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1.
Clin Cosmet Investig Dermatol ; 17: 751-761, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38566887

RESUMO

Purpose: Alopecia areata (AA) is an autoimmune disease characterized by hair loss that has significant psychosocial implications. This study aims to describe the patient-reported burden of severe AA, coping mechanism and information needs using data from the multinational AA Patient Satisfaction and Unmet Need Survey. Patients and Methods: Participants with current or previous ≥50% scalp hair loss (n = 747) were recruited from 11 countries and completed a web-based survey that assessed demographics, clinical characteristics, disease burden and psychosocial impact. Data were stratified according to sex, current age, disease duration and current severity of scalp hair loss. Results: The mean (SD) age of participants was 43.8 (7.1) years, 55.3% were women, and 63.5% reported AA symptoms within 6 months of diagnosis. Most participants had black or brown hair (88.4%), reported a disease duration of 2 years or more (75.6%) and had current scalp hair loss of ≥50% (87.4%). Severe hair loss also extended to eyebrow (46.9%), eyelash (48.7), beard (61.5%) and body hair (73.2%). Participants commonly reported comorbidities such as anxiety (26.1%), depression (18.1%) and sleep problems (28.1%). The Dermatology Life Quality Index revealed a severe impact on quality of life; 86.2% of participants scored >10. Mental health/mood was significantly affected; 55.8% of participants reported a substantial impact. Long-term effects included decreased self-esteem (32.9%), poor mental health (28.1%) and challenges in day-to-day activities (27.2%). Information needs were centered around treatment expectations, mental health, and available treatment options. More severe symptoms and a greater daily impact were reported by women and those with a longer disease duration. Conclusion: The study emphasizes the substantial burden, including impaired quality of life and psychological well-being, of severe AA on the lives of surveyed participants. The findings highlight the importance of comprehensive disease management strategies that address both physical and psychosocial aspects of AA.


Alopecia areata (AA) is a disease that results in hair loss and can greatly affect quality of life and well-being. The authors wanted to understand how this condition affects people's lives and what they need to cope with it. A survey was completed by adults from 11 different countries who had current or past severe AA. The participants were asked about their demographics, their experiences with the condition and how it impacted their daily lives. The results showed that AA has a severe impact on their quality of life, including their mental health and daily activities. Participants also experienced decreased self-esteem and faced challenges in their relationships and daily routines, and many reported feeling anxious, depressed, and having trouble sleeping. Participants found different ways to cope with their condition and expressed a need for realistic expectations about treatment results, information about mental health, and treatment options. The study also found that women and those with a longer duration of AA tended to have more severe symptoms and the impact on their lives was greater. Overall, this study shows that current or previous episodes of severe AA had a significant impact on people's lives, including their mental health and daily activities. It emphasizes the need for information about the condition and treatment options with realistic expectations. The findings help to better understand the experiences of people with AA and may aid the provision of appropriate support and information.

2.
Front Immunol ; 12: 728322, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34512662

RESUMO

Novel molecules that directly target the neonatal Fc receptor (FcRn) and/or Fc gamma receptors (FcγRs) are emerging as promising treatments for immunoglobulin G (IgG)-dependent autoimmune pathologies. Mutated Fc regions and monoclonal antibodies that target FcRn are currently in clinical development and hold promise for reducing the levels of circulating IgG. Additionally, engineered structures containing multimeric Fc regions allow the dual targeting of FcRn and FcγRs; however, their tolerance needs to first be validated in phase I clinical studies. Here, for the first time, we have developed a modified monomeric recombinant Fc optimized for binding to all FcRns and FcγRs without the drawback of possible tolerance associated with FcγR cross-linking. A rational approach using Fc engineering allowed the selection of LFBD192, an Fc with a combination of six mutations that exhibits improved binding to human FcRn and FcγR as well as mouse FcRn and FcγRIV. The potency of LFBD192 was compared with that of intravenous immunoglobulin (IVIg), an FcRn blocker (Fc-MST-HN), and a trimeric Fc that blocks FcRn and/or immune complex-mediated cell activation through FcγR without triggering an immune reaction in several in vitro tests and validated in three mouse models of autoimmune disease.


Assuntos
Antirreumáticos/farmacologia , Artrite Experimental/prevenção & controle , Autoimunidade/efeitos dos fármacos , Fragmentos Fc das Imunoglobulinas/farmacologia , Receptores Fc/antagonistas & inibidores , Receptores de IgG/antagonistas & inibidores , Animais , Antirreumáticos/metabolismo , Artrite Experimental/genética , Artrite Experimental/imunologia , Artrite Experimental/metabolismo , Ligação Competitiva , Complemento C5a/metabolismo , Feminino , Antígenos de Histocompatibilidade Classe I/genética , Antígenos de Histocompatibilidade Classe I/imunologia , Antígenos de Histocompatibilidade Classe I/metabolismo , Humanos , Fragmentos Fc das Imunoglobulinas/genética , Fragmentos Fc das Imunoglobulinas/imunologia , Fragmentos Fc das Imunoglobulinas/metabolismo , Interleucina-2/metabolismo , Células Jurkat , Cinética , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mutação , Fagocitose/efeitos dos fármacos , Agregação Plaquetária/efeitos dos fármacos , Ligação Proteica , Engenharia de Proteínas , Receptores Fc/genética , Receptores Fc/imunologia , Receptores Fc/metabolismo , Receptores de IgG/genética , Receptores de IgG/imunologia , Receptores de IgG/metabolismo , Via Secretória , Transdução de Sinais , Células THP-1
3.
Front Immunol ; 12: 683902, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34163482

RESUMO

Respiratory syncytial virus (RSV) is a public health concern that causes acute lower respiratory tract infection. So far, no vaccine candidate under development has reached the market and the only licensed product to prevent RSV infection in at-risk infants and young children is a monoclonal antibody (Synagis®). Polyclonal human anti-RSV hyper-immune immunoglobulins (Igs) have also been used but were superseded by Synagis® owing to their low titer and large infused volume. Here we report a new drug class of immunoglobulins, derived from human non hyper-immune plasma that was generated by an innovative bioprocess, called Ig cracking, combining expertises in plasma-derived products and affinity chromatography. By using the RSV fusion protein (F protein) as ligand, the Ig cracking process provided a purified and concentrated product, designated hyper-enriched anti-RSV IgG, composed of at least 15-20% target-specific-antibodies from normal plasma. These anti-RSV Ig displayed a strong in vitro neutralization effect on RSV replication. Moreover, we described a novel prophylactic strategy based on local nasal administration of this unique hyper-enriched anti-RSV IgG solution using a mouse model of infection with bioluminescent RSV. Our results demonstrated that very low doses of hyper-enriched anti-RSV IgG can be administered locally to ensure rapid and efficient inhibition of virus infection. Thus, the general hyper-enriched Ig concept appeared a promising approach and might provide solutions to prevent and treat other infectious diseases. IMPORTANCE: Respiratory Syncytial Virus (RSV) is the major cause of acute lower respiratory infections in children, and is also recognized as a cause of morbidity in the elderly. There are still no vaccines and no efficient antiviral therapy against this virus. Here, we described an approach of passive immunization with a new class of hyper-enriched anti-RSV immunoglobulins (Ig) manufactured from human normal plasma. This new class of immunoglobulin plasma derived product is generated by an innovative bioprocess, called Ig cracking, which requires a combination of expertise in both plasma derived products and affinity chromatography. The strong efficacy in a small volume of these hyper-enriched anti-RSV IgG to inhibit the viral infection was demonstrated using a mouse model. This new class of immunoglobulin plasma-derived products could be applied to other pathogens to address specific therapeutic needs in the field of infectious diseases or even pandemics, such as COVID-19.


Assuntos
Anticorpos Antivirais/administração & dosagem , Imunização Passiva , Imunoglobulina G/administração & dosagem , Infecções por Vírus Respiratório Sincicial/prevenção & controle , Vírus Sincicial Respiratório Humano/imunologia , Administração Intranasal , Animais , Anticorpos Antivirais/imunologia , Anticorpos Antivirais/isolamento & purificação , Modelos Animais de Doenças , Humanos , Imunoglobulina G/imunologia , Imunoglobulina G/isolamento & purificação , Pulmão/efeitos dos fármacos , Pulmão/virologia , Testes de Neutralização , Infecções por Vírus Respiratório Sincicial/virologia , Conchas Nasais/efeitos dos fármacos , Conchas Nasais/virologia , Proteínas Virais de Fusão/imunologia , Replicação Viral/efeitos dos fármacos
4.
Haematologica ; 105(9): 2335-2340, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-33054058

RESUMO

Rendering coagulation factor X sensitive to thrombin was proposed as a strategy that can bypass the need for factor VIII. In this paper, this non-replacement strategy was evaluated in vitro and in vivo in its ability to correct factor VIII but also factor IX, X and XI deficiencies. A novel modified factor X, named Actiten, was generated and produced in the HEK293F cell line. The molecule possesses the required post-translational modifications, partially keeps its ability to be activated by RVV-X, factor VIIa/tissue factor, factor VIIIa/factor IXa and acquires the ability to be activated by thrombin. The potency of the molecule was evaluated in respective deficient plasmas or hemophilia A plasmas, for some with inhibitors. Actiten corrects dose dependently all the assayed deficient plasmas. It is able to normalize the thrombin generation at 20 µg/mL showing however an increased lagtime. It was then assayed in a rabbit antibody-induced model of hemophilia A where, in contrast to recombinant factor X wild-type, it normalized the bleeding time and the loss of hemoglobin. No sign of thrombogenicity was observed and the generation of activated factor X was controlled by the anticoagulation pathway in all performed coagulation assays. This data indicates that Actiten may be considered as a possible non replacement factor to treat hemophilia's with the advantage of being a zymogen correcting bleedings only when needed.


Assuntos
Fator X , Hemofilia A , Animais , Fator IX , Fator VIII/genética , Fator VIIa , Fator X/genética , Hemofilia A/tratamento farmacológico , Hemofilia A/genética , Coelhos , Trombina
5.
Pan Afr Med J ; 36: 5, 2020.
Artigo em Francês | MEDLINE | ID: mdl-32550968

RESUMO

Fractures of the upper end of the humerus raise a therapeutic problem in particular for three-fragment and 3 and 4-fragment complex fractures. The purpose of our study is to determine the epidemio-clinic features of complex fractures of the upper end of the humerus in adults and to assess the functional and radiological results in our case series. The study involved 25 patients whose data were collected in the Department of Orthopaedics at the Habib Bourguiba University Hospital between 2012 and 2017. We listed the epidemiological data of patients and the circumstances of the occurrence of the traumatism. Treatment was based on surgery: plate or nail osteosynthesis or prosthetics replacement. Post-operative radiographs were used to asses´ reduction. Constant-Murley score was used to assess functional outcomes at the follow-up visit. Twelve men and thirteen women were enrolled, the average age of patients was 55 years, public road accidents were reported in 48% of cases, and 4-fragment fractures were found in 76% of cases. Screwed plate osteosynthesis was used in 40% of cases and anterograde nailing was performed in 40% of cases. A prosthesis was put in place in 5 patients. Mean Constant-Murley score was 65.24, ranging between 35 years and 88 years. Consolidation of the fractures without malunions was reported in 68% of patients. In complex fractures of the upper end of the humerus, osteosynthesis performed according to patients´ needs and fracture types as well as early post-operative rehabilitation allow for acceptable functional outcomes.Domain: Orthopedic surgery.


Assuntos
Fixação Interna de Fraturas/métodos , Fraturas do Úmero/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Pinos Ortopédicos , Placas Ósseas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
6.
Thromb Res ; 167: 88-95, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29800795

RESUMO

Antithrombin (AT) binds in vitro and in vivo to endothelial cells through various receptors, including heparan sulphate glycosaminoglycan (HSPG) that could modulate the AT activity. A thrombin generation assay (TGA) was set up at the surface of HUVEC and HMVEC evaluating their participation in the coagulation-anticoagulation processes. TGA induced by 0.5 pM Tissue Factor was performed in normal or AT-deficient plasma spiked with various amounts of recombinant or plasma-derived AT (0, 0.1, 0.5 and 1.0 U/ml). To evaluate the role of HSPG or cellular anticoagulant receptors, cells were treated or not with heparin, a mix of heparanase I, II and III, a neutralizing anti-Endothelial Protein C Receptor (EPCR) or with an anti-Tissue Factor Pathway Inhibitor (TFPI) antibody. The presence of the cells diminished the TG in normal plasma and maintained anticoagulation in AT-deficient plasma. Spiking the AT-deficient plasma with different doses of AT demonstrated that the cells did not amplify the anticoagulant activity of AT. The recombinant AT binds the cells with a higher avidity than the plasma-derived one but this did not affect its anticoagulant potency. Moreover both bindings are independent of the HSPG. The antithrombotic activity kept in absence of AT was not inhibited by blocking antibodies directed against EPCR or TFPI. Our data did not reveal a major co-factor activity for AT from endothelial cells that could have been mediated by HSPG. In contrast, it reveals the presence of alternative anti-coagulant system(s) in two venous cell types that maintain an antithrombotic activity.


Assuntos
Antitrombinas/uso terapêutico , Coagulação Sanguínea/efeitos dos fármacos , Células Endoteliais/metabolismo , Antitrombinas/farmacologia , Humanos
7.
MAbs ; 10(4): 651-663, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29553870

RESUMO

Plasmacytoid dendritic cells (pDCs) play a central role for both innate and adaptive antiviral responses, as they direct immune responses through their unique ability to produce substantial concentrations of type I interferon (IFNs) upon viral encounter while also activating multiple immune cells, including macrophages, DCs, B, natural killer and T cells. Recent evidence clearly indicates that pDCs also play a crucial role in some cancers and several auto-immune diseases. Although treatments are currently available to patients with such pathologies, many are not fully efficient. We are proposing here, as a new targeted-based therapy, a novel chimeric monoclonal antibody (mAb) that mediates a strong cellular cytotoxicity directed against a specific human pDC marker, CD303. This antibody, ch122A2 mAb, is characterized by low fucose content in its human IgG1 constant (Fc) region, which induces strong in vitro and in vivo activity against human pDCs. We demonstrated that this effect relates in part to its specific Fc region glycosylation pattern, which increased affinity for CD16/FcγRIIIa. Importantly, ch122A2 mAb induces the down-modulation of CpG-induced IFN-α secretion by pDCs. Additionally, ch122A2 mAb shows in vitro high pDC depletion mediated by antibody-dependent cell-mediated cytotoxicity and antibody-dependent cellular phagocytosis. Remarkably, in vivo ch122A2 mAb efficacy is also demonstrated in humanized mice, resulting in significant pDC depletion in bloodstream and secondary lymphoid organs such as spleen. Together, our data indicates that ch122A2 mAb could represent a promising cytotoxic mAb candidate for pathologies in which decreasing type I IFNs or pDCs depleting may improve patient prognosis.


Assuntos
Anticorpos Monoclonais/imunologia , Células Dendríticas , Lectinas Tipo C/antagonistas & inibidores , Glicoproteínas de Membrana/antagonistas & inibidores , Receptores Imunológicos/antagonistas & inibidores , Animais , Anticorpos Monoclonais/farmacologia , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/imunologia , Humanos , Camundongos , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/farmacologia
8.
BioDrugs ; 31(3): 251-261, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28508264

RESUMO

BACKGROUND: A highly purified 10% liquid intravenous immunoglobulin, IQYMUNE®, has been developed using an innovative manufacturing process including an affinity chromatography step for the removal of anti-A and anti-B hemagglutinins. OBJECTIVES: The pathogen (viruses and prions) clearance efficacy of the manufacturing process and its robustness for critical steps were investigated. METHODS: The manufacturing process of IQYMUNE® includes two dedicated complementary virus reduction steps: solvent/detergent (S/D) treatment and 20 nm nanofiltration as well as two contributing steps, namely caprylic acid fractionation and anion-exchange chromatography. The clearance capacity and robustness of these steps were evaluated with a wide range of viruses (enveloped and non-enveloped) and with a model of human transmissible spongiform encephalopathies (TSEs). RESULTS: The IQYMUNE® manufacturing process demonstrated a high and robust virus removal capacity with global reduction factors (RFs) of relevant and model viruses: ≥14.8 log10 for human immunodeficiency virus type 1 (HIV-1), ≥16.9 log10 for bovine viral diarrhoea virus (BVDV)/Sindbis virus, ≥15.7 log10 for pseudorabies virus (PRV), ≥12.8 log10 for encephalomyocarditis virus (EMCV) and 11.0 log10 for porcine parvovirus (PPV). The process also exhibited a high removal capacity for the TSE agent with an overall RF of ≥12.9 log10 due to the complementary actions of the caprylic acid fractionation, anion-exchange chromatography and nanofiltration steps. CONCLUSION: Data from virus and prion clearance studies fully support the high safety profile of IQYMUNE®, with a minimal reduction of 11 log10 for the smallest and most resistant non-enveloped virus, PPV, and more than 12 log10 for the TSE agent.


Assuntos
Imunoglobulinas Intravenosas/química , Plasma/química , Animais , Caprilatos/química , Cromatografia de Afinidade/métodos , Cricetinae , Contaminação de Medicamentos/prevenção & controle , Hemaglutininas/química , Humanos , Imunoglobulinas Intravenosas/farmacologia , Doenças Priônicas/tratamento farmacológico , Doenças Priônicas/virologia , Príons/efeitos dos fármacos , Solventes/química , Inativação de Vírus/efeitos dos fármacos , Vírus/efeitos dos fármacos
9.
J Chromatogr A ; 1489: 39-50, 2017 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-28179082

RESUMO

Nucleic acid aptamers are promising ligands for analytical and preparative-scale affinity chromatography applications. However, a full industrial exploitation requires that aptamer-grafted chromatography media provide a number of high technical standards that remained largely untested. Ideally, they should exhibit relatively high binding capacity associated to a very high degree of specificity. In addition, they must be highly resistant to harsh cleaning/sanitization conditions, as well as to prolonged and repeated exposure to biological environment. Here, we present practical examples of aptamer affinity chromatography for the purification of three human therapeutic proteins from various sources: Factor VII, Factor H and Factor IX. In a single chromatographic step, three DNA aptamer ligands enabled the efficient purification of their target protein, with an unprecedented degree of selectivity (from 0.5% to 98% of purity in one step). Furthermore, these aptamers demonstrated a high stability under harsh sanitization conditions (100h soaking in 1M NaOH). These results pave the way toward a wider adoption of aptamer-based affinity ligands in the industrial-scale purification of not only plasma-derived proteins but also of any other protein in general.


Assuntos
Aptâmeros de Nucleotídeos , Proteínas Sanguíneas/isolamento & purificação , Cromatografia de Afinidade/métodos , Aptâmeros de Nucleotídeos/química , DNA/química , Humanos , Ligantes
10.
Mutat Res ; 679(1-2): 65-71, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19619668

RESUMO

An increase in the number of revertant colonies in the Ames test is generally taken as a strong indication of mutagenic activity of a test compound. However, irrelevant positive findings may constitute a major problem in regulatory drug testing. In this study, mixtures containing only amino acids such as glycine, lysine, arginine and isoleucine, routinely used as peptide preservatives in polypeptide pharmaceutical products, were investigated for mutagenesis in the Ames Salmonella typhimurium test. The results demonstrated that in the presence of metabolic activation, all the solutions containing arginine induced an increase in the number of revertant colonies in strains TA98, TA100 and TA1535 compared with the solvent control. More specifically, for strain TA98, all arginine doses tested, i.e. from 0.4 to 8 mg/plate induced a statistically significant increase in the number of revertants. This increase was biologically significant from 1.2 to 8 mg/plate. For strain TA100, the five highest test doses, i.e., from 1.2 to 8 mg/plate, induced statistically and biologically significant increases in the number of revertants. A statistically significant increase in colony number was also observed in strain TA1535, but only at the maximal test dose of 8 mg/plate arginine. These increases were observed with arginine from two different sources, suggesting that the observed effect would not be due to the presence of potential impurities in the type of arginine used. Our findings show that a functional metabolic activation system was required to induce an increase in the number of colonies. The presence of vitamin C inhibited the arginine-induced increase in the number of revertant colonies in S. typhimurium strain TA98, suggesting a potential involvement of oxidative stress.


Assuntos
Arginina/farmacologia , Reações Falso-Positivas , Testes de Mutagenicidade , Aminoácidos/farmacologia , Animais , Ácido Ascórbico/farmacologia , Biotransformação , Salmonella typhimurium/genética
11.
Glycoconj J ; 25(9): 827-42, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18642129

RESUMO

Factor VII (FVII) is a vitamin K-dependent glycoprotein which, in its activated form (FVIIa), participates in the coagulation process by activating factor X and factor IX. FVII is secreted as single peptide chain of 406 residues. Plasma-derived FVII undergoes many post-translational modifications such as gamma-carboxylation, N- and O-glycosylation, beta-hydroxylation. Despite glycosylation of recombinant FVIIa has been fully characterized, nothing is reported on the N- and O-glycans of plasma-derived FVII (pd-FVII) and on their structural heterogeneity at each glycosylation site. N- and O-glycosylation sites and site specific heterogeneity of pd-FVII were studied by various complementary qualitative and quantitative techniques. A MALDI-MS analysis of the native protein indicated that FVII is a 50.1 kDa glycoprotein modified on two sites by diantennary, disialylated non-fucosylated (A2S2) glycans. LC-ESIMS/MS analysis revealed that both light chain and heavy chain were N-glycosylated mainly by A2S2 but also by triantennary sialylated glycans. Nevertheless, lower amounts of triantennary structures were found on Asn(322) compared to Asn(145). Moreover, the triantennary glycans were shown to be fucosylated. In parallel, quantitative analysis of the isolated glycans by capillary electrophoresis indicated that the diantennary structures represented about 50% of the total glycan content. Glycan sequencing using different glycanases led to the identification of triantennary difucosylated structures. Last, MS and MS/MS analysis revealed that FVII is O-glycosylated on the light chain at position Ser(60) and Ser(52) which are modified by oligosaccharide structures such as fucose and Glc(Xyl)(0-1-2), respectively. These latter three O-glycans coexist in equal amounts in plasma-derived FVII.


Assuntos
Fator VII/química , Espectrometria de Massas , Polissacarídeos/química , Alquilação , Sequência de Aminoácidos , Cromatografia Líquida , Eletroforese Capilar , Fator VII/análise , Fluorescência , Glicopeptídeos/análise , Glicopeptídeos/química , Glicosilação , Humanos , Dados de Sequência Molecular , Peso Molecular , Subunidades Proteicas/análise , Subunidades Proteicas/química , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Espectrometria de Massas em Tandem , Tripsina/metabolismo
12.
Thromb Haemost ; 99(6): 1090-6, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18521513

RESUMO

The development of antibodies (Abs) against infused factor VIII (FVIII) is currently one of the most serious complications in the treatment of patients suffering from haemophilia A. Improved prevention and eradication of these anti-FVIII Abs remain a challenge for both clinicians and scientists. Here we describe an immunoassay to simultaneously detect and map the epitope specificity of haemophilia A patients' inhibitors by screening plasma against both heavy and light chains (HC and LC) of human plasma-derived FVIII (pFVIII). The format used was a two-site sandwich assay, where one monoclonal antibody (mAb) specific for the HC or LC was first immobilized on beads, and then incubated with the different forms of pFVIII. After incubation with patients' plasma samples, binding was revealed by a phycoerythrin-labeled secondary Ab. Samples from haemophilia patients with autoantibodies (autoAb) or alloantibodies (alloAb) were screened in this format. The former preferentially recognized the LC, whereas the latter were directed against both LC and HC. This technology appears attractive as it is fast and requires only 100 microl of patient's plasma. Furthermore, not only are anti-FVIII Abs detected, but information on their epitopic specificity is also obtained.


Assuntos
Anticorpos Monoclonais , Autoanticorpos/sangue , Mapeamento de Epitopos , Fator VIII/imunologia , Hemofilia A/imunologia , Imunoensaio/métodos , Isoanticorpos/sangue , Animais , Reações Antígeno-Anticorpo , Estudos de Viabilidade , França , Humanos , Camundongos , Suíça
13.
Haematologica ; 92(10): 1423-6, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18024377

RESUMO

Von Willebrand factor (VWF) has been proposed to reduce the immunogenicity of therapeutic factor VIII (FVIII) in patients with hemophilia A. Using FVIII-deficient mice, we compared the immunogenicity of different preparations of plasma-derived (pd) and recombinant (r) FVIII. Treatment of mice with pdFVIII induced significantly lower titers of FVIII inhibitors, as measured by ELISA and in vitro coagulation assays, compared with rFVIII. Furthermore, pre-incubation of rFVIII with excess VWF significantly reduced rFVIII immunogenicity. Our data confirm that pdFVIII induces lower levels of inhibitors than rFVIII, and that VWF is an immuno-chaperone molecule for FVIII.


Assuntos
Modelos Animais de Doenças , Fator VIII/imunologia , Fator VIII/uso terapêutico , Hemofilia A/tratamento farmacológico , Hemofilia A/imunologia , Animais , Fator VIII/genética , Feminino , Hemofilia A/genética , Humanos , Imunoglobulina G/imunologia , Masculino , Camundongos
14.
Blood Coagul Fibrinolysis ; 16(3): 187-92, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15795537

RESUMO

Replacement therapy is the treatment of choice for patients with von Willebrand disease who are unresponsive to desmopressin. In order to prevent transmission of non-enveloped viruses, a solvent/detergent-treated plasma-derived von Willebrand factor available in France since 1989 has been subjected to additional removal/inactivation steps by 35 nm filtration and dry heating for 72 h at 80 degrees C. This preclinical study evaluates the potential immunogenicity of this new product by comparing the antibodies raised in pigs affected with von Willebrand disease after intravenous injection of either a solvent/detergent-treated product or a triple-secured product. Our data showed that there is no difference between the two products in terms of the rate and intensity of the humoral response measured by both binding and neutralizing antibody levels. It was concluded that no antigenic alterations of von Willebrand factor molecules during the nanofiltration and final dry-heating steps were detected in our animal model.


Assuntos
Anticorpos/sangue , Doenças de von Willebrand/imunologia , Fator de von Willebrand/química , Fator de von Willebrand/imunologia , Animais , Anticorpos/química , Anticorpos/imunologia , Formação de Anticorpos/imunologia , Modelos Animais de Doenças , Relação Dose-Resposta Imunológica , Humanos , Imunização , Injeções Intravenosas , Suínos , Doenças de von Willebrand/sangue , Fator de von Willebrand/administração & dosagem
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