Project description:Atypical hemolytic uremic syndrome (aHUS), also called complement-mediated hemolytic uremic syndrome (CM-HUS), is a rare disease caused by dysregulation in the alternative complement activation pathway. It is a life-threatening condition causing ischemia of a number of organs, and it typically causes acute kidney injury. This disorder may be triggered by various factors including viral or bacterial infections, pregnancy, surgery, and injuries. In about 60% of cases, the genetic origin of the disease can be identified-commonly mutations affecting complementary factor H and MCP protein. Eculizumab, a monoclonal antibody to the C5 component of the complement, represents the current effective treatment.We describe a case of a young woman with a previous history of polyvalent allergies, who developed atypical hemolytic uremic syndrome after vaccination with mRNA vaccine against SARS-CoV-2. The disease manifested by scleral bleeding, acute renal insufficiency, anemia, and thrombocytopenia. The patient was treated with plasma exchanges without sufficient effect; remission occurred only after starting treatment with eculizumab. Genetic examination showed that the patient is a carrier of multiple inherited risk factors (a rare pathogenic variant in CFH, MCPggaac haplotype of the CD46 gene, and the risk haplotype CFH H3). The patient is currently in hematological remission with persistent mild renal insufficiency, continuing treatment with eculizumab/ravulizumab. By this case report, we meant to point out the need for careful monitoring of people after vaccination, as it may trigger immune-mediated diseases, especially in those with predisposing factors.
Project description:Hemolytic uremic syndrome (HUS) is a triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. The atypical form of HUS is a disease characterized by complement overactivation. Inherited defects in complement genes and acquired autoantibodies against complement regulatory proteins have been described. Incomplete penetrance of mutations in all predisposing genes is reported, suggesting that a precipitating event or trigger is required to unmask the complement regulatory deficiency. The underlying genetic defect predicts the prognosis both in native kidneys and after renal transplantation. The successful trials of the complement inhibitor eculizumab in the treatment of atypical HUS will revolutionize disease management.
Project description:Atypical hemolytic uremic syndrome (aHUS) treatment consists of eculizumab. Severe acute respiratory syndrome coronavirus 2 causes severe pneumonia and endothelial injury that leads to a prothrombotic state that may be complicated by macrovascular and microvascular thrombosis. Complement activation is thought to contribute to endothelial injury and there are at least seven ongoing clinical trials testing six different anti-complement strategies for coronavirus disease 2019 (COVID-19), including eculizumab. We herein report on a kidney transplant patient with aHUS on chronic eculizumab therapy that developed severe COVID-19 despite eculizumab administration early in the course of the disease. Although eculizumab was unable to prevent the development of severe endothelial cell injury, as assessed by increasing D-dimer levels from 292 to 10 586 ng/mL, the patient eventually recovered following dexamethasone and convalescent plasma administration.
Project description:Atypical hemolytic uremic syndrome (aHUS) is a disease characterized by the triad of microangiopathic hemolytic anemia, thrombocytopenia and acute kidney injury. The histopathologic lesions of aHUS include thrombotic microangiopathy involving the glomerular capillaries and thrombosis involving arterioles or interlobar arteries. Extra-renal manifestations occur in up to 20% of patients. The majority of aHUS is caused by complement system defects impairing ordinary regulatory mechanisms. Activating events therefore lead to unbridled, ongoing complement activity producing widespread endothelial injury. Pathologic mutations include those resulting in loss-of-function in a complement regulatory gene (CFH, CFI, CD46 or THBD) or gain-of-function in an effector gene (CFB or C3). Treatment with the late complement inhibitor, eculizumab - a monoclonal antibody directed against C5 - is effective.
Project description:Introduction and importantThere is a high incidence of acute kidney injury with COVID-19 infections. We report a child with atypical Hemolytic Uremic Syndrome (aHUS) admitted to Intensive care Unit (ICU) due to severe SARS-COV-2 infection. Children are recognised as at lower risk of severe COVID-19 compared with adults, but the impact of atypical Hemolytic Uremic Syndrome is yet to be determined.Case presentationAn eleven years old male presented to Mohammed Alamin Hamid Pediatric Hospital with generalize body swelling, skin rash and red urine. Examination reveal hepatomegaly and hemic murmur. Investigations reveal anemia, normal platelets, and impaired renal function. Peripheral blood picture shows shistocytes, crenated RBCs, occasional poikilocytes and mild neutrophilia.During hospital stay the patient developed severe shortness of breath and fever, diagnosed as COVID-19 and required ICU admission 2 days later due to severe respiratory compromised.Clinical discussionAn atypical Hemolytic Uremic Syndrome with normal platelets is extremely rare condition. SARS-COV-2 infection in patients atypical Hemolytic Uremic Syndrome has not been reported in literature.ConclusionOur study shown that severe SARS-COV-2 infection can be developed in pediatric patients patients with co-existing atypical Hemolytic Uremic Syndrome.
Project description:Atypical hemolytic uremic syndrome (aHUS) is a disorder characterized by thrombocytopenia and microangiopathic hemolytic anemia due to endothelial injury. aHUS is felt to be caused by defective complement regulation due to underlying genetic mutations in complement regulators or activators, most often of the alternative pathway. Mutations causing aHUS can be subdivided into two groups, loss of function mutations (affecting factor H, factor H-related proteins, membrane co-factor protein, and factor I), and gain of function mutations (affecting factor B and C3). As more information becomes available on the relationship between specific mutations and clinical outcome, complete genetic workup of aHUS patients becomes more and more important. In this review, we will discuss the genetic background of aHUS, the role of complement for aHUS pathogenesis, and the different groups of specific mutations known to be involved in the pathogenesis of aHUS.
Project description:The hemolytic-uremic syndrome consists of the triad of microangiopathic hemolytic anemia, thrombocytopenia, and renal failure. The common form of the syndrome is triggered by infection with Shiga toxin-producing bacteria and has a favorable outcome. The less common form of the syndrome, called atypical hemolytic-uremic syndrome, accounts for about 10% of cases, and patients with this form of the syndrome have a poor prognosis. Approximately half of the patients with atypical hemolytic-uremic syndrome have mutations in genes that regulate the complement system. Genetic factors in the remaining cases are unknown. We studied the role of thrombomodulin, an endothelial glycoprotein with anticoagulant, antiinflammatory, and cytoprotective properties, in atypical hemolytic-uremic syndrome.We sequenced the entire thrombomodulin gene (THBD) in 152 patients with atypical hemolytic-uremic syndrome and in 380 controls. Using purified proteins and cell-expression systems, we investigated whether thrombomodulin regulates the complement system, and we characterized the mechanisms. We evaluated the effects of thrombomodulin missense mutations associated with atypical hemolytic-uremic syndrome on complement activation by expressing thrombomodulin variants in cultured cells.Of 152 patients with atypical hemolytic-uremic syndrome, 7 unrelated patients had six different heterozygous missense THBD mutations. In vitro, thrombomodulin binds to C3b and factor H (CFH) and negatively regulates complement by accelerating factor I-mediated inactivation of C3b in the presence of cofactors, CFH or C4b binding protein. By promoting activation of the plasma procarboxypeptidase B, thrombomodulin also accelerates the inactivation of anaphylatoxins C3a and C5a. Cultured cells expressing thrombomodulin variants associated with atypical hemolytic-uremic syndrome had diminished capacity to inactivate C3b and to activate procarboxypeptidase B and were thus less protected from activated complement.Mutations that impair the function of thrombomodulin occur in about 5% of patients with atypical hemolytic-uremic syndrome.
Project description:Complement dysregulation leads to atypical hemolytic uremic syndrome (aHUS), while ADAMTS13 deficiency causes thrombotic thrombocytopenic purpura. We investigated whether genetic variations in the ADAMTS13 gene partially explain the reduced activity known to occur in some patients with aHUS. We measured complement activity and ADAMTS13 function, and completed mutation screening of multiple complement genes and ADAMTS13 in a large cohort of aHUS patients. In over 50% of patients we identified complement gene mutations. Surprisingly, 80% of patients also carried at least 1 nonsynonymous change in ADAMTS13, and in 38% of patients, multiple ADAMTS13 variations were found. Six of the 9 amino acid substitutions in ADAMTS13 were common single nucleotide polymorphisms; however, 3 variants-A747V, V832M, and R1096H- were rare, with minor allele frequencies of 0.0094%, 0.5%, and 0.32%, respectively. Reduced complement and ADAMTS13 activity (<60% of normal activity) were found in over 60% and 50% of patients, respectively. We concluded that partial ADAMTS13 deficiency is a common finding in aHUS patients and that genetic screening and functional tests of ADAMTS13 should be considered in these patients.
Project description:BackgroundPregnancy outcomes in patients with atypical hemolytic uremic syndrome (aHUS) are not well-documented. Here, we present characteristics of and outcomes for patients with aHUS who became pregnant while enrolled in the Global aHUS Registry.MethodsThe observational Global aHUS Registry (NCT01522183), initiated in April 2012, collects demographics, disease history, treatment, and outcomes data for patients with aHUS, regardless of treatment approach. This descriptive analysis includes patients from the Registry with evaluable pregnancy data supplemented with pharmacovigilance information; the number of pregnancies, outcomes, and exposure to eculizumab were evaluated.ResultsAs of April 1, 2019, 44 pregnancies were recorded in 41 patients, with 24 pregnancies exposed to eculizumab. Pathogenic variants were identified in 48.8% of patients. Three patients were on dialysis and 6 patients had a kidney graft at the time of pregnancy. Excluding elective terminations, 85.3% of pregnancies resulted in live births. Elective terminations were recorded in 22.7% of pregnancies, miscarriages occurred in 9.1% of pregnancies, and late fetal death in 2.3% of pregnancies. No malformations or anomalies were reported.ConclusionsOur results show that in women with aHUS, even on dialysis or with a kidney graft, pregnancy is possible with careful monitoring for aHUS flares and prematurity. Prophylactic or therapeutic eculizumab offers disease control with low-risk of fetal abnormalities.
Project description:Pathologic thrombosis is a major cause of mortality. Hemolytic-uremic syndrome (HUS) features episodes of small-vessel thrombosis resulting in microangiopathic hemolytic anemia, thrombocytopenia and renal failure. Atypical HUS (aHUS) can result from genetic or autoimmune factors that lead to pathologic complement cascade activation. Using exome sequencing, we identified recessive mutations in DGKE (encoding diacylglycerol kinase ?) that co-segregated with aHUS in nine unrelated kindreds, defining a distinctive Mendelian disease. Affected individuals present with aHUS before age 1 year, have persistent hypertension, hematuria and proteinuria (sometimes in the nephrotic range), and develop chronic kidney disease with age. DGKE is found in endothelium, platelets and podocytes. Arachidonic acid-containing diacylglycerols (DAG) activate protein kinase C (PKC), which promotes thrombosis, and DGKE normally inactivates DAG signaling. We infer that loss of DGKE function results in a prothrombotic state. These findings identify a new mechanism of pathologic thrombosis and kidney failure and have immediate implications for treating individuals with aHUS.