Hemolytic Uremic Syndrome Patients Research Articles

Shiga toxin-producing escherichia coli infections in Norway, 1992-2012: characterization of isolates and identification of risk factors for haemolytic uremic syndrome.

BackgroundShiga toxin-producing E. coli (STEC) infection is associated with haemolytic uremic syndrome (HUS). Therefore Norway has implemented strict guidelines for prevention and control of STEC infection. However, only a subgroup of STEC leads to HUS. Thus, identification of determinants differentiating high risk STEC (HUS STEC) from low risk STEC (non-HUS STEC) is needed to enable implementation of graded infectious disease response.MethodsA national study of 333 STEC infections in Norway, including one STEC from each patient or outbreak over two decades (1992–2012), was conducted. Serotype, virulence profile, and genotype of each STEC were determined by phenotypic or PCR based methods. The association between microbiological properties and demographic and clinical data was assessed by univariable analyses and multiple logistic regression models.ResultsFrom 1992 through 2012, an increased number of STEC cases including more domestically acquired infections were notified in Norway. O157 was the most frequent serogroup (33.6 %), although a decrease of this serogroup was seen over the last decade. All 25 HUS patients yielded STEC with stx2, eae, and ehxA. In a multiple logistic regression model, age ≤5 years (OR = 16.7) and stx2a (OR = 30.1) were independently related to increased risk of HUS. eae and hospitalization could not be modelled since all HUS patients showed these traits. The combination of low age (≤5 years) and the presence of stx2a, and eae gave a positive predictive value (PPV) for HUS of 67.5 % and a negative predictive value (NPV) of 99.0 %. SF O157:[H7] and O145:H?, although associated with HUS in the univariable analyses, were not independent risk factors. stx1 (OR = 0.1) was the sole factor independently associated with a reduced risk of HUS (NPV: 79.7 %); stx2c was not so.ConclusionsOur results indicate that virulence gene profile and patients’ age are the major determinants of HUS development.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-015-1017-6) contains supplementary material, which is available to authorized users.

Draft Genome Sequences of Human-Pathogenic Escherichia coli O26:H11 Strains Carrying the stx2 Gene Only and Circulating in France.

Shiga toxin-producing Escherichia coli (STEC) O26:H11 is one of the most frequent pathogens associated with diarrhea and hemolytic-uremic syndrome (HUS). In this report, we present the draft genome sequences of seven strains of STEC O26:H11 carrying the stx2a or stx2d gene only and isolated in France from HUS patients.

Efficacy and safety of therapeutic plasma exchange by using apheresis devices in pediatric atypical hemolytic uremic syndrome patients.

Therapeutic plasma exchange (TPE) in atypical hemolytic uremic syndrome (aHUS) is considered as first line treatment as per current American Society for Apheresis (ASFA) guidelines. But there is very limited data available in the literature regarding efficacy and safety of TPE procedures in pediatric aHUS patients. To assess the safety and efficacy of TPE by using apheresis devices in pediatric aHUS patients. We did a retrospective analysis of all TPE procedures performed in aHUS pediatric patients over a period of 13 years (2001-2013). TPE procedures were done on two different devices daily or on alternate days depending on clinical condition of the patient. Adverse events if any were noted and analyzed. Pre and post procedural laboratory profiles were analyzed to assess the response to TPE therapy and patients were categorized accordingly. A total of 169 TPE procedures (range of 1-22/patient with an average of 7.6 procedures/patient) were performed on 30 pediatric patients. Twenty four patients had more than 3 TPE procedures. Sixteen patients were complete responders, 5 were partial responders and 3 were non responders. The time between onset of illness and start of TPE therapy was 1-4 days in complete responders, 5-7 days in partial responders and 8-9 days in non- responders. Adverse events were observed in 13 (7.7%) procedures. TPE is a safe and effective therapeutic modality in pediatric aHUS if instituted early in the course of disease with a minimum of four to five procedures. J. Clin. Apheresis 31:381-387, 2016. © 2015 Wiley Periodicals, Inc.

Overactivation of Complement Alternative Pathway in Postpartum Atypical Hemolytic Uremic Syndrome Patients with Renal Involvement.

Postpartum atypical hemolytic uremic syndrome (aHUS) is a life-threatening syndrome with unclear pathogenesis. The current study aimed to investigate the clinical and pathological features, complement activation status, and the genetic variations in a Chinese cohort of patients with renal biopsy-proven postpartum aHUS. Five patients with postpartum aHUS were recruited. Renal biopsy specimens were examined and scored. Plasma levels of complements were detected, and coding sequences of complement regulators were screened. Anti-CFH/CFI autoantibodies were further detected. Patients with postpartum aHUS patients presented with severe clinical manifestations and renal involvement. The renal biopsies of the five patients showed typical features of thrombotic microangiopathies. The levels of the following complement components, C4d, Bb, C3a, C5a, and SC5b-9, were significantly elevated in patients with postpartum aHUS compared with normal non-pregnant controls. The plasma levels of CFH and CFI significantly decreased in patients with postpartum aHUS compared with normal pregnant women. Three CFH single nucleotide polymorphisms (SNPs) were identified in the five patients. Two patients presented with CFH autoantibodies. Postpartum aHUS is a clinical syndrome with severe renal damage. Genetic deficiencies and autoantibodies of CFH may lead to alternative pathway overactivation and participated in the pathogenesis of postpartum aHUS.

Association of haemolytic uraemic syndrome with dysregulation of chemokine receptor expression in circulating monocytes.

Haemolytic uraemic syndrome (HUS) is the major complication of Escherichia coli gastrointestinal infections that are Shiga toxin (Stx) producing. Monocytes contribute to HUS evolution by producing cytokines that sensitize endothelial cells to Stx action and migration to the injured kidney. As CC chemokine receptors (CCRs) are involved in monocyte recruitment to injured tissue, we analysed the contribution of these receptors to the pathogenesis of HUS. We analysed CCR1, CCR2 and CCR5 expression in peripheral monocytes from HUS patients during the acute period, with healthy children as controls. We observed an increased expression of CCRs per cell in monocytes from HUS patients, accompanied by an increase in the absolute number of monocytes CCR1+, CCR2+ and CCR5+. It is interesting that prospective analysis confirmed that CCR1 expression positively correlated with HUS severity. The evaluation of chemokine levels in plasma showed that regulated on activation of normal T-cell-expressed and -secreted (RANTES) protein was reduced in plasma from patients with severe HUS, and this decrease correlated with thrombocytopenia. Finally, the expression of the higher CCRs was accompanied by a loss of functionality which could be due to a mechanism for desensitization to compensate for altered receptor expression. The increase in CCR expression correlates with HUS severity, suggesting that the dysregulation of these receptors might contribute to an increased risk of renal damage. Activated monocytes could be recruited by chemokines and then receptors could be dysregulated. The dysregulation of CCRs and their ligands observed during the acute period suggests that a chemokine pathway would participate in HUS development.

Mutations in complement C3 from aHUS patients

In this issue of Blood, Schramm et al demonstrate that the majority of mutations in complement C3 identified in atypical hemolytic uremic syndrome (aHUS) patients cause dysregulation in the alternative pathway of complement.

Severe Case of Thrombotic Microangiopathy with a Delayed Diagnosis of Atypical Haemolytic Uraemic Syndrome Successfully Managed with Eculizumab

Objectives : To describe the diagnosis and treatment of a severely ill patient presenting with thrombotic microangiopathy (TMA) of unknown cause. Case presentation: An adult female presented to intensive care with abdominal pain and haemorrhagic shock, requiring reanimation. Results: Features of TMA were present, but initial plasma exchange was ineffective. Treatment with the anti-C5 antibody, eculizumab, improved laboratory parameters and organ function, albeit slowly. Eculizumab remains effective and well tolerated after 30 months of treatment. Conclusion: This case demonstrates the complexities and importance of early identification of atypical haemolytic uraemic syndrome in patients presenting with TMA.

Soluble plasma VE-cadherin concentrations are elevated in patients with STEC infection and haemolytic uraemic syndrome: a case–control study

ObjectivesTo investigate whether the adherens junction protein vascular endothelial cadherin (VE-cadherin) is released during Shiga toxin 2 producing Escherichia coli (STEC) infection with haemolytic uraemic syndrome (HUS) and thus could...

Shiga Toxin–Induced Complement-Mediated Hemolysis and Release of Complement-Coated Red Blood Cell–Derived Microvesicles in Hemolytic Uremic Syndrome

Shiga toxin (Stx)-producing Escherichia coli (STEC) cause hemolytic uremic syndrome (HUS). This study investigated whether Stx2 induces hemolysis and whether complement is involved in the hemolytic process. RBCs and/or RBC-derived microvesicles from patients with STEC-HUS (n = 25) were investigated for the presence of C3 and C9 by flow cytometry. Patients exhibited increased C3 deposition on RBCs compared with controls (p < 0.001), as well as high levels of C3- and C9-bearing RBC-derived microvesicles during the acute phase, which decreased after recovery. Stx2 bound to P1 (k) and P2 (k) phenotype RBCs, expressing high levels of the P(k) Ag (globotriaosylceramide), the known Stx receptor. Stx2 induced the release of hemoglobin and lactate dehydrogenase in whole blood, indicating hemolysis. Stx2-induced hemolysis was not demonstrated in the absence of plasma and was inhibited by heat inactivation, as well as by the terminal complement pathway Ab eculizumab, the purinergic P2 receptor antagonist suramin, and EDTA. In the presence of whole blood or plasma/serum, Stx2 induced the release of RBC-derived microvesicles coated with C5b-9, a process that was inhibited by EDTA, in the absence of factor B, and by purinergic P2 receptor antagonists. Thus, complement-coated RBC-derived microvesicles are elevated in HUS patients and induced in vitro by incubation of RBCs with Stx2, which also induced hemolysis. The role of complement in Stx2-mediated hemolysis was demonstrated by its occurrence only in the presence of plasma and its abrogation by heat inactivation, EDTA, and eculizumab. Complement activation on RBCs could play a role in the hemolytic process occurring during STEC-HUS.

Functional characterization of two novel non-synonymous alterations in CD46 and a Q950H change in factor H found in atypical hemolytic uremic syndrome patients

Atypical hemolytic uremic syndrome (aHUS) is a disease of complement dysregulation, characterized by hemolytic anemia, thrombocytopenia and acute renal failure. Mutations in complement inhibitors are major risk factors for development of aHUS. The three aHUS patients reported in this study had several previously identified alterations in complement inhibitors; e.g. risk haplotypes in CD46 and factor H but we also identified two novel heterozygous non-synonymous CD46 alterations (p.E142Q and p.G259V). Presence of G259V caused decreased expression of the recombinant mutant CD46 compared to wild type (WT). Western blot analysis showed that the majority of the expressed G259V protein was in the precursor form, suggesting that it is processed less efficiently than WT. Low CD46 expression on the surface of the patient's neutrophils confirmed the in vitro results. Further, G259V had a substantially impaired ability to act as a cofactor to factor I, in the degradation of both C3b and C4b. The E142Q mutant showed neither decreased expression nor impaired function. Two of the patients also had a heterozygous non-synonymous alteration in factor H (p.Q950H), reported previously in aHUS but not functionally tested. This variant showed moderately impaired function in hemolytic assays, both using patient sera and recombinant proteins. The recombinant Q950H also showed a somewhat decreased expression compared to WT but the complement inhibitory function in fluid phase was normal. Taken together, we report a novel CD46 alteration showing both a decreased protein expression and substantially impaired cofactor function (G259V) and another without an effect on expression or cofactor function (E142Q). Moreover, mild consequences of a previously reported aHUS associated rare variant in factor H (Q950H) was also revealed, underlining the clear need for functional characterization of each new aHUS associated mutation.

End-stage renal disease from hemolytic uremic syndrome in the United States, 1995-2010.

Management of hemolytic uremic syndrome (HUS) has evolved rapidly, and optimal treatment strategies are controversial. However, it is unknown whether the burden of end-stage renal disease (ESRD) from HUS has changed, and outcomes on dialysis in the United States are not well described. We retrospectively examined data for patients initiating maintenance renal replacement therapy (RRT) (n = 1,557,117), 1995-2010, to define standardized incidence ratios (SIRs) and outcomes of ESRD from HUS) (n = 2241). Overall ESRD rates from HUS in 2001-2002 were 0.5 cases/million per year and were higher for patients characterized by age 40-64 years (0.6), ≥65 years (0.7), female sex (0.6), and non-Hispanic African American race (0.7). Standardized incidence ratios remained unchanged (P ≥ 0.05) between 2001-2002 and 2009-2010 in the overall population. Compared with patients with ESRD from other causes, patients with HUS were more likely to be younger, female, white, and non-Hispanic. Over 5.4 years of follow-up, HUS patients differed from matched controls with ESRD from other causes by lower rates of death (8.3 per 100 person-years in cases vs. 10.4 in controls, P < 0.001), listing for renal transplant (7.6 vs. 8.6 per 100 person-years, P = 0.04), and undergoing transplant (6.9 vs. 9 per 100 person-years, P < 0.001). The incidence of ESRD from HUS appears not to have risen substantially in the last decade. However, given that HUS subtypes could not be determined in this study, these findings should be interpreted with caution.

Eculizumab (ECU) safety and efficacy in atypical hemolytic uremic syndrome (aHUS) patients with long disease duration and chronic kidney disease (CKD): 2-year results

Abstract 985 Introduction: aHUS is a rare, life-threatening genetic disease of chronic, uncontrolled activation of the alternative complement pathway, leading to thrombotic microangiopathy (TMA) and vital organ damage. After the first clinical manifestation, 33%–40% of aHUS patients (pts) will progress to end-stage renal disease (ESRD) or die. Long-term dialysis and high graft rejection rates complicate aHUS management. We previously reported a statistically significant suppression of TMA in a phase 2 trial of the terminal complement inhibitor ECU in pts with persistent aHUS, CKD, and previous chronic plasma exchange/infusion (PE/PI). Here we report 2-year (y) results. Methods: aHUS pts ≥12 y (N=20) treated with chronic PE/PI enrolled in an open-label, phase 2 trial. After 8 weeks (wk) of observation, pts stopped PE/PI and initiated ECU for 26 wk, followed by a long-term ECU treatment extension. Results: Twenty pts received ECU through wk 26, and 19 pts continued ECU in the extension phase. Data analysis was performed in the intention to treat population (n=19). Median time from diagnosis to screening was 48 months (mo) (range 0.66–286). 50% of pts had baseline (BL) estimated glomerular filtration rate (eGFR) Conclusions: In aHUS pts with substantial renal damage despite prior chronic PE/PI, those expected to reach ESRD and those with renal transplant, long-term ECU treatment was associated with sustained TMA inhibition and continued significant improvements in eGFR and proteinuria. Earlier intervention with ECU resulted in greater improvement in eGFR. All pts eliminated PE/PI and no pt required new dialysis. Long-term ECU treatment was well tolerated and led to significant improvements in QOL in pts with chronic aHUS disease. Disclosures: Licht:Alexion Pharmaceuticals, Inc.: Consultancy, Honoraria, Research Funding. Muus:Alexion Pharmaceuticals: Sat on advisory board of Alexion Pharmaceuticals. Other. Legendre:Alexion Pharmaceuticals: Speakers Bureau. Herthelius:Alexion Pharmaceuticals: Coordinator of Alexion trials of eculizumab in atypical HUS for France. Honoraria for conferences. Other. Goodship:Alexion Pharmaceuticals: Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding, Speakers Bureau. Bedrosian:Alexion Pharmaceuticals: Employment, Equity Ownership. Loirat:Alexion Pharmaceuticals: Coordinator of Alexion trials of eculizumab in atypical HUS for France. Honoraria for conferences. Other.

Hematologic and renal improvements in response to eculizumab in atypical hemolytic uremic syndrome patients with long disease duration and chronic kidney disease

Hematologic and renal improvements in response to eculizumab in atypical hemolytic uremic syndrome patients with long disease duration and chronic kidney disease

Consequences of hemolytic uremic syndrome among hemodialysis patients.

BackgroundHemolytic uremic syndrome (HUS) is characterized by hemolytic anemia, low platelets, and renal impairment and is mediated by thrombotic microangiopathy (TMA). A common perception is that HUS becomes dormant in dialysis patients with end-stage renal disease (ESRD). We analyzed patients in a large dialysis organization to understand the potential consequences and burden of HUS.MethodsWe identified patients with ESRD ascribed to HUS and those with ESRD ascribed to another cause (control patients) who received hemodialysis or peritoneal dialysis from 01 January 2007 to 31 December 2012. Outcomes were survival, hospitalization, and longitudinal laboratory values associated with TMA, including lactate dehydrogenase, red cell distribution width (RDW), platelets, and hemoglobin.ResultsHUS patients (n = 217) were propensity-score matched 1:5 to control patients (n = 1,085) for age, gender, race, dry weight, insurance, access, comorbidities, and Charlson comorbidity index. Compared to control patients, HUS patients had significantly greater risk for hospitalizations overall (RR = 2.3, p = 0.004) and hospitalization for hematologic (RR = 5.6, p = 0.001), cardiovascular (RR = 2.1, p = 0.02), and pancreatic (RR = 7.9, p = 0.04) causes. HUS patients also had evidence of ongoing TMA: higher lactate dehydrogenase and RDW, lower platelets and hemoglobin, and more frequent lactate dehydrogenase spikes.ConclusionsDialysis patients with HUS were at significantly higher risk than matched control patients for hospitalizations due to cardiovascular, hematologic, and pancreatic disease, which were associated with ongoing TMA. Additional studies are needed to determine whether targeted therapy for HUS reduces hospitalizations.

Modern Trends in Demographics and Inpatient Healthcare Utilization for Hemolytic Uremic Syndrome in the U.S.A.

Background Hemolytic-uremic syndrome (HUS) is characterized by hemolytic anemia, thrombocytopenia, and acute kidney injury. Extrarenal manifestations complicate HUS, damaging the gastrointestinal tract, central nervous system, and respiratory tract. Despite potentially serious sequelae, few studies have characterized demographics, clinical outcomes, and economic burden of HUS in the US. Methods Pediatric admissions with a primary diagnosis of HUS between 2000-2009 were evaluated via the Kids' Inpatient Database of the Healthcare Utilization Project. Results From 2000-2009, 1133 children were hospitalized annually with HUS. Overall hospital length of stay (LOS) decreased significantly. Females predominated (53.7%) and 49.1% of patients were 1-4 years of age. Extrarenal manifestations were associated with increased likelihood of dialysis. Almost one-third received red blood cell (RBC) transfusions, and RBC transfusion frequency increased over time. Overall mortality rate was 2.4% and significantly decreased over time. Neurological and respiratory complications and sepsis were associated with increased mortality. Conclusions Despite serious complications associated with HUS, there is a lack of data describing demographics and impact of HUS on the US healthcare system. This study provides the largest review of HUS cases and provides impetus to prospectively evaluate interventions that reduce morbidity and mortality in HUS patients.

Molecular typing of VTEC strains isolated from food, feed and animals

Molecular typing of VTEC strains isolated from food, feed and animals

Draft Whole-Genome Sequences of Three Shiga Toxin-Producing Escherichia coli O91:H21 Isolates, Two from Hemolytic Uremic Syndrome Patients and One of Porcine Origin.

This study presents three genomes of O91:H21 isolates, two from hemolytic uremic syndrome patients and one of porcine origin. Genome analyses reveal that one of the human isolates contains both Shiga toxin-encoding genes (stx1 and stx2), and all three isolates contain putative adhesin (iha and eaeH) and antibiotic resistance (ampC) genes.

Immunoproteomic analysis to identify Shiga toxin-producing Escherichia coli outer membrane proteins expressed during human infection.

Shiga-toxin producing Escherichia coli (STEC) is the etiologic agent of acute diarrhea, dysentery, and hemolytic-uremic syndrome (HUS). There is no approved vaccine for STEC infection in humans, and antibiotic use is contraindicated, as it promotes Shiga toxin production. In order to identify STEC-associated antigens and immunogenic proteins, outer membrane proteins (OMPs) were extracted from STEC O26:H11, O103, O113:H21, and O157:H7 strains, and commensal E. coli strain HS was used as a control. SDS-PAGE, two-dimensional-PAGE analysis, Western blot assays using sera from pediatric HUS patients and controls, and matrix-assisted laser desorption ionization-tandem time of flight analyses were used to identify 12 immunogenic OMPs, some of which were not reactive with control sera. Importantly, seven of these proteins have not been previously reported to be immunogenic in STEC strains. Among these seven proteins, OmpT and Cah displayed IgG and IgA reactivity with sera from HUS patients. Genes encoding these two proteins were present in a majority of STEC strains. Knowledge of the antigens produced during infection of the host and the immune response to those antigens will be important for future vaccine development.

Phylogenetic Clades 6 and 8 of Enterohemorrhagic Escherichia coli O157:H7 With Particular stx Subtypes are More Frequently Found in Isolates From Hemolytic Uremic Syndrome Patients Than From Asymptomatic Carriers

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 infection causes severe diseases such as bloody diarrhea and hemolytic uremic syndrome (HUS). Although EHEC O157:H7 strains have exhibited high genetic variability, their abilities to cause human diseases have not been fully examined. Clade typing and stx subtyping of EHEC O157:H7 strains, which were isolated in Japan during 1999-2011 from 269 HUS patients and 387 asymptomatic carriers (ACs) and showed distinct pulsed-field gel electrophoresis patterns, were performed to determine relationships between specific lineages and clinical presentation. Clades 6 and 8 strains were more frequently found among the isolates from HUS cases than those from ACs (P = .00062 for clade 6, P < .0001 for clade 8). All clade 6 strains isolated from HUS patients harbored stx2a and/or stx2c, whereas all clade 8 strains harbored either stx2a or stx2a/stx2c. However, clade 7 strains were predominantly found among the AC isolates but less frequently found among the HUS isolates, suggesting a significant association between clade 7 and AC (P < .0001). Logistic regression analysis revealed that 0-9 year old age is a significant predictor of the association between clade 8 and HUS. We also found an intact norV gene, which encodes for a nitric oxide reductase that inhibits Shiga toxin activity under anaerobic condition, in all clades 1-3 isolates but not in clades 4-8 isolates. Early detection of EHEC O157:H7 strains that belonged to clades 6/8 and harbored specific stx subtypes may be important for defining the risk of disease progression in EHEC-infected 0- to 9-year-old children.

Statistical Approaches for Competing Risk in Kidney Transplant (KT) Outcome Research.

Introduction: In transplant outcomes research, Kaplan-Meier (KM) and Cox regression are often used to calculate death censored graft failure (DCGF). However, death with functioning graft (DFG) is a competing risk which may cause standard analyses to overestimate the rate of DCGF. Cumulative incidence function (CIF) and regression with Fine-Gray model have been suggested as better methods to account for competing events. We hypothesize that large variations in DFG may induce imprecise standard analyses of DCGF. Methods: Based on SRTR data from 1/99 to 12/09, we studied adult KT recipients who had ESRD due to diabetes (DM) or hemolytic uremic syndrome (HUS). We arranged the subjects into 3 groups in order of increasing variation in DFG: 1)DM vs HUS; 2)DM and age over 65 vs HUS and age below 40, and 3)DM and age over 70 and donor age over 60 vs HUS and age below 30 and donor age below 30. We compared DCGF rates using 1-KM and CIF, and adjusted hazard ratios (aHR) using Cox and Fine-Gray model. Results: Total 42671, 8603, and 599 DM patients, and 490, 293, and 75 HUS patients were included in 3 groups. The difference of DFG between DM and HUS patients increases from groups 1 to 3 (group 1: 16% vs 9%, P<.0001; group 2: 24.5% vs 4.8%, P<.0001; group 3: 30.1% vs 0%, P<.0001). The differences between 1-KM and CIF for the changed crude rates of DCGF from DM and HUS patients increases from group 1 to 3 (Mean ± SE in group 1: 0.0002±0.0018, P=0.80; group 2: 0.003±0.002, P=0.02; group 3: 0.015±0.011, P=0.02). The difference of aHR of DCGF (HUS vs DM patients) obtained from Cox regression and Fine-Gray model increases from group 1 to 3 as well(Fig.1). Conclusion: 1-KM and Cox regression overestimates the incidence and aHR of DCGF. The overestimation becomes significant with over 20% of difference in DGF. We advocate assessing the rate of DFG to help guide the analysis of DCGF.Fig 1: Comparison of aHR of DCGF.