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Sasaki D, Kashiwagura H, Teruuchi Y. Development of an LC-MS/MS method for absolute quantification of IgG4 by evaluating dependence on the digestion efficiency using a non-cleavable/dually-cleavable internal calibrator set. Biochem Biophys Res Commun 2023; 682:381-385. [PMID: 37844447 DOI: 10.1016/j.bbrc.2023.10.021] [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: 09/27/2023] [Revised: 10/04/2023] [Accepted: 10/05/2023] [Indexed: 10/18/2023]
Abstract
The measurement of serum IgG4 levels is mandatory for the diagnosis of IgG4-related disease, but no widely accepted reference material exists due to a lack of consensus on the standard assay. Therefore, we developed here an LC-MS/MS method for absolute quantification of IgG4 in a purified IgG sample, addressing a concern over the reliability depending on the proteolytic digestion efficiency. Our method uses internal calibrator sets containing unique amino acid sequences within IgG4, each of which comprises non-cleavable and dually-cleavable peptides labeled with different numbers of isotopes for mass separation, to determine digestion efficiency. Surrogate peptides generated by trypsin or lysyl endopeptidase digestion were selected based on selectivity, stability, and identifiability. IgG4 quantification using synthetic calibrator peptides showed high precision across the two conditions with different peptidases (relative differences ≤6.1%), even with low digestion efficiencies (<20%), which was within the interday precision under an established condition (% coefficient of variation ≤6.9%, digestion efficiencies >90%, n = 5). These results indicate that the LC-MS/MS method for quantifying IgG4 is robust against digestion efficiency variations and is applicable to validating an IgG4 reference material.
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Affiliation(s)
- Daisuke Sasaki
- Medical R&D Center, Nitto Boseki Co., Ltd., Koriyama, Japan
| | | | - Yuya Teruuchi
- Medical R&D Center, Nitto Boseki Co., Ltd., Koriyama, Japan.
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Yan S, Peng Y, Cheng L, Li H, Zhan H, Zhang X, Li Z, Zhang W, Li Y. A Unified Serum IgG4 Cutoff Level for the Diagnosis of IgG4-Related Disease Using a Wide Array of Kits. Mod Rheumatol 2022; 33:594-598. [PMID: 35570374 DOI: 10.1093/mr/roac047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 04/25/2022] [Accepted: 05/11/2022] [Indexed: 11/13/2022]
Abstract
Abstract
Objectives
An IgG4 level above 1350 mg/L is one of the comprehensive criteria for the diagnosis of IgG4-related disease (IgG4-RD). The purpose of this study was to evaluate the differences in IgG4 levels determined using reagents from two main manufacturers and their concordance with clinical diagnosis.
Methods
IgG4 levels were measured in 309 patients, including 146, 40, 42, 41, and 40 patients with untreated IgG4-RD, pancreatic cancer, primary Sjogren syndrome, systemic lupus erythematosus, and idiopathic retroperitoneal fibrosis, respectively, and 141 healthy controls. The results obtained using the Binding Site and Siemens reagents were compared in patients with IgG4-RD.
Results
The serum IgG4 level measured using the Siemens reagent was almost two times that measured using the Binding Site reagent. The rate of IgG4-negative patients, which was 19.9% based on measurement using the Binding Site reagent, was only 4.8% based on measurement using the Siemens reagent (P < 0.001).
Conclusions
There were significant differences in serum IgG4 levels based on commonly used reagents from different manufacturers. The IgG4 cutoff level of 1350 mg/L was not suitable for all detection reagents. Clinicians and patients should be cognizant of these differences associated with the specific detection reagents when evaluating the test results.
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Affiliation(s)
- Songxin Yan
- Department of Clinical Laboratory, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Yu Peng
- Department of Rheumatology, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - linlin Cheng
- Department of Clinical Laboratory, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Haolong Li
- Department of Clinical Laboratory, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Haoting Zhan
- Department of Clinical Laboratory, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Xinyao Zhang
- Department of Clinical Laboratory, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Zepeng Li
- Department of Clinical Laboratory, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Wen Zhang
- Department of Rheumatology, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Yongzhe Li
- Department of Clinical Laboratory, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
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Usami Y, Sugano M, Uehara T, Koinuma M, Ishimine N, Kawasaki K, Yamauchi K, Hamano H, Honda T. Cut-off values of serum IgG4 among three reagents, including a novel IgG4 reagent: a multicenter study. Sci Rep 2021; 11:7280. [PMID: 33790306 PMCID: PMC8012344 DOI: 10.1038/s41598-021-86024-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 03/04/2021] [Indexed: 12/26/2022] Open
Abstract
Elevated serum IgG4 is a useful marker of IgG4-related disease (IgG4-RD) activity. However, there is no uniformity in the cut-off values of IgG4 among the various reagents. The aim of this study was to compare the measured and cut-off values of IgG4 assessed using three different reagents. This study enrolled 466 IgG4-RD and non-IgG4-RD patients who required measurement of serum IgG4 levels to diagnose or treat IgG4-RD. Serum IgG4 was measured using three reagents: N-assay LA IgG4 Nittobo (Nittobo), BS-NIA IgG4 (TBS), and N Latex IgG4 (Siemens). The values obtained using the three reagents were compared, and cut-off values were calculated for each. Although there was good correlation among the results with the three reagents, the measured and cut-off values were all different. The Nittobo values were 1.4 times the TBS values and the TBS values were almost half those of the Siemens values. ROC curve analysis showed cut-off values for the Nittobo, TBS, and Siemens reagents of 1.42, 1.31, and 2.38 g/L, respectively. The measured and cut-off values of serum IgG4 vary depending on the reagents used for the assay, although there is good correlation among the values measured by the three reagents.
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Affiliation(s)
- Yoko Usami
- Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan
| | - Mitsutoshi Sugano
- Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan
| | - Takeshi Uehara
- Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan. .,Department of Laboratory Medicine, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, 390-8621, Japan.
| | - Masayoshi Koinuma
- Faculty of Pharmaceutical Sciences, Teikyo Heisei University, Tokyo, Japan.,Center of Clinical Research, Shinshu University Hospital, Matsumoto, Japan
| | - Nau Ishimine
- Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan
| | - Kenji Kawasaki
- Department of Laboratory Medicine, Chiba University School of Medicine, Chiba, Japan
| | - Kazuyoshi Yamauchi
- Department of Laboratory Medicine, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | | | - Takayuki Honda
- Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan.,Department of Laboratory Medicine, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, 390-8621, Japan
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Napodano C, Marino M, Stefanile A, Pocino K, Scatena R, Gulli F, Rapaccini GL, Delli Noci S, Capozio G, Rigante D, Basile U. Immunological Role of IgG Subclasses. Immunol Invest 2020; 50:427-444. [PMID: 32522062 DOI: 10.1080/08820139.2020.1775643] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The loss of tolerance to self-antigens is the unequivocal "red line" of autoimmunity: both development of autoreactive T and B cells and production of polyclonal autoantibodies represent seminal keys to the pathogenesis of protean autoimmune diseases. Most of these autoantibodies are immunoglobulins G (IgG), functionally distinguished in four subclasses named IgG1, IgG2, IgG3, and IgG4, due to structural differences in the hinge and heavy chain constant regions. Different studies analyzed serum levels of IgG subclasses in the course of different disorders, showing that they might have a pathogenic role by regulating interactions among immunoglobulins, Fc-gamma receptors, and complement. To date, the mechanisms promoting different IgG subclasses distribution during the natural history of most autoimmune diseases remain somewhat unclear. Evidence from the medical literature shows that the serum IgG profile is peculiar for many autoimmune diseases, suggesting that different subclasses could be specific for the underlying driving autoantigens. A better knowledge of IgG subsets may probably help to elucidate their pathological task, but also to define their relevance for diagnostic purposes, patients' personalized management, and prognosis assessment.
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Affiliation(s)
- Cecilia Napodano
- Department of Internal Medicine and Gastroenterology, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Rome, Italy
| | - MariaPaola Marino
- Institute of General Pathology, Dipartimento Di Medicina E Chirurgia Traslazionale, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Rome, Italy
| | - Annunziata Stefanile
- Area Diagnostica di Laboratorio, Fondazione Policlinico Universitario "A. Gemelli", Rome, Italy
| | - Krizia Pocino
- Department of Internal Medicine and Gastroenterology, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Rome, Italy
| | - Roberto Scatena
- Dipartimento Di Medicina Di Laboratorio, Ospedale Madre Giuseppina Vannini, Rome, Italy
| | - Francesca Gulli
- Dipartimento Di Medicina Di Laboratorio, Ospedale Madre Giuseppina Vannini, Rome, Italy
| | - Gian Lodovico Rapaccini
- Department of Internal Medicine and Gastroenterology, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Rome, Italy.,Università Cattolica del Sacro Cuore, Rome, Italy
| | - Stefano Delli Noci
- Department of Life Sciences and Public Health, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Rome, Italy
| | - Giovanna Capozio
- Department of Life Sciences and Public Health, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Rome, Italy
| | - Donato Rigante
- Università Cattolica del Sacro Cuore, Rome, Italy.,Department of Life Sciences and Public Health, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Rome, Italy
| | - Umberto Basile
- Area Diagnostica di Laboratorio, Fondazione Policlinico Universitario "A. Gemelli", Rome, Italy.,Università Cattolica del Sacro Cuore, Rome, Italy
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Li G, Liu T, Zheng J, Kang W, Xu J, Gao Z, Ma J. Untypical autoimmune pancreatitis and pancreatic cancer: differential diagnosis experiences extracted from misdiagnose of two cases. Orphanet J Rare Dis 2019; 14:245. [PMID: 31699117 PMCID: PMC6839088 DOI: 10.1186/s13023-019-1217-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 10/03/2019] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Differentiation between pancreatic cancer (PC) and focal form of autoimmune pancreatitis (AIP) is very challenging, with similar clinical presentations, laboratory results and morphologic imagings of US, CT, EUS, MRI, ERCP, PET-CT. Even serum IgG4 and biopsy sometimes cannot give clear-cut differential accurate diagnostis. Considering the totally different management strategy of the two diseases, accurate diagnostic value is urgently needed to remind the clinicians of the rare diagnosis of untypical AIP among frequent PC-suspected patients. RESULTS We present 2 laparotomy cases of AIP that had a high similar characteristic to PC and retrospectively extracted the warning signs that may help select untypical AIP in PC-suspected patients. CONCLUSIONS We find that mild fluctuating jaundice with abdominal pain, young age, tumor marker of TPS, TPA and diverse results between variable radiological tests can help to differentiate AIP mass from PC, through retrospectively analyzing work-up process of AIP in two patients who underwent laparotomy for suspected PC.
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Affiliation(s)
- Gaopeng Li
- Department of general surgery, Shanxi Cancer Hospital, Shanxi Medical University, Taiyuan, Shanxi Province China
| | - Ting Liu
- Department of general surgery, Shanxi Cancer Hospital, Shanxi Medical University, Taiyuan, Shanxi Province China
| | - Jian Zheng
- Department of critical care medicine, The first hospital of Shanxi medical University, The Hospital of Shanxi University of Traditional Chinese Medicine, Taiyuan, Shanxi Province China
| | - Wenqin Kang
- Department of general surgery, The Hospital of Shanxi University of Traditional Chinese Medicine, Taiyuan, Shanxi Province China
| | - Jun Xu
- Department of general surgery, Shanxi Dayi Hospital, Shanxi academy of Medical science, Taiyuan, Shanxi Province China
| | - Zefeng Gao
- Department of general surgery, Shanxi Cancer Hospital, Shanxi Medical University, Taiyuan, Shanxi Province China
| | - Jinfeng Ma
- Department of general surgery, Shanxi Cancer Hospital, Shanxi Medical University, Taiyuan, Shanxi Province China
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