. Recently, anecdotal case reports have described long-term resolution of nephrotic syndrome due to MCNS or FSGS after treatment with rituximab. We present four patients with nephrotic syndrome due to MCNS, FSGS or recurrence of FS GS after kidney transplantation, who were treated with rituximab with variable success. A review of the recent literature suggests that anti-CD20 antibodies may be a promising therapy, especially for patients with MCNS or idiopathic FSGS. Controlled studies are required to determine the efficacy of rituximab and to define which patients will benefit.

REducing STEroids in Relapsing Nephrotic syndrome: the RESTERN study- protocol of a national, double-blind, randomised, placebo-controlled, non-inferiority intervention study.

INTRODUCTION: Oral corticosteroids are the first-line treatment for idiopathic childhood nephrotic syndrome. Most children experience several relapses, needing repeated courses of corticosteroid therapy. This exposes them to side effects and long-term complications. For most patients, long-term prognosis is for complete resolution of the disease over time and maintenance of normal kidney function. Therefore, it is vital to focus on minimising adverse events of the disease and its therapy. Unfortunately, no randomised controlled trials are available to determine the optimal corticosteroid treatment of an infrequent relapse of nephrotic syndrome. Recent studies show that treatment schedules for the first episode can safely be shortened to 2 months. The hypothesis of the REducing STEroids in Relapsing Nephrotic syndrome (RESTERN) study is that a 4-week reduction of alternate-day steroids after inducing remission is effective and safe, reduces steroid exposure by 35% on average and is therefore preferable. METHODS AND ANALYSIS: The RESTERN study is a nationwide, double-blind, randomised, placebo-controlled, non-inferiority intervention study. Children aged 1-18 years with a relapse of steroid-sensitive nephrotic syndrome are eligible for this study. Study subjects (n=144) will be randomly assigned to either current standard therapy in the Netherlands or a reduced prednisolone schedule. The primary outcome of the RESTERN study is the time to first relapse after the final prednisolone dose. The secondary outcomes are the number or relapses, progression to frequent relapsing or steroid dependent nephrotic syndrome and the cumulative dosage of prednisolone during the study period. ETHICS AND DISSEMINATION: This non-inferiority trial will be performed in accordance with the Declaration of Helsinki and has been approved by the medical ethical committee of Arnhem-Nijmegen and the Dutch Competent Authority (Central Committee on Research Involving Human Subjects, CCMO). After completion of this study, results will be published in national and international peer-reviewed scientific journals. Papers will be published according to CCMO guidelines. The final report will be made available to trial participants. TRIAL REGISTRATION NUMBER: NTR5670, EudraCT no 2016-002430-76.

Verocytotoxin-producing Escherichia coli infection in household members of children with hemolytic-uremic syndrome in The Netherlands.

BACKGROUND: Strains of verocytotoxin-producing Escherichia coli (VTEC) belonging to serogroup O157 (O157 VTEC) can cause a spectrum of disease that includes nonspecific diarrhea, hemorrhagic colitis and the diarrhea-associated form of the hemolytic uremic syndrome (D+ HUS). METHODS: We conducted a retrospective study of 34 children with D+ HUS caused by O157 VTEC to determine the frequency of VTEC infection in their household members. RESULTS: Gastrointestinal tract symptoms were reported in 1 or more household contacts of 17 (50%) of the 34 index cases. Of the 26 household members with gastrointestinal tract symptoms, 15 were parents and 11 were siblings. Evidence of VTEC infection was reported in 1 or more household contacts in 23 (68%) of the 34 families (in 46% of the siblings and in 28% of the parents). Nineteen (48%) siblings had a positive stool sample and in only 5 (12%) of the siblings IgM class serum antibodies to O157-lipopolysaccharide (LPS) were detected. Nineteen (31%) parents had a positive stool sample. Antibodies to O157-LPS were not detected in any of the parents. The occurrence of (bloody) diarrhea significantly correlated with the occurrence of IgM class serum antibodies to O157-LPS. CONCLUSIONS: It was concluded that household members of children with D+ HUS are often asymptomatically infected with O157 VTEC. Differences in the pathogenesis of the infection between infected individuals may be related to differences in the number of ingested O157 VTEC bacteria and to differences in susceptibility.

Four cases of hemolytic uremic syndrome--source contaminated swimming water?

In June '93, 4 children, aged 1.5-3.5 years, all living in one town, were admitted to our hospital with the diagnosis hemolytic uremic syndrome (HUS) within one week. In cooperation with the local health authorities a common source was searched for. Questionnaires indicated that the single condition shared by all patients was swimming water. The patients were not acquainted, visited different daycares, and had no food resources in common. All 4 patients bathed in the same, shallow, recreational lake within a period of 5 days. During this time the air temperature was high according to Dutch standards (around 27 degrees C), and many people visited the lake, estimated several hundreds a day. The water level was lower than normal. Diarrhea followed 3-11 days after swimming and the first clinical symptoms of HUS developed 6-7 days after the onset of diarrhea. The lake was closed for swimming when the fourth HUS patient was diagnosed and the possibility of transmission by way of the lake was mentioned. E. coli O157: H7 was demonstrated in the fecal samples of 2 index patients. The samples were taken 9-20 days after the start of diarrhea. Antibodies to O157 and verotoxin 2 were strongly positive in all patients. A local outbreak of diarrheal illness was not registered. Of 16 family members who also swam in the same lake, 7 developed symptoms of enteritis, 3 had positive cultures of their fecal samples and 5 had positive serology. Pulsed-field gel electrophoresis of the E. coli isolates of the patients and family members showed an identical pattern. No O157: H7-DNA could be detected in filter concentrated lake water samples using polymerase chain reaction (PCR) enhancement. These samples were, however, taken 16 days after the latest possible date of contamination of our patients, 15 days after decrease of the air temperature to 15-17 degrees C, and 14 days after the inlet from water from the environment. It could thus very well be that the microorganism was no longer present. This third report of swimming water associated HUS should direct environmental surveys in similar cases of local HUS outbreaks.

Is biopsy required prior to cyclophosphamide in steroid-sensitive nephrotic syndrome?

AIM: The present studywas designed to retrospectively evaluate the use of renal biopsies prior to cyclophosphamide therapy. The aim of the study was to determine in how many cases histological outcome of the biopsies had subsequently changed the decision to treat or refrain from treatment. PATIENTS AND METHODS: Between January 1980 and September 2001, 85 children with steroid-sensitive nephrotic syndrome (SSNS) underwent a renal biopsy in the University Hospitals of Utrecht and Nijmegen before the start of an 8-week cyclophosphamide treatment. MCNS was suspected in all children because of the following criteria: edema, proteinuria, hypoalbuminemia, absence of macroscopic hematuria and in rare cases microscopic hematuria, no permanent hypertension, normal C3 serum level, a normal glomerular filtration rate as determined by creatinine clearance and age > 1 year. Cyclophosphamide therapy was indicated because of a frequently relapsing (FR) course of illness in 8 children, because of steroid dependence (SD) in 22 children and because of combined FR and SD in 55 children. Steroid-resistant children were excluded from this study. RESULTS: Histology confirmed the diagnosis MCNS in 84 out of 85 children. In addition to MCNS, IgA deposits were observed in renal specimens of 2 children. In 1 SD child, the initial diagnosis MCNS was changed 3 years later when a repeated biopsy showed progression into focal segmental glomerulosclerosis (FSGS). CONCLUSION: In summary, no renal biopsy is required prior to cytotoxic therapy in children with uncomplicated steroid-sensitive nephrotic syndrome.

[Infections with verocytotoxin-producing Escherichia coli and hemolytic-uremic syndrome]. / Infecties met verocytotoxine-producerende Escherichia coli en het hemolytisch-uremisch syndroom.

Infections with verocytotoxin-producing Escherichia coli and (VTEC), and especially with serotype O157, are the main cause of haemolytic-uraemic syndrome (HUS) in children in the Netherlands. 8% of the patients infected develop HUS; the incidence is 2/105/year in children under 5 years. The infection may be asymptomatic, but may also lead to mild to haemorrhagic diarrhoea and to haemorrhagic colitis. Up to 10% of the patients die in the acute phase of the disease and in up to another 10% the renal damage does not resolve completely. In 1993 bovine meat samples examined by polymerase chain reaction revealed VTEC in 16% of the cases; however none of the isolated serotypes was known to be pathogenic in humans. Epidemiological investigations are being carried out in the cattle population. Verocytotoxins are exotoxins that bind to surface receptors on cells after which part of the toxin is internalized where it inhibits protein synthesis. The functional receptor is glycosphingolipid globotriaosylceramide, a molecule normally only expressed in the renal glomeruli of children under three years of age.

[From gene to disease; congenital thrombotic thrombocytopenic purpura due to mutations in the ADAMTS13 gene]. / Van gen naar ziekte; congenitale trombotische trombocytopenische purpura door mutaties in het ADAMTS13-gen.

Thrombotic thrombocytopenic purpura (TTP) is characterised by haemolytic anaemia with fragmented erythrocytes and thrombocytopenia, accompanied by other symptoms such as renal dysfunction, neurological signs and fever. Proteolysis of the Von Willebrand blood-clotting factor (VWF) by a VWF cleaving protease or ADAMTS13 is decreased in patients with TTP, leading to ultra-large Von Willebrand multimers in the circulation. A lack of ADAMTS13 activity can be caused by autoimmune inhibitors or may be due to a constitutional deficiency of this protein. Recently, the ADAMTS13 gene that encodes for the ADAMTS13 protein was found. It was mapped to chromosome 9q34 and consists of 29 exons. Several mutations have been identified in the ADAMTS13 gene in patients with the congenital form of TTP. Symptomatic episodes in congenital TTP can be prevented by prophylactic plasma infusions every 2-3 weeks, hereby preventing further organ damage due to thrombotic microangiopathy.

Living kidney transplantation in adult patients with atypical haemolytic uraemic syndrome.

BACKGROUND: Dysregulation of complement activation is the most common cause of the atypical haemolytic uraemic syndrome (aHUS). Many patients with aHUS develop end-stage renal disease and consider kidney transplantation. However, the recurrence rate after transplantation ranges from 45-90% in patients with known abnormalities in circulating complement proteins. It was recently proposed that patients with aHUS should be treated prophylactically with plasma exchange or eculizumab to prevent recurrence after transplantation. METHODS: A case series describing the successful outcome of kidney transplantation without prophylactic therapy in four adult patients with aHUS and a high risk of disease recurrence. Patients received a living donor kidney and immunosuppression consisting of basiliximab induction, low-dose tacrolimus, prednisone and mycophenolate mofetil. Patients received a statin, and were targeted to a low blood pressure preferably using blockers of the renin-angiotensin system. RESULTS: After a follow-up of 16-21 months, none of the patients developed recurrent aHUS. Also, no rejection was observed. CONCLUSIONS: Kidney transplantation in adult patients with aHUS can be successful without prophylactic eculizumab, using a protocol that minimises cold ischaemia time, reduces the risk of rejection and provides endothelial protection. Our data suggest that in patients with aHUS, controlled trials are needed to demonstrate the optimal strategy.

A new era in the diagnosis and treatment of atypical haemolytic uraemic syndrome.

The haemolytic uraemic syndrome (HUS) is characterised by haemolytic anaemia, thrombocytopenia and acute renal failure. The majority of cases are seen in childhood and are preceded by an infection with Shiga-like toxin producing Escherichia coli (STEC-HUS; so-called typical HUS). Non-STEC or atypical HUS (aHUS) is seen in 5 to 10% of all cases and occurs at all ages. These patients have a poorer outcome and prognosis than patients with STEC-HUS. New insights into the pathogenesis of aHUS were revealed by the identification of mutations in genes encoding proteins of the alternative pathway of the complement system in aHUS patients. Specific information of the causative mutation is important for individualised patient care with respect to choice and efficacy of therapy, the outcome of renal transplantation, and the selection of living donors. This new knowledge about the aetiology of the disease has stimulated the development of more specific treatment modalities. Until now, plasma therapy was used with limited success in aHUS, but recent clinical trials have demonstrated that patients with aHUS can be effectively treated with complement inhibitors, such as the monoclonal anti-C5 inhibitor eculizumab.

Renal transplantation in patients with atypical haemolytic uraemic syndrome: a tailor made approach is necessary.

A 33-year-old woman with a history of chronic transplant dysfunction because of repeated bouts of haemolytic uraemic syndrome (HUS) was considered for a second transplant. Extensive genetic investigation of the complement system was executed to rule out known mutations prone to development of HUS. This case illustrates the importance of genetic screening in patients with recurrent HUS.

The haemolytic-uraemic syndrome in childhood.

Haemolytic-uraemic syndrome (HUS) is a clinical syndrome characterized by acute haemolytic anaemia with fragmented erythocytes, thrombocytopenia and acute renal failure. It is one of the leading causes of acute renal failure in childhood. HUS in children can be divided into the so-called typical, diarrhoea-associated HUS, and atypical HUS, which is not preceded by acute gastroenteritis. Infection with verocytotoxin-producing Escherichia coli is the main cause of diarrhoea-associated HUS. In this chapter the pathogenesis of diarrhoea-associated HUS and the role of verocytotoxin-producing Escherichia coli in this form of HUS is emphasized.

Tumor necrosis factor and interleukin 1 induce expression of the glycolipid verotoxin receptor in human endothelial cells. Implications for the pathogenesis of the haemolytic uraemic syndrome.

Activation of the endothelium by TNF or IL-1 results in altered haemostatic properties of and leukocyte binding to the endothelium. In haemolytic uraemic syndrome, the endothelium of the kidney and sometimes other tissues is severely damaged, presumably by a bacterial toxin, verotoxin (VT). In vitro studies have demonstrated that endothelial cells become sensitive to this toxin when they are exposed to TNF alpha or IL-1, inflammatory mediators which are produced by monocytes and mesangial cells and which may play a role in the kidney. In this report we demonstrate the influence of inflammatory mediators on the binding of VT to endothelial cells. Preincubation of human endothelial cells with TNF alpha for 24 h resulted in a ten- to hundred-fold increase of specific binding sites for 125I-VT-1. IL-1 and lymphotoxin (TNF beta) also markedly increased VT-1 binding. An exposure of only 6 h to TNF alpha was already enough to enhance the number of VT-1 binding sites on endothelial cells for at least 2 days. In order to demonstrate that the increases in VT binding was due to an increase in the functional VT receptor, glycolipid extracts of TNF alpha-treated cells were analyzed by thin layer chromatography. An increase of globotriaosylceramide (Gb3) was observed, suggesting that that preincubation of endothelial cells with TNF alpha leads to an increase in Gb3 synthesis in these cells. Inhibition of protein synthesis by cycloheximide prevented the increase in VT receptors induced by TNF alpha.(ABSTRACT TRUNCATED AT 250 WORDS)

The fibrinolytic system in the hemolytic uremic syndrome: in vivo and in vitro studies.

Fibrinolytic parameters and von Willebrand factor (vWF) antigen were measured in the plasma of 10 patients with hemolytic uremic syndrome (HUS). Samples were taken at presentation and again 2 wk later, before and after infusion of 1-desamino-8-arginine vasopressin. Compared with the plasma values of healthy control children, levels of tissue-plasminogen activator (t-PA) antigen, plasminogen activator inhibitor type I (PAI-1) activity, and vWF as well as fibrin(ogen) degradation products were significantly elevated in the plasma of HUS patients on admission. No response of the fibrinolytic parameters and vWF were seen when 1-desamino-8-arginine vasopressin infusion was given on admission. After 2 wk, t-PA antigen and vWF had partially returned to basal values, and t-PA antigen increased rapidly again after 1-desamino-8-arginine vasopressin infusion. To investigate whether verocytotoxin contributes to the alteration of the fibrinolytic system found in HUS patients, purified verocytotoxin-1 (VT-1) was added to the media of cultured human endothelial cells. Addition of VT-1 alone did not change the production of t-PA, plasminogen activator inhibitor type I, and vWF antigen in these cells. However, when the endothelial cells were preincubated with tumor necrosis factor-alpha to increase the number of VT-1 receptors, VT-1 induced a marked decrease of the synthesis of t-PA, plasminogen activator inhibitor type I, and vWF. This was caused by a decrease in overall protein synthesis in the tumor necrosis factor-alpha- and VT-1-treated endothelial cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Tumor necrosis factor and interleukin-1 induce expression of the verocytotoxin receptor globotriaosylceramide on human endothelial cells: implications for the pathogenesis of the hemolytic uremic syndrome.

The epidemic form of the hemolytic uremic syndrome (HUS), beginning with an acute gastroenteritis, has been associated with a verocytotoxin-producing Escherichia coli infection. The endothelial cell is believed to play an important role in the pathogenesis of HUS. Endothelial cell damage by verocytotoxin-1 (VT-1) in vitro is potentiated by the additional exposure of inflammatory mediators, such as tumor necrosis factor-alpha (TNF-alpha). Preincubation of human umbilical vein endothelial cells (HUVEC) with TNF-alpha resulted in a 10- to 100-fold increase of specific binding sites for 125I-VT-1. Furthermore, interleukin-1 (IL-1), lymphotoxin (TNF-beta), and lipopolysaccharide (LPS) also markedly increase VT-1 binding. Several hours' exposure to TNF-alpha was enough to enhance the number of VT-1 receptors on the endothelial cells for 2 days. The TNF-alpha-induced increase in VT-1 binding could be inhibited by simultaneous addition of the protein synthesis inhibitor cycloheximide. Glycolipid extracts of TNF-alpha-treated cells tested on thin-layer chromatography demonstrated an increase of globotriaosylceramide (GbOse3cer), a functional receptor for VT-1, which suggests that preincubation of human endothelial cells with TNF-alpha leads to an increase in GbOse3cer synthesis in these cells. We conclude from this study that TNF-alpha and IL-1 induce one (or more) enzyme(s) that is (are) rate-limiting in the synthesis of the glycolipid VT-1 receptor, GbOse3cer. These in vitro studies suggest that, in addition to VT-1, inflammatory mediators play an important role in the pathogenesis of HUS.

Tumor necrosis factor alpha induces endothelial galactosyl transferase activity and verocytotoxin receptors. Role of specific tumor necrosis factor receptors and protein kinase C.

Infections with verocytotoxin (VT) producing Escherichia coli have been strongly implicated in the epidemic form of hemolytic uremic syndrome (HUS). Endothelial damage plays a central role in the pathogenesis of HUS. In vitro studies have shown that VT can damage endothelial cells after interaction with its cellular receptor globotriaosylceramide (GbOse3cer). Cytokines, such as tumor necrosis factor alpha (TNF alpha) and interleukin-1 (IL-1) can potentiate the toxic effect of VT by inducing a protein-synthesis dependent increase in VT receptors on endothelial cells. In this study, the mechanisms underlying the increase in endothelial VT receptors induced by TNF alpha were studied in more detail. To investigate which proteins were involved in this induction, endothelial cells were incubated with and without TNF alpha in the presence of 14C-galactose or 14C-glucose. Thin-layer chromatography (TLC) analysis of the glycolipid extracts of these cells demonstrated a markedly enhanced incorporation of 14C-galactose in GbOse3cer and other galactose-containing glycolipids, suggesting that TNF alpha enhanced galactosyl-transferase activity. To examine the role of the two recently cloned TNF-receptors (TNFR-p75 and TNFR-p55) in the TNF alpha-induced increase in GbOse3cer in human endothelial cells, cells were incubated with TNF alpha, the TNFR-p55 selective R32W-S86T-TNF alpha-mutant, or the TNFR-p75 selective D143N-A145R-TNF alpha-mutant. The effect of TNF alpha activation, determined by binding-experiments with 125I-VT-1, could be largely, but not completely mimicked by R32W-S86T-TNF alpha. Although incubation of cells with D143N-A145R-TNF alpha did not show an increase in VT-1 binding, the monoclonal antibody utr-1, which prevents binding to TNFR-p75, decreased the TNF alpha-induced VT-1 binding. Activation of protein kinase C (PKC) by phorbol ester increases the expression of VT-1 receptors; this effect was prevented by the PKC inhibitor Ro31-8220 and by homologous desensitization by pretreatment with phorbol ester. In contrast, the presence of the protein kinase inhibitor Ro31-8220 or desensitization of PKC activity reduced the TNF alpha-induced increase in VT-1 receptors maximally by 50% and 24%, respectively. Comparable reductions in overall protein synthesis and the synthesis of E-selectin and plasminogen activator inhibitor-1 (PAI-1) were observed. This suggests an effect on general protein synthesis rather than a specific effect of PKC in the signal transduction pathway, by which TNF alpha induces VT-1 receptors. Our results indicate that TNF alpha can increase the VT-1 receptors on endothelial cells by inducing galactosyl-transferase activity, that this action of TNF alpha mainly occurs via the TNFR-p55; and that PKC activation increases expression of VT-1 receptors by a separate mechanism that acts additively to the TNF alpha-induced increase in VT-1 receptors.

Characterization of verocytotoxin-producing Escherichia coli O157 isolates from patients with haemolytic uraemic syndrome in Western Europe.

Fifty verocytotoxin (VT)-producing Escherichia coli (VTEC) strains of serogroup O157 were characterized by phage typing, polymerase chain reaction (PCR) for VT genes and the E. coli attaching and effacing (eae) gene, and random amplified polymorphic DNA-PCR (RAPD-PCR) fingerprinting. The collection represented isolates obtained from patients with diarrhoea-associated haemolytic-uraemic syndrome (D+ HUS) and their family contacts, isolated in the Netherlands, Belgium and Germany between 1989 and 1993. Based on isolates from separate families (n = 27) seven different phage types were identified, types 2 (44%) and 4 (33%) were predominant. Eighty-five percent of the strains contained only VT2 gene sequences and 15% both VT1 and VT2. All strains of the dominant phage types 2 and 4 carried the VT2 gene. Strains that belonged to the minor phage types 8, 14, 32 carried both VT1 and VT2 genes, with the exception of two isolates identified as phage types 49 and 54 which contained only VT2 genes. All O157 VTEC strains possessed the chromosomally-located eae gene, which indicates its usefulness as virulence marker. RAPD-PCR fingerprinting identified four distinct banding patterns, with one profile found among 79% of the strains. Based on the combined results of all typing methods used in this study, the collection of 50 O157 VTEC strains could be divided into nine distinct groups. Strains isolated from different persons within one family could not be distinguished by any of these methods. The data suggest that O157 VTEC strains are members of one clone that has become widely distributed.

Plasma cytokine levels in hemolytic uremic syndrome.

The cytokines tumor necrosis factor-alpha (TNF-alpha) and its soluble TNF receptors 55 and 75 (sTNFR55, sTNFR75), interleukin-1 beta (IL-1BETA) and interleukin-6 (IL-6) were measured in plasma from 13 patients with the hemolytic uremic syndrome (HUS) on admission. No significant changes in the plasma levels of TNF-alpha and IL-1beta were detected in the HUS patients as compared to the plasma levels of the control groups. Levels of IL-6 were significantly elevated in the plasma of those HUS patients who had external manifestations, consisting of seizures, loss of consciousness, coma and pancreatic necrosis. Although the exact function of IL-6 in the plasma of HUS patients is still unknown and the group of HUS patients is small, plasma IL-6 is associated with the the severity and outcome of the disease. Plasma levels of sTNR55 and sTNFR75 were significantly elevated in all HUS patients compared to the healthy controls, but they were also elevated in the children with chronic renal failure. This indicates that elevated levels of circulating sTNFR should be carefully interpreted when kidney failure exists.

Verocytotoxin-producing Escherichia coli infection in hemolytic uremic syndrome in part of western Europe.

UNLABELLED: From September 1989 until September 1993, stool specimens and sera from 113 children with diarrhoea-associated haemolytic uraemic syndrome (HUS) from the Netherlands, two university hospitals in Belgium and one university hospital in Germany were examined for the presence of verocytotoxin-producing Escherichia coli (VTEC) infection. Evidence for VTEC infection was observed in 88 (78%) patients with HUS compared to 2 (3%) of the 65 children with acute gastro-enteritis Serotype O157 was the causative agent in 76 (86%) of these 88 patients with VTEC-associated HUS and verocytotoxin-2 (VT-2) was the most frequent toxin produced. Serological testing for antibodies to O157 O-antigen yielded the highest number of positive results compared to the other test methods. Antibodies to O157 were found in sera of 71 (65%) of 110 patients with HUS and one control serum. Stool and sera examination for VTEC in 95 family contacts of 28 patients with HUS demonstrated an evidence for VTEC infection 33 (35%). In contrast, in patients with HUS serological antibodies to O157 O-antigen were found in only 3 (4%) of 85 family contacts. CONCLUSION: In this part of Western Europe, VT2-producing Escherichia coli, mainly those belonging to serogroup O157, are the major cause of HUS in childhood.