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Connaughton DM, Bhai P, Isenring P, Mahdi M, Sadikovic B, Schenkel LC. Genotypic analysis of a large cohort of patients with suspected atypical hemolytic uremic syndrome. J Mol Med (Berl) 2023; 101:1029-1040. [PMID: 37466676 PMCID: PMC10400659 DOI: 10.1007/s00109-023-02341-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 06/14/2023] [Accepted: 06/16/2023] [Indexed: 07/20/2023]
Abstract
Atypical hemolytic uremic syndrome (aHUS) is characterized by microangiopathic hemolytic anemia, thrombocytopenia, and renal impairment. Complement and coagulation gene variants have been associated with aHUS susceptibility. We assessed the diagnostic yield of a next-generation sequencing (NGS) panel in a large cohort of Canadian patients with suspected aHUS. Molecular testing was performed on peripheral blood DNA samples from 167 patients, collected between May 2019 and December 2021, using a clinically validated NGS pipeline. Coding exons with 20 base pairs of flanking intronic regions for 21 aHUS-associated or candidate genes were enriched using a custom hybridization protocol. All sequence and copy number variants were assessed and classified following American College of Medical Genetics guidelines. Molecular diagnostic results were reported for four variants in three individuals (1.8%). Twenty-seven variants of unknown significance were identified in 25 (15%) patients, and 34 unique variants in candidate genes were identified in 28 individuals. An illustrative patient case describing two genetic alterations in complement genes is presented, highlighting that variable expressivity and incomplete penetrance must be considered when interpreting genetic data in patients with complement-mediated disease, alongside the potential additive effects of genetic variants on aHUS pathophysiology. In this cohort of patients with suspected aHUS, using clinical pipelines for genetic testing and variant classification, pathogenic/likely pathogenic variants occurred in a very small percentage of patients. Our results highlight the ongoing challenges in variant classification following NGS panel testing in patients with suspected aHUS, alongside the need for clear testing guidance in the clinical setting. KEY MESSAGES: • Clinical molecular testing for disease associated genes in aHUS is challenging. • Challenges include patient selection criteria, test validation, and interpretation. • Most variants were of uncertain significance (31.7% of patients; VUS + candidates). • Their clinical significance may be elucidated as more evidence becomes available. • Low molecular diagnostic rate (1.8%), perhaps due to strict classification criteria. • Case study identified two likely pathogenic variants; one each in MCP/CD46 and CFI.
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Affiliation(s)
- Dervla M Connaughton
- Schulich School of Medicine & Dentistry, University of Western, London, ON, Canada
- Department of Medicine, Division of Nephrology, London Health Sciences Centre, 339 Windermere Road, London, ON, Canada
| | - Pratibha Bhai
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre (LHSC), London, ON, Canada
| | - Paul Isenring
- Faculty of Medicine, Université Laval, Quebec City, QC, Canada
| | | | - Bekim Sadikovic
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre (LHSC), London, ON, Canada
- Pathology and Laboratory Medicine, Western University, London, ON, Canada
| | - Laila C Schenkel
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre (LHSC), London, ON, Canada.
- Pathology and Laboratory Medicine, Western University, London, ON, Canada.
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Mrabet S, Dahmane R, Raja B, Fradi A, Aicha NB, Sahtout W, Azzabi A, Guedri Y, Zellama D, Achour A, Sfar I, Goucha R, Abdessayed N, Mokni M. Thrombotic microangiopathy due to acquired complement factor I deficiency in a male receiving interferon-beta treatment for multiple sclerosis. Br J Clin Pharmacol 2022; 89:1682-1685. [PMID: 36480744 DOI: 10.1111/bcp.15631] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 11/20/2022] [Accepted: 11/29/2022] [Indexed: 12/13/2022] Open
Abstract
AIMS Interferon-beta (IFNβ), the most widely prescribed medication for multiple sclerosis, is generally considered safe. Nevertheless, rare serious and/or life-threatening side effects have been reported such as thrombotic microangiopathy. A few mechanisms have been proposed to explain how interferon causes thrombotic microangiopathy, but immunological studies have been unable to pin this phenomenon down to a single pathophysiologic pathway. The aim of this article was to report a new mechanism explaining Interferon beta related thrombotic microangiopathy. METHODS We report thrombotic microangiopathy in a 28-year-old male receiving interferon-beta treatment for multiple sclerosis. RESULTS After three years of starting interferon beta therapy, the patient presented with malignant hypertension causing seizures, rapidly progressive renal failure requiring haemodialysis and haemolytic anaemia. Corticosteroid and plasma exchange sessions permitted haemolysis control. Nonetheless, the patient remained hemodialysis-dependent. Exploration of the complement system found a complement factor I deficiency whose activity normalized at the control carried out after 2 years. CONCLUSION IFNβ treatment may cause complement factor I deficit, which can lead to thrombotic microangiopathy and severe renal failure.
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Affiliation(s)
- Sanda Mrabet
- Department of Nephrology, Dialysis, and Transplantation, Université de Sousse, Faculté de Médecine de Sousse, Hôpital Sahloul, Sousse, Tunisia
| | - Rihem Dahmane
- Department of Nephrology, Dialysis, and Transplantation, Université de Sousse, Faculté de Médecine de Sousse, Hôpital Sahloul, Sousse, Tunisia
| | - Boukadida Raja
- Department of Nephrology, Dialysis, and Transplantation, Université de Sousse, Faculté de Médecine de Sousse, Hôpital Sahloul, Sousse, Tunisia
| | - Asma Fradi
- Department of Nephrology, Dialysis, and Transplantation, Université de Sousse, Faculté de Médecine de Sousse, Hôpital Sahloul, Sousse, Tunisia
| | - Narjess Ben Aicha
- Department of Nephrology, Dialysis, and Transplantation, Université de Sousse, Faculté de Médecine de Sousse, Hôpital Sahloul, Sousse, Tunisia
| | - Wissal Sahtout
- Department of Nephrology, Dialysis, and Transplantation, Université de Sousse, Faculté de Médecine de Sousse, Hôpital Sahloul, Sousse, Tunisia
| | - Awatef Azzabi
- Department of Nephrology, Dialysis, and Transplantation, Université de Sousse, Faculté de Médecine de Sousse, Hôpital Sahloul, Sousse, Tunisia
| | - Yosra Guedri
- Department of Nephrology, Dialysis, and Transplantation, Université de Sousse, Faculté de Médecine de Sousse, Hôpital Sahloul, Sousse, Tunisia
| | - Dorsaf Zellama
- Department of Nephrology, Dialysis, and Transplantation, Université de Sousse, Faculté de Médecine de Sousse, Hôpital Sahloul, Sousse, Tunisia
| | - Abdellatif Achour
- Department of Nephrology, Dialysis, and Transplantation, Université de Sousse, Faculté de Médecine de Sousse, Hôpital Sahloul, Sousse, Tunisia
| | - Imen Sfar
- Laboratory of immunology Charles Nicolle Hospital, El Manar University, Tunis, Tunisia
| | - Rim Goucha
- Department of Nephrology, Dialysis, and Transplantation La Marsa Hospital, El Manar University, Tunis, Tunisia
| | - Nihed Abdessayed
- Department of Pathology, Université de Sousse, Faculté de Médecine de Sousse, Hôpital Sahloul, Sousse, Tunisia
| | - Moncef Mokni
- Department of Pathology, Université de Sousse, Faculté de Médecine de Sousse, Hôpital Sahloul, Sousse, Tunisia
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Kerboua KE, Djenouhat K. Complementology's foundation: The 100-year anniversary of the Nobel Prize to Jules Bordet. J Immunoassay Immunochem 2020; 41:106-116. [PMID: 31747841 DOI: 10.1080/15321819.2019.1689999] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The discovery of the complement system was associated with the creation of medical serodiagnosis in the early 20th century. Its biotechnological applications, usable even a century after its development by Jules Bordet, preceded for decades the proof of its biochemical rather than biophysical nature. Complement science has begun to emerge, thanks to the labs of Michael Heidelberger and his student Manfred Martin Mayer. Complementology had known difficult moments like the suicide of Louis Pillemer by swallowing the reagents of his laboratory following the criticisms of his discovery by Robert A. Nelson, Jr., in March 1957, at the Walter Reed Army Institute. This alternative complement pathway continues to revolutionize medicine by its implications as the principal component of immunosurveillance and as an amplification loop for plasma proteolytic cascades. Moreover, the drug designed in pathologies related to this pathway, eculizumab, was the most expensive drug in the world at the beginning of its marketing. Complementology promises great hopes in inflammatory and degenerative diseases, regenerative medicine, transplantation, and vector nanotechnology and as a diagnostic tool primarily in transplantation and inflammatory imaging. The moral and historical responsibility requires to make known this legacy to the new generation of doctors and scientists and also the technicians of the clinical laboratory of complementology throughout the world.
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Affiliation(s)
- Kheir Eddine Kerboua
- Laboratory of Immunology, Faculty of Medicine, University of Kasdi Merbah Ouargla, ouargla, Algeria
| | - Kamal Djenouhat
- Laboratory of Immunology, Faculty of Medicine, University of Youcef Benkhadda Algiers, Algiers, Algeria
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Understanding the Role of Anti-PEG Antibodies in the Complement Activation by Doxil in Vitro. Molecules 2018; 23:molecules23071700. [PMID: 30002298 PMCID: PMC6100003 DOI: 10.3390/molecules23071700] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 07/06/2018] [Accepted: 07/10/2018] [Indexed: 11/27/2022] Open
Abstract
Infusion reactions (IRs) are common immune-mediated side effects in patients treated with a variety of drug products, including, but not limited to, nanotechnology formulations. The mechanism of IRs is not fully understood. One of the best studied mechanisms of IRs to nanomedicines is the complement activation. However, it is largely unknown why some patients develop reactions to nanomedicines while others do not, and why some nanoparticles are more reactogenic than others. One of the theories is that the pre-existing anti-polyethylene glycol (PEG) antibodies initiate the complement activation and IRs in patients. In this study, we investigated this hypothesis in the case of PEGylated liposomal doxorubicin (Doxil), which, when used in a clinical setting, is known to induce IRs; referred to as complement activation-related pseudoallergy (CARPA) in sensitive individuals. We conducted the study in vitro using plasma derived from C57BL/6 mice and twenty human donor volunteers. We used mouse plasma to test a library of well-characterized mouse monoclonal antibodies with different specificity and affinity to PEG as it relates to the complement activation by Doxil. We determined the levels of pre-existing polyclonal antibodies that bind to PEG, methoxy-PEG, and PEGylated liposomes in human plasma, and we also assessed complement activation by Doxil and concentrations of complement inhibitory factors H and I in these human plasma specimens. The affinity, specificity, and other characteristics of the human polyclonal antibodies are not known at this time. Our data demonstrate that under in vitro conditions, some anti-PEG antibodies contribute to the complement activation by Doxil. Such contribution, however, needs to be considered in the context of other factors, including, but not limited to, antibody class, type, clonality, epitope specificity, affinity, and titer. In addition, our data contribute to the knowledge base used to understand and improve nanomedicine safety.
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