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Typical hemolytic uremic syndrome (HUS) can occur as a severe systemic complication of infections with Shiga toxin (Stx)-producing Escherichia coli . Its pathology can be induced by Stx types, resulting in toxin-mediated damage to renal barriers, inflammation, and the development of acute kidney injury (AKI). Two sphingosine kinase (SphK) isozymes, SphK1 and SphK2, have been shown to be involved in barrier maintenance and renal inflammatory diseases. Therefore, we sought to determine their role in the pathogenesis of HUS. Experimental HUS was induced by the repeated administration of Stx2 in wild-type (WT) and SphK1 (SphK1 -/- ) or SphK2 (SphK2 -/- ) null mutant mice. Disease severity was evaluated by assessing clinical symptoms, renal injury and dysfunction, inflammatory status and sphingolipid levels on day 5 of HUS development. Renal inflammation and injury were found to be attenuated in the SphK2 -/- mice, but exacerbated in the SphK1 -/- mice compared to the WT mice. The divergent outcome appeared to be associated with oppositely altered sphingolipid levels. This study represents the first description of the distinct roles of SphK1 -/- and SphK2 -/- in the pathogenesis of HUS. The identification of sphingolipid metabolism as a potential target for HUS therapy represents a significant advance in the field of HUS research.

Shiga toxin (Stx)-producing Escherichia coli (STEC) infections cause outbreaks of severe disease in children ranging from bloody diarrhea to hemolytic uremic syndrome (HUS). The adherent factor intimin, encoded by eae , can facilitate the colonization process of strains and is frequently associated with severe disease. The purpose of this study was to examine and analyze the prevalence and polymorphisms of eae in clinical STEC strains from pediatric patients under 17 years old with and without HUS, and to assess the pathogenic risk of different eae subtypes. We studied 240 STEC strains isolated from pediatric patients in Finland with whole genome sequencing. The gene eae was present in 209 (87.1%) strains, among which 49 (23.4%) were from patients with HUS, and 160 (76.6%) were from patients without HUS. O157:H7 (126, 60.3%) was the most predominant serotype among eae -positive STEC strains. Twenty-three different eae genotypes were identified, which were categorized into five eae subtypes, i.e., γ1, β3, ε1, θ and ζ3. The subtype eae -γ1 was significantly overrepresented in strains from patients aged 5-17 years, while β3 and ε1 were more commonly found in strains from patients under 5 years. All O157:H7 strains carried eae -γ1; among non-O157 strains, strains of each serotype harbored one eae subtype. No association was observed between the presence of eae /its subtypes and HUS. However, the combination of eae -γ1+ stx2a was significantly associated with HUS. In conclusion, this study demonstrated a high occurrence and genetic variety of eae in clinical STEC from pediatric patients under 17 years old in Finland, and that eae is not essential for STEC-associated HUS. However, the combination of certain eae subtypes with stx subtypes, i.e., eae -γ1+ stx2a , may be used as risk predictors for the development of severe disease in children., Competing Interests: The authors declare no conflicts of interest.

Background: Hemolytic uremic syndrome secondary to Shiga-toxin-producing Escherichia coli infection (STEC-HUS) generally shows a favorable outcome. Few cases develop extra-renal complications, since neurological involvement is an important cause of morbidity and mortality. The role of complement in STEC-HUS has been recently highlighted, and the use of eculizumab in severe cases has been communicated. HUS results from environmental and genetic factors, but the simultaneous occurrence of STEC and complement mutations remains undetermined., Methods: A pediatric case with severe STEC-HUS carrying CFH mutations, with favorable response to eculizumab is analyzed., Results: STEC-HUS was diagnosed in a 4-year-old girl with classic HUS, including low C3. Peritoneal dialysis was started due to hypertension, oligoanuria, and pleural effusion. She evolved with generalized tonic-clonic seizures and required mechanical ventilation. MRI reported multiple supra- and infratentorial ischemic lesions with laminar/striatal cortical necrosis and leukoencephalopathy. After two eculizumab doses, a significative stabilization in diuresis, blood pressure, creatinine, and C3 was achieved. At the third week, episodes of massive digestive bleeding and a life-threatening condition required a colectomy thus preserving the ileocecal valve. Due to atypical evolution, a genetic study was considered, identifying two heterozygous variants (CFH S1191L/V1197A)., Conclusion: STEC-HUS in patients with a genetic predisposition has been previously reported, but the low frequency of occurrence makes it a rare disease. As in the present case, patients with atypical course might benefit from genetic analysis to evaluate early eculizumab initiation and to better understand its phenotype. A higher resolution version of the Graphical abstract is available as Supplementary information., (© 2022. The Author(s), under exclusive licence to International Pediatric Nephrology Association.)

Complement-mediated hemolytic uremic syndrome (CM-HUS) following chemotherapy for pediatric acute lymphoid neoplasms has rarely been reported. We report the case of an 8-year-old boy with T-lymphoblastic lymphoma (T-LBL) who developed CM-HUS with complement factor H (CFH) mutations (S1191L, V1197A) during induction therapy. Safe administration of chemotherapy after CM-HUS recovery was challenging. By closely monitoring hemolytic and renal parameters during the 2-year treatment period, we observed four episodes of microangiopathic hemolytic anemia (MAHA) with hypocomplementemia and low haptoglobin but no renal dysfunction or thrombocytopenia. Here, we describe the MAHA and CM-HUS episodes in the hopes of elucidating the complex pathophysiology of disorders associated with CFH mutation., (© 2022. Japanese Society of Hematology.)

The syndrome of thrombotic microangiopathy (TMA) is a clinical-pathological entity characterized by microangiopathic hemolytic anemia, thrombocytopenia, and end organ involvement. It comprises a spectrum of underlying etiologies that may differ in children and adults. In children, apart from ruling out shigatoxin-associated hemolytic uremic syndrome (HUS) and other infection-associated TMA like Streptococcus pneumoniae-HUS, rare inherited causes including complement-associated HUS, cobalamin defects, and mutations in diacylglycerol kinase epsilon gene must be investigated. TMA should also be considered in the setting of solid organ or hematopoietic stem cell transplantation. In this review, acquired and inherited causes of TMA are described with a focus on particularities of the main causes of TMA in children. A pragmatic approach that may help the clinician tailor evaluation and management is provided. The described approach will allow for early initiation of treatment while waiting for the definitive diagnosis of the underlying TMA., (© 2022. The Author(s), under exclusive licence to International Pediatric Nephrology Association.)

Shiga toxin 2 (Stx2) and lipopolysaccharide (LPS) contribute to the development of hemolytic uremic syndrome (HUS). Mouse models of HUS induced by LPS/Stx2 have been used for elucidating HUS pathophysiology and for therapeutic development. However, the underlying molecular mechanisms and detailed injury sites in this model remain unknown. We analyzed mouse kidneys after LPS/Stx2 administration using microarrays. Decreased urinary osmolality and urinary potassium were observed after LPS/Stx2 administration, suggestive of distal nephron disorders. A total of 1,212 and 1,016 differentially expressed genes were identified in microarrays at 6 h and 72 h after LPS/Stx2 administration, respectively, compared with those in controls. Ingenuity pathway analysis revealed activation of TNFR1/2, iNOS, and IL-6 signaling at both time points, and inhibition of pathways associated with lipid metabolism at 72 h only. The strongly downregulated genes in the 72-h group were expressed in the distal nephrons. In particular, genes associated with distal convoluted tubule (DCT) 2/connecting tubule (CNT) and principal cells of the cortical collecting duct (CCD) were downregulated to a greater extent than those associated with DCT1 and intercalated cells. Stx receptor globotriaosylceramide 3 (Gb3) revealed no colocalization with DCT1-specific PVALB and intercalated cell-specific SLC26A4 but did present colocalization with SLC12A3 (present in both DCT1 and DCT2), and AQP2 in principal cells. Gb3 localization tended to coincide with the segment in which the downregulated genes were present. Thus, the LPS/Stx2-induced kidney injury model represents damage to DCT2/CNT and principal cells in the CCD, based on molecular, biological, and physiological findings.

Hemolytic uremic syndrome (HUS) is clinically rare, with high mortality and case fatality rates. In recent years, the research on HUS has been intensified and the pathophysiological mechanism has been continuously improved. At present, the main mechanism of pathogenesis is the excessive activation of complement alternative pathways mediated by complement-related gene mutations or the existence of antibodies. The treatment methods and strategies are also constantly updated, mainly including complement-blocking drugs such as Eculizumab, Lavalizumab, and Ravulizumab. In this review, the new developments in the pathogenesis and treatment of HUS is summarized, and provide references for the clinical treatment of HUS.

Aim: Pregnancy-associated hemolytic uremic syndrome (P-aHUS) is an important cause of peripartum acute kidney injury. Studies from Europe have described mutations in complement regulator genes, and data in Indian patients is scarce. Hence this study used multiplex ligation-dependent probe amplification (MLPA) to identify variants in complement genes in P-aHUS patients., Methods: We present 17 patients of P-aHUS who were investigated for complement protein levels and genetic analysis with MLPA for complement genes. Plasma exchange therapy was offered to all patients presenting in acute phase., Results: Mean age 26.74 (3.36) years with 15/17 delivered by caesarean section. Eleven patients received early (within 7 days) plasma exchange, three were dialysis-dependent at 3 months and seven were dialysis-free. Only one of the three patients receiving late (after 7 days) plasma exchange was dialysis-free. MLPA showed that 11 patients had heterozygous deletions of exons 3, 5, 6 of CFHR1 and upstream region of exons 1, 2, 3, 6 and intron 4 of CFHR3 gene while four patients had homozygous deletions at the same loci. Two patients had no MLPA-detectable variations., Conclusion: This study reports a high proportion of deletions of exons of CFHR1 & CFHR3 genes in Indian P-aHUS patients detectable by MLPA by copy number variations. This needs confirmation in large multicentre studies. Plasma exchange can be an effective therapy in the non-availability of Eculizumab., (© 2021 Asian Pacific Society of Nephrology.)

The formation of attaching and effacing (A/E) lesions on intestinal epithelium, combined with Shiga toxin production, are hallmarks of enterohemorrhagic Escherichia coli (EHEC) infection that can lead to lethal hemolytic uremic syndrome. Although an animal infection model that fully recapitulates human disease remains elusive, mice orally infected with Citrobacter rodentium(ϕStx2dact), a natural murine pathogen lysogenized with an EHEC-derived Shiga toxin 2-producing bacteriophage, develop intestinal A/E lesions and toxin-dependent systemic disease. This model has facilitated investigation of how: (A) phage gene expression and prophage induction contribute to disease and are potentially triggered by antibiotic treatment; (B) virulence gene expression is altered by microbiota and the colonic metabolomic milieu; and (C) innate immune signaling is affected by Stx. Thus, the model provides a unique tool for accessing diverse aspects of EHEC pathogenesis., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Shiga toxins (Stxs) are classic bacterial toxins and major virulence factors of toxigenic Shigella dysenteriae and enterohemorrhagic Escherichia coli (EHEC). These toxins recognize a glycosphingolipid globotriaosylceramide (Gb3/CD77) as their receptor and inhibit protein synthesis in cells by cleaving 28S ribosomal RNA. They are the major cause of life-threatening complications such as hemolytic uremic syndrome (HUS), associated with severe cases of EHEC infection, which is the leading cause of acute kidney injury in children. The threat of Stxs is exacerbated by the lack of toxin inhibitors and effective treatment for HUS. Here, we briefly summarize the Stx structure, subtypes, in vitro and in vivo models, Gb3 expression and HUS, and then introduce recent studies using CRISPR-Cas9-mediated genome-wide screens to identify the host cell factors required for Stx action. We also summarize the latest progress in utilizing and engineering Stx components for biomedical applications.

Shiga toxin-producing E. coli (STEC) is a common foodborne pathogen in developed countries. STEC generates "attaching and effacing" (AE) lesions on colonic epithelium, characterized by effacement of microvilli and the formation of actin "pedestals" beneath intimately attached bacteria. In addition, STEC are lysogenized with a phage that, upon induction, can produce potent Shiga toxins (Stx), potentially leading to both hemorrhagic colitis and hemolytic uremic syndrome. Investigation of the pathogenesis of this disease has been challenging because STEC does not readily colonize conventional mice.Citrobacter rodentium (CR) is a related mouse pathogen that also generates AE lesions. Whereas CR does not produce Stx, a murine model for STEC utilizes CR lysogenized with an E. coli-derived Stx phage, generating CR(Φstx), which both colonizes conventional mice and readily gives rise to systemic disease. We present here key methods for the use of CR(Φstx) infection as a highly predictable murine model for infection and disease by STEC. Importantly, we detail CR(Φstx) inoculation by feeding, determination of pathogen colonization, production of phage and toxin, and assessment of intestinal and renal pathology. These methods provide a framework for studying STEC-mediated systemic disease that may aid in the development of efficacious therapeutics.

Enterohemorrhagic Escherichia coli is a significant human pathogen that causes disease ranging from hemorrhagic colitis to hemolytic uremic syndrome. The latter can lead to potentially fatal renal failure and is caused by the release of Shiga toxins that are encoded within lambdoid bacteriophages. The toxins are encoded within the late transcript of the phage and are regulated by antitermination of the P R' late promoter during lytic induction of the phage. During lysogeny, the late transcript is prematurely terminated at t R' immediately downstream of P R' , generating a short RNA that is a byproduct of antitermination regulation. We demonstrate that this short transcript binds the small RNA chaperone Hfq, and is processed into a stable 74-nt regulatory small RNA that we have termed StxS. StxS represses expression of Shiga toxin 1 under lysogenic conditions through direct interactions with the stx1AB transcript. StxS acts in trans to activate expression of the general stress response sigma factor, RpoS, through direct interactions with an activating seed sequence within the 5' UTR. Activation of RpoS promotes high cell density growth under nutrient-limiting conditions. Many phages utilize antitermination to regulate the lytic/lysogenic switch and our results demonstrate that short RNAs generated as a byproduct of this regulation can acquire regulatory small RNA functions that modulate host fitness., Competing Interests: The authors declare no competing interest., (Copyright © 2020 the Author(s). Published by PNAS.)

Atypical haemolytic uraemic syndrome and steroid-resistant nephrotic syndrome are highly rare kidney diseases that can occur in childhood. In some cases, genetic variants may trigger these conditions, although in atypical haemolytic uraemic syndrome they mostly confer only a predisposition to the disease. Most variants causing atypical haemolytic uraemic syndrome were identified in genes encoding proteins regulating the complement pathway; on the other hand, there are approximately 58 genes encoding distinct proteins primarily causing steroid-resistant nephrotic syndrome. We present a child with steroid-resistant nephrotic syndrome and a confirmed homozygous c.966G > A, p.Trp322Ter pathogenic variant in DGKE. This variant was also found in compound with a novel DGKE heterozygous deletion c.171delG, p.Ser58Alafs*111 in a patient from our paediatric cohort with atypical haemolytic uraemic syndrome. Both cases presented with hypertension, nephrotic proteinuria and severe acute kidney injury followed by renal recovery; however, their renal histology was different. In this paper, we deal with the clinical course of children with disrupted DGKE, including the steroid-resistant nephrotic syndrome and atypical haemolytic uraemic syndrome overlap., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

Hemolytic uremic syndrome (HUS) is a severe renal disease that is often preceded by infection with Shiga toxin (Stx)-producing Escherichia coli (STEC). The exact mechanism of Stx-mediated inflammation on human glomerular microvascular endothelial cells (HGMVECs) during HUS is still not well understood. In this study, we investigated the effect of Stx1 on the gene expression of proteins involved in leucocyte-mediated and complement-mediated inflammation. Our results showed that Stx1 enhances the mRNA and protein expression of heparan sulfate proteoglycan (HSPG) syndecan-4 in HGMVECs pre-stimulated with tumor necrosis factor α (TNFα). CD44 was upregulated on mRNA but not on protein level; no effect on the mRNA expression of other tested HSPGs glypican-1 and betaglycan was observed. Furthermore, Stx1 upregulated the mRNA, cell surface expression, and supernatant levels of the intercellular adhesion molecule-1 (ICAM-1) in HGMVECs. Interestingly, no effect on the protein levels of alternative pathway (AP) components was observed, although C3 mRNA was upregulated. All observed effects were much stronger in HGMVECs than in human umbilical endothelial cells (HUVECs), a common model cell type used in endothelial studies. Our results provide new insights into the role of Stx1 in the pathogenesis of HUS. Possibilities to target the overexpression of syndecan-4 and ICAM-1 for STEC-HUS therapy should be investigated in future studies.

Hemolytic uremic syndrome is characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. Disseminated intravascular coagulation, thrombotic thrombocytopenic purpura, and hemolytic uremic syndrome have a similar clinical presentation. Diagnostic needs to be prompt to decrease mortality, because identifying the different disorders can help to tailor specific, effective therapies. However, diagnosis is challenging and morbidity and mortality remain high, especially in the critically ill population. Development of clinical prediction scores and rapid diagnostic tests for hemolytic uremic syndrome based on mechanistic knowledge are needed to facilitate early diagnosis and assign timely specific treatments to patients with hemolytic uremic syndrome variants., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Thrombocytopenia-associated multiple organ failure is a clinical phenotype encompassing a spectrum of syndromes associated with disseminated microvascular thromboses. Autopsies performed in patients that died with thrombotic thrombocytopenic purpura, hemolytic uremic syndrome, or disseminated intravascular coagulation reveal specific findings that can differentiate these 3 entities. Significant advancements have been made in our understanding of the pathologic mechanisms of these syndromes. Von Willebrand factor and ADAMTS-13 play a central role in thrombotic thrombocytopenic purpura. Shiga toxins and the complement pathway drive the hemolytic uremic syndrome pathology. Tissue factor activity is vital in the development of disseminated intravascular coagulation., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Typical hemolytic uremic syndrome is caused by Shiga toxin (Stx2) and lipopolysaccharide (LPS) of Escherichia coli and leads to acute kidney injury. The role of innate immunity in this pathogenesis is unclear. We analyzed the role of high mobility group box 1 (HMGB1) at the onset of disease in a murine model. C57BL/6 mice were intraperitoneally administered saline ( group A ), anti-HMGB1 monoclonal antibody ( group B ), Stx2 and LPS to elicit severe disease ( group C ), or Stx2, LPS, and anti-HMGB1 antibody ( group D ). While all mice in group C died by day 5 of the experiment, all mice in group D survived. Anemia and thrombocytopenia were pronounced and plasma creatinine levels were significantly elevated in group C only at 72 h. While at 72 h after toxin administration the glomerulus tissue in group C showed pathology similar to that of humans, mesangial cell proliferation was seen in group D . Plasma HMGB1 levels in group C peaked 3 h after administration and were higher than those in other groups. Expression of the receptor of advanced glycation end products and NF-κB, involved in HMGB1 signaling, was significantly elevated in group C but not in group D . Administration of anti-HMGB1 antibody in a murine model of severe disease inhibited plasma HMGB1 and promoted amelioration of tissue damage. HMGB1 was found to be involved in the disease pathology; therefore, controlling HMGB1 activity might inhibit disease progression.

Thrombotic microangiopathies include hemolytic uremic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP). Measurement of plasma levels of "a disintegrin-like and metalloproteinase with thrombospondin type 1 motifs 13" (ADAMTS13) activity can distinguish HUS from TTP. Reduced plasma ADAMTS13 activity (< 10% normal range) is atypical for HUS, but not for TTP. However, we detected reduced ADAMTS13 activity in a patient with Shiga toxin-producing Escherichia coli-associated HUS caused by non-IgG anti-ADMTS13 autoantibodies. Furthermore, the patient exhibited possible genetic abnormalities associated with atypical HUS. The patient fully recovered after administration of supportive therapy. To the best of our knowledge, very few cases of STEC-HUS with reduced ADAMTS13 activity have been reported; thus far, none have described the presence of non-IgG anti-ADMTS13 autoantibodies. Therefore, we suggest that anti-ADAMTS13 analyses should be performed in patients diagnosed with STEC-HUS, especially in those who present with prolonged healing or unexpected clinical symptoms.

Shiga toxin (Stx) is the main virulence factor of enterohemorrhagic Escherichia coli (EHEC), that cause gastrointestinal infection leading to hemolytic uremic syndrome. The aim of this study was to investigate if Stx signals via ATP and if blockade of purinergic receptors could be protective. Stx induced ATP release from HeLa cells and in a mouse model. Toxin induced rapid calcium influx into HeLa cells, as well as platelets, and a P2X1 receptor antagonist, NF449, abolished this effect. Likewise, the P2X antagonist suramin blocked calcium influx in Hela cells. NF449 did not affect toxin intracellular retrograde transport, however, cells pre-treated with NF449 exhibited significantly higher viability after exposure to Stx for 24 hours, compared to untreated cells. NF449 protected HeLa cells from protein synthesis inhibition and from Stx-induced apoptosis, assayed by caspase 3/7 activity. The latter effect was confirmed by P2X1 receptor silencing. Stx induced the release of toxin-positive HeLa cell- and platelet-derived microvesicles, detected by flow cytometry, an effect significantly reduced by NF449 or suramin. Suramin decreased microvesicle levels in mice injected with Stx or inoculated with Stx-producing EHEC. Taken together, we describe a novel mechanism of Stx-mediated cellular injury associated with ATP signaling and inhibited by P2X receptor blockade.

Post-hoc subgroup analysis of the negative trial of interleukin-1β receptor antagonist (IL1RA) for septic shock suggested that patients with features of macrophage activation syndrome (MAS) experienced a 50% relative risk reduction for mortality with treatment. Here we seek a genetic basis for this differential response. From 1341 patients enrolled in the ProCESS trial of early goal directed therapy for septic shock, we selected 6 patients with MAS features and the highest ferritin, for whole exome sequencing (mean 24,030.7 ηg/ml, ±SEM 7,411.1). In total 11 rare (minor allele frequency <5%) pathogenic or likely pathogenic variants causal for the monogenic disorders of Familial Hemophagocytic Lymphohistiocytosis, atypical Hemolytic Uremic Syndrome, Familial Mediterranean Fever, and Cryopyrin-associated Periodic Fever were identified. In these conditions, seven of the identified variants are currently targeted with IL1RA and four with anti-C5 antibody. Gene-targeted precision medicine may benefit this subgroup of patients with septic shock and pathogenic immune variation.

Background & Objectives: : Shiga toxin (Stx) is produced by Shigella dysenteriae, a Gram-negative, facultative anaerobic bacillus that causes shigellosis, haemolytic uraemic syndrome (HUS) and Reiter's syndrome. The detection methods for shiga toxin needs to be rapid, accurate, reliable and must be extensively evaluated under field conditions. The aim of this study was to develop rapid, sensitive and specific detection method for Stx., Methods: : Mice and rabbits were immunized with purified recombinant Shiga toxin B (rStxB). Using these antibodies dot ELISA, sandwich ELISA and flow through assay were developed., Results: : The high-titre antibodies specifically reacted with purified rStxB. Dot-ELISA, sandwich ELISA and flow-through assay were developed and standardized that could detect StxB with limit of detection (LOD) of 9.75, 9.7 ng/ml and 0.46 μg/cassette, respectively., Interpretation & Conclusions: : The rStxB was used to produce antibodies to avoid handling of pathogen. The Flow through assay 'developed was specific, rapid and field amenable., Competing Interests: None

Pathogenic variants in specific complement-related genes lead to atypical hemolytic uremic syndrome (aHUS). Some reports have indicated that patients with digenic variants in these genes might present severer phenotypes. Upon detecting novel intronic variants, transcriptional analysis is necessary to prove pathogenicity; however, when intronic variants are located in intron 1 and, as a result, no transcript is produced, no appropriate method had been established to reveal the pathogenicity. Recently, the minigene assay was used to assess the pathogenicity of intronic variants. Here, we report an infantile case of aHUS caused by digenic mutations in two different complement-related genes, C3 and MCP. Targeted sequencing detected a known variant in C3 and a novel variant in the intron 1 splicing donor site of MCP. To assess the pathogenicity of this intronic variant, we conducted functional splicing assay using a minigene construct and quantitative PCR analysis of the MCP transcript, revealing the pathogenicity of the intronic variant. In conclusion, the minigene assay revealed the pathogenicity of the intron 1 splicing donor site variant for the first time. This case showed a severe phenotype of infantile-onset aHUS associated with digenic variants in two complement-related genes.

Thrombotic microangiopathy (TMA) arises in a variety of clinical circumstances with the potential to cause significant dysfunction of the kidneys, brain, gastrointestinal tract and heart. TMA should be considered in all patients with thrombocytopenia and anaemia, with an immediate request to the haematology laboratory to look for red cell fragments on a blood film. Although TMA of any aetiology generally demands prompt treatment, this is especially so in thrombotic thrombocytopenic purpura (TTP) and atypical haemolytic uraemic syndrome (aHUS), where organ failure may be precipitous, irreversible and fatal. In all adults, urgent, empirical plasma exchange (PE) should be started within 4-8 h of presentation for a possible diagnosis of TTP, pending a result for ADAMTS13 (a disintegrin and metalloprotease thrombospondin, number 13) activity. A sodium citrate plasma sample should be collected for ADAMTS13 testing prior to any plasma therapy. In children, Shiga toxin-associated haemolytic uraemic syndrome due to infection with Escherichia coli (STEC-HUS) is the commonest cause of TMA, and is managed supportively. If TTP and STEC-HUS have been excluded, a diagnosis of aHUS should be considered, for which treatment is with the monoclonal complement C5 inhibitor, eculizumab. Although early confirmation of aHUS is often not possible, except in the minority of patients in whom auto-antibodies against factor H are identified, genetic testing ultimately reveals a complement-related mutation in a significant proportion of aHUS cases. The presence of other TMA-associated conditions (e.g. infection, pregnancy/postpartum and malignant hypertension) does not exclude TTP or aHUS as the underlying cause of TMA., (© 2018 Royal Australasian College of Physicians.)

Thrombotic microangiopathies are rare disorders characterized by the concomitant occurrence of severe thrombocytopenia, microangiopathic hemolytic anemia, and a variable degree of ischemic end-organ damage. The latter particularly affects the brain, the heart, and the kidneys. The primary forms, thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS), although their clinical presentations often overlap, have distinctive pathophysiologies. TTP is the consequence of a severe ADAMTS-13 deficiency, either immune-mediated as a result of circulating autoantibodies, or caused by mutations in ADAMTS-13. HUS develops following an infection with Shiga-toxin producing bacteria, or as the result of excessive activation of the alternative pathway of the complement system because of mutations in genes encoding complement system proteins., (© 2018 International Society on Thrombosis and Haemostasis.)

Background: Postdiarrheal hemolytic-uremic syndrome (D+HUS) following Shiga toxin-producing Escherichia coli (STEC) infection is a serious condition lacking specific treatment. Host immune dysregulation and genetic susceptibility to complement hyperactivation are implicated in non-STEC-related HUS. However, genetic susceptibility to D+HUS remains largely uncharacterized., Methods: Patients with culture-confirmed STEC diarrhea, identified through the Centers for Disease Control and Prevention FoodNet surveillance system (2007-2012), were serotyped and classified by laboratory and/or clinical criteria as having suspected, probable, or confirmed D+HUS or as controls and underwent genotyping at 200 loci linked to nondiarrheal HUS or similar pathologies. Genetic associations with D+HUS were explored by multivariable regression, with adjustment for known risk factors., Results: Of 641 enrollees with STEC O157:H7, 80 had suspected D+HUS (41 with probable and 32 with confirmed D+HUS). Twelve genes related to cytokine signaling, complement pathways, platelet function, pathogen recognition, iron transport, and endothelial function were associated with D+HUS in multivariable-adjusted analyses (P ≤ .05). Of 12 significant single-nucleotide polymorphisms (SNPs), 5 were associated with all levels of D+HUS (intergenic SNP rs10874639, TFRC rs3804141, EDN1 rs5370, GP1BA rs121908064, and B2M rs16966334), and 7 SNPs (6 non-complement related) were associated with confirmed D+HUS (all P < .05)., Conclusions: Polymorphisms in many non-complement-related genes may contribute to D+HUS susceptibility. These results require replication, but they suggest novel therapeutic targets in patients with D+HUS., (© The Author(s) 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Fifteen cases of Shiga toxin-producing Escherichia coli (STEC) O157 infection were associated with the consumption of contaminated food from two related butchers' premises in the north-east of England. Ten cases were admitted to hospital and seven cases developed haemolytic uraemic syndrome. A case control study found a statistically significant association with the purchase of raw and/or ready-to-eat (RTE) food supplied by the implicated butchers' shops. Isolates of STEC O157 were detected in two raw lamb burgers taken from one of the butchers' premises. Subsequent environmental sampling identified STEC O157 in bovine faecal samples on the farm supplying cattle to the implicated butchers for slaughter. Whole genome sequencing (WGS) was performed on the Illumina HiSeq 2500 platform on all cultures isolated from humans, food and cattle during the investigation. Quality trimmed Illumina reads were mapped to the STEC O157 reference genome Sakai using bwa-mem, and single nucleotide polymorphisms (SNPs) were identified using gatk2. Analysis of the core genome SNP positions (>90 % consensus, minimum depth 10×, mapping quality (MQ)≥30) revealed that all isolates from humans, food and cattle differed by two SNPs. WGS analysis provided forensic-level microbiological evidence to support the epidemiological links between the farm, the butchers' premises and the clinical cases. Cross-contamination from raw meat to RTE foods at the butchers' premises was the most plausible transmission route. The evidence presented here highlights the importance of taking measures to mitigate the risks of cross-contamination in this setting.

Background: Pregnancy is associated with various forms of thrombotic microangiopathy, including hemolytic uremic syndrome. A previous small French study suggested that pregnancy-associated hemolytic uremic syndrome was to be included in the spectrum of atypical hemolytic uremic syndrome linked to complement alternative pathway dysregulation., Design, Setting, Participants, & Measurements: We sought to retrospectively analyze the presentation, outcome, and frequency of complement alternative pathway gene variants in a larger international (France, United Kingdom, Italy) cohort of patients with pregnancy-associated hemolytic uremic syndrome., Results: Eighty-seven patients with pregnancy-associated hemolytic uremic syndrome were included. Hemolytic uremic syndrome occurred mainly during the first pregnancy (58%) and in the postpartum period (76%). At diagnosis, 56 (71%) patients required dialysis. Fifty-six (78%) patients underwent plasma exchanges, 21 (41%) received plasma infusions, and four (5%) received eculizumab. During follow-up (mean duration of 7.2 years), 41 (53%) patients reached ESRD, 15 (19%) had CKD, and 18 (28%) patients experienced hemolytic uremic syndrome relapse. Twenty-four patients (27%) received a kidney transplant and a recurrence of hemolytic uremic syndrome occurred in 13 (54%) patients. Variants in complement genes were detected in 49 (56%) patients, mainly in the CFH (30%) and CFI genes (9%)., Conclusions: Pregnancy-associated hemolytic uremic syndrome and atypical hemolytic uremic syndrome nonrelated to pregnancy have the same severity at onset and during follow-up and the same frequency of complement gene variants., (Copyright © 2017 by the American Society of Nephrology.)

Background: Hemolytic uremic syndrome (HUS) can occur as a primary process due to mutations in complement genes or secondary to another underlying disease. HUS sometimes occurs in the setting of glomerular diseases, and it has been described in association with Denys-Drash syndrome (DDS), which is characterized by the triad of abnormal genitourinary development; a pathognomonic glomerulopathy, diffuse mesangial sclerosis; and the development of Wilms tumor., Case Presentation: We report the case of a 46, XX female infant who presented with HUS and biopsy-proven thrombotic microangiopathy. Next generation sequencing of genes with known mutations causative of atypical HUS found that she was homozygous for the Complement Factor H H3 haplotype and heterozygous for a variant of unknown significance in the DGKE gene. Whole exome sequencing identified a de novo heterozygous WT1 c.1384C > T; p.R394W mutation, which is classically associated with Denys-Drash syndrome (DDS). At the time of bilateral nephrectomy five months after her initial biopsy, she had diffuse mesangial sclerosis, typical of Denys-Drash syndrome, without evidence of thrombotic microangiopathy., Conclusion: This unique case highlights HUS as a rare but important manifestation of WT1 mutation and provides new insight into the genetics underlying this association.

Background: Complement factor B gene (CFB) is an important component of the alternate pathway of complement activation that provides an active subunit that associates with C3b to form the C3 convertase, which is an essential element in complement activation. Among the complement-associated disorders, mutations and pathogenic variants in the CFB gene are relatively rare phenomena. Moreover, mutated CFB affiliation with immune-complex diffuse membranoproliferative glomerulonephritis (IC-MPGN) and atypical hemolytic uremic syndrome (aHUS) are considered a highly rare occurrence., Case Presentation: We describe the clinical presentation, course, and pathological findings in a 7-year-old boy who has confirmed CFB heterozygous variants with pathological features compatible with IC-MPGN. Mutational analysis revealed a heterozygous variant p.Glu566Arg in exon 13 of the CFB gene. The patient did not respond to steroids and mycophenolate mofetil (MMF) therapy but responded clinically and biochemically to eculizumab treatment. This is the first case report of CFB alteration associated with IC-MPGN and aHUS that was successfully treated with eculizumab., Conclusions: Heterozygous variants in the CFB gene can be pathogenic and associated with IC-MPGN and aHUS. Early diagnosis and prompt management can be essential in preventing end-stage renal disease. Eculizumab may provide an effective modality of treatment.

Background: Anti-complement factor H (CFH) autoantibody-associated hemolytic uremic syndrome (HUS) is a severe sub-type of HUS., Methods: We assessed the clinical and renal pathological features, circulating complement levels, and genetic background of Chinese pediatric patients with this sub-type of HUS. Thirty-three consecutive patients with acute kidney injury who tested positive for serum anti-CFH autoantibodies were enrolled in this study., Results: All of the eight patients who underwent renal biopsies presented with changes typical of thrombotic microangiopathy, especially changes in chronic characteristics. Compared to patients in remission and normal control subjects, patients with acute disease had significantly lower plasma CFH levels and significantly higher plasma complement 3a (C3a), C5a, and terminal complement complex (SC5b-9) levels. The CFH-anti-CFH immunoglobin G (IgG) circulating immunocomplex (CFH-CIC) titers were more closely correlated with CFH plasma levels than anti-CFH IgG levels. Of the 22 patients, four (18%) were homozygous for CFHR3-1Δ and ten were heterozygous for CFHR1 or CFHR3 deletions. Most patients responded well to a combination of plasma and immunosuppressive therapies, with a remission rate of 87%. At the end of the follow-up, nine patients reached the combined end-points, including two with end-stage renal disease and seven with relapses., Conclusion: Plasma C3a, C5a, and SC5b-9 levels predicted disease activity in anti-CFH autoantibody-associated HUS patients enrolled in this study. These patients responded well to plasma therapy combined with immunosuppression.

Methylmalonic aciduria and homocystinuria, cobalamin C (cblC) type, is the most common genetic type of functional cobalamin (vitamin B 12 ) deficiency. This metabolic disease is characterized by marked heterogeneity of neurocognitive disease (microcephaly, seizures, developmental delay, ataxia, hypotonia) and variable extracentral nervous system involvement (failure to thrive, cardiovascular, renal, ocular) manifesting predominantly early in life, sometimes during gestation. To enhance awareness and understanding of renal disease associated with cblC defect, we studied biochemical, genetic, clinical, and histopathological data from 36 patients. Consistent clinical chemistry features of renal disease were intravascular hemolysis, hematuria, and proteinuria in all patients, with nephrotic-range proteinuria observed in three. Renal function ranged from normal to renal failure, with eight patients requiring (intermittent) dialysis. Two thirds were diagnosed with atypical (diarrhea-negative) hemolytic uremic syndrome (HUS). Renal histopathology analyses of biopsy samples from 16 patients revealed glomerular lesions typical of thrombotic microangiopathy (TMA). Treatment with hydroxycobalamin improved renal function in the majority, including three in whom dialysis could be withdrawn. Neurological sequelae were observed in 44 % and cardiopulmonary involvement in 39 % of patients, with half of the latter group demonstrating pulmonary hypertension. Mortality reached 100 % in untreated patients and 79 and 56 % in those with cardiopulmonary or neurological involvement, respectively. In all patients presenting with unclear intravascular hemolysis, hematuria, and proteinuria, cblC defect should be ruled out by determination of blood/plasma homocysteine levels and/or genetic testing, irrespective of actual renal function and neurological status, to ensure timely diagnosis and treatment.

Complement plays a key role in host defense, but its dysregulation can cause autologous tissue injury. Complement activation is normally controlled by regulatory proteins, including factor H (FH) in plasma and membrane cofactor protein (MCP) on the cell surface. Mutations in FH and MCP are linked to atypical hemolytic uremic syndrome, a type of thrombotic microangiopathy (TMA) that causes renal failure. We describe here that disruption of FH function on the cell surface can also lead to disseminated complement-dependent macrovascular thrombosis. By gene targeting, we introduced a point mutation (W1206R) into murine FH that impaired its interaction with host cells but did not affect its plasma complement-regulating activity. Homozygous mutant mice carrying this mutation developed renal TMA as well as systemic thrombophilia involving large blood vessels in multiple organs, including liver, lung, spleen, and kidney. Approximately 30% of mutant mice displayed symptoms of stroke and ischemic retinopathy, and 48% died prematurely. Genetic deficiency of complement C3 and factor D prevented both the systemic thrombophilia and renal TMA phenotypes. These results demonstrate a causal relationship between complement dysregulation and systemic angiopathy and suggest that complement activation may contribute to various human thrombotic disorders involving both the micro- and macrovasculature., (© 2017 by The American Society of Hematology.)

Introduction: Hemolytic uremic syndrome (HUS) isaninfectious disease caused by Shiga toxin-producing Escherichia coli. The objective of this study was to assess the risk of transmission and clinical course between siblings with typical HUS., Population and Methods: Medical records of children with typical HUS between 1997 and 2012 were reviewed. Sibling pairs were established as inclusion criteria. A severity score was defined., Results: A total of 133 patients with HUS were recorded; 40 had siblings and 4 progressed to HUS (10%). The mean age of the 4 sibling pairs was 29.3 months old (SD ± 11.5); 5 (62.5%) were girls. The mean time between each case was 5.7 days (SD ± 3). HUS was more severe in the siblings who became infected in the second place., Conclusion: The risk of HUS transmission between siblings was 10%, and the clinical course of the second sibling was less favorable., (Sociedad Argentina de Pediatría)

The alternative pathway (AP) of complement can recognize nonself structures by only two molecules, C3b and factor H. The AP deposits C3b covalently on nonself structures via an amplification system. The actual discrimination is performed by factor H, which has binding sites for polyanions (sialic acids, glycosaminoglycans, phospholipids). This robust recognition of 'self' protects our own intact viable cells and tissues, while activating structures are recognized by default. Foreign targets are opsonized for phagocytosis or killed. Mutations in factor H predispose to severe diseases. In hemolytic uremic syndrome, they promote complement attack against blood cells and vascular endothelial cells and lead, for example, to kidney and brain damage. Even pathogens can exploit factor H. In fact, the ability to bind factor H discriminates most pathogenic microbes from nonpathogenic ones., (© 2016 Federation of European Biochemical Societies.)

Background: Over the last forty years, our laboratory has accumulated a collection of over 1000 cultured fibroblast lines derived from patients from around the world referred with signs of inborn errors of cobalamin or folate metabolism, including several hundred with complementation-confirmed diagnoses. By accurately classifying patient disorders into classes representing blocks affecting specific reactions, we have provide the basis for rational assessment of phenotypic heterogeneity, and development of methods for diagnosis, treatment and prognosis. These resources have been valuable in identification of causal genes for known inborn errors. Since 2000, we and our collaborators identified the genes for the cblA (MMAA), cblB (MMAB), cblC (MMACHC), cblD (MMADHC), and cblF (LMBRD1) disorders., Results: Whole exome sequencing of DNA from a patient with severe combined immunodeficiency (SCID), megaloblastic anemia and hemolytic uremic syndrome identified mutations in the MTHFD1 gene, which encodes a trifunctional enzyme involved in interconversion of folate coenzyme derivatives. This disorder demonstrates the importance de novo pyrimidine synthesis in the etiology of SCID. Mutations in the ABCD4 gene have been identified in four patients with accumulation of unbound cobalamin in lysosomes; this gene encodes a lysosomal membrane protein that plays a role in the transport of cobalamin across this membrane. Mutations in the HCFC1 gene on the X chromosome have been identified in several male patients that had received a diagnosis of cblC on the basis of complementation studies in cultured fibroblasts. HCFC1 encodes a transcription factor that regulates expression of a number of genes, including MMACHC, the gene that is mutated in patients with the cblC disorder. These studies demonstrate that with the advent of affordable whole exome sequencing, it has been possible to identify genes for novel inborn errors of cobalamin metabolism, often working from a small number of affected patients., (Copyright © 2016 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.)

Background: We report the case of a patient with Shiga toxin (Stx)-associated hemolytic-uremic syndrome (HUS) (STEC-HUS) with a concomitant heterozygous mutation of the gene coding for complement Factor H (CFH)., Case Diagnosis/treatment: An 18-month-old patient presented with hemolytic anemia and thrombotic microangiopathy in the context of acute gastroenteritis. While the patient did not show kidney or other organ failure, he had persistent hemolysis and complement 3 activation (low C3), leading to the decision to commence immunotherapy with eculizumab (Soliris®) together with transient antibiotic coverage and meningococcal vaccination. Patient outcome was favorable. Diagnostic work-up identified Escherichia coli-associated Type 2 Shiga toxin. Complement analysis showed a heterozygous mutation of the CFH gene (c.2103 G>A, p. Trp701X) resulting in a quantitative CFH defect., Conclusions: We report a case of STEC-HUS with a quantitative CFH defect caused by a mutation of the CFH gene. To the best of our knowledge, very few cases of STEC-HUS with complement gene mutation have been reported, but none to date with a CFH mutation. We therefore suggest that complement analyses be performed in patients diagnosed with STEC-HUS in association with low C3 levels, especially in patients presenting with severe or unexpected clinical symptoms.

Infection with Escherichia coli O157:H7 may develop into hemorrhagic colitis, or hemolytic uremic syndrome (HUS), which usually causes kidney failure or even death. The adhesion and toxins are the important virulent factors. In this study, a novel vaccine candidate rSOBGs was constructed based on the bacterial ghost (BG). rSOBGs maintained the integrity of cellular morphology and displayed the linear Stx2Am-Stx1B antigen on the surface of outer membrane. rSOBGs induced Stxs-specific IgA/IgG antibodies and stronger intimin-specific IgA/IgG antibodies effectively in sera in this study. In vivo, the rSOBGs provided the higher protection rate (52%) than native bacterial ghost-OBGs (12%) when challenged intragastricly with high dose (500 LD50) viable E. coli O157:H7. Meanwhile, the rSOBGs provided higher protection rate (73.33%) than OBGs when challenged with 2 LD50 even to 5 LD50 lysed E. coli O157:H7. In vitro, the rSOBGs-immunized sera possessed neutralizing activity to lysed pathogenic bacteria. Furthermore, the results of histopathology also displayed that the administration of rSOBGs have the ability to reduce or inhibit the adhesion lesions and toxins damages of organs. The novel vaccine candidate rSOBGs induced both anti-toxin and anti-adhesion immune protection, suggesting the possibility to prevent the infectious diseases caused by Escherichia coli O157:H7.

Background: Shiga toxin (Stx)-producing E. coli (STEC) are responsible for foodborne outbreaks that can result in severe human disease. During an outbreak, differential disease outcomes are observed after infection with the same STEC strain. One question of particular interest is why some infected people resolve infection after hemorrhagic colitis whereas others progress to the hemolytic uremic syndrome (HUS). Host age and infection dose have been implicated; however, these parameters do not appear to fully account for all of the observed variation in disease severity. Therefore, we hypothesized that additional host genetic factors may play a role in progression to HUS., Methods and Results: To mimic the genetic diversity in the human response to infection by STEC, we measured the capacity of an O157:H7 outbreak isolate to colonize mouse strains from the advanced recombinant inbred (ARI) BXD panel. We first infected the BXD parental strains C57BL/6 J (B6) and DBA/2 J (D2) with either 86-24 (Stx2a+) or TUV86-2, an Stx2a-negative isogenic mutant. Colonization levels were determined in an intact commensal flora (ICF) infection model. We found a significant difference in colonization levels between the parental B6 and D2 strains after infection with TUV86-2 but not with 86-24. This observation suggested that a host factor that may be masked by Stx2a affects O157:H7 colonization in some genetic backgrounds. We then determined the TUV86-2 colonization levels of 24 BXD strains in the ICF model. We identified several quantitative trait loci (QTL) associated with variation in colonization by correlation analyses. We found a highly significant QTL on proximal chromosome 9 (12.5-26.7 Mb) that strongly predicts variation in colonization levels and accounts for 15-20 % of variance. Linkage, polymorphism and co-citation analyses of the mapped region revealed 36 candidate genes within the QTL, and we identified five genes that are most likely responsible for the differential colonization., Conclusions: The identification of the QTL on chromosome 9 supports our hypothesis that individual genetic makeup affects the level of colonization after infection with STEC O157:H7.

Despite the fact that was one of the first systems to be discovered and investigated in the innate immunity, Complement is continuing to receive growing attention by the scientific community. Complement is involved in several diseases such as diabetes, atherosclerosis or Systemic Lupus Erythematous. Successful therapeutic intervention in treating Complement-mediated diseases such as Hemolytic Uremic Syndrome represent a promising advance to continue the research on Complement to develop specific inhibitors for treating human diseases., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Hemolytic-uremic syndrome (HUS) is a thrombotic microangiopathy that is characterized by microangiopathic hemolytic anemia, thrombocytopenia, and renal failure. Excess complement activation underlies atypical HUS and is evident in Shiga toxin-induced HUS (STEC-HUS). This Spotlight focuses on new knowledge of the role of Escherichia coli-derived toxins and polyphosphate in modulating complement and coagulation, and how they affect disease progression and response to treatment. Such new insights may impact on current and future choices of therapies for STEC-HUS., (© 2015 by The American Society of Hematology.)

Thrombocytopenia-associated multiple organ failure (TAMOF) is a clinical phenotype that encompasses a spectrum of syndromes associated with disseminated microvascular thromboses, such as the thrombotic microangiopathies thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS) and disseminated intravascular coagulation (DIC). Autopsies findings in TTP, HUS, or DIC reveal specific findings that can differentiate these 3 entities. Von Willebrand factor and ADAMTS-13 play a central role in TTP. Shiga toxins and the complement pathway are vital in the development of HUS. Tissue factor is the major protease that drives the pathology of DIC. Acute kidney injury (AKI) is a common feature in patients with TAMOF., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background: Shiga toxin-producing Escherichia coli O157:H7 is a foodborne pathogen that causes severe human diseases including hemolytic uremic syndrome (HUS). The virulence factor that mediates HUS, Shiga toxin (Stx), is encoded within the genome of a lambdoid prophage. Although draft sequences are publicly available for a large number of E. coli O157:H7 strains, the high sequence similarity of stx-converting bacteriophages with other lambdoid prophages poses challenges to accurately assess the organization and plasticity among stx-converting phages due to assembly difficulties., Methods: To further explore genome plasticity of stx-converting prophages, we enriched phage DNA from 45 ciprofloxacin-induced cultures for subsequent 454 pyrosequencing to facilitate assembly of the complete phage genomes. In total, 22 stx2a-converting phage genomes were closed., Results: Comparison of the genomes distinguished nine distinct phage sequence types (PSTs) delineated by variation in obtained sequences, such as single nucleotide polymorphisms (SNPs) and insertion sequence element prevalence and location. These nine PSTs formed three distinct clusters, designated as PST1, PST2 and PST3. The PST2 cluster, identified in two clade 8 strains, was related to stx2a-converting phages previously identified in non-O157 Shiga-toxin producing E. coli (STEC) strains associated with a high incidence of HUS. The PST1 cluster contained phages related to those from E. coli O157:H7 strain Sakai (lineage I, clade 1), and PST3 contained a single phage that was distinct from the rest but most related to the phage from E. coli O157:H7 strain EC4115 (lineage I/II, clade 8). Five strains carried identical stx2a-converting phages (PST1-1) integrated at the same chromosomal locus, but these strains produced different levels of Stx2., Conclusion: The stx2a-converting phages of E. coli O157:H7 can be categorized into at least three phage types. Diversification within a phage type is mainly driven by IS629 and by a small number of SNPs. Polymorphisms between phage genomes may help explain differences in Stx2a production between strains, however our data indicates that genes encoded external to the phage affect toxin production as well.

For decades immunological research has relied, with variable success, on mouse models to investigate diseases and possible therapeutic interventions. With the approval of the first therapeutic antibody targeting complement, called eculizumab, as therapy in paroxysmal nocturnal hemoglobinuria (PNH) and more recently atypical hemolytic uremic syndrome (aHUS), the viability of targeting the complement system was demonstrated. The potent, endogenous complement regulators have become of increasing interest as templates for designing and developing new therapeutics. Recently, complement inhibitors based on (parts of) the human complement regulator factor H (FH) are being examined for therapeutic intervention in inflammatory conditions. The first step to evaluate the potency of a new drug is often testing it in a mouse model for the target disease. However, translating results to human conditions requires a good understanding of similarities and, more importantly, differences between the human and mouse complement system and particularly regulation. This review will provide a comprehensive overview of the complement regulator FH and its closely related proteins and current views on their role in mice and men., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Background: The present study was undertaken to investigate the clinical characteristics of hemolytic uremic syndrome (HUS) secondary to cobalamin C disorder (cbl-C disorder)., Methods: We reviewed retrospectively the medical records of 3 children with HUS secondary to cbl-C disorder who had been treated between April 1, 2009 and October 31, 2013., Results: The 3 patients with HUS secondary to cbl-C disorder presented with progressive hemolytic anemia, acute renal failure, thrombocytopenia, poor feeding, and failure to thrive. Two of the 3 patients once had high blood pressure. The mutations of c.609G>A (p.W203X), c.217C>T (p.R73X) and c.365A>T (p.H122L) in the methylmalonic aciduria (cobalamin deficiency) cbl-C type, with homocystinuria gene were detected in the 3 patients. In these patients the levels of lactate dehydrogenase and homocysteine in serum were elevated and the level of methylmalonic acid (MMA) in urine was also elevated. After treatment with hydroxocobalamin, 2 patients were discharged with no obvious abnormal growth and neurological development and 1 patient died of multiple organ failure., Conclusions: The results of this study demonstrated that cbl-C disorder should be investigated in any child presenting with HUS. The high concentrations of homocysteine and MMA could be used for timely recognization of the disease. Once the high levels of plasma homocystein and/or plasma or urine MMA are detected, the treatment with parenteral hydroxocobalamin should be prescribed immediately. The early diagnosis and treatment would contribute to the good prognosis of the disease.

Hemolytic uremic syndrome is a rare disease, frequently responsible for renal insufficiency in children. Recent findings have led to renewed interest in this pathology. The discovery of new gene mutations in the atypical form of HUS and the experimental data suggesting the involvement of the complement pathway in the typical form, open new perspectives for treatment. This review summarizes the current state of knowledge on both typical and atypical hemolytic uremic syndrome pathophysiology and examines new perspectives for treatment., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

This review is a commentary on an article entitled "Genetic variants in C5 and poor response to eculizumab" (N Engl J Med. 2014; 370: 632-639). The molecular basis for the poor response to eculizumab in Japanese patients is unclear. Of 345 Japanese patients with paroxysmal nocturnal hemoglobinuria (PNH) who received eculizumab, 11 showed a poor response. All 11 had a single missense C5 heterozygous mutation, c.2654 G>A, which predicts the polymorphism p.Arg885His. The prevalence of this mutation among patients with PNH (3.2%) was similar to that in healthy Japanese persons (3.5%). This polymorphism was also identified in a Han Chinese population. Non-mutant and mutant C5 both caused hemolysis in vitro, but only non-mutant C5 bound to and was blocked by eculizumab. In vitro hemolysis due to non-mutant and mutant C5 was completely blocked by N19-8, a monoclonal antibody that binds to a different site on C5 than does eculizumab. The functional capacity of the C5 polymorphism p.Arg885His, together with its failure to undergo blockade by eculizumab, accounts for the poor response to this agent in patients who carry this mutation.

Since the proposal to define a separate subgroup of inborn errors of metabolism involved in the biosynthesis and remodelling of phospholipids, sphingolipids and long chain fatty acids in 2013, this group is rapidly expanding. This review focuses on the disorders involved in the biosynthesis of phospholipids. Phospholipids are involved in uncountable cellular processes, e.g. as structural components of membranes, by taking part in vesicle and mitochondrial fusion and fission or signal transduction. Here we provide an overview on both pathophysiology and the extremely heterogeneous clinical presentations of the disorders reported so far (Sengers syndrome (due to mutations in AGK), MEGDEL syndrome (or SERAC defect, SERAC1), Barth syndrome (or TAZ defect, TAZ), congenital muscular dystrophy due to CHKB deficiency (CHKB). Boucher-Neuhäuser/Gordon Holmes syndrome (PNPLA6), PHARC syndrome (ABHD12), hereditary spastic paraplegia type 28, 54 and 56 (HSP28, DDHD1; HSP54, DDHD2; HSP56, CYP2U1), Lenz Majewski syndrome (PTDSS1), spondylometaphyseal dysplasia with cone-rod dystrophy (PCYT1A), atypical haemolytic-uremic syndrome due to DGKE deficiency (DGKE).