Atypical Hemolytic Uremic Syndrome Research Articles

Treatment discontinuation in adults with atypical hemolytic uremic syndrome (aHUS): a qualitative study of international experts' perspectives with associated cost-consequence analysis.

Atypical hemolytic uremic syndrome (aHUS) is a rare, life-threatening thrombotic microangiopathy (TMA) related to congenital mutations impeding control of the alternative pathway of complement. Following approval of the complement C5 inhibitor eculizumab by the European Medicines Agency and the US Food and Drug Administration, initial guidelines suggested lifelong therapy. Yet, growing evidence indicates that discontinuation of eculizumab, or its long-acting form ravulizumab, is possible for many patients. This mixed-methods study sought to explore international experts' perspectives and experiences related to treatment duration in adult patients with aHUS, while also estimating the financial and potential health consequences of early discontinuation. Between January and December 2023, we conducted 10 qualitative interviews with experts in the treatment of aHUS, based upon which we constructed a quantitative decision tree, designed to estimate time on treatment and treatment- and disease-related adverse events. Thematic analysis of the interview data identified four main themes: (1) Concerns and prior experience; (2) High-risk vs. low-risk groups; (3) Patient preference and adherence; and (4) Funding for monitoring and re-treatment. Although most interviewees were in favour of considering treatment discontinuation for many patients (citing the high cost, burden, and potential side effects of lifelong treatment as key reasons), a prior negative experience of discontinuation seemed to make others more reluctant to stop. Deciding which patients required lifelong treatment and which not involved consideration of a wide range of factors, including patient- and system-related factors. Cost-consequence analysis demonstrated the financial savings associated with early treatment discontinuation at the expense of increased risk of recurrent TMA events. Close monitoring for these events had the potential to minimise any long-term injury, primarily renal, with an estimated one event per 100 patient years. For patients at high risk of TMA and with poor adherence to monitoring, rates of renal injury rose to three events per 100 patient years. aHUS treatment protocols are changing globally in response to new clinical evidence. Against this backdrop, our mixed-methods study provides compelling evidence on the complexity of factors influencing treatment discontinuation decisions in aHUS, as well as the financial and health consequences of early discontinuation.

A Unique Presentation of Atypical Hemolytic Uremic Syndrome With Unilateral Blindness and Ischemic Stroke: A Case Report

A Unique Presentation of Atypical Hemolytic Uremic Syndrome With Unilateral Blindness and Ischemic Stroke: A Case Report

Prospective validation of initial eculizumab dosing in adults with atypical hemolytic uremic syndrome.

Prospective validation of initial eculizumab dosing in adults with atypical hemolytic uremic syndrome.

Approaches to early detection of atypical hemolytic-uremic syndrome after childbirth

Introduction. Differentiating conditions accompanied by the development of thrombotic microangiopathy (TMA) in obstetrics is still rather challenging. Our present opinion is that the effect of childbirth on the TMA symptom regression is the key to differential diagnosis. If hemolysis and thrombocytopenia regress after childbirth, we can talk about HELLP syndrome. If not, we should think about atypical hemolytic uremic syndrome (aHUS). aHUS is an extremely rare disease characterized by TMA predominantly involving acute kidney injury. However, the diagnostic task can also be difficult due to possible overlapping one process with another: for example, HELLP syndrome can trigger aHUS, but which of the patients is more susceptible to this transformation is unclear.Aim. To identify clinical and laboratory criteria that can be used to early detect aHUS immediately after childbirth.Materials and methods. A total of 230 patients were enrolled in the study, of whom 71 women were diagnosed with aHUS, 124 patients with HELLP syndrome, and 35 patients without signs of TMA were enrolled in the control group. We assessed and compared the main clinical, anamnestic and laboratory findings.Results. Women with HELLP syndrome and aHUS were comparable in terms of age, frequency of operative delivery and gestational age at delivery, and adverse perinatal outcomes. Peak serum creatinine and LDH values after delivery were the most useful to early predict aHUS. Serum creatinine > 142 μmol/L and LDH > 1391 U/L were associated with the transformation of HELLP syndrome into aHUS.Conclusion. We concluded that standard laboratory data, most specifically peak serum creatinine and LDH, may be used to aid in the early diagnosis of aHUS.

Case Report of Dinutuximab-induced Atypical Hemolytic Uremic Syndrome.

Limited evidence exists describing the relationship between the development of atypical hemolytic uremic syndrome (aHUS) and the administration of dinutuximab. This case report describes a 20-year-old male with neuroblastoma who experienced aHUS post-dinutuximab administration. The patient presented with uncontrolled hypertension and renal dysfunction, ultimately receiving a definitive diagnosis of aHUS through a renal biopsy. The patient required complement-directed therapy with eculizmab and later transitioned to ravulizumab. This case further describes a sequential relationship between dinutuximab administration and aHUS development.

Changing Epidemiology and Outcomes of Hemolytic Uremic Syndrome in Children: A Prospective National Cohort Study from the Polish Pediatric HUS Registry and the Polish Registry of Renal Replacement Therapy in Children.

Background/Objectives: Hemolytic uremic syndrome (HUS) is a known cause of acute kidney injury in children, but there are few recent reports on its epidemiology and outcome. We aimed to investigate trends in the incidence and the long-term outcomes of both Shiga toxin-producing Escherichia coli -HUS (STEC-HUS) and atypical HUS (aHUS) in Poland over the last 12 years (2012-2023), based on the Polish Pediatric HUS and Pediatric Renal Replacement Therapy (RRT) Registries. Methods: A total of 436 patients (301 with STEC-HUS and 135 with aHUS) were included. Results: The incidence of STEC-HUS increased during the observation period, with a mean of 3.9 cases per million age-related population (marp). The incidence of aHUS was relatively constant with a mean of 1.8/marp. The majority of patients fully recovered, although kidney sequelae were observed at 5-year follow-ups in 31% of children with STEC-HUS, 57% of aHUS subjects in the pre-eculizumab era, and 37% of aHUS subjects who had received eculizumab. The overall mortality rate was 2% for STEC-HUS and 3.7% for aHUS, with no deaths reported in children on eculizumab and mortality mainly attributed to neurological damage. A decreasing incidence of chronic kidney disease stage 5 (CKD5) due to HUS was observed. Conclusions: Despite an unchanging incidence of aHUS and an increasing incidence of STEC-HUS, the kidney outcomes of both diseases have improved significantly over the last 12 years. Mortality from HUS has dropped due to improved symptomatic treatment and the introduction of anti-C5 therapy. The development of CKD5 in childhood as a consequence of HUS has become exceptional.

Correlation between a 2-week change in platelet count and clinical outcomes after the initiation of ravulizumab treatment in adult patients with atypical hemolytic uremic syndrome: post-hoc analysis of the phase III trial

Correlation between a 2-week change in platelet count and clinical outcomes after the initiation of ravulizumab treatment in adult patients with atypical hemolytic uremic syndrome: post-hoc analysis of the phase III trial

Beyond the Norm: Gastroenteritis-Induced Atypical Hemolytic Uremic Syndrome in the Absence of Complement Dysfunction

Beyond the Norm: Gastroenteritis-Induced Atypical Hemolytic Uremic Syndrome in the Absence of Complement Dysfunction

The Inhibitory Effects of a Factor B-Binding DNA Aptamer Family Supersede the Gain of Function of Factor B Variants Associated with Atypical Hemolytic Uremic Syndrome.

Aptamers are short, single-stranded oligonucleotides that selectively bind to target biomolecules. Although they generally exhibit good binding specificity, their affinities are often limited because of the relative lack of hydrophobic groups in nucleic acids. Chemically modified nucleotides incorporating hydrophobic structures into uracil have been synthesized to address this obstacle. Modified DNA aptamers containing such nonstandard nucleotides have been developed for >20 different complement proteins. These modified aptamers show increased affinity and enhanced serum stability and have potential value as therapeutic agents. We recently conducted a structure/function study on a family of modified DNA aptamers that bind specifically to complement Factor B (FB). This work revealed that these aptamers selectively inhibit the complement alternative pathway (AP) by preventing the formation of the AP complement component C3 (C3) proconvertase complex, C3bB. Certain patients with atypical hemolytic uremic syndrome express gain-of-function variants of FB that enhance the formation of the proconvertase complex and/or decrease the efficacy of endogenous regulators against the C3 convertases they form. To investigate whether these FB-binding aptamers could override the effects of disease-causing mutations in FB, we examined how they interacted with several FB variants, including D279G, F286L, K323E, and K350N, in various assays of complement function. We found that the inhibitory effect of the FB-binding aptamers superseded the gain-of-function mutations in FB, although the aptamers could not dissociate preformed C3 convertases. These findings suggest that FB-binding aptamers could be further developed as a potential treatment for certain atypical hemolytic uremic syndrome patients or those with other diseases characterized by excessive complement activity.

Bone impairment in atypical hemolytic and uremic syndrome treated by long-term eculizumab.

Atypical hemolytic uremic syndrome (aHUS) is a thrombotic microangiopathy, related to complement dysregulation, including Factor H deficiency (FH) treated by lifelong eculizumab therapy. Its long-term tolerance is not yet fully described. We report two patients with genetic FH deficiency receiving long-term eculizumab and displaying a peculiar bone phenotype. First case is a 13-year-old girl, presenting with bone pains, arthritis, and deformities, for which X-rays and MRI described multifocal osteochondritis. Bone biopsy revealed an active remodeling bone (many areas of bone formation and resorption) and C3c accumulation on immunohistochemical staining. The second patient is an 11-year-oldgirl, displaying mechanical bone pains, for which bone scintigraphy found hypofixation of wrists and ankles. These findings could be consistent with a side effect of eculizumab, as C3c accumulation may result from the downstream C5-blockade. Alternatively, bone alterations could be due to the absence of FH, as described in murine models. Further investigations are required to characterize bone disease in aHUS.

Ravulizumab in adults and children with atypical hemolytic uremic syndrome: a plain language summary of three studies.

This summary gives an overview of three published articles that report the results of research studies of ravulizumab, an approved treatment for people with atypical hemolytic uremic syndrome (often shortened to aHUS). This is a rare and serious condition where blood clots form in small blood vessels. Blood vessels are structures that transport blood around the body. Blood clots are the body's way of stopping someone from bleeding too much. However, if they form when they are not needed, they can cause harm. In atypical hemolytic uremic syndrome, the blood clots can cause injury to organs like the kidney. In the three studies, the researchers wanted to know if ravulizumab could decrease the formation of these clots and improve kidney function. Children who had never received ravulizumab or a similar treatment took part in the first study. Adults who had never received ravulizumab or a similar treatment took part in the second study. In the third study, children whose disease was already controlled by a medication called eculizumab switched to ravulizumab. Ravulizumab is dosed less frequently than eculizumab. The researchers looked at kidney function and the levels of different blood components to see how well the treatment was working. They also monitored the adverse effects that participants experienced. Across the three studies, ravulizumab improved indicators of blood clotting in small vessels and improved kidney function in both children and adults. In addition, ravulizumab was similarly effective to eculizumab for children who were already receiving eculizumab and switched to ravulizumab. Overall, the adverse effects that people experienced with ravulizumab were manageable. These studies showed that ravulizumab is a treatment option for children and adults with aHUS. In addition, a switch to ravulizumab can be considered for children who are already responding well to eculizumab and would benefit from less frequent dosing. Clinical Trial Registration: NCT03131219, NCT02949128, NCT03131219 (ClinicalTrials.gov).

Exploring the Intersection of Atypical Hemolytic Uremic Syndrome and Substance Use: A Comprehensive Narrative Review.

Hemolytic uremic syndrome (HUS) is a thrombotic microangiopathy characterized by hemolytic anemia, renal failure, and thrombocytopenia. While the typical form of HUS is often associated with Shiga toxin-producing Escherichia coli (STEC) infections, atypical hemolytic uremic syndrome (aHUS) is caused by uncontrolled complement system activation, leading to endothelial damage, microthrombi formation, and other complications. Although aHUS is commonly linked to genetic mutations and infections, emerging evidence suggests that certain substances, particularly illicit drugs like heroin, cocaine, and ecstasy, can also trigger this condition, adding complexity to its diagnosis and management. This narrative review examines the mechanisms by which substance use can lead to aHUS, discusses its clinical presentation, and highlights the diagnostic challenges in distinguishing it from other thrombotic microangiopathies, such as thrombotic thrombocytopenic purpura (TTP) and STEC-HUS. A thorough literature search identified relevant case reports, case series, and observational studies, underscoring the need for genetic testing and complement assays to confirm aHUS in substance users. The review also explores the role of complement inhibitors, such as eculizumab and ravulizumab, which target the underlying pathophysiology and have shown promise in improving patient outcomes. However, the management of substance-induced aHUS remains challenging due to limited data, varying clinical presentations, and the need to optimize treatment protocols. Early recognition and tailored therapy are crucial for effective management. Further research is needed to refine diagnostic criteria, develop new therapeutic approaches, and improve care for patients with this under-recognized condition.

Complement biosensors identify a classical pathway stimulus in complement-mediated thrombotic microangiopathy

AbstractComplement-mediated thrombotic microangiopathy (CM-TMA) or hemolytic uremic syndrome, previously identified as atypical hemolytic uremic syndrome, is a TMA characterized by germ line variants or acquired antibodies to complement proteins and regulators. Building upon our prior experience with the modified Ham (mHam) assay for ex vivo diagnosis of complementopathies, we have developed an array of cell-based complement “biosensors” by selective removal of complement regulatory proteins (CD55 and CD59, CD46, or a combination thereof) in an autonomously bioluminescent HEK293 cell line. These biosensors can be used as a sensitive method for diagnosing CM-TMA and monitoring therapeutic complement blockade. Using specific complement pathway inhibitors, this model identifies immunoglobulin M (IgM)–driven classical pathway stimulus during both acute disease and in many patients during clinical remission. This provides a potential explanation for ∼50% of patients with CM-TMA who lack an alternative pathway “driving” variant and suggests at least a subset of CM-TMA is characterized by a breakdown of IgM immunologic tolerance.

Complement-mediated hemolytic uremic syndrome associated with postpartum hemorrhage: case series and systematic review of individual participant data

BackgroundPostpartum hemorrhage is considered a risk factor for pregnancy-associated complement-mediated hemolytic uremic syndrome (CM-HUS; previously known as atypical hemolytic uremic syndrome) but has not been systematically studied. MethodsA systematic review of individual participant data from case series and reports in addition to a case series from our institution. Search terms were “thrombotic microangiopathy,” “atypical hemolytic uremic syndrome,” and “complement mediated” combined with “pregnancy,” “postpartum,” and/or postpartum hemorrhage. Cases of thrombotic microangiopathy other than CM-HUS were excluded. Outcomes were clinical and laboratory characteristics of postpartum hemorrhage-associated CM-HUS, treatment, and outcomes. ResultsThirty-three studies including 48 women with postpartum hemorrhage-associated CM-HUS and 3 patients from our institution were included in the study. Most women presented at term (28/45; 62%), delivered by cesarean section (21/41; 51%), and had pregnancy complications, mainly preeclampsia (16/51; 31%) or fetal demise (/51; 18%). Hematological and renal abnormalities usually appeared within the first 24 hours postdelivery. The median platelet count was 46 × 109/L (IQR, 45), and the median maximal lactate dehydrogenase was 2638 U/L (IQR, 1866). Renal function normalized in 20/23 (87%) women treated with C5 inhibitors with or without plasma exchange; in 7/11 (63%) women treated with plasma exchange alone, but only in 3/17 (18%) patients treated with supportive care. Patients treated with C5 inhibitors and/or plasma exchange achieved significantly better renal outcomes compared with supportive care alone (P < .001). ConclusionCM-HUS is a rare complication following postpartum hemorrhage and occurs mainly in women with preeclampsia and/or following cesarean section. Patients treated with C5 inhibitors and/or plasma exchange had a better renal prognosis compared with patients who received supportive treatment alone.

The current diagnosis and treatment situation of rare disease in the pediatric intensive care unit

Objective: To analyze the diagnosis and treatment of children with rare diseases in the pediatric intensive care unit (PICU), the distribution of disease types and populations, clinical characteristics, and the use of orphan drugs. Methods: A retrospective case summary was conducted. Data were collected from 105 children aged 29 days to <18 years with a confirmed diagnosis of rare diseases according to the "First Batch of Rare Disease Catalogue in China" who were admitted to the PICU of Beijing Children's Hospital, Capital Medical University from January 2020 to December 2022. Data including general information, auxiliary examinations, and treatment details for each patient were collected from the hospital's electronic medical record system. Patients were divided into age groups: infancy (29 days to<1 year), early childhood (1 to <3 years), preschool age (3 to<7 years), school age (7 to<13 years), and adolescence (13 to<18 years). The chi-square test was used to compare gender distribution differences among various rare diseases. Results: A total of 105 patients with 130 cases meeting the diagnostic criteria were included, accounting for 4.7% (130/2 754) of the total admissions to the PICU. The age at PICU admission was 5.3 (0.8, 9.5) years and there were 81 cases in male. The 3 most common types of diseases were endocrine, nutritional, and metabolic diseases (37 cases); followed by neurological disorders(32 cases); and congenital malformations, deformities, and chromosomal abnormalities(17 cases). The 5 most common rare diseases were methylmalonic acidemia (14 cases), mitochondrial encephalomyopathy (14 cases), atypical hemolytic uremic syndrome (12 cases), autoimmune encephalitis (12 cases), and idiopathic cardiomyopathy (9 cases). The distributions of common rare diseases varied among different age groups. In infants, atypical hemolytic uremic syndrome was most common (6 children). There was no statistically significant difference regarding gender among children with mitochondrial encephalomyopathy (13.6% (11/81) vs. 6.1% (3/49), χ2=1.77, P=0.184). Respiratory failure (36 cases) was the primary reason for rare diseases children to be admitted to the PICU. A total of 95 cases underwent mechanical ventilation, 39 cases received multidisciplinary collaborative diagnosis and treatment, and only 6 children received orphan drug therapy during their stay in the PICU. Conclusions: Rare diseases are not uncommon in PICU. Endocrine, nutritional and metabolic disorders, neurological disorders, congenital malformations, deformities, and chromosomal abnormalities were common. Methylmalonic acidemia, mitochondrial encephalomyopathy, atypical hemolytic uremic syndrome and autoimmune encephalitis have higher cases. Many children with rare diseases in the PICU have complex conditions those are challenging to treat, requiring multidisciplinary collaboration. The utilization rate of orphan drugs among children with rare diseases in PICU needs to be improved.

Therapeutic Apheresis in Pediatric Renal Transplant Recipients.

Clear guidelines for therapeutic apheresis in children after renal transplant do not exist. This article reviews the current experiences with therapeutic apheresis in pediatric transplant recipients. The ideal characteristics of removable substances should have all of the following criteria for an effective therapeutic apheresis: large molecular weight (>15 kDa), prolonged half-life, rapid elimination from the plasma, high intravascular distribution, and low turnover rate. Among these molecules, immunoglobulin M is ~75% intravascular; thus, only 1 or 2 therapeutic apheresis procedures are needed to reduce immunoglobulin M levels efficiently. In contrast, immunoglobulin G is distributed 45% intravascularly and returns to ~60% of preapheresis level within 48 hours; thus, the regimen involves 5 procedures and immunosuppressive therapy is crucial to reduce immunoglobulin G levels. Therapeutic apheresis can also remove cytokines. Immunomodulatory effects of therapeutic apheresis do not only remove unwanted substances but involve other important mechanisms, including increased T-regulatory cells compared with T-effector cells. Many modalities of therapeutic apheresis are used for pediatric transplant recipients, including plasmapheresis, double filtration plasmapheresis, photopheresis, lipopheresis, and immunoadsorption, which is the most effective but has a high cost. Therapeutic apheresis in pediatric transplant recipients is effective for posttransplant nephrotic syndrome (mainly focal segmental glomerulosclerosis). Therapeutic apheresis has also resulted in partial or complete remission for 66% of patients with atypical hemolytic uremic syndrome and 75% response rate for chronic antibody-mediated rejection. However, therapeutic apheresis should be accompanied by other immunosuppressive drugs to prevent rebound phenomena. Potential complications of therapeutic apheresis in pediatric transplant recipients include fluid and electrolyte imbalances, infection, bleeding, and reactions to replacement fluids during therapeutic apheresis. However, therapeutic apheresis (combined with immunosuppression) is an effective tool in most pediatric renal transplant recipients for management of antibody-mediated rejection, focal segmental glomerulosclerosis, and atypical hemolytic uremic syndrome.

S4740 A Case of Small and Large Bowel Ischemic Ulcerations in a Patient With Atypical Hemolytic Uremic Syndrome

S4740 A Case of Small and Large Bowel Ischemic Ulcerations in a Patient With Atypical Hemolytic Uremic Syndrome

Safety and Effectiveness of Switching to Ravulizumab from Eculizumab in Kidney Transplant Recipients with Atypical Hemolytic Uremic Syndrome: A Global Registry Analysis

Safety and Effectiveness of Switching to Ravulizumab from Eculizumab in Kidney Transplant Recipients with Atypical Hemolytic Uremic Syndrome: A Global Registry Analysis

Atypical Hemolytic Uremic Syndrome with Peripheral Gangrene

Atypical Hemolytic Uremic Syndrome with Peripheral Gangrene

Real-World Effectiveness of Ravulizumab among C5 Inhibitor-Naive Patients with Atypical Hemolytic Uremic Syndrome (aHUS): A Physician Panel-Based Chart Review Study (aHUS IMPACT)

Real-World Effectiveness of Ravulizumab among C5 Inhibitor-Naive Patients with Atypical Hemolytic Uremic Syndrome (aHUS): A Physician Panel-Based Chart Review Study (aHUS IMPACT)