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Che M, Moran SM, Smith RJ, Ren KYM, Smith GN, Shamseddin MK, Avila-Casado C, Garland JS. A case-based narrative review of pregnancy-associated atypical hemolytic uremic syndrome/complement-mediated thrombotic microangiopathy. Kidney Int 2024; 105:960-970. [PMID: 38408703 DOI: 10.1016/j.kint.2023.12.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 12/07/2023] [Accepted: 12/14/2023] [Indexed: 02/28/2024]
Abstract
Atypical hemolytic uremic syndrome is a complement-mediated thrombotic microangiopathy caused by uncontrolled activation of the alternative complement pathway in the setting of autoantibodies to or rare pathogenic genetic variants in complement proteins. Pregnancy may serve as a trigger and unmask atypical hemolytic uremic syndrome/complement-mediated thrombotic microangiopathy (aHUS/CM-TMA), which has severe, life-threatening consequences. It can be difficult to diagnose aHUS/CM-TMA in pregnancy due to overlapping clinical features with other thrombotic microangiopathy syndromes including hypertensive disorders of pregnancy. However, the distinction among thrombotic microangiopathy etiologies in pregnancy is important because each syndrome has specific disease management and treatment. In this narrative review, we discuss 2 cases to illustrate the diagnostic challenges and evolving approach in the management of pregnancy-associated aHUS/CM-TMA. The first case involves a 30-year-old woman presenting in the first trimester who was diagnosed with aHUS/CM-TMA and treated with eculizumab from 19 weeks' gestation. Genetic testing revealed a likely pathogenic variant in CFI. She successfully delivered a healthy infant at 30 weeks' gestation. In the second case, a 22-year-old woman developed severe postpartum HELLP syndrome, requiring hemodialysis. Her condition improved with supportive management, yet investigations assessing for aHUS/CM-TMA remained abnormal 6 months postpartum consistent with persistent complement activation but negative genetic testing. Through detailed case discussion describing tests assessing for placental health, fetal anatomy, complement activation, autoantibodies to complement regulatory proteins, and genetic testing for aHUS/CM-TMA, we describe how these results aided in the clinical diagnosis of pregnancy-associated aHUS/CM-TMA and assisted in guiding patient management, including the use of anticomplement therapy.
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Affiliation(s)
- Michael Che
- Division of Nephrology, Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Sarah M Moran
- Department of Nephrology, Cork University, Cork, Ireland
| | - Richard J Smith
- University of Iowa Molecular Otolaryngology and Renal Research Laboratories, Iowa City, Iowa, USA
| | - Kevin Y M Ren
- Department of Pathology and Molecular Medicine, Queen's University, Kingston, Ontario, Canada
| | - Graeme N Smith
- Department of Obstetrics and Gynecology, Queen's University, Kingston, Ontario, Canada
| | - M Khaled Shamseddin
- Division of Nephrology, Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Carmen Avila-Casado
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada; University Health Network, Toronto General Hospital, Toronto, Ontario, Canada
| | - Jocelyn S Garland
- Division of Nephrology, Department of Medicine, Queen's University, Kingston, Ontario, Canada.
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2
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Werion A, Storms P, Zizi Y, Beguin C, Bernards J, Cambier JF, Dahan K, Dierickx D, Godefroid N, Hilbert P, Lambert C, Levtchenko E, Meyskens T, Poiré X, van den Heuvel L, Claes KJ, Morelle J. Epidemiology, Outcomes, and Complement Gene Variants in Secondary Thrombotic Microangiopathies. Clin J Am Soc Nephrol 2023; 18:881-891. [PMID: 37094330 PMCID: PMC10356144 DOI: 10.2215/cjn.0000000000000182] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 04/13/2023] [Indexed: 04/26/2023]
Abstract
BACKGROUND The identification of complement defects as major drivers of primary atypical hemolytic uremic syndrome (HUS) has transformed the landscape of thrombotic microangiopathies (TMAs), leading to the development of targeted therapies and better patient outcomes. By contrast, little is known about the presentation, genetics, and outcomes of TMA associated with specific diseases or conditions, also referred to as secondary TMA. METHODS In this study, we assessed the relative incidence, clinical and genetic spectra, and long-term outcomes of secondary TMA versus other TMAs in consecutive patients hospitalized with a first episode of TMA from 2009 to 2019 at two European reference centers. RESULTS During the study period, 336 patients were hospitalized with a first episode of TMA. Etiologies included atypical HUS in 49 patients (15%), thrombotic thrombocytopenic purpura (TTP) in 29 (9%), shigatoxin-associated HUS in 70 (21%), and secondary TMA in 188 (56%). The main causes of secondary TMA were hematopoietic stem-cell transplantation ( n =56, 30%), solid-organ transplantation ( n =44, 23%), and malignant hypertension ( n =25, 13%). Rare variants in complement genes were identified in 32 of 49 patients (65%) with atypical HUS and eight of 64 patients (13%) with secondary TMA; pathogenic or likely pathogenic variants were found in 24 of 49 (49%) and two of 64 (3%) of them, respectively ( P < 0.001). After a median follow-up of 1157 days, death or kidney failure occurred in 14 (29%), eight (28%), five (7%), and 121 (64%) patients with atypical HUS, TTP, shigatoxin-associated HUS, and secondary TMA, respectively. Unadjusted and adjusted Cox regressions showed that patients with secondary TMA had the highest risk of death or kidney failure (unadjusted hazard ratio [HR], 3.35; 95% confidence interval [CI], 1.85 to 6.07; P < 0.001; adjusted HR, 4.11; 95% CI, 2.00 to 8.46; P < 0.001; considering atypical HUS as reference). CONCLUSIONS Secondary TMAs represent the main cause of TMA and are independently associated with a high risk of death and progression to kidney failure.
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Affiliation(s)
- Alexis Werion
- Division of Nephrology, Cliniques universitaires Saint-Luc, Brussels, Belgium
- Institut de Recherche Expérimentale et Clinique, UCLouvain, Brussels, Belgium
| | - Pauline Storms
- Department of Hematology, University Hospitals Leuven, Leuven, Belgium
| | - Ysaline Zizi
- Division of Nephrology, Cliniques universitaires Saint-Luc, Brussels, Belgium
| | - Claire Beguin
- Department of Medical Informatics and Statistics, Cliniques universitaires Saint-Luc, Brussels, Belgium
| | - Jelle Bernards
- Department of Nephrology, Dialysis, and Renal Transplantation, University Hospitals Leuven, Leuven, Belgium
- Department of Nephrology, ZNA Middelheim, Antwerpen, Belgium
| | | | - Karin Dahan
- Institut de Pathologie et de Génétique, Gosselies, Belgium
| | - Daan Dierickx
- Department of Hematology, University Hospitals Leuven, Leuven, Belgium
| | - Nathalie Godefroid
- Institut de Recherche Expérimentale et Clinique, UCLouvain, Brussels, Belgium
- Division of Pediatric Nephrology, Cliniques universitaires Saint-Luc, Brussels, Belgium
| | | | - Catherine Lambert
- Institut de Recherche Expérimentale et Clinique, UCLouvain, Brussels, Belgium
- Division of Hematology, Cliniques universitaires Saint-Luc, Brussels, Belgium
| | - Elena Levtchenko
- Department of Pediatrics, University Hospitals Leuven, Leuven, Belgium
| | | | - Xavier Poiré
- Institut de Recherche Expérimentale et Clinique, UCLouvain, Brussels, Belgium
- Division of Hematology, Cliniques universitaires Saint-Luc, Brussels, Belgium
| | - Lambert van den Heuvel
- Department of Pediatrics, University Hospitals Leuven, Leuven, Belgium
- Department of Pediatric Nephrology, Radboud Institute for Molecular Life Sciences, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Kathleen J. Claes
- Department of Nephrology, Dialysis, and Renal Transplantation, University Hospitals Leuven, Leuven, Belgium
- Department of Microbiology, Immunology, and Transplantation, Nephrology and Renal Transplantation Research Group, KU Leuven, Leuven, Belgium
| | - Johann Morelle
- Division of Nephrology, Cliniques universitaires Saint-Luc, Brussels, Belgium
- Institut de Recherche Expérimentale et Clinique, UCLouvain, Brussels, Belgium
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Haninger-Vacariu N, Gleiss A, Gaggl M, Aigner C, Kain R, Prohászka Z, Szilágyi Á, Csuka D, Böhmig GA, Sunder-Plassmann R, Sunder-Plassmann G, Schmidt A. Pregnancy in Complement-Mediated Thrombotic Microangiopathy: Maternal and Neonatal Outcomes. Kidney Med 2023; 5:100669. [PMID: 37492116 PMCID: PMC10363558 DOI: 10.1016/j.xkme.2023.100669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2023] Open
Abstract
Rationale & Objective Pregnancy, delivery, and neonatal outcomes in women with complement-mediated thrombotic microangiopathy (cTMA) have not been well described. A better understanding of these outcomes is necessary to provide women with competent pregnancy counseling. Study Design Cohort study. Setting and Participants Women with a history of cTMA and pregnancies enrolled into the Vienna thrombotic microangiopathy cohort. Exposure New onset or relapses of cTMA. Outcomes Pregnancy, delivery, and neonatal outcomes of pregnancies in women (a) before cTMA manifestation, (b) complicated by pregnancy-associated cTMA (P-cTMA), and (c) after first manifestation of cTMA or P-cTMA. Analytical Approach Mixed models were used to adjust the comparison of pregnancy, delivery, and neonatal outcomes between conditions (before, with, and after cTMA) for repeated pregnancies using the mother's ID as random factor. In addition, the fixed factors, mother's age and neonate's sex, were used for adjustment. For (sex-adjusted and age-adjusted) centile outcomes, only the mother's age was used. Adjusted odds ratios were derived from a generalized linear mixed model with live birth as the outcome. Least squares means and pairwise differences between them were derived from the linear mixed models for the remaining outcomes. Results 28 women reported 74 pregnancies. Despite higher rates of fetal loss before the diagnosis of P-cTMA and preterm births with P-cTMA, most of the women were able to conceive successfully. Neonatal development in all 3 conditions of pregnancies was excellent. Pregnancy and neonatal outcomes were better in women with a pregnancy after the diagnosis of cTMA. Limitations Although our data set comprises a considerable number of 74 pregnancies, the effective sample size is lower because only 28 mothers with multiple pregnancies were observed. The statistical power for detecting clinically relevant effects was probably low. A recall bias for miscarriages cannot be ruled out. Conclusions Prepregnancy counseling of women with a history of cTMA can be supportive of their desire to become pregnant.
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Affiliation(s)
- Natalja Haninger-Vacariu
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Andreas Gleiss
- Center for Medical Science, Institute of Clinical Biometrics, Medical University of Vienna, Vienna, Austria
| | - Martina Gaggl
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Christof Aigner
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Renate Kain
- Department of Pathology, Medical University of Vienna, Vienna, Austria
| | - Zoltán Prohászka
- Research Laboratory, Department of Internal Medicine and Hematology, and MTA-SE Research Group of Immunology and Hematology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - Ágnes Szilágyi
- Research Laboratory, Department of Internal Medicine and Hematology, and MTA-SE Research Group of Immunology and Hematology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - Dorottya Csuka
- Research Laboratory, Department of Internal Medicine and Hematology, and MTA-SE Research Group of Immunology and Hematology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - Georg A. Böhmig
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Raute Sunder-Plassmann
- Genetics Laboratory, Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
| | - Gere Sunder-Plassmann
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Alice Schmidt
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria
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Balwani MR, Pasari AS, Gurjar P, Bhawane A, Bawankule C, Tolani P, Kashiv P, Dubey S, Katekhaye VM. Profile and Post-Kidney Retrieval Outcomes in Asymptomatic Kidney Donors With Genetic Mutations in Complement Factors–Related Genes. Transplant Proc 2023:S0041-1345(23)00105-7. [PMID: 36990884 DOI: 10.1016/j.transproceed.2023.02.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 02/20/2023] [Indexed: 03/29/2023]
Abstract
BACKGROUND Atypical hemolytic uremic syndrome (aHUS) is a rare disorder triggered by various stressors. Most of the time, stressors may not be identified in patients with aHUS. The disease may remain quiescent without manifestation throughout life. BACKGROUND To assess the outcome of an asymptomatic carrier of genetic mutations of patients with aHUS who had undergone donor kidney retrieval surgery. METHODS We retrospectively included the patients diagnosed with a genetic abnormality in complement factor H (CHF) or CHF-related (CFHR) genes without manifestation of the aHUS and who had undergone donor kidney retrieval surgery. The data were analyzed with descriptive statistics. RESULTS Among patients who were the kidney recipients from the prospective donors, 6 donors were screened for genetic mutations in CFH and CFHR genes. Four donors showed positive mutation for CFH and CFHR. The mean age was 54.5 years (range, 50-64 years). After over a year since donor kidney retrieval surgery, all prospective mother donors are alive without aHUS activation and with a normal kidney function on a single kidney. CONCLUSION Asymptomatic carriers of genetic mutations in CFH and CFHR can be the prospective donors for their first-degree family member who have active aHUS. A genetic mutation in an asymptomatic donor should not be a contraindication for refuting the prospective donor.
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Differentiating and Managing Rare Thrombotic Microangiopathies During Pregnancy and Postpartum. Obstet Gynecol 2023; 141:85-108. [PMID: 36455925 DOI: 10.1097/aog.0000000000005024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 08/04/2022] [Indexed: 12/05/2022]
Abstract
The most common thrombotic microangiopathy (TMA) of pregnancy is the well-recognized syndrome of preeclampsia with hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome. However, rare TMAs, including thrombotic thrombocytopenic purpura, complement-mediated hemolytic-uremic syndrome, and catastrophic antiphospholipid syndrome, may occur during pregnancy or postpartum and present with features similar to those of preeclampsia with severe features. Early recognition and treatment of these infrequently encountered conditions are key for avoiding serious maternal morbidities with long-term sequelae and possible maternal or fetal death. Differentiating between preeclampsia with severe features and these rare TMAs is diagnostically challenging as there is significant overlap in their clinical and laboratory presentation. Given the rarity of these TMAs, high-quality evidence-based recommendations on diagnosis and management during pregnancy are lacking. Using current objective information and recommendations from working groups, this report provides practical clinical approaches to diagnose and manage these rare TMAs. This report also discusses how to manage individuals with a history of these rare TMAs who are planning to conceive. To optimize favorable outcomes, a multidisciplinary approach including obstetricians, maternal-fetal medicine specialists, hematologists, and nephrologists alongside close clinical and laboratory monitoring is vital.
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Riedl Khursigara M, Matsuda-Abedini M, Radhakrishnan S, Hladunewich MA, Lemaire M, Teoh CW, Noone D, Licht C. A Guide for Adult Nephrologists and Hematologists to Managing Atypical Hemolytic Uremic Syndrome and C3 Glomerulopathy in Teens Transitioning to Young Adults. Adv Chronic Kidney Dis 2022; 29:231-242. [PMID: 36084970 DOI: 10.1053/j.ackd.2022.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Accepted: 04/11/2022] [Indexed: 11/11/2022]
Abstract
Atypical hemolytic uremic syndrome and C3 glomerulopathy/immune complex membranoproliferative glomerulonephritis are ultra-rare chronic, complement-mediated diseases with childhood manifestation in a majority of cases. Transition of clinical care of patients from pediatric to adult nephrologists-typically with controlled disease in native or transplant kidneys in case of atypical hemolytic uremic syndrome and often with chronic progressive disease despite treatment efforts in case of C3 glomerulopathy/immune complex membranoproliferative glomerulonephritis-identifies a challenging juncture in the journey of these patients. Raising awareness for the vulnerability of this patient cohort; providing education on disease pathophysiology and management including the use of new, high-precision complement antagonists; and establishing an ongoing dialog of patients, families, and all members of the health care team involved on either side of the age divide will be inevitable to ensure optimal patient outcomes and a safe transition of these patients to adulthood.
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Affiliation(s)
| | - Mina Matsuda-Abedini
- Division of Nephrology, The Hospital for Sick Children, Toronto, ON, Canada; Department of Paediatrics, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Seetha Radhakrishnan
- Division of Nephrology, The Hospital for Sick Children, Toronto, ON, Canada; Department of Paediatrics, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Michelle A Hladunewich
- Division of Nephrology and Obstetric Medicine, Department of Medicine, Sunnybrook Health Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Mathieu Lemaire
- Division of Nephrology, The Hospital for Sick Children, Toronto, ON, Canada; Department of Paediatrics, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Cell Biology Program, Research Institute, The Hospital for Sick Children, Toronto, ON, Canada
| | - Chia Wei Teoh
- Division of Nephrology, The Hospital for Sick Children, Toronto, ON, Canada; Department of Paediatrics, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Damien Noone
- Division of Nephrology, The Hospital for Sick Children, Toronto, ON, Canada; Department of Paediatrics, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Christoph Licht
- Division of Nephrology, The Hospital for Sick Children, Toronto, ON, Canada; Department of Paediatrics, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Cell Biology Program, Research Institute, The Hospital for Sick Children, Toronto, ON, Canada.
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Prével R, Delmas Y, Guillotin V, Gruson D, Rivière E. Complement Blockade Is a Promising Therapeutic Approach in a Subset of Critically Ill Adult Patients with Complement-Mediated Hemolytic Uremic Syndromes. J Clin Med 2022; 11:jcm11030790. [PMID: 35160242 PMCID: PMC8837052 DOI: 10.3390/jcm11030790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/24/2022] [Accepted: 01/28/2022] [Indexed: 02/04/2023] Open
Abstract
Thrombotic microangiopathy (TMA) gathers consumptive thrombocytopenia, mechanical haemolytic anemia, and organ damage. Hemolytic uremic syndromes (HUS) are historically classified as primary or secondary to another disease once thrombotic thrombocytopenic purpura (TTP), Shiga-toxin HUS, and cobalamin C-related HUS have been ruled out. Complement genetics studies reinforced the link between complement dysregulation and primary HUS, contributing to reclassifying some pregnancy- and/or post-partum-associated HUS and to revealing complement involvement in severe and/or refractory hypertensive emergencies. By contrast, no firm evidence allows a plausible association to be drawn between complement dysregulation and Shiga-toxin HUS or other secondary HUS. Nevertheless, rare complement gene variants are prevalent in healthy individuals, thus providing an indication that an investigation into complement dysregulation should be carefully balanced and that the results should be cautiously interpreted with the help of a trained geneticist. Several authors have suggested reclassifying HUS in two entities, regardless of they are complement-mediated or not, since the use of eculizumab, an anti-C5 antibody, dramatically lowers the proportion of patients who die or suffer from end-stage renal disease within the year following diagnosis. Safety and the ideal timing of eculizumab discontinuation is currently under investigation, and the long-term consequences of HUS should be closely monitored over time once patients exit emergency departments.
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Affiliation(s)
- Renaud Prével
- CHU Bordeaux, Medical Intensive Care Unit, F-33000 Bordeaux, France; (V.G.); (D.G.)
- University Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, Inserm UMR 1045, F-33000 Bordeaux, France
- Correspondence: ; Tel.: +33-(0)5-56-79-55-17; Fax: +33-(0)5-56-79-54-18
| | - Yahsou Delmas
- CHU Bordeaux, Nephrology Transplantation Dialysis Apheresis Unit, F-33076 Bordeaux, France;
| | - Vivien Guillotin
- CHU Bordeaux, Medical Intensive Care Unit, F-33000 Bordeaux, France; (V.G.); (D.G.)
| | - Didier Gruson
- CHU Bordeaux, Medical Intensive Care Unit, F-33000 Bordeaux, France; (V.G.); (D.G.)
- University Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, Inserm UMR 1045, F-33000 Bordeaux, France
| | - Etienne Rivière
- CHU Bordeaux, Internal Medicine Department, F-33000 Bordeaux, France;
- University Bordeaux, Biology of Cardiovascular Diseases, InsermU1034, F-33604 Pessac, France
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8
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The Syndromes of Thrombotic Microangiopathy: A Critical Appraisal on Complement Dysregulation. J Clin Med 2021; 10:jcm10143034. [PMID: 34300201 PMCID: PMC8307963 DOI: 10.3390/jcm10143034] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 07/05/2021] [Accepted: 07/06/2021] [Indexed: 01/12/2023] Open
Abstract
Thrombotic microangiopathy (TMA) is a rare and potentially life-threatening condition that can be caused by a heterogeneous group of diseases, often affecting the brain and kidneys. TMAs should be classified according to etiology to indicate targets for treatment. Complement dysregulation is an important cause of TMA that defines cases not related to coexisting conditions, that is, primary atypical hemolytic uremic syndrome (HUS). Ever since the approval of therapeutic complement inhibition, the approach of TMA has focused on the recognition of primary atypical HUS. Recent advances, however, demonstrated the pivotal role of complement dysregulation in specific subtypes of patients considered to have secondary atypical HUS. This is particularly the case in patients presenting with coexisting hypertensive emergency, pregnancy, and kidney transplantation, shifting the paradigm of disease. In contrast, complement dysregulation is uncommon in patients with other coexisting conditions, such as bacterial infection, drug use, cancer, and autoimmunity, among other disorders. In this review, we performed a critical appraisal on complement dysregulation and the use of therapeutic complement inhibition in TMAs associated with coexisting conditions and outline a pragmatic approach to diagnosis and treatment. For future studies, we advocate the term complement-mediated TMA as opposed to the traditional atypical HUS-type classification.
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9
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Timmermans SAMEG, Damoiseaux JGMC, Werion A, Reutelingsperger CP, Morelle J, van Paassen P. Functional and Genetic Landscape of Complement Dysregulation Along the Spectrum of Thrombotic Microangiopathy and its Potential Implications on Clinical Outcomes. Kidney Int Rep 2021; 6:1099-1109. [PMID: 33912760 PMCID: PMC8071658 DOI: 10.1016/j.ekir.2021.01.034] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Accepted: 01/25/2021] [Indexed: 01/30/2023] Open
Abstract
Introduction The syndromes of thrombotic microangiopathy (TMA) are diverse and represent severe endothelial damage caused by various mechanisms. The complement system plays a major role in a subset of patients with TMA, and its recognition is of clinical importance because it guides choice and duration of treatment. Methods We studied a well-defined cohort of patients with TMA and hypothesized that assessment of serum-induced ex vivo C5b9 formation on the endothelium and screening for rare variants in complement genes can better categorize TMA. Results Massive ex vivo C5b9 formation was found in all patients with primary atypical hemolytic uremic syndrome (n/N = 11/11) and in 59% of patients with TMA and coexisting conditions (n/N = 30/51). Massive ex vivo C5b9 formation was associated with rare genetic variants (45% [n/N = 20/44] vs. 0% [n/N = 0/21] patients with normal ex vivo C5b9 formation; P < 0.001). Massive ex vivo C5b9 formation was associated with favorable renal response to therapeutic complement inhibition in patients with TMA and coexisting conditions (86% [n/N = 12/14] vs. 31% [n/N = 5/16] of untreated patients; P < 0.001), indicating complement-mediated TMA rather than secondary disease. Among treated patients, the odds ratio for 1-year kidney survival was 12.0 (95% confidence interval 1.2-115.4). TMA recurrence was linked to rare genetic variants in all cases. Patients with normal ex vivo C5b9 formation had an acute, nonrelapsing form of TMA. Conclusions Ex vivo C5b9 formation and genetic testing appears to categorize TMAs into different groups because it identifies complement as a driving factor of disease, with potential therapeutic and prognostic implications.
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Affiliation(s)
- Sjoerd A M E G Timmermans
- Department of Nephrology and Clinical Immunology.,Department of Biochemistry, Cardiovascular Research Institute, Maastricht, The Netherlands
| | - Jan G M C Damoiseaux
- Central Diagnostic Laboratory, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Alexis Werion
- Division of Nephrology, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | | | - Johann Morelle
- Division of Nephrology, Cliniques Universitaires Saint-Luc, Brussels, Belgium.,Institut de Recherche Experimentale et Clinique, UCLouvain, Brussels, Belgium
| | - Pieter van Paassen
- Department of Nephrology and Clinical Immunology.,Department of Biochemistry, Cardiovascular Research Institute, Maastricht, The Netherlands
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10
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Malinowski AK. Thrombotic microangiopathy in pregnancy: when you hear hoofbeats, consider the zebras? Br J Haematol 2020; 190:306-308. [PMID: 32342505 DOI: 10.1111/bjh.16694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 04/05/2020] [Indexed: 11/29/2022]
Affiliation(s)
- Ann Kinga Malinowski
- Division of Maternal-Fetal Medicine, Department of Obstetrics & Gynaecology, Mount Sinai Hospital, Toronto, Canada.,Department of Medicine, University of Torointo, Toronto, Canada.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada
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