1
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Kitchen S, Bowyer A, Makris M. Both one-stage and chromogenic factor VIII assays are required for the diagnosis of mild hemophilia A. J Thromb Haemost 2023; 21:773-775. [PMID: 36990519 DOI: 10.1016/j.jtha.2022.12.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 12/15/2022] [Indexed: 03/29/2023]
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2
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Al Moosawi M, Nicolson H, Wong SK, Dallas KL, Jackson S. Treatment changes in hemophilia A with chromogenic factor VIII assay implementation. Res Pract Thromb Haemost 2023; 7:100098. [PMID: 37063773 PMCID: PMC10099308 DOI: 10.1016/j.rpth.2023.100098] [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: 07/02/2022] [Revised: 01/15/2023] [Accepted: 02/11/2023] [Indexed: 03/06/2023] Open
Abstract
Background The one-stage assay (OSA) and the chromogenic assay (CSA) are 2 factor VIII (FVIII) assays used for the diagnosis and classification of hemophilia A. Discrepancies between the 2 assays exist in approximately one-third of patients with mild hemophilia A. Objectives The objectives of this study were to report the proportion of patients with mild or moderate hemophilia A and OSA-CSA discrepancies and to report the observed changes in treatment approach prompted by the presence of assay discrepancy. The study aimed to identify OSA:CSA ratio associated with the highest sensitivity for identification of patients in whom modification of treatment approach may be recommended. Methods This is a retrospective cohort study including adult (>18-year-old) patients with mild or moderate hemophilia A who were followed up at the Adult British Columbia Hemophilia Program between January 2013 and March 2019. Results A total of 75 patients with mild and 23 with moderate hemophilia A based on baseline OSA were included. Overall, 52% of study patients had OSA-CSA discrepancies, and change in treatment approach was observed in 27% of patients with OSA-CSA discrepancy. The OSA:CSA ratio of 1.8 to 3.5 demonstrated the highest area under the receiver operating characteristics curve and sensitivity for identification of patients in which modification of treatment approach may be recommended (AUC 0.75; sensitivity 71%). Conclusion In our population, OSA-CSA discrepancy was observed in 52% of patients with mild or moderate hemophilia A, and the treatment approach in 27% of these patients had to be modified.
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Affiliation(s)
- Muntadhar Al Moosawi
- Department of Pathology and Laboratory Medicine, University of British Columbia, British Columbia, Canada
| | - Hamish Nicolson
- Department of Pathology and Laboratory Medicine, University of British Columbia, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, St. Paul's Hospital, British Columbia, Canada
| | - Steven K.W. Wong
- Department of Pathology and Laboratory Medicine, St. Paul's Hospital, British Columbia, Canada
| | - Karen L. Dallas
- Department of Pathology and Laboratory Medicine, University of British Columbia, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, St. Paul's Hospital, British Columbia, Canada
| | - Shannon Jackson
- Department of Medicine, University of British Columbia, British Columbia, Canada
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3
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Yacoub OA, Duncan EM. Chromogenic Factor VIII Assay for Patients with Hemophilia A and on Emicizumab Therapy. Methods Mol Biol 2023; 2663:597-610. [PMID: 37204739 DOI: 10.1007/978-1-0716-3175-1_39] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
This chapter will describe a method for measuring endogenous and infused Factor VIII (FVIII) in patients on emicizumab therapy (Hemlibra, Genetec, Inc). Emicizumab is a bispecific monoclonal antibody used in patients with hemophilia A, with or without inhibitors. The mechanism of action for emicizumab is novel and mimics the role that FVIII plays in vivo by binding and bridging FIXa and FX. It is vital that the laboratory understands the effect this drug has on coagulation tests and uses a suitable chromogenic assay which is not affected by emicizumab, for determination of FVIII coagulant activity and inhibitors.
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Affiliation(s)
- Olivia A Yacoub
- Haematology, SA Pathology, Royal Adelaide Hospital, Adelaide, SA, Australia.
| | - Elizabeth M Duncan
- Haematology, SA Pathology, Royal Adelaide Hospital, Adelaide, SA, Australia
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4
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Marlar RA, Gausman JN, Rollins-Raval MA. Guidance for establishing a factor VIII testing protocol for the myriad of factor VIII products. Int J Lab Hematol 2021; 44:414-423. [PMID: 34786864 DOI: 10.1111/ijlh.13763] [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: 06/02/2021] [Revised: 10/14/2021] [Accepted: 10/31/2021] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Management of hemophilia A has changed significantly in the past few years with the expansion of new and/or modified products as treatment options. Unfortunately, many of the standard factor VIII assays do not always accurately measure all available treatment products; therefore, the laboratory must investigate various assay algorithms to ensure the reporting of the correct results. METHODS Requirements for factor testing, diagnosis and severity levels, product testing, factor VIII inhibitor detection and titers, are evaluated, and potential algorithms are created for optimal assessment of patients with hemophilia A. RESULTS The potential for inaccurate result reporting for patients with hemophilia A or those being treated with the myriad of products has left many laboratories uncertain as to which assay algorithm to implement to ensure reporting the correct results for all products used in their hemophilia program. Algorithms for using either One-stage Clotting assays or Chromogenic assays or a combination of both types of assays are presented for each laboratory to implement based on their clinical situation. CONCLUSIONS Several algorithms are considered based on the needs of the clinical providers and their patients. Each laboratory must select a testing algorithm that is cost-effective and within available resources, yet that encompasses the needs of their providers and patients. Laboratory personnel must consider all assay uses (factor VIII levels, different products, interfering products, and inhibitor titers) in determining the best algorithm for their laboratory. This paper is a starting guide for developing the best factor VIII testing assays and protocols for your laboratory.
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Affiliation(s)
- Richard A Marlar
- Department of Pathology, University of New Mexico, TriCore Reference Laboratories, Albuquerque, New Mexico, USA
| | - Jana N Gausman
- OU Medicine, Inc., Laboratory, University of Oklahoma Medical Center, Oklahoma City, Oklahoma, USA
| | - Marian A Rollins-Raval
- Department of Pathology, University of New Mexico, TriCore Reference Laboratories, Albuquerque, New Mexico, USA
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5
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Inaba H, Nishikawa S, Shinozawa K, Shinohara S, Nakazawa F, Amano K, Kinai E. Coagulation assay discrepancies in Japanese patients with non-severe hemophilia A. Int J Hematol 2021; 115:173-187. [PMID: 34751920 DOI: 10.1007/s12185-021-03256-x] [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] [Received: 07/21/2021] [Revised: 10/29/2021] [Accepted: 10/29/2021] [Indexed: 11/29/2022]
Abstract
Patients with non-severe hemophilia A often show discrepancies in factor VIII (FVIII) activity. However, information on variant-specific coagulation assay characteristics in Japanese patients is limited. Pathogenic variants were classified into three groups, thrombin-cleavage site (TC), A1-A2-A3 interface (IF), and non-discrepant, with reference to previous studies. Cutoff values for the one-stage assay (OSA)/chromogenic substrate assay (CSA) ratio, which is suitable for distinguishing discrepancies, were determined for all five aPTT reagents. TGA and CWA parameters and bleeding scores were compared between groups. Two of the 39 patients with non-severe hemophilia A (5%) were classified as TC, 10 (26%) as IF, and 27 (69%) as non-discrepant. The OSA/CSA cutoff values between the groups varied widely by aPTT reagent and tended to be relatively low compared to previous studies. As an indicator of bleeding tendency, TGA had a low correlation coefficient for the IF variant, but this was not significant and was comparable to FVIII activity and CWA. Moreover, various parameters and bleeding tendency differed among patients with the same variants. Thus, our findings suggest that it is difficult to adequately assess the bleeding tendency of individual patients, even with the various assessments currently available.
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Affiliation(s)
- Hiroshi Inaba
- Department of Laboratory Medicine, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo, 160-0023, Japan.
| | - Satomi Nishikawa
- Scientific Research, Scientific Affairs, Sysmex Corporation, Kobe, Japan
| | - Keiko Shinozawa
- Department of Laboratory Medicine, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo, 160-0023, Japan
| | - Sho Shinohara
- Reagent Engineering, Sysmex Corporation, Kobe, Japan
| | - Fumie Nakazawa
- Scientific Research, Scientific Affairs, Sysmex Corporation, Kobe, Japan
| | - Kagehiro Amano
- Department of Laboratory Medicine, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo, 160-0023, Japan
| | - Ei Kinai
- Department of Laboratory Medicine, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo, 160-0023, Japan
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6
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Population pharmacokinetic modeling of factor concentrates in hemophilia: an overview and evaluation of best practice. Blood Adv 2021; 5:4314-4325. [PMID: 34496017 PMCID: PMC8945640 DOI: 10.1182/bloodadvances.2021005096] [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: 04/28/2021] [Accepted: 06/10/2021] [Indexed: 12/30/2022] Open
Abstract
The accuracy of pharmacokinetic (PK)-guided dosing depends on the clinical and laboratory data used to construct a population PK model, as well as the patient’s individual PK profile. This review provides a detailed overview of data used for published population PK models for factor VIII (FVIII) and factor IX (FIX) concentrates, to support physicians in their choices of which model best suits each patient. Furthermore, to enhance detailed data collection and documentation, we do suggestions for best practice. A literature search was performed; publications describing prophylactic population PK models for FVIII and FIX concentrates based on original patient data and constructed using nonlinear mixed-effect modeling were included. The following data were collected: detailed demographics, type of product, assessed and included covariates, laboratory specifications, and validation of models. Included models were scored according to our recommendations for best practice, specifically scoring the quality of data documentation as reported. Respectively, 20 models for FVIII and 7 for FIX concentrates were retrieved. Although most models (22/27) included pediatric patients, only 4 reported detailed demographics. The wide range of body weights suggested that overweight and obese adults were represented. Twenty-six models reported the assay applied to measure factor levels, whereas only 16 models named reagents used. Eight models were internally validated using a data subset. This overview presents detailed information on clinical and laboratory data used for published population PK models. We provide recommendations on data collection and documentation to increase the reliability of PK-guided prophylactic dosing of factor concentrates in hemophilia A and B.
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7
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Valikhani A, Mirakhorly M, Namvar A, Rastegarlari G, Toogeh G, Shirayeh FV, Ahmadinejad M. Genetic analysis of non-severe hemophilia A phenotype with A discrepancy between one-stage and chromogenic factor VIII activity assays. Transfus Apher Sci 2021; 60:103194. [PMID: 34275734 DOI: 10.1016/j.transci.2021.103194] [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: 03/29/2021] [Revised: 05/26/2021] [Accepted: 06/11/2021] [Indexed: 10/20/2022]
Abstract
INTRODUCTION The diagnosis of hemophilia A (HA) is based on the measurement of factor VIII activity (VIII:C). About one-third of non-severe HA patients show a discrepancy of VIII:C measured by one-stage (VIII:C 1st) and chromogenic (VIII:C chr) assays. Different mutations in the F8 gene may cause the discrepancy in results of the FVIII activity assay. The aim of this study was to investigate F8 gene mutations in patients with assay discrepancies and to evaluate their impact on the results of VIII:C assays. METHODS Mutation analysis was performed on 41 individuals with a discrepancy in VIII:C 1st and FVIII: C chr assays by direct sequencing. In addition, the effect of the variants on FVIII macromolecule structure was investigated by in silico and bioinformatics tools. RESULTS Genetic analysis disclosed 22 different variants, of which 19 were identified for the first time to be involved in the phenotype of VIII:C discrepancy. Most of the variants related to the higher VIII:C 1st were found in A1, A2, A3 domains. The variant related to VIII:C chr > VIII:C 1st was located in the thrombin cleavage site. In silico analysis showed the effect of variants on FVIII macromolecule stability, which may be the possible mechanism causing the discrepancy. CONCLUSION Our data shed light on the impact of genetic defects on VIII:C assay and provided evidence that the consideration of these mutations may open a new window to the proper diagnosis and treatment monitoring of non-severe HA patients.
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Affiliation(s)
- Amir Valikhani
- Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran
| | | | - Ali Namvar
- Iranian Comprehensive Haemophilia Care Center, Tehran, Iran
| | | | - Gholamreza Toogeh
- Imam Khomeini Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Fatemeh Vossough Shirayeh
- Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran
| | - Minoo Ahmadinejad
- Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran.
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8
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Activated protein C has a regulatory role in factor VIII function. Blood 2021; 137:2532-2543. [PMID: 33512448 DOI: 10.1182/blood.2020007562] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 12/17/2020] [Indexed: 11/20/2022] Open
Abstract
Mechanisms thought to regulate activated factor VIII (FVIIIa) cofactor function include A2-domain dissociation and activated protein C (APC) cleavage. Unlike A2-domain dissociation, there is no known phenotype associated with altered APC cleavage of FVIII, and biochemical studies have suggested APC plays a marginal role in FVIIIa regulation. However, the in vivo contribution of FVIIIa inactivation by APC is unexplored. Here we compared wild-type B-domainless FVIII (FVIII-WT) recombinant protein with an APC-resistant FVIII variant (FVIII-R336Q/R562Q; FVIII-QQ). FVIII-QQ demonstrated expected APC resistance without other changes in procoagulant function or A2-domain dissociation. In plasma-based studies, FVIII-WT/FVIIIa-WT demonstrated dose-dependent sensitivity to APC with or without protein S, whereas FVIII-QQ/FVIIIa-QQ did not. Importantly, FVIII-QQ demonstrated approximately fivefold increased procoagulant function relative to FVIII-WT in the tail clip and ferric chloride injury models in hemophilia A (HA) mice. To minimize the contribution of FV inactivation by APC in vivo, a tail clip assay was performed in homozygous HA/FV Leiden (FVL) mice infused with FVIII-QQ or FVIII-WT in the presence or absence of monoclonal antibody 1609, an antibody that blocks murine PC/APC hemostatic function. FVIII-QQ again demonstrated enhanced hemostatic function in HA/FVL mice; however, FVIII-QQ and FVIII-WT performed analogously in the presence of the PC/APC inhibitory antibody, indicating the increased hemostatic effect of FVIII-QQ was APC specific. Our data demonstrate APC contributes to the in vivo regulation of FVIIIa, which has the potential to be exploited to develop novel HA therapeutics.
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9
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Activity of transgene-produced B-domain-deleted factor VIII in human plasma following AAV5 gene therapy. Blood 2021; 136:2524-2534. [PMID: 32915950 DOI: 10.1182/blood.2020005683] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 08/25/2020] [Indexed: 12/18/2022] Open
Abstract
Adeno-associated virus (AAV)-based gene therapies can restore endogenous factor VIII (FVIII) expression in hemophilia A (HA). AAV vectors typically use a B-domain-deleted FVIII transgene, such as human FVIII-SQ in valoctocogene roxaparvovec (AAV5-FVIII-SQ). Surprisingly, the activity of transgene-produced FVIII-SQ was between 1.3 and 2.0 times higher in one-stage clot (OS) assays than in chromogenic-substrate (CS) assays, whereas recombinant FVIII-SQ products had lower OS than CS activity. Transgene-produced and recombinant FVIII-SQ showed comparable specific activity (international units per milligram) in the CS assay, demonstrating that the diverging activities arise in the OS assay. Higher OS activity for transgene-produced FVIII-SQ was observed across various assay kits and clinical laboratories, suggesting that intrinsic molecular features are potential root causes. Further experiments in 2 participants showed that transgene-produced FVIII-SQ accelerated early factor Xa and thrombin formation, which may explain the higher OS activity based on a kinetic bias between OS and CS assay readout times. Despite the faster onset of coagulation, global thrombin levels were unaffected. A correlation with joint bleeds suggested that both OS and CS assay remained clinically meaningful to distinguish hemophilic from nonhemophilic FVIII activity levels. During clinical development, the CS activity was chosen as a surrogate end point to conservatively assess hemostatic efficacy and enable comparison with recombinant FVIII-SQ products. Relevant trials are registered on clinicaltrials.gov as #NCT02576795 and #NCT03370913 and, respectively, on EudraCT (European Union Drug Regulating Authorities Clinical Trials Database; https://eudract.ema.europa.eu) as #2014-003880-38 and #2017-003215-19.
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10
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Baker P, Platton S, Gibson C, Gray E, Jennings I, Murphy P, Laffan M. Guidelines on the laboratory aspects of assays used in haemostasis and thrombosis. Br J Haematol 2020; 191:347-362. [PMID: 32537743 DOI: 10.1111/bjh.16776] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Peter Baker
- Oxford Haemophilia and Thrombosis Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Sean Platton
- Haemophilia Centre, Barts Health NHS Trust, London, UK
| | - Claire Gibson
- Specialist Haemostasis, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Elaine Gray
- Haemostasis Section, Biotherapeutics Group, National Institute for Biological Standards and Controls, Hertfordshire, UK
| | | | - Paul Murphy
- Department of Haematology, the Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Mike Laffan
- Centre for Haematology, Imperial College and Hammersmith Hospital, London, UK
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11
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Suzuki A, Suzuki N, Kanematsu T, Okamoto S, Tamura S, Kikuchi R, Katsumi A, Kiyoi H, Kojima T, Matsushita T. Impact of variation in reagent combinations for one-stage clotting assay on assay discrepancy in nonsevere haemophilia A. Int J Lab Hematol 2020; 43:131-138. [PMID: 32915508 DOI: 10.1111/ijlh.13335] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/01/2020] [Accepted: 08/17/2020] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Factor VIII activity (FVIII:C) is measured by one-stage clotting assay (OSA) or chromogenic substrate assay (CSA). Significant differences in FVIII:C between OSA (FVIII:C1st ) and CSA (FVIII:CChr ) are described as assay discrepancy in nonsevere haemophilia A (HA). A large number of reagent combinations (APTT reagent and FVIII-deficient plasma) are used for OSA, but the impact of variations in reagent combinations on assay discrepancy has not been fully characterized. AIM To clarify the variations in FVIII:C1st /FVIII:CChr ratios according to OSA reagent combination in HA subjects with/without assay discrepancy. METHODS Thirty-nine patients previously diagnosed with nonsevere HA were enrolled, and their FVIII genes were investigated and FVIII:C levels were assessed by a single CSA reagent and 11 OSA reagent combinations. Receiver operating characteristic (ROC) curve analysis was used to predict possible cut-off values of the FVIII:C1st /FVIII:CChr ratio to define FVIII assay discrepancy for each reagent combination. RESULTS Patients were categorized into nondiscrepant (n = 25), discrepant (n = 5) and unclassified (n = 9) groups according to their genotypes and information in the database. The FVIII:C1st /FVIII:CChr ratio in nondiscrepant HA varied widely, depending on the APTT reagents and FVIII-deficient plasma used. The ratio in discrepant HA patients differed with respect to their genotype and the reagent combination used. ROC curve analyses revealed that cut-off values to distinguish the assay discrepancy differed depending on the reagents used, but revealed two novel genotype variants, p.Cys573Gly and p.Gly582Arg, associated with FVIII assay discrepancy. CONCLUSION Our findings showed that the FVIII:C1st /FVIII:CChr ratio is dependent on the reagent combination used for OSA.
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Affiliation(s)
- Atsuo Suzuki
- Department of Medical Technique, Nagoya University Hospital, Nagoya, Japan
| | - Nobuaki Suzuki
- Department of Transfusion Medicine, Nagoya University Hospital, Nagoya, Japan
| | - Takeshi Kanematsu
- Department of Clinical Laboratory, Nagoya University Hospital, Nagoya, Japan
| | - Shuichi Okamoto
- Department of Haematology-Oncology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Shogo Tamura
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Ryosuke Kikuchi
- Department of Medical Technique, Nagoya University Hospital, Nagoya, Japan
| | - Akira Katsumi
- Department of Haematology, National Centre for Geriatrics and Gerontology, Obu, Japan
| | - Hitoshi Kiyoi
- Department of Haematology-Oncology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tetsuhito Kojima
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tadashi Matsushita
- Department of Transfusion Medicine, Nagoya University Hospital, Nagoya, Japan.,Department of Clinical Laboratory, Nagoya University Hospital, Nagoya, Japan
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12
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Strålfors A, Mikovic D, Schmidt D, Onelöv L, Soutari NMH, Berndtson M, Chaireti R, Holmström M, Antovic JP, Bruzelius M. Genetics and Hemostatic Potential in Persons with Mild to Moderate Hemophilia A with a Discrepancy between One-Stage and Chromogenic FVIII Assays. Thromb Haemost 2020; 121:27-35. [PMID: 32791533 DOI: 10.1055/s-0040-1715443] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND Factor VIII (FVIII) activity (FVIII:C) can be measured by different methods including one-stage clotting assays (OSAs) and chromogenic assays (CSAs). Discrepancy between FVIII:C assays is known and associated with genetic variations causing mild and moderate hemophilia A (HA). We aimed to study the discrepancy phenomenon and to identify associated genetic alterations. Further, we investigated if hemostatic global assays could discriminate the group with discrepant FVIII:C from them. METHODS The study contained plasma samples from 45 patients with HA (PwHA) from Hemophilia Centers in Stockholm, Sweden, and Belgrade, Serbia. We measured FVIII:C with OSA and CSA, sequenced the F8 gene, and performed two global hemostatic assays; endogenous thrombin potential and overall hemostatic potential. RESULTS Nineteen of 45 PwHA had a more than twofold higher FVIII:C using OSA compared to CSA and were considered discrepant. Thirty-four causal mutations were detected, where of five had not previously been associated with assay discrepancy. These novel mutations were p.Tyr25Cys, p.Phe698Leu, p.Met699Leu, p.Ile1698Thr, and Ala2070Val. We found no difference between discrepant and nondiscrepant cases with either of the global assays. CONCLUSION There was a discrepancy between FVIII:C assays in almost half of the PwHA, which for some could lead to missed HA diagnoses or misclassification of severity. Genotyping confirmed that mutations associated with FVIII:C discrepancy cluster in the A domains of F8, and five mutations not previously associated with FVIII:C discrepancy was identified. Global hemostatic assays did not contribute to distinguish assay discrepancy in PwHA.
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Affiliation(s)
- Annelie Strålfors
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.,Clinical Chemistry, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
| | - Danijela Mikovic
- Hemostasis Department and Hemophilia Center, Blood Transfusion Institute of Serbia, Belgrade, Serbia
| | - David Schmidt
- Coagulation Unit, Department of Hematology, Karolinska University Hospital, Stockholm, Sweden.,Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Liselotte Onelöv
- Clinical Chemistry, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
| | - Nida Mahmoud Hourani Soutari
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.,Clinical Chemistry, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
| | - Maria Berndtson
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.,Clinical Chemistry, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
| | - Roza Chaireti
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.,Coagulation Unit, Department of Hematology, Karolinska University Hospital, Stockholm, Sweden
| | - Margareta Holmström
- Coagulation Unit, Department of Hematology, Karolinska University Hospital, Stockholm, Sweden.,Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Jovan P Antovic
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.,Clinical Chemistry, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
| | - Maria Bruzelius
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.,Coagulation Unit, Department of Hematology, Karolinska University Hospital, Stockholm, Sweden.,Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
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13
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Al-Huniti A, Sharathkumar A, Krantz M, Watkinson K, Bhagavathi S. Discrepant Hemophilia A: An Underdiagnosed Disease Entity. Am J Clin Pathol 2020; 154:78-87. [PMID: 32232366 DOI: 10.1093/ajcp/aqaa024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES The term discrepant hemophilia A (DHA) denotes the discrepancy between factor VIII activity (FVIII:C) measured by different assay methodologies in patients with nonsevere hemophilia A (HA). The objective was to review the characteristics and the current understanding of mechanisms contributing to assay discrepancy in DHA. METHODS Characteristics of the DHA patients treated were examined by retrospective chart review. In addition, a literature review was performed to determine the current understanding of DHA. RESULTS Three cases of DHA were diagnosed based on bleeding phenotype: 2 cases represented missed diagnoses of HA, and 1 represented misclassification of hemophilia severity. The revised diagnosis and classification of hemophilia directly affected clinical management. Review of the literature identified 18 articles with an estimated pooled prevalence of 36% (95% CI, 23%-56%; I2 = 85%; P < .01) among nonsevere HA. Furthermore, literature indicated that DHA is a feature of how different FVIII gene mutations affect FVIII:C activity within different assay methodologies. CONCLUSIONS Our experience and literature review suggested that DHA is not only a laboratory phenomenon-it can affect clinical management in a subset of patients. A high index of suspicion for DHA is necessary while evaluating bleeding patients and/or classifying nonsevere HA.
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Affiliation(s)
- Ahmad Al-Huniti
- Division of Hematology Oncology, Stead Family Children’s Hospital, University of Iowa, Iowa City
| | - Anjali Sharathkumar
- Division of Hematology Oncology, Stead Family Children’s Hospital, University of Iowa, Iowa City
| | - Michelle Krantz
- Division of Hematology Oncology, Stead Family Children’s Hospital, University of Iowa, Iowa City
| | - Karla Watkinson
- Division of Hematology Oncology, Stead Family Children’s Hospital, University of Iowa, Iowa City
| | - Sharathkumar Bhagavathi
- Department of Pathology and Laboratory Medicine, University of Iowa Carver College of Medicine, Iowa City
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14
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Gray E, Kitchen S, Bowyer A, Chowdary P, Jenkins PV, Murphy P, Platton S, Riddell A, Lester W. Laboratory measurement of factor replacement therapies in the treatment of congenital haemophilia: A United Kingdom Haemophilia Centre Doctors’ Organisation guideline. Haemophilia 2019; 26:6-16. [DOI: 10.1111/hae.13907] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 11/26/2019] [Accepted: 11/26/2019] [Indexed: 02/03/2023]
Affiliation(s)
- Elaine Gray
- Haemostasis Section, Biotherapeutics Group National Institute for Biological Standards and Control Potters Bar UK
| | - Steve Kitchen
- Department of Coagulation Royal Hallamshire Hospital Sheffield UK
| | - Annette Bowyer
- Department of Coagulation Royal Hallamshire Hospital Sheffield UK
| | - Pratima Chowdary
- Katharine Dormandy Haemophilia and Thrombosis Centre Royal Free Hospital London UK
| | - P. Vincent Jenkins
- Haematology Department Haemostasis Laboratory University Hospital of Wales Cardiff UK
| | - Paul Murphy
- Haemostasis Department Newcastle Upon Tyne Hospitals Newcastle upon Tyne UK
| | - Sean Platton
- The Royal London Hospital Haemophilia Centre The Royal London Hospital London UK
| | - Anne Riddell
- Katharine Dormandy Haemophilia and Thrombosis Centre Royal Free Hospital London UK
| | - Will Lester
- Haemophilia Unit University Hospitals Birmingham Birmingham UK
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15
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Novembrino C, Boscolo Anzoletti M, Mancuso ME, Shinohara S, Peyvandi F. Evaluation of an automated chromogenic assay for Factor VIII clotting activity measurement in patients affected by haemophilia A. Haemophilia 2019; 25:521-526. [PMID: 31044485 DOI: 10.1111/hae.13746] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 02/27/2019] [Accepted: 03/07/2019] [Indexed: 01/26/2023]
Abstract
INTRODUCTION The original one-stage clotting assay is still the most widely used method to measure Factor VIII clotting activity (FVIII:C) in patients with haemophilia A (HA), although the use of chromogenic assays is increasing significantly. AIM Evaluation of the analytical performance and diagnostic accuracy of BIOPHEN™ FVIII:C (HYPHEN BioMed, Neuville-sur-Oise, France) assay on Sysmex CS-2400 (Sysmex, Kobe, Japan) analyser. METHODS Sixty patients with haemophilia A (HA; any severity) and 120 healthy Italian subjects were included. All the assays were performed on citrate platelet-poor plasmas stored at -80°C. Chromogenic BIOPHEN™ FVIII:C was compared with the one-stage assay using Actin FS and Factor VIII deficient plasma (Siemens Healthcare Diagnostics, Marburg, Germany) on Sysmex CS-2400 and with another chromogenic automated assay (COAMATIC™ Factor VIII, CHROMOGENIX on ACL TOP analyzer; Instrumentation Laboratory, Milan, Italy). RESULTS Intra-assay and inter-assay coefficient of variation were <6%. Linearity was good up to 1/128 dilution (r = 0.99); mean recovery was 91.7% and limit of detection was 0.2%. BIOPHEN™ FVIII:C assay showed a good correlation and diagnostic agreement with the chromogenic COAMATIC™ assay: the Spearmen's Rank correlation coefficient was 0.98 and the inter-rate agreement K Cohen coefficient was 0.61. The K coefficient was 0.91 when BIOPHEN™ FVIII:C was compared with the historical classification of the patients, demonstrating an optimal diagnostic accuracy in HA. CONCLUSIONS BIOPHEN™ FVIII:C showed good analytical performance and diagnostic accuracy and could be considered suitable for the introduction in routine analytical panel of coagulation for the diagnosis of HA patients.
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Affiliation(s)
- Cristina Novembrino
- Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Massimo Boscolo Anzoletti
- Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Maria Elisa Mancuso
- Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | | | - Flora Peyvandi
- Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.,Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Milan, Italy
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16
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Makris M, Oldenburg J, Mauser-Bunschoten EP, Peerlinck K, Castaman G, Fijnvandraat K. The definition, diagnosis and management of mild hemophilia A: communication from the SSC of the ISTH. J Thromb Haemost 2018; 16:2530-2533. [PMID: 30430726 DOI: 10.1111/jth.14315] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 08/19/2018] [Indexed: 02/03/2023]
Affiliation(s)
- M Makris
- Sheffield Haemophilia and Thrombosis Centre, Royal Hallamshire Hospital, Sheffield, UK
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - J Oldenburg
- Institute of Experimental Haematology and Transfusion Medicine, University Clinic Bonn, Bonn, Germany
| | | | - K Peerlinck
- Department of Vascular Medicine and Haemostasis, Haemophilia Centre, University Hospitals Leuven, Leuven, Belgium
| | - G Castaman
- Centre for Bleeding Disorders, Department of Oncology, Careggi University Hospital, Florence, Italy
| | - K Fijnvandraat
- Department of Pediatric Hematology, Academic Medical Centre, Amsterdam, the Netherlands
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17
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Franchini M, Marano G, Pupella S, Vaglio S, Veropalumbo E, Liumbruno GM. Management of mild hemophilia A. Expert Opin Orphan Drugs 2018. [DOI: 10.1080/21678707.2018.1529563] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Massimo Franchini
- Italian National Blood Centre, National Institute of Health, Rome, Italy
- Department of Hematology and Transfusion Medicine, Carlo Poma Hospital, Mantua, Italy
| | - Giuseppe Marano
- Italian National Blood Centre, National Institute of Health, Rome, Italy
| | - Simonetta Pupella
- Italian National Blood Centre, National Institute of Health, Rome, Italy
| | - Stefania Vaglio
- Italian National Blood Centre, National Institute of Health, Rome, Italy
| | - Eva Veropalumbo
- Italian National Blood Centre, National Institute of Health, Rome, Italy
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18
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Van den Bossche D, Peerlinck K, Jacquemin M. New challenges and best practices for the laboratory monitoring of factor VIII and factor IX replacement. Int J Lab Hematol 2018; 40 Suppl 1:21-29. [PMID: 29741261 DOI: 10.1111/ijlh.12813] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Accepted: 02/07/2018] [Indexed: 11/29/2022]
Abstract
Several recombinant factor VIII and factor IX concentrates with extended half-life (EHL) have recently been validated by clinical studies. The availability of these novel concentrates is expected to significantly facilitate the treatment of patients with hemophilia A and B. However, the modification applied to these molecules has introduced variations in their activity measurement in routine coagulation assays. Depending on the assays, underestimations of up to 10-fold or overestimations of up to approximately 30-fold in the measurements of the recovery have been reported in some factor concentrates. Such biases in monitoring may lead to major under- or overtreatment, as well as unnecessary searching for inhibitor antibodies. In this review, we discuss the guidelines and recommendations that allow the selection of optimal strategies to monitor patients treated with these novel factor concentrates. Based on the specificities of the assays and on local regulations, different chromogenic substrate assays in addition to one-stage clotting assays may be validated to allow the accurate measurement of all novel products. An efficient communication between the clinical laboratory and the clinicians is essential to ensure that the appropriate assays are carried out in laboratories and that the clinicians correctly evaluate the data. Further laboratory and clinical studies are still required for the optimization of the laboratory assays that can be used in the measurement of novel factor VIII and factor IX concentrates with EHL.
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Affiliation(s)
- D Van den Bossche
- Department of Laboratory Medicine, University Hospitals of Leuven, Leuven, Belgium
| | - K Peerlinck
- Center for Molecular and Vascular Biology, University of Leuven, Leuven, Belgium.,Department of Vascular Medicine and Hemostasis, University Hospitals Leuven, Leuven, Belgium.,National Coordinating Hemophilia Center, University Hospitals Leuven, Leuven, Belgium
| | - M Jacquemin
- Department of Laboratory Medicine, University Hospitals of Leuven, Leuven, Belgium.,Center for Molecular and Vascular Biology, University of Leuven, Leuven, Belgium.,Department of Vascular Medicine and Hemostasis, University Hospitals Leuven, Leuven, Belgium.,National Coordinating Hemophilia Center, University Hospitals Leuven, Leuven, Belgium
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19
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Teichman J, Chaudhry HR, Sholzberg M. Novel assays in the coagulation laboratory: a clinical and laboratory perspective. Transfus Apher Sci 2018; 57:480-484. [PMID: 30093248 DOI: 10.1016/j.transci.2018.07.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The ability to monitor Factor VIII (FVIII) and Factor IX (FIX) levels is integral to the clinical management of hemophilia A and B patients, respectively. Factor activity levels are checked during regular follow-up, post-infusion of factor concentrates, during pre- and post-operative assessments, and when the presence of an inhibitor is suspected. However, the ability to accurately and reproducibly measure factor activity levels with standard coagulation assays has been challenging due to the emergence of recombinant factor concentrates with extended half-lives. Similarly, special considerations must be given to the type of inhibitor assay used in patients with acquired hemophilia receiving recombinant porcine FVIII replacement. Alternative approaches to achieve hemostasis with clotting factor mimetics and interference of endogenous anticoagulants lack standardized assays for monitoring hemostatic efficacy. Laboratory assays measuring dynamic clotting parameters such as thrombin generation or whole blood viscoelasticity may provide a way forward, but have yet to enter routine clinical use. This review highlights the role of specialized coagulation assays in an era where multiple new hemostatic therapeutics for hemophilia are available, and underscores the need for clear communication between bedside and laboratory clinicians.
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Affiliation(s)
| | | | - Michelle Sholzberg
- University of Toronto, Department of Medicine, Toronto, Canada; St. Michael's Hospital Hemostasis and Thrombosis Laboratory, Toronto, Canada; Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Canada
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20
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Bowyer AE, Duncan EM, Antovic JP. Role of chromogenic assays in haemophilia A and B diagnosis. Haemophilia 2018; 24:578-583. [DOI: 10.1111/hae.13520] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/25/2018] [Indexed: 01/22/2023]
Affiliation(s)
- A. E. Bowyer
- Coagulation; Sheffield Haemophilia and Thrombosis Centre; Sheffield UK
| | - E. M. Duncan
- Haematology; SA Pathology; Adelaide SA Australia
| | - J. P. Antovic
- Coagulation Research; Karolinska Institutet; Stockholm Sweden
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21
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Strandberg K, Astermark J. The role of the laboratory in diagnosis and management of inhibitory antibodies in haemophilia. Haemophilia 2018; 24 Suppl 6:9-14. [DOI: 10.1111/hae.13474] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/14/2018] [Indexed: 01/01/2023]
Affiliation(s)
- K. Strandberg
- Department of Clinical Chemistry; Institution of Laboratory Medicine; Malmö Sweden
| | - J. Astermark
- Department for Hematology Oncology and Radiation Physics; Center for Thrombosis and Hemostasis; Skåne University Hospital; Malmö Sweden
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22
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Pavlova A, Delev D, Pezeshkpoor B, Müller J, Oldenburg J. Haemophilia A mutations in patients with non-severe phenotype associated with a discrepancy between one-stage and chromogenic factor VIII activity assays. Thromb Haemost 2017; 111:851-61. [DOI: 10.1160/th13-08-0690] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 12/16/2013] [Indexed: 11/05/2022]
Abstract
SummaryAbout one-third of patients with non-severe haemophilia A (HA) show a discrepancy of factor (F)VIII activity (FVIII:C) measured by one-stage (FVIII:C1st), two-stage assays or the chromogenic method (FVIII:Cchr). The aim of the study was to characterise the mutation profile in patients with FVIII:C assay discrepancies. FVIII:C discrepancy was considered significant if the calculated ratio between FVIII:C1st and FVIII:Cchr was ≤ 0.6. In 16 patients FVIII:C1st was higher than FVIII:Cchr. The reverse phenomenon was observed in 83 patients. Genetic analysis revealed 23 different missense mutations of which 17 were novel. Most mutations, exhibiting a higher FVIII:C1st were localised in the A1-A2-A3 interface. The majority of mutations associated with FVIII:Cchr>FVIII:C1st discrepancy were located close to or within the thrombin cleavage sites, FIX or vWF binding sites. Our data show a correlation between FVIII:C and thrombin generation testing with a clear differentiation between patients with haemophilia and normal controls. However, in the subgroup of FVIII:C1st>FVIII:Cchr discrepancy, the endogenous thrombin potential and peak thrombin parameters were similar to non-discrepant haemophilia patients, while in the inverse discrepancy FVIII:Cchr>FVIII:C1st, these variables showed values close to that of the normal control group. Certain hereditary F8 mis-sense mutations cause discrepancy in FVIII:C as measured with different assays. This can lead to failure in diagnosing HA or incorrectly classifying the severity of the disease. Therefore, we recommend that initial diagnosis of non-severe HA phenotypes should be based on results of both FVIII:C1st and FVIII:Cchr assays.
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23
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Kihlberg K, Strandberg K, Rosén S, Ljung R, Astermark J. Discrepancies between the one-stage clotting assay and the chromogenic assay in haemophilia B. Haemophilia 2017; 23:620-627. [DOI: 10.1111/hae.13219] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/15/2017] [Indexed: 02/03/2023]
Affiliation(s)
- K. Kihlberg
- Department of Haematology; Oncology and Radiation Physics; Centre for Thrombosis and Haemostasis; Skåne University Hospital; Malmö Sweden
| | - K. Strandberg
- Institution of Laboratory Medicine; Department of Clinical Chemistry; Skåne University Hospital; Malmö Sweden
| | - S. Rosén
- Private consultant; Kållered Sweden
| | - R. Ljung
- Lund University; Department of Clinical Sciences - Pediatrics and Pediatric Clinic; Skåne University Hospital; Lund/Malmö Sweden
| | - J. Astermark
- Department of Haematology; Oncology and Radiation Physics; Centre for Thrombosis and Haemostasis; Skåne University Hospital; Malmö Sweden
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24
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Abstract
Hemophilia A is an inherited bleeding disorder caused by a reduced level of factor VIII coagulant activity (FVIII:C) in blood. Bleeding episodes may occur spontaneously in the severe form of hemophilia or after trauma in the milder forms. It is important that patients are diagnosed correctly, which includes placing them into the correct severity category of the disorder so that appropriate treatment can be given. Diagnosis is made by determination of the amount of FVIII:C in the blood, usually using a one-stage factor VIII:C assay. However, approximately one third of patients with mild or moderate hemophilia will have much lower results by the chromogenic assay, with some of them having normal results by the one-stage assay. The chromogenic factor VIII assay is used in some specialized hemophilia reference centers and is recommended for the diagnosis of mild hemophilia A, as this assay is considered to better reflect the severity status of hemophilia patients than the one-stage assay.
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Affiliation(s)
- Susan Rodgers
- Haematology Division, IMVS, SA Pathology, Frome Rd., Adelaide, SA, Australia.
| | - Elizabeth Duncan
- Haematology Division, IMVS, SA Pathology, Frome Rd., Adelaide, SA, Australia
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25
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Kitchen S, Kershaw G, Tiefenbacher S. Recombinant to modified factor VIII and factor IX - chromogenic and one-stage assays issues. Haemophilia 2016; 22 Suppl 5:72-7. [DOI: 10.1111/hae.13012] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2016] [Indexed: 01/26/2023]
Affiliation(s)
- S. Kitchen
- Sheffield Haemophilia and Thrombosis Centre; Sheffield UK
| | - G. Kershaw
- Institute of Haematology; Royal Prince Alfred Hospital; Sydney NSW Australia
| | - S. Tiefenbacher
- Laboratory Corporation of America; Colorado Coagulation; Denver CO USA
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26
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Monaghan M, Wakabayashi H, Griffiths AE, Fay PJ. Stabilizing interactions between D666-S1787 and T657-Y1792 at the A2-A3 interface support factor VIIIa stability in the blood clotting pathway. J Thromb Haemost 2016; 14:1021-30. [PMID: 26878264 PMCID: PMC4870127 DOI: 10.1111/jth.13292] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 01/20/2016] [Indexed: 12/01/2022]
Abstract
UNLABELLED Essentials Factor VIIIa (FVIIIa) is unstable due to loss of A2; D666 and Y1792 contribute to its stability. We conducted a study to identify the interactions made at these residues at the A2-A3 interface. We present evidence for stabilizing interactions between D666-S1787 and T657-Y1792 in FVIIIa. A D666C/S1788C variant with a disulfide A2-A3 linkage has a FVIIIa decay rate that is 1% of wild-type. SUMMARY Background Factor (F)VIIIa activity and stability depends on the non-covalent association of the A2 subunit with the A1/A3C1C2 dimer, but the interactions that contribute to A2 association are not well defined. Previous work had shown that D666A and Y1792F mutations at the A2-A3 interface resulted in increased FVIIIa decay, suggesting that the residues were involved in bonding interactions important for FVIIIa stability. Objectives Several potential hydrogen bonding partners of D666 and Y1792 across the A2-A3 interface were selected from the low-resolution FVIII crystal structure, and we used mutagenesis and biochemical analysis to examine the bonding interactions occurring at D666 and Y1792. Methods Using a series of stability and functional analyses, we analyzed FVIII variants in which D666 and Y1792 were each swapped with the residues of potential bonding partners. Results and conclusions We present evidence for hydrogen bonds between D666 and S1787 and between Y1792 and T657 that are important for FVIIIa stability. D666S/S1787D and T657Y/Y1792T variants each displayed wild-type (WT)-like FVIIIa stability and performed like WT FVIII in a series of functional analyses, whereas D666S, S1787D, and Y1792T single variants showed increased FVIIIa decay and a T657Y variant had little FVIIIa activity. These results suggest that WT hydrogen bonds are disrupted with the single mutations but maintained in the swap variants. Furthermore, mutation of D666 and S1788 to cysteine resulted in disulfide bond formation across the A2-A3 interface, confirming the close proximity of D666 and S1787, and this covalent attachment of the A2 subunit significantly increased FVIIIa stability.
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Affiliation(s)
- M Monaghan
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, Rochester, NY 14642, USA
| | - H Wakabayashi
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, Rochester, NY 14642, USA
| | - AE Griffiths
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, Rochester, NY 14642, USA
| | - PJ Fay
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, Rochester, NY 14642, USA
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27
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Peyvandi F, Oldenburg J, Friedman KD. A critical appraisal of one-stage and chromogenic assays of factor VIII activity. J Thromb Haemost 2016; 14:248-61. [PMID: 26663865 DOI: 10.1111/jth.13215] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 11/22/2015] [Indexed: 12/20/2022]
Abstract
Accurate and precise potency determination by manufacturers of different types of factor VIII product (plasma-derived and recombinant FVIII [rFVIII]) is vital to clinicians and patients using FVIII concentrates. A separate, but related, requirement is ascertaining the FVIII activity levels in clinical samples for diagnosing and treating hemophilia A. The one-stage clotting assay (OSA) and the chromogenic substrate assay (CSA) are the main assays used for these measurements, with both assays being used for potency assignments, and the OSA also being widely used for clinical monitoring. Although the assays can produce concordant results, discrepancies often occur, e.g. when measuring FVIII levels in patients with mild or moderate hemophilia A, or when assaying high-purity FVIII products. Modifications to rFVIII proteins, such as B-domain deletion (BDD), and technologies for improving the pharmacokinetic profile of rFVIII may exacerbate assay discrepancies. The CSA appears to be essentially unaffected by these modifications. However, the OSA underestimates the FVIII activity levels and therapeutic potential of some further modified BDD rFVIII products, especially those conjugated to poly(ethylene glycol); the extent of the effects is dependent on the specific OSA reagents used. Although the OSA remains the preferred choice for clinical monitoring in Europe and the USA, an awareness of the limitations of that assay has prompted more laboratories to adopt the CSA.
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Affiliation(s)
- F Peyvandi
- Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, and Department of Pathophysiology and Transplantation, University of Milan, Luigi Villa Foundation, Milan, Italy
| | - J Oldenburg
- Institute of Experimental Hematology and Transfusion Medicine, University Clinic Bonn, Bonn, Germany
| | - K D Friedman
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI, USA
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28
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A subset of high-titer anti-factor VIII A2 domain antibodies is responsive to treatment with factor VIII. Blood 2016; 127:2028-34. [PMID: 26825708 DOI: 10.1182/blood-2015-09-670034] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Accepted: 01/20/2016] [Indexed: 11/20/2022] Open
Abstract
The primary B-cell epitopes of factor VIII (fVIII) are in the A2 and C2 domains. Within the C2 domain, antibody epitope and kinetics are more important than inhibitor titer in predicting pathogenicity in a murine bleeding model. To investigate this within the A2 domain, the pathogenicity of a diverse panel of antihuman fVIII A2 domain monoclonal antibodies (MAbs) was tested in the murine model. MAbs were injected into hemophilia A mice, followed by injection of human B domain-deleted fVIII. Blood loss after a 4-mm tail snip was measured. The following anti-A2 MAbs were tested: high-titer type 1 inhibitors 4A4, 2-76, and 1D4; 2-54, a high-titer type 2 inhibitor; B94, a type 2 inhibitor; and noninhibitory MAbs GMA-012, 4C7, and B25. All high-titer type 1 MAbs produced blood loss that was significantly greater than control mice, whereas all non-inhibitory MAbs produced blood loss that was similar to control. The type 2 MAbs were not pathogenic despite 2-54 having an inhibitor titer of 34 000 BU/mg immunoglobulin G. In addition, a patient with a high-titer type 2 anti-A2 inhibitor who is responsive to fVIII is reported. The discrepancy between inhibitor titer and bleeding phenotype combined with similar findings in the C2 domain stress the importance of inhibitor properties not detected in the standard Bethesda assay in predicting response to fVIII therapy.
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29
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Makris M, Peyvandi F. Assaying FVIII activity: one method is not enough, and never was. Haemophilia 2015; 20:301-3. [PMID: 24731127 DOI: 10.1111/hae.12446] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/24/2014] [Indexed: 12/01/2022]
Affiliation(s)
- M Makris
- Department of Cardiovascular Science, University of Sheffield, Sheffield, UK; Sheffield Haemophilia and Thrombosis Centre, Royal Hallamshire Hospital, Sheffield, UK
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30
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Potgieter JJ, Damgaard M, Hillarp A. One-stage vs. chromogenic assays in haemophilia A. Eur J Haematol 2015; 94 Suppl 77:38-44. [DOI: 10.1111/ejh.12500] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/18/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Joachim J. Potgieter
- Department of Haematology; National Health Laboratory Service; Tshwane Academic Division; University of Pretoria; Pretoria South Africa
| | - Michael Damgaard
- Department of Haematology; Coagulation Centre; Sahlgrenska University Hospital; Gothenburg Sweden
| | - Andreas Hillarp
- Malmö Thrombosis and Haemostasis Centre; University and Regional Laboratories Region Skåne University Hospital; Malmö Sweden
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31
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Moser KA, Adcock Funk DM. Chromogenic factor VIII activity assay. Am J Hematol 2014; 89:781-4. [PMID: 24676945 DOI: 10.1002/ajh.23723] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 03/20/2014] [Accepted: 03/24/2014] [Indexed: 11/07/2022]
Abstract
Factor VIII (FVIII) may be measured by three different methodologies in the clinical laboratory: one-stage clotting assay, two-stage clotting assay, and chromogenic assay. These assays differ in ease of use, variety of reagents available, sensitivity to mild hemophilia A, and interference from lupus anticoagulants. This review will outline the methodology for each of the FVIII activity assays, with a discussion of assay interferences and variability. In some cases, chromogenic FVIII activity assays may be preferable to clot-based assays, and these clinical situations will be reviewed as well.
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Affiliation(s)
- Karen A Moser
- Colorado Coagulation, Laboratory Corporation of America® Holdings, Englewood, Colorado
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32
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Armstrong E, Hillarp A. Assay discrepancy in mild haemophilia A. Eur J Haematol 2014; 76:48-50. [DOI: 10.1111/ejh.12374] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/28/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Elina Armstrong
- Coagulation Unit of the Helsinki University Central Hospital; Helsinki Finland
| | - Andreas Hillarp
- Malmö Thrombosis and Haemostasis Centre; Department of Clinical Chemistry; University and Regional Laboratories Region Skåne; Malmö Sweden
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33
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Monaghan M, Wakabayashi H, Griffiths A, Wintermute J, Fay PJ. Enhanced factor VIIIa stability of A2 domain interface variants results from an increased apparent affinity for the A2 subunit. Results from an increased apparent affinity for the A2 subunit. Thromb Haemost 2014; 112:495-502. [PMID: 24899227 DOI: 10.1160/th14-01-0086] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 04/10/2014] [Indexed: 11/05/2022]
Abstract
Factor (F)VIIIa, a heterotrimer comprised of A1, A2, and A3C1C2 subunits, is labile due to the tendency of the A2 subunit to dissociate from the A1/A3C1C2 dimer. As dissociation of the A2 subunit inactivates FVIIIa activity, retention of A2 defines FVIIIa stability and thus, FXase activity. Earlier results showed that replacing residues D519, E665, and E1984 at the A2 domain interface with Ala or Val reduced rates of FVIIIa decay, increasing FXa and thrombin generation. We now show the enhanced FVIIIa stability of these variants results from increases in inter-A2 subunit affinity. Using a FVIIIa reconstitution assay to monitor inter-subunit affinity by activity regeneration, the apparent Kd value for the interaction of wild-type (WT) A2 subunit with WT A1/A3C1C2 dimer (43 ± 2 nM) was significantly higher than values observed for the A2 point mutants D519A/V, E665A/V, and E1984A/V which ranged from ~5 to ~19 nM. Val was determined to be the optimal hydrophobic residue at position 665 (apparent Kd = 5.1 ± 0.7 nM) as substitutions with Ile or Leu at this position increased the apparent Kd value by ~3- and ~7-fold, respectively. Furthermore, the double mutant (D519V/E665V) showed an ~47-fold lower apparent Kd value (0.9 ± 0.6 nM) than WT. Thus these hydrophobic mutations at the A2 subunit interfaces result in high binding affinities for the A2 subunit and correlate well with previously observed reductions in rates in FVIIIa decay.
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Affiliation(s)
- M Monaghan
- Morgan Monaghan, PO Box 712, Department of Biochemistry and Biophysics, 601 Elmwood Ave., Rochester, NY 14642, USA, Tel.: +1 585 275 6576, Fax: +1 585 275 6007, E-mail:
| | - H Wakabayashi
- Hironao Wakabayashi, PO Box 712, Department of Biochemistry and Biophysics, 601 Elmwood Ave., Rochester, NY 14642, USA, Tel.: +1 585 275 6576, Fax: +1 585 275 6007, E-mail:
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Trossaert M, Lienhart A, Nougier C, Fretigny M, Sigaud M, Meunier S, Fouassier M, Ternisien C, Negrier C, Dargaud Y. Diagnosis and management challenges in patients with mild haemophilia A and discrepant FVIII measurements. Haemophilia 2014; 20:550-8. [DOI: 10.1111/hae.12381] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/27/2013] [Indexed: 11/28/2022]
Affiliation(s)
- M. Trossaert
- Centre Regional du Traitement de l'Hemophilie; CHU de Nantes; Nantes France
| | - A. Lienhart
- Unite d'Hemostase Clinique; CHU de Lyon; Lyon France
| | - C. Nougier
- Laboratoire d'Hemostase; CHU de Lyon; Lyon France
| | - M. Fretigny
- Laboratoire d'Hemostase; CHU de Lyon; Lyon France
| | - M. Sigaud
- Centre Regional du Traitement de l'Hemophilie; CHU de Nantes; Nantes France
| | - S. Meunier
- Unite d'Hemostase Clinique; CHU de Lyon; Lyon France
| | - M. Fouassier
- Centre Regional du Traitement de l'Hemophilie; CHU de Nantes; Nantes France
| | - C. Ternisien
- Centre Regional du Traitement de l'Hemophilie; CHU de Nantes; Nantes France
| | - C. Negrier
- Unite d'Hemostase Clinique; CHU de Lyon; Lyon France
- EA 4174 Unite de Recherche sur l'Hemophilie; Universite Lyon 1; Lyon France
| | - Y. Dargaud
- Unite d'Hemostase Clinique; CHU de Lyon; Lyon France
- EA 4174 Unite de Recherche sur l'Hemophilie; Universite Lyon 1; Lyon France
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Bowyer AE, Van Veen JJ, Goodeve AC, Kitchen S, Makris M. Specific and global coagulation assays in the diagnosis of discrepant mild hemophilia A. Haematologica 2013; 98:1980-7. [PMID: 23812942 DOI: 10.3324/haematol.2013.088088] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The activity of the factor VIII coagulation protein can be measured by three methods: a one or two-stage clotting assay and a chromogenic assay. The factor VIII activity of most individuals with mild hemophilia A is the same regardless of which method is employed. However, approximately 30% of patients show marked discrepancies in factor VIII activity measured with the different methods. The objective of this study was to investigate the incidence of assay discrepancy in our center, assess the impact of alternative reagents on factor VIII activity assays and determine the usefulness of global assays of hemostasis in mild hemophilia A. Factor VIII activity was measured in 84 individuals with mild hemophilia A using different reagents. Assay discrepancy was defined as a two-fold or greater difference between the results of the one-stage and two-stage clotting assays. Rotational thromboelastometry and calibrated automated thrombography were performed. Assay discrepancy was observed in 31% of individuals; 12% with lower activity in the two-stage assay and 19% with lower activity in the one-stage assay. The phenotype could not always be predicted from the individual's genotype. Chromogenic assays were shown to be a suitable alternative to the two-stage clotting assay. Thromboelastometry was found to have poor sensitivity in hemophilia. Calibrated automated thrombography supported the results obtained by the two-stage and chromogenic assays. The current international guidelines do not define the type of assay to be used in the diagnosis of mild hemophilia A and some patients could be misclassified as normal. In our study, 4% of patients would not have been diagnosed on the basis of the one-stage factor VIII assay. Laboratories should use both one stage and chromogenic (or two-stage) assays in the diagnosis of patients with possible hemophilia A.
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Gouws W, Botha E, Visser A. Method validation and clinical utility of chromogenic factor VIII assay compared to one-stage assay. J Thromb Thrombolysis 2013; 37:210-5. [DOI: 10.1007/s11239-013-0910-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Mackie I, Cooper P, Lawrie A, Kitchen S, Gray E, Laffan M. Guidelines on the laboratory aspects of assays used in haemostasis and thrombosis. Int J Lab Hematol 2012; 35:1-13. [DOI: 10.1111/ijlh.12004] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 08/06/2012] [Indexed: 11/30/2022]
Affiliation(s)
- I. Mackie
- Haemostasis Research Unit; Department of Haematology; University College London; London; UK
| | - P. Cooper
- Department of Coagulation; Royal Hallamshire Hospital; Sheffield; UK
| | - A. Lawrie
- Haemostasis Research Unit; Department of Haematology; University College London; London; UK
| | - S. Kitchen
- Department of Coagulation; Royal Hallamshire Hospital; Sheffield; UK
| | - E. Gray
- Haemostasis Section; Biotherapeutics Group; National Institute for Biological Standards and Control; Potters Bar; UK
| | - M. Laffan
- Department of Haematology; Imperial College at Hammersmith Hospital; London; UK
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Srivastava A, Brewer AK, Mauser-Bunschoten EP, Key NS, Kitchen S, Llinas A, Ludlam CA, Mahlangu JN, Mulder K, Poon MC, Street A. Guidelines for the management of hemophilia. Haemophilia 2012; 19:e1-47. [PMID: 22776238 DOI: 10.1111/j.1365-2516.2012.02909.x] [Citation(s) in RCA: 1274] [Impact Index Per Article: 106.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/06/2012] [Indexed: 01/23/2023]
Affiliation(s)
- A. Srivastava
- Department of Hematology; Christian Medical College; Vellore; India
| | - A. K. Brewer
- Department of Oral Surgery; The Royal Infirmary; Glasgow; Scotland
| | - E. P. Mauser-Bunschoten
- Van Creveldkliniek and Department of Hematology; University Medical Center Utrecht; Utrecht; The Netherlands
| | - N. S. Key
- Department of Medicine; University of North Carolina; Chapel Hill; NC; USA
| | - S. Kitchen
- Sheffield Haemophilia and Thrombosis Centre; Royal Hallamshire Hospital; Sheffield; UK
| | - A. Llinas
- Department of Orthopaedics and Traumatology; Fundación Santa Fe University Hospital Fundación Cosme y Damián and Universidad de los Andes and Universidad del Rosario; Bogotá; Colombia
| | - C. A. Ludlam
- Comprehensive Care Haemophilia and Thrombosis Centre; Royal Infirmary; Edinburgh; UK
| | - J. N. Mahlangu
- Haemophilia Comprehensive Care Centre; Johannesburg Hospital and Department of Molecular Medicine and Haematology; Faculty of Health Sciences; National Health Laboratory Services and University of the Witwatersrand; Johannesburg; South Africa
| | - K. Mulder
- Bleeding Disorders Clinic; Health Sciences Center; Winnipeg; Canada
| | - M. C. Poon
- Departments of Medicine; Pediatrics and Oncology, and Southern Alberta Rare Blood and Bleeding Disorders Comprehensive Care Program; University of Calgary, Foothills Hospital and Calgary Health Region; Calgary; Canada
| | - A. Street
- Haematology; Alfred Hospital; Melbourne; Victoria; Australia
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Plantier JL, Saboulard D, Pellequer JL, Négrier C, Delcourt M. Functional mapping of the A2 domain from human factor VIII. Thromb Haemost 2012; 107:315-27. [PMID: 22234396 DOI: 10.1160/th11-07-0492] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 11/24/2011] [Indexed: 11/05/2022]
Abstract
Coagulation factor VIII (FVIII) is a multidomain glycoprotein in which the FVIII A2 domain is a key structural element. We aimed at identifying residues within FVIII A2 domain that are crucial for the maintenance of the cofactor function. A high number (n=206) of mutants were generated by substituting original residues with alanine. The mutants were expressed in COS-1 cells and their antigen levels and procoagulant activities were measured. The residues were classified in three categories: those with a non-detrimental alteration of their activities (activity >50 % of control FVIII; n=98), those with a moderate alteration (15 %<activity<50%; n=45) and those that were severely affected (activity<15%; n=63). The mutants sensitive to mutation were retrieved in the HAMSTeRS database with a higher percentage than those that were not affected (58.8% vs. 9.2%). The results revealed the existence of clusters of residues that are sensitive (Arg418-Phe436, Thr459-Ile475, Ser535-Gly549, Asn618-Ala635) or not (Leu398-Arg418, Pro485-Asp500, Gly506-Gly520, Pro596-Asp605) to mutations. The stretches of residues sensitive to mutations were buried within the molecule suggesting that these amino acids participate in the maintenance of the A2 domain structure. In contrast, residues resistant to mutations formed external loops without well- defined structures suggesting that these loops were not crucial for the process of factor X activation. This study provided a detailed map of the FVIII A2 domain between residues 371 and 649, identifying residues crucial for maintaining FVIII function and residues that can be mutated without jeopardising the coagulant activity.
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Affiliation(s)
- Jean-Luc Plantier
- Laboratoire d’Hémobiologie EA4174-IFR62 Faculté de Médecine RTH Laennec, Université de Lyon, Lyon, France.
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Ninivaggi M, Dargaud Y, van Oerle R, de Laat B, Hemker HC, Lindhout T. Thrombin generation assay using factor IXa as a trigger to quantify accurately factor VIII levels in haemophilia A. J Thromb Haemost 2011; 9:1549-55. [PMID: 21605333 DOI: 10.1111/j.1538-7836.2011.04358.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND The available methods for measuring factor VIII (FVIII) activity suffer reportedly from lack of sensitivity and precision in the < 1 IU dL(-1) range. This precludes correlation of clinical phenotype with FVIII levels. OBJECTIVES To study a possible association between clinical phenotype in patients with FVIII levels < 1 IU dL(-1). METHODS/RESULTS The FIXa-driven FVIII assay (FVIII-CAT) has a detection limit of 0.05 IU dL(-1). For the range of 0-2 IU dL(-1) FVIII, the intra-assay coefficient of variation (CV) is around 2% and the inter-assay CV is about 8%. We tested 30 hemophiliacs with FVIII:C between < 1 and 6 IU dL(-1) as measured in the one-stage clotting assay using the FVIII-CAT assay. For genetic defects related to moderate hemophilia, the FVIII-CAT test finds FVIII levels that are in good agreement with those determined with the one-stage assay. Of the 21 hemophilic patients with FVIII < 1 IU dL(-1), four patients exhibited a mild bleeding phenotype. When we applied TF-initiated thrombin generation, patients with a mild clinical phenotype showed significantly higher endogenous thrombin potentials. CONCLUSION The novel developed FVIII assay measures accurately FVIII levels below 1 IU dL(-1). Its application demonstrated that the clinical heterogeneity in individuals with < 1 IU dL(-1) FVIII is not associated with their FVIII level.
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Bowyer AE, Goodeve A, Liesner R, Mumford AD, Kitchen S, Makris M. p.Tyr365Cys change in factor VIII: haemophilia A, but not as we know it. Br J Haematol 2011; 154:618-25. [DOI: 10.1111/j.1365-2141.2011.08688.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Trossaërt M, Boisseau P, Quemener A, Sigaud M, Fouassier M, Ternisien C, Lefrançois-Bettembourg A, Tesson C, Thomas C, Bezieau S. Prevalence, biological phenotype and genotype in moderate/mild hemophilia A with discrepancy between one-stage and chromogenic factor VIII activity. J Thromb Haemost 2011; 9:524-30. [PMID: 21166991 DOI: 10.1111/j.1538-7836.2010.04174.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND In most laboratories, the severity of hemophilia A is assessed by the factor VIII activity (FVIII:C) one-stage assay. However, comparisons of these results with those of two-stage assays can reveal discrepancies and suggest misdiagnosis. PATIENTS/METHODS In this monocentric study, we measured FVIII:C with two methods (one-stage chronometric and chromogenic assays) in 307 (173 families) patients with moderate/mild hemophilia A. To compare results, we used a chronometric/chromogenic ratio. Discrepancy was defined as a ratio < 0.5 or > 1.5. We studied their putative involvement at known FVIII functional sites, their interspecies conservation status, and their spatial position within the FVIII structure. RESULTS Thirty-six patients from 17 families exhibited a discrepancy between the two assays: 12 (6.9%) families had a low ratio (< 0.5), and five (2.9%) families had a high ratio (> 1.5). Qualitative deficiency was diagnosed in about 16% of the families. Molecular studies were performed in 15 of these 17 families, resulting in each case in the identification of missense mutations, including three novel mutations. We were further able to propose a pathophysiologic explanation. CONCLUSIONS In this monocentric study, we have demonstrated a discrepancy between FVIII:C assay results in 10% of families with moderate/mild hemophilia A. The prevalence of 'inverse' discrepancy (i.e. low chronometric/chromogenic ratio) is high as compared with previous reports. We suggest that both FVIII:C assays are recommended in patients with moderate/mild hemophilia A for a complete biological phenotype. This could also improve our knowledge of the FVIII structure-function relationships.
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Affiliation(s)
- M Trossaërt
- Centre Régional de Traitement de l'Hémophilie, CHU Nantes, Nantes, France.
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Peerlinck K, Jacquemin M. Mild haemophilia: a disease with many faces and many unexpected pitfalls. Haemophilia 2011; 16 Suppl 5:100-6. [PMID: 20590864 DOI: 10.1111/j.1365-2516.2010.02306.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
SUMMARY Despite major advances in diagnosis and treatment, the management of patients with mild haemophilia (MH) remains a major challenge. Mild haemophilia is defined by factor levels between 0.05 and 0.40 IU mL(-1). The bleeding associated with mild haemophilia is most frequently episodic, occurring during surgery or following trauma. Spontaneous bleeding is rare. Diagnosis is sometimes delayed because of insensitivity of screening clotting assays or discrepancies in factor VIII activity as measured by different assays. The treatment of choice in mild haemophilia A is desmopressin, which typically induces a 2-6-fold increase of factor VIII over baseline. However, desmopressin has its limitations in this setting such as the occurrence of tachyphylaxis and failure to respond in an undetermined proportion of patients. Factors underlying poor biological response or magnitude of response to desmopressin are incompletely understood. Inhibitor development in mild haemophilia is particularly distressing. This complication arises at an older age in this patient group because of infrequent need for factor VIII replacement. Inhibitors in mild haemophilia patients often cross-react with endogenous factor VIII resulting in severe spontaneous bleeding frequently in a postoperative setting. Intensive perioperative use of factor VIII and some specific mutations induce a particularly high risk for inhibitor development, but risk factors are incompletely understood. For reasons of the older age of the patients, treatment of bleeding with bypassing agents may cause major thrombotic complications. Data on therapeutic options for inhibitor eradication in patients with mild haemophilia are particularly scarce. With increased life-expectancy for all haemophilia patients, the group of elderly patients with mild haemophilia requiring major surgery will further increase. Prevention of inhibitors, particularly in this patient group, should be a major topic of interest in both clinic and research.
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Affiliation(s)
- K Peerlinck
- Hemophilia Center, Universitaire Ziekenhuizen Leuven and Center for Molecular and Vascular Biology, Katholieke Universiteit Leuven, Leuven, Belgium.
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Discrepancy in factor VIII 1-stage/2-stage activity in a child with Arg531 → His mutation. Blood Coagul Fibrinolysis 2010; 21:474-5. [DOI: 10.1097/mbc.0b013e328338db53] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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KITCHEN S, HAYWARD C, NEGRIER C, DARGAUD Y. New developments in laboratory diagnosis and monitoring. Haemophilia 2010; 16 Suppl 5:61-6. [DOI: 10.1111/j.1365-2516.2010.02295.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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GILMORE R, HARMON S, GANNON C, BYRNE M, O’DONNELL JS, JENKINS PV. Thrombin generation in haemophilia A patients with mutations causing factor VIII assay discrepancy. Haemophilia 2010; 16:671-4. [DOI: 10.1111/j.1365-2516.2009.02190.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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RODGERS SE, DUNCAN EM, SOBIERAJ-TEAGUE M, LLOYD JV. Evaluation of three automated chromogenic FVIII kits for the diagnosis of mild discrepant haemophilia A. Int J Lab Hematol 2009; 31:180-8. [DOI: 10.1111/j.1751-553x.2007.01021.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Wakabayashi H, Griffiths AE, Fay PJ. Combining mutations of charged residues at the A2 domain interface enhances factor VIII stability over single point mutations. J Thromb Haemost 2009; 7:438-44. [PMID: 19067791 PMCID: PMC3136035 DOI: 10.1111/j.1538-7836.2008.03256.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Factor (F) VIII consists of a heavy chain (A1A2B domains) and light chain (A3C1C2 domains), while the contiguous A1A2 domains are separate subunits in the cofactor, FVIIIa. Recently we reported that procofactor stability at elevated temperature and cofactor stability over an extended time course were increased following replacement of individual charged residues (Asp(D)519, Glu(E)665 or Glu(E)1984) with either Ala (A) or Val (V) (Wakabayashi et al., Blood, 112, 2761, 2008). OBJECTIVES In the current study we generated combination mutants at these three sites to examine any additive and/or synergistic effects of these mutations on stability. METHODS Studies assessing FVIII stability involved monitoring decay rates of FVIII at 55 degrees C or in guanidinium, decay of FVIIIa following A2 subunit dissociation, and thrombin generation at low (0.3 nmol L(-1)) FVIII concentration. RESULTS AND CONCLUSIONS Similar tendencies were observed within each group of variants. Variants with mutations at D519 and either E665 or E1984 (Group A) generally showed significantly better stability as compared with single mutants. Most variants with mutations at E665 and at E1984 (Group B) did not show significant improvement. Triple mutants with mutations at D519, E665 and E1984 (Group C) showed improvement to a similar degree as the Group A double mutants. Overall, these results indicate that selected combinations of mutations to reduce charge and/or increase hydrophobicity at the A2/A1 and A2/A3 domain interfaces yield FVIII reagents with improved stability parameters.
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Affiliation(s)
- H Wakabayashi
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, Rochester, NY 14642, USA
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POULSEN AL, PEDERSEN LH, HVAS AM, POULSEN LH, THYKJAER H, INGERSLEV J. Assay discrepancy in mild haemophilia A: entire population study in a National Haemophilia Centre. Haemophilia 2009; 15:285-9. [DOI: 10.1111/j.1365-2516.2008.01899.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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CID AR, CALABUIG M, CORTINA V, CASAÑA P, HAYA S, MORET A, CABRERA N, AZNAR JA. One-stage and chromogenic FVIII:C assay discrepancy in mild haemophilia A and the relationship with the mutation and bleeding phenotype. Haemophilia 2008; 14:1049-54. [DOI: 10.1111/j.1365-2516.2008.01781.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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