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Ray D, Kumar N, Hans C, Kler A, Jain R, Bansal D, Trehan A, Jain A, Malhotra P, Ahluwalia J. Inhibitor; An Uncommon But Vexing Challenge In North Indian Patients With Hemophilia A. Indian J Hematol Blood Transfus 2022; 38:703-709. [PMID: 36258733 PMCID: PMC9569402 DOI: 10.1007/s12288-022-01539-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 04/09/2022] [Indexed: 10/18/2022] Open
Abstract
Factor VIII replacement is the mainstay of treatment in hemophilia A but may lead to the development of inhibitors. While a vexing clinical problem, some observations suggest that the presence of inhibitors may not necessarily portend a higher bleeding risk. Our aim was to assess the prevalence and clinicopathological correlates of inhibitors in a well characterized cohort of Indian patients with HA patients. We retrospectively reviewed the clinical details and laboratory findings of consecutive hemophilia A patients attending a north-Indian tertiary-care center from 2010 to 2020. Among 592 patients with HA, inhibitors were detected in 35 patients (5.9%). Prevalence of inhibitors in moderate and severe hemophilia was 4.2% and 6.7%, respectively. Most patients with inhibitors had history of transfusion with factor VIII alone (54.3%) or a combination of factor VIII concentrate and other blood-products (42.9%). Intracranial bleed was significantly more frequent in patients with inhibitors compared to those without inhibitors (20% vs. 4.1%; p-0.001). Time dependent and immediately acting inhibitors were seen in 60% and 40% patients, respectively. High-titre (> 5 BU) and low-titre inhibitors (< 5 BU) were detected in 28 (80%) and 7 (20%) patients, respectively. Prevalence of inhibitors in our cohort was 5.9% and most had high-titre, time dependent inhibitors. These patients may have a higher risk of intracranial bleeding.
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Affiliation(s)
- Debadrita Ray
- Department of Hematology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Narender Kumar
- Department of Hematology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Chander Hans
- Department of Hematology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Anita Kler
- Department of Hematology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Richa Jain
- Department of Pediatric Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Deepak Bansal
- Department of Pediatric Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Amita Trehan
- Department of Pediatric Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Arihant Jain
- Department of Clinical Hematology & Medical Oncology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Pankaj Malhotra
- Department of Clinical Hematology & Medical Oncology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Jasmina Ahluwalia
- Department of Hematology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
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Chansavang A, Philippe A, Bozinovic I, Ben Hadj Ali K, Smadja D, Helley D, Darnige L, Mauge L. Usefulness of anti-factor VIII IgG ELISA in acquired hemophilia A follow-up. Ann Hematol 2022. [PMID: 36125542 DOI: 10.1007/s00277-022-04972-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 08/28/2022] [Indexed: 11/01/2022]
Abstract
Acquired hemophilia A (AHA) is a rare autoimmune bleeding disorder due to the presence of neutralizing autoantibodies directed against the coagulation factor VIII (FVIII). The reference method to detect and quantify anti-FVIII antibodies is the Bethesda assay (BA), but it presents some limitations such as a lack of sensitivity for low titers of inhibitor and the need for experienced laboratory. A commercially available ELISA detecting anti-FVIII antibodies has demonstrated excellent sensitivity and specificity. The aim of our study was to assess the performance of this ELISA for the detection of anti-FVIII IgG in AHA patients during the follow-up. In total, 11 acquired hemophilia A patients were recruited, and anti-FVIII antibody levels were monitored by BA and ELISA. Anti-FVIII IgG ELISA showed 100% sensitivity and 100% specificity, and it correlated with the BA. Discrepancies observed in 13.3% of cases were consistent with patients' biological evolution. All these data suggest the possible use of anti-FVIII IgG ELISA for both diagnosis and follow-up of AHA patients.
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Kulkarni BP, Ghargi K, Shanmukhaiah C, Shetty SD. Rare Occurrence of Inhibitors in Von Willebrand Disease: A Case Report. Front Med (Lausanne) 2022; 8:807664. [PMID: 35087851 PMCID: PMC8787104 DOI: 10.3389/fmed.2021.807664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 12/13/2021] [Indexed: 11/13/2022] Open
Abstract
Introduction: Type 3 Von Willebrand Disease (VWD) is the least common but the most severe form of a disease, with a prevalence of about 0. 5 to 1 per million in Western countries. The prevalence of type 3 VWD in the developing countries, with a high degree of consanguinity, is about 6 per million. Moreover, due to underdiagnosis of the milder cases, the prevalence of type 3 VWD is about 50% of the cases. Rarely, some patients develop the Von Willebrand Factor (VWF) inhibitors, which may subsequently develop severe anaphylactic reactions on further exposure to the VWF containing factor replacement therapy. The prevalence of inhibitor development in patients with type 3 VWD has been shown to be in the range of 5.8 to 9.5%. In the absence of a gold standard assay for the quantitation of VWF inhibitors, a correct diagnosis and management of these patients are often challenging. Objectives: The objective of this study is to standardize the Bethesda assay for the VWF inhibitors and to estimate the VWD inhibitor titer in two cases of congenital type 3 VWD, which developed the VWF inhibitors. Results and Conclusions: We could successfully standardize the Bethesda assay for the quantitation of VWF inhibitors in two patients with congenital type 3 VWD with inhibitors.
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Affiliation(s)
- Bipin P Kulkarni
- ICMR- National Institute of Immunohaematology, KEM Hospital Campus, Mumbai, India
| | - Kirti Ghargi
- ICMR- National Institute of Immunohaematology, KEM Hospital Campus, Mumbai, India
| | | | - Shrimati D Shetty
- ICMR- National Institute of Immunohaematology, KEM Hospital Campus, Mumbai, India
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Bonnefoy A, Merlen C, Dubé E, Claus-Desbonnet H, Rivard GE, St-Louis J. Predictive significance of anti-FVIII immunoglobulin patterns on bleeding phenotype and outcomes in acquired hemophilia A: Results from the Quebec Reference Center for Inhibitors. J Thromb Haemost 2021; 19:2947-2956. [PMID: 34455699 DOI: 10.1111/jth.15515] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 08/23/2021] [Accepted: 08/26/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Acquired hemophilia A (AHA) is a potentially life-threatening bleeding disorder caused by factor VIII (FVIII) autoantibodies, involving various immunoglobulin (Ig) isotypes and IgG subclasses. OBJECTIVES We analyzed the profile of Ig against FVIII in patients with AHA to identify Ig patterns predictive of bleeding phenotype and outcomes. PATIENTS/METHODS Ig detection and titration were determined by enzyme-linked immunosorbent assay (ELISA) at disease presentation in a cohort of 66 subjects from the Quebec Reference Centre for Inhibitors registry. RESULTS Most of plasma samples analyzed (97%) contained multiple anti-FVIII Ig isotypes and IgG subclasses, IgG(1,2,3,4) (24.2%), [IgG(1,2,3,4),IgA] (16.7%) and IgG(2.4) (13.6%) being the most prevalent combinations of Ig detected. AHA patients who presented with IgA antibodies were more likely to have an associated auto-immune disease (p = .049). The presence of IgG4-was associated with bleeding symptoms at presentation (p = .002). IgG1-positive patients were more likely to require transfusions with red packed cell (p = .014) whereas IgM detection was associated with a higher probability of death linked to AHA (p = .011). CONCLUSION The Ig pattern of AHA patients at diagnosis is widely heterogeneous and is at least partially associated with some underlying conditions. Our data supports the differential predictive significance for IgG1, IgG4 and IgM on bleeding severity and suggests that the early determination of Ig profile may help to identify AHA patients at higher risk of poorer outcomes.
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Affiliation(s)
- Arnaud Bonnefoy
- Division of Hematology-Oncology, Department of Pediatrics, CHU Sainte-Justine, Université de Montréal, Montreal, Quebec, Canada
| | - Clémence Merlen
- Division of Hematology-Oncology, Department of Pediatrics, CHU Sainte-Justine, Université de Montréal, Montreal, Quebec, Canada
| | - Evemie Dubé
- Division of Hematology-Oncology, Department of Pediatrics, CHU Sainte-Justine, Université de Montréal, Montreal, Quebec, Canada
| | - Hadrien Claus-Desbonnet
- Division of Hematology-Oncology, Department of Pediatrics, CHU Sainte-Justine, Université de Montréal, Montreal, Quebec, Canada
| | - Georges-Etienne Rivard
- Division of Hematology-Oncology, Department of Pediatrics, CHU Sainte-Justine, Université de Montréal, Montreal, Quebec, Canada
| | - Jean St-Louis
- Division of Hematology-Oncology, Hôpital Maisonneuve-Rosemont, Montreal, Quebec, Canada
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Gandhi T, Lawler P, Foxton E, Chowdary P, Riddell A. Clinical utility of sample preheat treatment in a modified Nijmegen- Bethesda assay (mNBA) for inhibitor monitoring in congenital and acquired haemophilia A: A single-centre four-year experience. Haemophilia 2020; 26:e300-e307. [PMID: 32892451 DOI: 10.1111/hae.14090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 06/07/2020] [Accepted: 06/08/2020] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Laboratory monitoring for factor VIII inhibitors ideally requires samples with the lowest possible factor VIII (FVIII) level, potentially challenging in patients with congenital haemophilia A (CHA) receiving regular prophylaxis and acquired haemophilia A (AHA) patients with endogenous FVIII. Inactivation of FVIII by preheating (preheat treatment, PHT) of patient plasma has been suggested to facilitate monitoring. AIM To evaluate the clinical utility of PHT prior to inhibitor analysis by modified Nijmegen-Bethesda assay (mNBA) in patients with CHA and AHA. METHODS Inhibitor screening by mNBA under standard conditions and with PHT at 56°C for 30, 60 and 90 minutes was evaluated. FVIII inhibitor results between 2007 and 2010 without PHT (720 results from 222 CHA and AHA patients), and between 2011 and 2014 post-PHT (1102 results from 302 patients) were available for analysis. RESULTS Of total 1822 results available, 61% were from severe HA patients, 22% from mild and moderate HA and 16% from AHA. Pre-PHT, 74% of samples were analysed by the mNBA, and the remaining 26% were not tested as FVIII levels were >20 IU/dL as per local protocol. Postintroduction of PHT (90 and 60 minutes), 96% of samples received were analysed for an inhibitor. Post-PHT in patients with AHA (n = 26), 69% of samples tested with factor VIII levels >20 IU/dL were found to have detectable inhibitor. CONCLUSION FVIII inhibitor testing using PHT at 56°C for 60 minutes facilitates inhibitor surveillance of CHA on prophylaxis. Potentially, 30 minutes at 56°C might be equally efficacious. In AHA receiving immunosuppression, monitoring of inhibitor titre after initial factor VIII response might enable personalized immunosuppression.
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Affiliation(s)
- Tejas Gandhi
- Haemophilia & Thrombosis Laboratory (Health Services Laboratories), Royal Free Hospital, London, UK
| | - Pura Lawler
- Haemophilia & Thrombosis Laboratory (Health Services Laboratories), Royal Free Hospital, London, UK
| | - Eleanor Foxton
- Haemophilia & Thrombosis Laboratory (Health Services Laboratories), Royal Free Hospital, London, UK
| | - Pratima Chowdary
- Katharine Dormandy Haemophilia & Thrombosis Centre, Royal Free Hospital, London, UK
| | - Anne Riddell
- Haemophilia & Thrombosis Laboratory (Health Services Laboratories), Royal Free Hospital, London, UK
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Gokozan HN, Friedman JD, Schmaier AH, Downes KA, Farah LA, Reeves HM. Acquired Hemophilia A After Nivolumab Therapy in a Patient With Metastatic Squamous Cell Carcinoma of the Lung Successfully Managed With Rituximab. Clin Lung Cancer 2019; 20:e560-e563. [PMID: 31311716 DOI: 10.1016/j.cllc.2019.06.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 05/11/2019] [Accepted: 06/15/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Hamza N Gokozan
- Department of Pathology, University Hospitals Cleveland Medical Center and Case Western Reserve University School of Medicine, Cleveland, OH
| | - Judah D Friedman
- Division of Hematology and Oncology, Department of Medicine, University Hospitals Cleveland Medical Center and Case Western Reserve University School of Medicine, Cleveland, OH
| | - Alvin H Schmaier
- Division of Hematology and Oncology, Department of Medicine, University Hospitals Cleveland Medical Center and Case Western Reserve University School of Medicine, Cleveland, OH
| | - Katharine A Downes
- Department of Pathology, University Hospitals Cleveland Medical Center and Case Western Reserve University School of Medicine, Cleveland, OH
| | - Lisa A Farah
- Clinical Oncology, University Hospitals Geauga Medical Center, Chardon, OH
| | - Hollie M Reeves
- Department of Pathology, University Hospitals Cleveland Medical Center and Case Western Reserve University School of Medicine, Cleveland, OH.
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Arshad S, Singh A, Awasthi NP, Kumari S, Husain N. Clinicopathological parameters influencing inhibitor development in patients with hemophilia A receiving on-demand therapy. Ther Adv Hematol 2018; 9:213-226. [PMID: 30181842 PMCID: PMC6116755 DOI: 10.1177/2040620718785363] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 05/27/2018] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Development of inhibitors to transfused factor VIII in patients with hemophilia A continues to be a challenge for professionals involved in hemophilia care. The majority of patients in India receive 'on-demand' rather than prophylactic therapy. The present study was done to assess the prevalence of factor VIII inhibitors in patients with hemophilia A (PWHA) receiving 'on-demand' therapy in a North Indian population and to study the clinicopathological parameters influencing the development of inhibitors. METHODS The study group comprised of 300 PWHA. Detailed clinical parameters, treatment history, bleeding profile including family history were recorded. Diagnosis of hemophilia A was confirmed by relevant coagulation tests. Inhibitors were screened using mixing based studies followed by quantification by Bethesda assay and Nijmegen modified Bethesda assay. Samples were collected from five cities in North India where a free supply of factor VIII was available and effectively used in three of these cities. RESULTS In the 300 PWHA, disease phenotype was severe in 219 (73%), moderate in 62 (20.67%) and mild in 19 (6.34%), based on the factor VIII bioassay. Inhibitor prevalence was 9.6% (n = 29) and seen only in the severe phenotype. Inhibitor titers ranged from 0.8 to 108.8 BU/ml. A total of 12 PWHA had low and 17 had high titers. Correlation of various clinicopathological parameters in inhibitor-positive versus negative PWHA showed significant correlation with age at onset of disease, severity of disease, age at first exposure to treatment, annual factor intake (IU/kg/year), intense treatment episodes and bleeding manifestations like central nervous system bleed and hematuria. The total study sample had blood group B in 33.34% PWHA, followed by O (27.34%), A (24.34%) and AB (15%), however, in inhibitor-positive samples, significant inhibitor formation was associated with the ABO subtype A (19/29, 65.51%). CONCLUSIONS Factor VIII inhibitor prevalence in PWHA receiving 'on-demand' therapy was 9.6%. Clinicopathological correlates of inhibitor development in such PWHA have been analyzed in this novel study.
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Affiliation(s)
- Sanya Arshad
- Dr. Ram Manohar Lohia Institute of Medical
Sciences, Lucknow, Uttar Pradesh, India
| | - Anshima Singh
- Dr. Ram Manohar Lohia Institute of Medical
Sciences, Lucknow, Uttar Pradesh, India
| | - Namrata Punit Awasthi
- Department of Pathology, Dr. Ram Manohar Lohia
Institute of Medical Sciences, Vibhuti Khand, Gomti Nagar, Lucknow 226010,
India
| | - Swati Kumari
- Dr. Ram Manohar Lohia Institute of Medical
Sciences, Lucknow, Uttar Pradesh, India
| | - Nuzhat Husain
- Dr. Ram Manohar Lohia Institute of Medical
Sciences, Lucknow, Uttar Pradesh, India
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Vendramin C, Thomas M, Westwood JP, Scully M. Bethesda Assay for Detecting Inhibitory Anti-ADAMTS13 Antibodies in Immune-Mediated Thrombotic Thrombocytopenic Purpura. TH Open 2018; 2:e329-e333. [PMID: 31249957 PMCID: PMC6524890 DOI: 10.1055/s-0038-1672187] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 08/09/2018] [Indexed: 11/16/2022] Open
Abstract
A diagnosis of thrombotic thrombocytopenic purpura (TTP) is confirmed by a severe deficiency (<10%) of a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13) activity. Autoantibodies to ADAMTS13 can be detected with a simplified enzyme-linked immunosorbent assay (ELISA). An alternative methodology is a Bethesda assay, which has never been formally assessed in TTP. This study aimed to investigate the inhibitory anti-ADAMTS13 antibody assay and determine if the Bethesda assay is advantageous compared with the ELISA, measuring total immunoglobulin G (IgG) antibodies to ADAMTS 13. The Bethesda method determines the neutralizing activity of anti-ADAMTS13 antibodies in pooled normal plasma. We selected six immune-mediated TTP (iTTP) patients with ADAMTS13 activity levels <10% and strong ADAMTS13 inhibitors by 50:50 mixing studies and analyzed anti-ADAMTS13 antibodies using the Bethesda and ELISA assays. ADAMTS13 activity was stable at room temperature, while a time-dependent decrease in activity was detected in assay conditions of 37°C. Adding 5 mM Ca 2+ to citrated plasma prevented loss of ADAMTS13 activity with time. There was time dependence to the antibody-mediated inactivation, after 2-hour incubation. Two of the iTTP patients had no detectable ADAMTS13 antibodies by the Bethesda assay, but had high titer of anti-ADAMTS13 antibodies and low ADAMTS13 antigen levels. The Bethesda assay can only detect anti-ADAMTS13 antibodies that functionally inhibit ADAMTS13. The anti-ADAMTS13 IgG ELISA instead allows the rapid identification of total IgG autoantibodies, detecting both inhibitory and noninhibitory antibodies.
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Affiliation(s)
- Chiara Vendramin
- Department of Haematology, University College London Hospital, London, United Kingdom
| | - Mari Thomas
- Department of Haematology, University College London Hospital, Cardiometabolic Programme NIHR UCLH/UCL BRC, London, United Kingdom
| | - John-Paul Westwood
- Department of Haematology, University College London Hospital, London, United Kingdom
| | - Marie Scully
- Department of Haematology, University College London Hospital, Cardiometabolic Programme NIHR UCLH/UCL BRC, London, United Kingdom
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Abstract
Specific coagulation factor inhibitors, most notably to coagulation factor VIII, can develop in patients with hemophilia after exposure to replacement factor or as an acquired (autoimmune) event. Such inhibitors can be detected by a combination of prolonged coagulation screening tests, such as the activated partial thromboplastin time, plus a non-correcting mixing test. Non-correction may only be evident, or else may be extenuated, with incubation at 37 °C. The Bethesda assay for quantitation of inhibitor strength is based on a combination of mixing tests followed by specific factor assays.
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Affiliation(s)
- Geoffrey Kershaw
- Institute of Haematology, Royal Prince Alfred Hospital, Missenden Road, Camperdown, NSW, 2050, Australia.
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Bravo MI, Da Rocha-Souto B, Grancha S, Jorquera JI. Native plasma-derived FVIII/VWF complex has lower sensitivity to FVIII inhibitors than the combination of isolated FVIII and VWF proteins. Impact on Bethesda assay titration of FVIII inhibitors. Haemophilia 2014; 20:905-11. [PMID: 25156825 PMCID: PMC4237173 DOI: 10.1111/hae.12494] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2014] [Indexed: 01/29/2023]
Abstract
Sensitivity to FVIII inhibitors of the native plasma-derived (pd) FVIII/VWF complex vs. the complexes formed after exogenous FVIII infusion in the haemophilic patient has not been thoroughly studied. The role of VWF in the interaction of FVIII with inhibitors was studied in vitro using different combinations of VWF and FVIII concentrates. Normal plasma, pdFVIII/VWF and isolated FVIII (recombinant FVIII, B-domain deleted and pdFVIII) were used. Titre (BU) was kinetically determined (up to 2 h) in serial dilutions of inhibitor IgG (purified from a pool of plasmas with inhibitors) mixed with VWF and then incubated with the different FVIII. Inhibitor was also added to previously mixed VWF+FVIII. Residual FVIII:C was determined. TGA assays were performed with FVIII-deficient plasma spiked with the FVIII-VWF mixtures with/without an ESH-8 antibody. Inhibitor titres for plasma and pdFVIII/VWF were comparable at all time points. Titres for all concentrates of isolated FVIII were significantly higher than those for plasma or pdFVIII/VWF (1.4–1.9 fold) even after preincubation with VWF. At t = 0 h, titres for plasma or pdFVIII/VWF were unquantifiable, but were detectable for isolated FVIII (0.6–1.6 BU). In contrast to pdFVIII/VWF, the decrease in thrombin generation parameters by isolated FVIII in the presence of ESH-8 was significant (P < 0.01) even when previously combined with VWF. In conclusion, VWF protection against FVIII inhibitor activity might be higher with native pdFVIII/VWF complex than with the corresponding compound formed from the isolated proteins. Bethesda assay titration using different FVIII concentrates would be advisable to guide the treatment of inhibitor patients.
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Affiliation(s)
- M I Bravo
- Research and Development Area, Instituto Grifols S.A., Parets del Vallès, Barcelona, Spain
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