OBJECTIVE: To explore the clinical characteristics and genetic etiology for a child with atypical Hemolytic uremic syndrome (aHUS) in conjunct with nephrotic level proteinuria. METHODS: A child patient who had visited the Affiliated Hospital of Qingdao University on June 25, 2020 was selected as the study subject. Clinical data of the patient was collected. Whole exome sequencing (WES) was carried out for the child, and candidate variant was verified by Sanger sequencing of the child and his parents. RESULTS: The child, an 8-month-old male, had presented mainly with edema, oliguria, hematuria, nephrotic level proteinuria, anemia, thrombocytopenia, increased creatinine and urea, hypercholesterolemia but normal complement levels. Genetic testing revealed that he has harbored compound heterozygous variants of the DGKE gene, namely c.12_18dupGAGGCGG (p.P7fs*37) and c.1042G>T (p.D348Y), which were respectively inherited from his father and mother. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variants were classified as likely pathogenic and variant of uncertain significance, respectively. By combining his clinical manifestations and results of genetic testing, the child was diagnosed with aHUS with nephrotic level proteinuria. CONCLUSION For infants and young children with aHUS in conjunct with nephrotic level proteinuria, variants of the DGKE gene should be screened. Above finding has expanded the mutational spectrum of the DGKE gene.
Infant ; Female ; Humans ; Child ; Male ; Child, Preschool ; Atypical Hemolytic Uremic Syndrome/diagnosis* ; Mutation ; Genetic Testing ; Thrombocytopenia/genetics* ; Proteinuria/genetics*

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.
Complement System Proteins/therapeutic use* ; Hemolytic-Uremic Syndrome/therapy* ; Humans ; Mutation

Antibodies, Monoclonal, Humanized/therapeutic use* ; Atypical Hemolytic Uremic Syndrome/drug therapy* ; Humans

Diagnosis of thrombotic microangiopathy (TMA) is challenging due to its close association with other forms of microangiopathic hemolytic anemia, such as malignant hypertension and disseminated intravascular coagulation, and because other manifestations including cytopenia and acute kidney injury are manifestations of other medical comorbidities. Further challenges for accurate diagnosis include distinguishing between primary and secondary TMA, as well as between hemolytic uremic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP). TTP is typically differentiated from HUS by the presence of more severe thrombocytopenia, along with a higher frequency of altered mental status with relatively preserved renal function. However, the clinical course can vary among patients, requiring polymerase chain reaction testing of patient stools for enterohemorrhagic Escherichia coli and a disintegrin and metalloproteinase with thrombospondin type 1 motif 13 (ADAMTS13) assay. To reduce the mortality rate, prompt initiation of plasmapheresis is important in cases where TPP cannot be excluded. Future advances enabling more rapid testing for ADAMTS13 levels will reduce the need for unnecessary plasmapheresis, so that treatment strategy can be more optimized.
Acute Kidney Injury ; Anemia, Hemolytic ; Comorbidity ; Diagnosis ; Diagnosis, Differential ; Disseminated Intravascular Coagulation ; Enterohemorrhagic Escherichia coli ; Hemolytic-Uremic Syndrome ; Humans ; Hypertension, Malignant ; Mortality ; Plasma Exchange ; Plasmapheresis ; Polymerase Chain Reaction ; Purpura, Thrombotic Thrombocytopenic ; Thrombocytopenia ; Thrombospondins ; Thrombotic Microangiopathies

No abstract available.
Escherichia ; Hemolytic-Uremic Syndrome

BACKGROUND: Atypical hemolytic uremic syndrome (aHUS) involves dysregulation of the complement system, but whether this also occurs in thrombotic thrombocytopenic purpura (TTP) remains unclear. Although these conditions are difficult to differentiate clinically, TTP can be distinguished by low (<10%) ADAMTS13 activity. The aim was to identify the differences in complement activation products between TTP and aHUS and investigate ADAMTS13 activity as a prognostic factor in aHUS. METHODS: We analyzed patients with thrombotic microangiopathy diagnosed as TTP (N=48) or aHUS (N=50), selected from a Korean registry (N=551). Complement activation products in the plasma samples collected from the patients prior to treatment and in 40 healthy controls were measured by ELISA. RESULTS: The levels of generalized (C3a), alternate (factor Bb), and terminal (C5a and C5b-9) markers were significantly higher (all P<0.01) in the patients than in the healthy controls. Only the factor Bb levels significantly differed (P=0.008) between the two disease groups. In aHUS patients, high normal ADAMTS13 activity (≥77%) was associated with improved treatment response (OR, 6.769; 95% CI, 1.605–28.542; P=0.005), remission (OR, 6.000; 95% CI, 1.693–21.262; P=0.004), exacerbation (OR, 0.242; 95% CI, 0.064–0.916; P=0.031), and disease-associated mortality rates (OR, 0.155; 95% CI, 0.029–0.813; P=0.017). CONCLUSION: These data suggest that complement biomarkers, except factor Bb, are similarly activated in TTP and aHUS patients, and ADAMTS13 activity can predict the treatment response and outcome in aHUS patients.
Atypical Hemolytic Uremic Syndrome ; Biomarkers ; Complement Activation ; Complement System Proteins ; Enzyme-Linked Immunosorbent Assay ; Humans ; Mortality ; Plasma ; Purpura, Thrombotic Thrombocytopenic ; Thrombotic Microangiopathies

Atypical hemolytic uremic syndrome (aHUS), a rare form of thrombotic microangiopathy, is distinguished from the typical form by the absence of a preceding verotoxin-producing Escherichia coli infection. Notably, aHUS occurs in association with genetic or acquired disorders causing dysregulation of the alternative complement pathway. Patients with aHUS may show the presence of anti-complement factor H (CFH) autoantibodies. This acquired form of aHUS (anti-CFH-aHUS) primarily affects children aged 9–13 years. We report a case of a 13-year-old Lao girl with clinical features of aHUS (most likely anti-CFH-aHUS). The initial presentation of the patient met the classical clinical triad of thrombotic microangiopathy (microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury) without preceding diarrheal illness. Low serum levels of complement 3 and normal levels of complement 4 indicated abnormal activation of the alternative complement pathway. Plasma infusion and high-dose corticosteroid therapy resulted in improvement of the renal function and hematological profile, although the patient subsequently died of infectious complications. This is the first case report that describes aHUS (possibly anti-CFH-aHUS) in Laos.
Adolescent ; Anemia, Hemolytic ; Atypical Hemolytic Uremic Syndrome ; Autoantibodies ; Child ; Complement C3 ; Complement C4 ; Complement Factor H ; Complement Pathway, Alternative ; Female ; Humans ; Immunosuppression ; Kidney ; Laos ; Plasma ; Shiga-Toxigenic Escherichia coli ; Thrombocytopenia ; Thrombotic Microangiopathies

BACKGROUND: Atypical hemolytic uremic syndrome (aHUS) is a rare disease that is often associated with genetic defects. Mutations of complement factor H (CFH) are the most common genetic defects that cause aHUS and often result in end-stage renal disease. Since CFH is mainly produced in the liver, liver transplantation (LT) has been performed in patients with defective CFH. METHODS: The clinical courses of four kidney allograft recipients who lost their native kidney functions due to aHUS associated with a CFH mutation were reviewed. RESULTS: Subject A underwent kidney transplantation (KT) twice, aHUS recurred and the allograft kidney failed within a few years. Subject B received a KT and soon experienced a recurrence of aHUS coinciding with infection. Her allograft kidney function has worsened, and she remains on plasma infusion therapy. Subject C underwent LT followed by KT. She is doing well without plasma infusion therapy after combined LT-KT for 3 years. Subject D received KT following LT and is now recurrence-free from aHUS. CONCLUSION: In patients with aHUS associated with a CFH mutation, KT without LT was complicated with a recurrence of aHUS, which might lead to allograft loss. Conversely, LT was successful in preventing the recurrence of aHUS and thus might be another option for a recurrence-free life for aHUS patients associated with CFH mutation.
Allografts ; Atypical Hemolytic Uremic Syndrome ; Complement Factor H ; Complement System Proteins ; Humans ; Kidney Failure, Chronic ; Kidney Transplantation ; Kidney ; Liver Transplantation ; Liver ; Plasma ; Rare Diseases ; Recurrence

Hemolytic uremic syndrome (HUS) is often encountered in children with acute kidney injury. Besides the well-known shiga toxin-producing Escherichia coli-associated HUS, atypical HUS (aHUS) caused by genetic complement dysregulation has been studied recently. aHUS is a rare, chronic, and devastating disorder that progressively damages systemic organs, resulting in stroke, end-stage renal disease, and death. The traditional treatment for aHUS is mainly plasmapheresis or plasma infusion; however, many children with aHUS will progress to chronic kidney disease despite plasma therapy. Eculizumab is a newly developed biologic that blocks the terminal complement pathway and has been successfully used in the treatment of aHUS. Currently, several guidelines for aHUS, including the Korean guideline, recommend eculizumab as the first-line therapy in children with aHUS. Moreover, life-long eculizumab therapy is generally recommended. Further studies on discontinuation of eculizumab are needed.
Acute Kidney Injury ; Atypical Hemolytic Uremic Syndrome ; Child ; Complement System Proteins ; Escherichia ; Hemolytic-Uremic Syndrome ; Humans ; Kidney Failure, Chronic ; Plasma ; Plasmapheresis ; Renal Insufficiency, Chronic ; Stroke

PURPOSE: Escherichia coli O157:H7 is one of the most important pathogens which create hemorrhagic colitis and hemolytic uremic syndrome in human. It is one of the most prevalent causes of diarrhea leading to death of many people every year. The first diagnosed gene in the locus of enterocyte effacement pathogenicity island is eae gene. The product of this gene is a binding protein called intimin belonging to the group of external membrane proteins regarded as a good stimulants of the immune system. Chitosan with its lipophilic property is an environmentally friendly agent able to return to the environment. MATERIALS AND METHODS: Intimin recombinant protein was expressed in pET28a vector with eae gene and purification was performed using Ni-NTA and finally the recombinant protein was approved through western blotting. This protein was encapsulated using chitosan nanoparticles and the size of nanoparticles was measured by Zetasizer. Intimin encapsulated was prescribed for three sessions among three groups of oral, injection, and oral-injection using Chitosan nanoparticles. Challenge was performed for all three groups with 108 E. coli O157:H7 bacteria. RESULTS: Intimin produced by chitosan nanoparticles improves immunological responses through the adjuvant nature of chitosan nanoparticles. Chitosan may be used as a carrier for transportation of the prescribed vaccine. Among the mice, encapsulated intimin could be able to provide suitable titers of IgG and IgA by the aid of chitosan nanoparticles. Results of mice challenge showed that decreased the bacterial shedding significantly. CONCLUSION: Results showed that the chitosan nanovaccine with intimin protein may be used as a suitable candidate vaccine against E. coli O157:H7.
Animals ; Bacteria ; Bacterial Shedding ; Blotting, Western ; Carrier Proteins ; Chitosan ; Colitis ; Diarrhea ; Enterocytes ; Escherichia coli ; Genomic Islands ; Hemolytic-Uremic Syndrome ; Humans ; Immune System ; Immunoglobulin A ; Immunoglobulin G ; Membrane Proteins ; Mice ; Nanoparticles ; Transportation