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Schönfelder K, Kühne L, Schulte-Kemna L, Kaufeld J, Rohn H, Kribben A, Schröppel B, Brinkkötter PT, Gäckler A. Clinical efficacy and safety of switching from eculizumab to ravulizumab in adult patients with aHUS- real-world data. BMC Nephrol 2024; 25:202. [PMID: 38898427 PMCID: PMC11188157 DOI: 10.1186/s12882-024-03638-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Accepted: 06/12/2024] [Indexed: 06/21/2024] Open
Abstract
BACKGROUND The complement factor 5 (C5)-inhibitor eculizumab has been established as standard-of-care for the treatment of atypical hemolytic uremic syndrome (aHUS). In 2021, the long-acting C5-inhibitor ravulizumab was approved, extending intervals of intravenous treatment from two to eight weeks resulting in improvement of quality of life for patients and lowering direct and indirect therapy associated costs. METHODS This multicenter, retrospective data analysis of 32 adult patients with aHUS (including 10 kidney transplant recipients) treated with eculizumab for at least three months and switched to ravulizumab aims to evaluate the safety and efficacy of switching medication in the real-world setting. Hematologic parameters, kidney function, concurrent therapy and aHUS associated events were evaluated three months before and until up to 12 months after switching to ravulizumab. RESULTS Mean age (range) at ravulizumab initiation was 41 years (19-78 years) and 59% of the patients were female. Genetic analysis was available for all patients with 72% showing a pathogenic variant. Median time (range) on eculizumab before switching was 20 months (3-120 months). No new events of TMA or worsening of renal function were reported during up to 12 months of follow-up during ravulizumab treatment. CONCLUSIONS This is the largest, non-industry derived, multi-center retrospective analysis of adult patients with aHUS switching C5-inhibitor treatment from eculizumab to ravulizumab in the real-world setting. Switching to ravulizumab was safe and efficient resulting in sustained hematological stability and preservation of renal function.
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Affiliation(s)
- Kristina Schönfelder
- Department of Nephrology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Lucas Kühne
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Lena Schulte-Kemna
- Section of Nephrology, Ulm University Hospital, University of Ulm, Ulm, Germany
| | - Jessica Kaufeld
- Division of Nephrology, Center for Internal Medicine, Hannover Medical School, Hannover, Germany
| | - Hana Rohn
- Department of Infectious Diseases, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Andreas Kribben
- Department of Nephrology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Bernd Schröppel
- Section of Nephrology, Ulm University Hospital, University of Ulm, Ulm, Germany
| | - Paul T Brinkkötter
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Anja Gäckler
- Department of Nephrology, University Hospital Essen, University Duisburg-Essen, Essen, Germany.
- Klinik Für Nephrologie, Universitätsklinikum Essen, Hufelandstr. 55, Essen, 45147, Germany.
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Bleathman F, Kausman JY, Hosking LM, Forbes TA. Ravulizumab facilitates reduced burden of vascular access, a major benefit in paediatric atypical haemolytic uraemic syndrome. J Paediatr Child Health 2024; 60:183-187. [PMID: 38661088 DOI: 10.1111/jpc.16552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/04/2024] [Accepted: 04/15/2024] [Indexed: 04/26/2024]
Abstract
BACKGROUND Atypical haemolytic uraemic syndrome (aHUS) is a rare thrombotic microangiopathy resulting from dysregulation of the alternative complement pathway, leading to multi-organ dysfunction and chronic kidney disease. Eculizumab is an anti-C5 monoclonal antibody therapy that has significantly improved aHUS disease control and patient outcomes, however it requires fortnightly intravenous dosing. This often necessitates long term central access and a high hospital attendance burden. Ravulizumab is a novel, next-generation anti-C5 monoclonal antibody engineered from eculizumab to reduce endosomal degradation of the antibody, increasing the dosing interval up to 8 weeks. CASE SERIES In this retrospective case series we present the transition of three children with aHUS from eculizumab to ravulizumab from a single tertiary paediatric nephrology service. All patients underwent genomic and immunological work up for aHUS, with no cause found. After stabilisation with eculizumab, two patients developed macrovascular thrombotic complications associated with indwelling central vascular catheters, ultimately leading to central access failure. All patients were transitioned from eculizumab to ravulizumab without relapse of aHUS. One patient successfully underwent deceased donor kidney transplantation with ravulizumab for complement inhibition. All patients have transitioned to peripheral access for infusions given the reduced frequency of dosing, maintaining good control of aHUS for 2-4 years. CONCLUSION Ravulizumab permits sufficiently reduced frequency of infusion to allow for administration by peripheral cannulation - removing the risks of long term central vascular access often required to deliver eculizumab to paediatric patients.
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Affiliation(s)
- Freya Bleathman
- Department of Nephrology, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Joshua Y Kausman
- Department of Nephrology, Royal Children's Hospital, Melbourne, Victoria, Australia
- Kidney Flagship, Murdoch Children's Research Institute, Melbourne, Victoria, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Laine M Hosking
- Immunology Laboratory, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Thomas A Forbes
- Department of Nephrology, Royal Children's Hospital, Melbourne, Victoria, Australia
- Kidney Flagship, Murdoch Children's Research Institute, Melbourne, Victoria, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
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3
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Kirschfink M, Frazer-Abel A, Balogh E, Goseberg S, Weiss N, Prohászka Z. External quality assurance program for diagnostic complement laboratories: evaluation of the results of the past seven years. Front Immunol 2024; 15:1368399. [PMID: 38596685 PMCID: PMC11002221 DOI: 10.3389/fimmu.2024.1368399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 03/07/2024] [Indexed: 04/11/2024] Open
Abstract
Introduction The complement external quality assurance (EQA) program was first organized in 2010 by a group of researchers working in diagnostic complement laboratories. Starting in 2016, INSTAND e.V., a German, non-profit interdisciplinary scientific medical society dedicated to providing expert EQA programs for medical laboratories, started organizing the EQAs for complement diagnostic laboratories together with the same group of experienced scientists and doctors who also work as EQA experts. The aim of the current work is to provide descriptive analysis of the past seven years' complement EQA results and evaluate timeline changes in proficiency testing. Methods Each year, in March and October, blinded samples (normal, pathological) were sent to the participating diagnostic laboratories, where complement parameters were evaluated exactly as in daily routine samples. Since no reference method/target values exist for these parameters, and participants used different units for measurement, the reported results were compared to the stable mean (Algorithm A) of the participants using the same method/measurement units. A reported result was qualified as "passed" if it fell into the 30-50% evaluation/target range around the mean of reported results (depending on the given parameter). Results While the number of participating laboratories has increased in the past years (from around 120 to 347), the number of complement laboratories providing multiple determinations remained mostly unchanged (around 30 worldwide). C3, C4, C1-inhibitor antigen and activity determinations provided the best proficiency results, with >90% passing quotas in the past years, independent of the applied method. Determination of the functional activity of the three activation pathways was good in general, but results showed large variance, especially with the pathological samples. Complement factor C1q and regulators FH and FI are determined by only a few laboratories, with variable outcomes (in general in the 85-90% pass range). Activation products sC5b-9 and Bb were determined in 30 and 10 laboratories, respectively, with typical passing quotas in the 70-90% range, without a clear tendency over the past years. Conclusion With these accumulated data from the past seven years, it is now possible to assess sample-, method-, and evaluation related aspects to further improve proficiency testing and protocolize diagnostic complement determinations.
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Affiliation(s)
- Michael Kirschfink
- Institute of Immunology, University of Heidelberg, Heidelberg, Germany
- Instand eV, Düsseldorf, Germany
| | | | - Emese Balogh
- Department of Pharmaceutics, Semmelweis University, Budapest, Hungary
| | | | | | - Zoltán Prohászka
- Instand eV, Düsseldorf, Germany
- Department of Internal Medicine and Hematology, Füst György Complement Diagnostic Laboratory, Semmelweis University, Budapest, Hungary
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4
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Dixon BP, Greenbaum LA, Huang L, Rajan S, Ke C, Zhang Y, Li L. Clinical Safety and Efficacy of Pegcetacoplan in a Phase 2 Study of Patients with C3 Glomerulopathy and Other Complement-Mediated Glomerular Diseases. Kidney Int Rep 2023; 8:2284-2293. [PMID: 38025230 PMCID: PMC10658235 DOI: 10.1016/j.ekir.2023.08.033] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 08/15/2023] [Accepted: 08/21/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction Dysregulated complement activation is likely the primary driver of disease in C3 glomerulopathy (C3G) and contributes to other complement-mediated diseases, including immunoglobulin A nephropathy (IgAN), lupus nephritis (LN), and primary membranous nephropathy (PMN). No complement inhibitors are proven to halt disease progression in these diseases. Pegcetacoplan, a targeted C3 and C3b inhibitor, may mitigate complement-mediated kidney damage in C3G and other glomerular diseases in which complement may have a pathogenic role. Methods This open-label, phase 2, 48-week study evaluated the preliminary efficacy and safety of subcutaneous pegcetacoplan for patients with complement-mediated glomerular diseases. The primary end point was proteinuria reduction, measured as 24-hour urine protein-to-creatinine ratio. Secondary end points included remission status, changes in estimated glomerular filtration rate (eGFR), and pharmacodynamic biomarkers. Treatment-emergent adverse events (TEAEs) were monitored. Results Efficacy results for the C3G cohort are reported herein, along with safety results for the study population. In the C3G cohort, mean proteinuria reduction from baseline to week 48 was 50.9% in the intent-to-treat (ITT) population (n = 7) and 65.4% in the per-protocol (PP) population (n = 4). Mean serum albumin normalized and mean eGFR was stable over 48 weeks. Mean serum C3 levels increased 6-fold and mean soluble C5b-9 levels decreased by 57.3% at week 48. The most common adverse events (AEs) were upper respiratory tract infection, injection site erythema, nausea, and headache. No meningitis or sepsis cases were reported, and no serious treatment-related AEs were observed. Conclusion Pegcetacoplan may provide therapeutic benefit for C3G and has a favorable safety profile across the 4 glomerular diseases studied.
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Affiliation(s)
- Bradley P. Dixon
- Renal Section, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Larry A. Greenbaum
- Emory University and Children’s Healthcare of Atlanta, Atlanta, Georgia, USA
| | - Liwei Huang
- Tidewater Kidney Specialists, Inc, Chesapeake, Virginia, USA
| | - Sandeep Rajan
- Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Chunlei Ke
- Apellis Pharmaceuticals, Inc., Waltham, Massachusetts, USA
| | - Yiwei Zhang
- Apellis Pharmaceuticals, Inc., Waltham, Massachusetts, USA
| | - Li Li
- Apellis Pharmaceuticals, Inc., Waltham, Massachusetts, USA
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5
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Ter Avest M, Langemeijer SMC, Blijlevens NMA, van de Kar NCAJ, Ter Heine R. Dose optimalization of subcutaneous ravulizumab is predicted to yield significant savings and to improve patient friendliness. Br J Clin Pharmacol 2023; 89:1211-1215. [PMID: 36394176 DOI: 10.1111/bcp.15602] [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: 09/02/2022] [Revised: 11/01/2022] [Accepted: 11/07/2022] [Indexed: 11/18/2022] Open
Abstract
Ravulizumab is an expensive complement C5-inhibitor for the treatment of paroxysmal nocturnal haemoglobinuria. Recently, a subcutaneous formulation has entered the market, for which the approved dosing regimen results in supratherapeutic ravulizumab concentrations in the majority of patients in the registration studies. Therefore, we explored alternative dosing regimens in silico based on the registration data of the manufacturer. Extending the interval from 1 to 2 weeks or individualized dosing based on therapeutic drug monitoring resulted in therapeutic ravulizumab concentrations and comparable predicted efficacy in terms of lactate dehydrogenase normalization, with dose reductions up to 64%. We here show that with an individualized dose, a substantial dose reduction for subcutaneous ravulizumab might be possible with improved patient-friendliness.
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Affiliation(s)
- Mendy Ter Avest
- Department of Pharmacy, Radboud Institute for Health Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
| | | | - Nicole M A Blijlevens
- Department of Haematology, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Nicole C A J van de Kar
- Deparment of Paediatric Nephrology, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Rob Ter Heine
- Department of Pharmacy, Radboud Institute for Health Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
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6
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Biomarkers and laboratory assessments for monitoring the treatment of patients with paroxysmal nocturnal hemoglobinuria: Differences between terminal and proximal complement inhibition. Blood Rev 2023; 59:101041. [PMID: 36732204 DOI: 10.1016/j.blre.2023.101041] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/15/2022] [Accepted: 01/09/2023] [Indexed: 01/15/2023]
Abstract
Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, life-threatening, acquired disease in which blood cells lacking complement regulatory proteins are destroyed because of uncontrolled complement activity. Since 2007, terminal complement inhibitors have revolutionized the treatment of this disease. However, patients treated with these inhibitors can still experience anemia because of C3-mediated extravascular hemolysis and clinically relevant levels of breakthrough or residual intravascular hemolysis. Proximal complement inhibitors, which are only just beginning to emerge, have the potential to address this problem by targeting components of the pathway upstream of C5, thereby protecting patients against both intra- and extravascular hemolysis. In this review, we describe different biomarkers that can be used to monitor complement pathway blockade and discuss key laboratory assessments for evaluating treatment efficacy. We also consider how these assessments are affected by each class of inhibitor and highlight how evolving treatment goals may influence the relative importance of these assessments.
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7
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Benoit SW, Fukuda T, VandenHeuvel K, Witte D, Fuller C, Willis J, Dixon BP, Drake KA. Case Report: Atypical HUS Presenting With Acute Rhabdomyolysis Highlights the Need for Individualized Eculizumab Dosing. Front Pediatr 2022; 10:841051. [PMID: 35281224 PMCID: PMC8906567 DOI: 10.3389/fped.2022.841051] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 01/31/2022] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Atypical hemolytic uremic syndrome (aHUS) is an ultra-rare orphan disease caused by dysregulated complement activation resulting in thrombotic microangiopathy. Although complement-mediated endothelial injury predominantly affects the renal microvasculature, extra-renal manifestations are present in a significant proportion of patients. While eculizumab has significantly improved the morbidity and mortality of this rare disease, optimizing therapeutic regimens of this highly expensive drug remains an active area of research in the treatment of aHUS. CASE PRESENTATION This report describes the case of a previously healthy 4 year-old male who presented with rhabdomyolysis preceding the development of aHUS with anuric kidney injury requiring dialysis. Clinical stabilization required increased and more frequent eculizumab doses compared with the standardized weight-based guidelines. In the maintenance phase of his disease, pharmacokinetic analysis indicated adequate eculizumab levels could be maintained with an individualized dosing regimen every 3 weeks, as opposed to standard 2 week dosing, confirmed in this patient over a 4 year follow up period. Cost analyses show that weight-based maintenance dosing costs $312,000 per year, while extending the dosing interval to every 3 weeks would cost $208,000, a savings of $104,000 per year, relative to the cost of $72,000 from more frequent eculizumab dosing during his initial hospitalization to suppress his acute disease. CONCLUSION This case exemplifies the potential of severe, multisystem involvement of aHUS presenting with extra-renal manifestations, including rhabdomyolysis as in this case, and highlights the possibility for improved clinical outcomes and higher value care with individualized eculizumab dosing in patients over the course of their disease.
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Affiliation(s)
- Stefanie W Benoit
- Division of Nephrology and Hypertension, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Division of Bone Marrow Transplantation and Immune Deficiency, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Tsuyoshi Fukuda
- University of Cincinnati College of Medicine, Cincinnati, OH, United States.,Division of Clinical Pharmacology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Katherine VandenHeuvel
- University of Cincinnati College of Medicine, Cincinnati, OH, United States.,Division of Pathology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - David Witte
- University of Cincinnati College of Medicine, Cincinnati, OH, United States.,Division of Pathology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Christine Fuller
- University of Cincinnati College of Medicine, Cincinnati, OH, United States.,Division of Pathology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | | | - Bradley P Dixon
- Renal Section, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States
| | - Keri A Drake
- Division of Pediatric Nephrology, University of Texas Southwestern Medical Center, Dallas, TX, United States
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8
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Ravulizumab: Characterization and quantitation of a new C5 inhibitor using isotype specific affinity purification and high-resolution mass spectrometry. J Mass Spectrom Adv Clin Lab 2021; 21:10-18. [PMID: 34820672 PMCID: PMC8601004 DOI: 10.1016/j.jmsacl.2021.08.002] [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: 03/12/2021] [Revised: 08/02/2021] [Accepted: 08/05/2021] [Indexed: 11/23/2022] Open
Abstract
Introduction Ravulizumab (RAVUL) is a new complement inhibitor, with a difference of 4 amino acids in the heavy chain from a predecessor compound, eculizumab (ECUL). Objectives First, to utilize mass spectrometry (MS) to characterize RAVUL and verify differences from its predecessor and, second, to validate and implement a lab developed test (LDT) for RAVUL that will allow for quantitative therapeutic monitoring. Methods A time-of-flight mass spectrometer (TOF-MS) was used to characterize and differentiate the molecular weight differences between RAVUL and ECUL by both digest and reduction experiments. In parallel, an LDT for RAVUL was validated and implemented utilizing IgG4 enrichment with light chain detection and quantitation on a high throughput orbitrap MS platform. Results The TOF-MS platform allowed for the mass difference between RAVUL and ECUL to be verified along with providing a proof of concept for a new intact protein quantitation software. An LDT on an orbitrap MS was validated and implemented using intact light chain quantitation, with the limitation that it cannot differentiate between ECUL and RAVUL. The LDT has an analytical measuring range from 5 to 600 mcg/mL, inter-assay imprecision of ≤13% CV (n = 13) and accuracy with <4% error from expected values (n = 20). Conclusion The TOF-MS is a versatile development platform that can be used to characterize and verify the molecular weight differences between the ECUL and RAVUL heavy chains. Routine laboratory testing for RAVUL was viable using an orbitrap-MS to quantitate using the mass of the intact light chain. These two platforms, combined, provide incomparable value in development of LDTs for the clinical laboratory.
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Key Words
- AMR, analytical measuring range
- C5, complement component 5
- DTT, dithiothreitol
- Da, daltons
- ECUL, eculizumab
- Eculizumab
- Fc, crystallizable fragment
- HPLC, high performance liquid chromatography
- IRB, Institutional Review Board
- IS, internal standard
- Intact light chain
- LC, liquid chromatography
- LDT, lab-developed test
- LLOD, lower limit of detection
- LLOQ, lower limit of quantitation
- LOB, limit of blankMS, mass spectrometry
- MW, molecular weight
- Mass spectrometry
- NHS, normal human serum
- NIVOL, nivolumab
- Orbitrap
- PBS, phosphate buffered saline
- PNH, paroxysmal nocturnal hemoglobinuria
- Q-TOF, quadrupole time-of-flight
- RAVUL, ravulizumab
- Ravulizumab
- Therapeutic monoclonal antibody
- Time of flight
- XIC, extracted ion chromatogram
- aHUS, atypical hemolytic uremic syndrome
- t-mAb, therapeutic monoclonal antibody
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Frazer-Abel A, Kirschfink M, Prohászka Z. Expanding Horizons in Complement Analysis and Quality Control. Front Immunol 2021; 12:697313. [PMID: 34434189 PMCID: PMC8381195 DOI: 10.3389/fimmu.2021.697313] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 07/19/2021] [Indexed: 01/09/2023] Open
Abstract
Complement not only plays a key role in host microbial defense but also modulates the adaptive immune response through modification of T- and B-cell reactivity. Moreover, a normally functioning complement system participates in hematopoiesis, reproduction, lipid metabolism, and tissue regeneration. Because of its powerful inflammatory potential, multiple regulatory proteins are needed to prevent potential tissue damage. In clinical practice, dysregulation and overactivation of the complement system are major causes of a variety of inflammatory and autoimmune diseases ranging from nephropathies, age-related macular degeneration (AMD), and systemic lupus erythematosus (SLE) to graft rejection, sepsis, and multi-organ failure. The clinical importance is reflected by the recent development of multiple drugs targeting complement with a broad spectrum of indications. The recognition of the role of complement in diverse diseases and the advent of complement therapeutics has increased the number of laboratories and suppliers entering the field. This has highlighted the need for reliable complement testing. The relatively rapid expansion in complement testing has presented challenges for a previously niche field. This is exemplified by the issue of cross-reactivity of complement-directed antibodies and by the challenges of the poor stability of many of the complement analytes. The complex nature of complement testing and increasing clinical demand has been met in the last decade by efforts to improve the standardization among laboratories. Initiated by the IUIS/ICS Committee for the Standardization and Quality Assessment in Complement Measurements 14 rounds of external quality assessment since 2010 resulted in improvements in the consistency of testing across participating institutions, while extending the global reach of the efforts to more than 200 laboratories in 30 countries. Worldwide trends of assay availability, usage, and analytical performance are summarized based on the past years’ experiences. Progress in complement analysis has been facilitated by the quality assessment and standardization efforts that now allow complement testing to provide a comprehensive insight into deficiencies and the activation state of the system. This in turn enables clinicians to better define disease severity, evolution, and response to therapy.
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Affiliation(s)
| | | | - Zoltán Prohászka
- Department of Medicine and Hematology, Research Laboratory Semmelweis University, Budapest, Hungary
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10
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Willrich MAV, Braun KMP, Moyer AM, Jeffrey DH, Frazer-Abel A. Complement testing in the clinical laboratory. Crit Rev Clin Lab Sci 2021; 58:447-478. [PMID: 33962553 DOI: 10.1080/10408363.2021.1907297] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The complement system is the human's first line of defense against microbial pathogens because of its important housekeeping and infection/inflammation roles. It is composed of a series of soluble and cell-bound proteins that are activated in a cascade effect, similar to the coagulation pathways. There are different pattern recognizing molecules that activate the complement system in response to stimuli or threats, acting through three initiation pathways: classical, lectin, and alternative. All three activation pathways converge at the C3 component and share the terminal pathway. The main outputs of the complement system action are lytic killing of microbes, the release of pro-inflammatory anaphylatoxins, and opsonization of targets. Laboratory testing is relevant in the setting of suspected complement deficiencies, as well as in the emerging number of diseases related to dysregulation (over-activation) of complement. Most common assays measure complement lytic activity and the different complement component concentrations. Specialized testing includes the evaluation of autoantibodies against complement components, activation fragments, and genetic studies. In this review, we cover laboratory testing for complement and the conditions with complement involvement, as well as current challenges in the field.
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Affiliation(s)
| | - Karin M P Braun
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Ann M Moyer
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - David H Jeffrey
- Exsera Biolabs, Department of Medicine, University of Colorado School of Medicine, Aurora, CO, USA
| | - Ashley Frazer-Abel
- Exsera Biolabs, Department of Medicine, University of Colorado School of Medicine, Aurora, CO, USA
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