Publications by authors named "Laurent Drouot"

38 Publications

Evaluation of Humoral Immunity to SARS-CoV-2: Diagnostic Value of a New Multiplex Addressable Laser Bead Immunoassay.

Front Microbiol 2020 26;11:603931. Epub 2020 Nov 26.

Normandie University, UNIROUEN, INSERM, U1234, Rouen, France.

Despite efforts to develop anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody (Ab) immunoassays, reliable serological methods are still needed. We developed a multiplex addressable laser bead immunoassay (ALBIA) to detect and quantify anti-Spike S1 and nucleocapsid N Abs. Recombinant S1 and N proteins were bound to fluorescent beads (ALBIA-IgG-S1/N). Abs were revealed using class-specific anti-human Ig Abs. The performances of the test were analyzed on 575 serum samples including 192 from SARS-CoV-2 polymerase chain reaction-confirmed patients, 13 from seasonal coronaviruses, 70 from different inflammatory/autoimmune diseases, and 300 from healthy donors. Anti-S1 IgM were detected by monoplex ALBIA-IgM-S1. Comparison with chemiluminescent assays or enzyme-linked immunosorbent assays was performed using commercial tests. Multiplex ALBIA-IgG-S1/N was effective in detecting and quantifying anti-SARS-CoV-2 IgG Abs. Two weeks after first symptoms, sensitivity and specificity were 97.7 and 98.0% (anti-S1), and 100 and 98.7% (anti-N), respectively. Agreement with commercial tests was good to excellent, with a higher sensitivity of ALBIA. ALBIA-IgG-S1/N was positive in 53% of patients up to day 7, and in 75% between days 7 and 13. For ALBIA-IgM-S1, sensitivity and specificity were 74.4 and 98.7%, respectively. Patients in intensive care units had higher IgG Ab levels (Mann-Whitney test, < 0.05). ALBIA provides a robust method for exploring humoral immunity to SARS-CoV-2. Serology should be performed after 2 weeks following first symptoms, when all COVID-19 (coronavirus disease 2019) patients had at least one anti-S1 or anti-N IgG Ab, illustrating the interest of a multiplex test.
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http://dx.doi.org/10.3389/fmicb.2020.603931DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7726470PMC
November 2020

T cell and antibody responses to SARS-CoV-2: Experience from a French transplantation and hemodialysis center during the COVID-19 pandemic.

Am J Transplant 2021 02 6;21(2):854-863. Epub 2020 Nov 6.

Department of Nephrology, Transplantation and hemodialysis, Rouen University Hospital, Rouen, France.

Immunosuppressed organ-transplanted patients are considered at risk for severe forms of COVID-19. Moreover, exaggerated innate and adaptive immune responses might be involved in severe progression of the disease. However, no data on the immune response to SARS-CoV-2 in transplanted patients are currently available. Here, we report the first assessment of antibody and T cell responses to SARS-CoV-2 in 11 kidney-transplanted patients recovered from RT-PCR-confirmed (n = 5) or initially suspected (n = 6) COVID-19. After reduction of immunosuppressive therapy, RT-PCR-confirmed COVID-19 transplant patients were able to mount vigorous antiviral T cell and antibody responses, as efficiently as two nontherapeutically immunosuppressed COVID-19 patients on hemodialysis. By contrast, six RT-PCR-negative patients displayed no antibody response. Among them, three showed very low numbers of SARS-CoV-2-reactive T cells, whereas no T cell response was detected in the other three, potentially ruling out COVID-19 diagnosis. Low levels of T cell reactivity to SARS-CoV-2 were also detected in seronegative healthy controls without known exposure to the virus. These results suggest that during COVID-19, monitoring both T cell and serological immunity might be helpful for the differential diagnosis of COVID-19 but are also needed to evaluate a potential role of antiviral T cells in the development of severe forms of the disease.
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http://dx.doi.org/10.1111/ajt.16348DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7675512PMC
February 2021

Lack of association between chilblains outbreak and severe acute respiratory syndrome coronavirus 2: Histologic and serologic findings from a new immunoassay.

J Am Acad Dermatol 2020 11 16;83(5):1434-1436. Epub 2020 Jul 16.

Normandie University, UNIROUEN, Inserm, U1234, FOCIS Center of Excellence PAn'THER, Department of Immunology and Biotherapy, Rouen University Hospital, Rouen, France.

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http://dx.doi.org/10.1016/j.jaad.2020.07.048DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7365061PMC
November 2020

The IgG2 Isotype of Anti-Transcription Intermediary Factor 1γ Autoantibodies Is a Biomarker of Cancer and Mortality in Adult Dermatomyositis.

Arthritis Rheumatol 2019 08 8;71(8):1360-1370. Epub 2019 Jul 8.

Normandy University, University of Rouen, INSERM U1234, Rouen University Hospital, Rouen, France.

Objective: Anti-transcription intermediary factor 1γ (anti-TIF1γ) antibodies are the main predictors of cancer in dermatomyositis (DM). Yet, a substantial proportion of anti-TIF1γ-positive DM patients do not develop cancer. This study was undertaken to identify biomarkers to better evaluate the risk of cancer and mortality in DM.

Methods: This multicenter study was conducted in adult anti-TIF1γ-positive DM patients from August 2013 to August 2017. Anti-TIF1γ autoantibody levels and IgG subclasses were identified using a newly developed quantitative immunoassay. Age, sex, DM signs and activity, malignancy, and creatine kinase (CK) level were recorded. Risk factors were determined by univariate and multivariate analysis according to a Cox proportional hazards regression model.

Results: Among the 51 adult patients enrolled (mean ± SD age 61 ± 17 years; ratio of men to women 0.65), 40 (78%) had cancer and 21 (41%) died, with a mean ± SD survival time of 10 ± 6 months. Detection of anti-TIF1γ IgG2 was significantly associated with mortality (P = 0.0011) and occurrence of cancer during follow-up (P < 0.0001), with a 100% positive predictive value for cancer when the mean fluorescence intensity of anti-TIF1γ IgG2 was >385. None of the patients developed cancer after 24 months of follow-up. Univariate survival analyses showed that mortality was also associated with age >60 years (P = 0.0003), active DM (P = 0.0042), cancer (P = 0.0031), male sex (P = 0.011), and CK level >1,084 units/liter (P = 0.005). Multivariate analysis revealed that age >60 years (P = 0.015) and the presence of anti-TIF1γ IgG2 (P = 0.048) were independently associated with mortality.

Conclusion: Our findings indicate that anti-TIF1γ IgG2 is a potential new biomarker of cancer that should be helpful in identifying the risk of mortality in anti-TIF1γ-positive DM patients.
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http://dx.doi.org/10.1002/art.40895DOI Listing
August 2019

pathogenicity of IgG from patients with anti-SRP or anti-HMGCR autoantibodies in immune-mediated necrotising myopathy.

Ann Rheum Dis 2019 01 11;78(1):131-139. Epub 2018 Oct 11.

Normandie Univ, UNIROUEN, IRIB, Inserm, U1234, Departement of Immunology, Rouen University Hospital, Rouen, France

Objectives: In autoimmunity, autoantibodies (aAb) may be simple biomarkers of disease or true pathogenic effectors. A form of idiopathic inflammatory myopathy associated with anti-signal recognition particle (SRP) or anti-3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) aAb has been individualised and is referred to as immune-mediated necrotising myopathy (IMNM). The level of aAb correlates with IMNM activity and disease may respond to immunosuppression, suggesting that they are pathogenic. We aimed to evaluate the pathogenicity of IgG from patients with anti-SRP or anti-HMGCR aAb by developing the first mouse model of IMNM.

Methods: IgG from patients suffering from anti-SRP or anti-HMGCR associated IMNM were passively transferred to wild-type, Rag2 or complement C3 mice. Muscle deficiency was evaluated by muscle strength on electrostimulation and grip test. Histological analyses were performed after haematoxylin/eosin staining or by immunofluorescence or immunohistochemistry analysis. Antibody levels were quantified by addressable laser bead assay (ALBIA).

Results: Passive transfer of IgG from patients suffering from IMNM to C57BL/6 or Rag2 mice provoked muscle deficiency. Pathogenicity of aAb was reduced in C3 mice while increased by supplementation with human complement. Breakage of tolerance by active immunisation with SRP or HMGCR provoked disease.

Conclusion: This study demonstrates that patient-derived anti-SRP and anti-HMGCR IgG are pathogenic towards muscle through a complement-mediated mechanism, definitively establishing the autoimmune character of IMNM. These data support the use of plasma exchanges and argue for evaluating complement-targeting therapies in IMNM.
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http://dx.doi.org/10.1136/annrheumdis-2018-213518DOI Listing
January 2019

Necrosis in anti-SRP and anti-HMGCRmyopathies: Role of autoantibodies and complement.

Neurology 2018 02 12;90(6):e507-e517. Epub 2018 Jan 12.

From the Departments of Neuropathology (Y.A., C.P., H.R., H.-H.G., W.S.) and Pathology (P.H., N.Z.), Charité-Universitätsmedizin, Berlin, Germany; Internal Medicine Department (Y.A., N.C., K.M., A.R., O. Benveniste), Reference for Neuro-muscular Diseases, Paris Est, Groupe Hospitalier Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris; Myology Research Center (Y.A., L.A.-D., G.B.-B., D.A., O. Benveniste), Sorbonne Universités UPMC Univ Paris 06, INSERM UMRS974, Pitié-Salpêtrière University Hospital; Department of Neuropathology (T.M., S.L.-L., C.D.) and Institut de Myologie (B.E.), Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière University Hospital, Paris; and Department of Immunology (C.B., L.D., O. Boyer), UNIROUEN, INSERM, U1234, Normandie University, Rouen University Hospital, France.

Objective: To characterize muscle fiber necrosis in immune-mediated necrotizing myopathies (IMNM) with anti-signal recognition particle (SRP) or anti-3-hydroxy-3-methylglutarylcoenzyme A reductase (HMGCR) antibodies and to explore its underlying molecular immune mechanisms.

Methods: Muscle biopsies from patients with IMNM were analyzed and compared to biopsies from control patients with myositis. In addition to immunostaining and reverse transcription PCR on muscle samples, in vitro immunostaining on primary muscle cells was performed.

Results: Creatine kinase levels and muscle regeneration correlated with the proportion of necrotic fibers ( = 0.6, < 0.001). CD68iNOS macrophages and a Th-1 immune environment were chiefly involved in ongoing myophagocytosis of necrotic fibers. T-cell densities correlated with necrosis but no signs of cytotoxicity were detected. Activation of the classical pathway of the complement cascade, accompanied by deposition of sarcolemmal immunoglobulins, featured involvement of humoral immunity. Presence of SRP and HMGCR proteins on altered myofibers was reproduced on myotubes exposed to purified patient-derived autoantibodies. Finally, a correlation between sarcolemmal complement deposits and fiber necrosis was observed ( = 0.4 and = 0.004). Based on these observations, we propose to update the pathologic criteria of IMNM.

Conclusion: These data further corroborate the pathogenic role of anti-SRP and anti-HMGCR autoantibodies in IMNM, highlighting humoral mechanisms as key players in immunity and myofiber necrosis.
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http://dx.doi.org/10.1212/WNL.0000000000004923DOI Listing
February 2018

The Spontaneous Autoimmune Neuromyopathy in ICOSL NOD Mice Is CD4 T-Cell and Interferon-γ Dependent.

Front Immunol 2017 31;8:287. Epub 2017 Mar 31.

INSERM U1016, Cochin Institute, Paris Descartes University, Sorbonne Paris Cité, Paris, France.

Abrogation of ICOS/ICOS ligand (ICOSL) costimulation prevents the onset of diabetes in the non-obese diabetic (NOD) mouse but, remarkably, yields to the development of a spontaneous autoimmune neuromyopathy. At the pathological level, ICOSL NOD mice show stronger protection from insulitis than their ICOS counterparts. Also, the ICOSL NOD model carries a limited C57BL/6 region containing the nul mutation, but, in contrast to ICOS NOD mice, no gene variant previously reported as associated to NOD diabetes. Therefore, we aimed at providing a detailed characterization of the ICOSL NOD model. The phenotype observed in ICOSL NOD mice is globally similar to that observed in ICOS and ICOSICOSL double-knockout NOD mice, manifested by a progressive locomotor disability first affecting the front paws as observed by catwalk analysis and a decrease in grip test performance. The pathology remains limited to peripheral nerve and striated muscle. The muscle disease is characterized by myofiber necrosis/regeneration and an inflammatory infiltrate composed of CD4 T-cells, CD8 T-cells, and myeloid cells, resembling human myositis. Autoimmune neuromyopathy can be transferred to NOD. recipients by CD4 but not by CD8 T-cells isolated from 40-week-old female ICOSL NOD mice. The predominant role of CD4 T-cells is further demonstrated by the observation that neuromyopathy does not develop in CIITAICOSL NOD in contrast to β2microglobulinICOSL NOD mice. Also, the cytokine profile of CD4 T-cells infiltrating muscle and nerve of ICOSL NOD mice is biased toward a Th1 pattern. Finally, adoptive transfer experiments show that diabetes development requires expression of ICOSL, in contrast to neuromyopathy. Altogether, the deviation of autoimmunity from the pancreas to skeletal muscles in the absence of ICOS/ICOSL signaling in NOD mice is strictly dependent on CD4 T-cells, leads to myofiber necrosis and regeneration. It provides the first mouse model of spontaneous autoimmune myopathy akin to human myositis.
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http://dx.doi.org/10.3389/fimmu.2017.00287DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5371727PMC
March 2017

Pathogenic role of anti-signal recognition protein and anti-3-Hydroxy-3-methylglutaryl-CoA reductase antibodies in necrotizing myopathies: Myofiber atrophy and impairment of muscle regeneration in necrotizing autoimmune myopathies.

Ann Neurol 2017 Apr;81(4):538-548

Pierre and Marie Curie University, Sorbonne Universities, National Institute of Health and Medical Research, National Center for Scientific Research, Myology Research Center, Pitié-Salpêtrière University Hospital, Paris, France.

Objective: Immune-mediated necrotizing myopathies (IMNM) may be associated with either anti-signal recognition protein (SRP) or anti-3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) antibodies (Abs), and the titer of these Abs is correlated with disease activity. We investigated whether anti-SRP and anti-HMGCR Abs could be involved in muscle damage.

Methods: Muscle biopsies of patients were analyzed for atrophy and regeneration by measuring fiber size and by performing immunostaining of neonatal myosin heavy chain. To further understand the role of the Abs in the pathology, we performed muscle cell coculture with the Abs. Atrophy and regeneration were evaluated based on the myotube surface area as well as gene and cytokine profiles.

Results: In muscle biopsies of patients with anti-SRP and anti-HMGCR Abs, a large number of small fibers corresponding to both atrophic and regenerating fibers were observed. In vitro, anti-SRP and anti-HMGCR Abs induced muscle fiber atrophy and increased the transcription of MAFbx and TRIM63. In addition, the muscle fiber atrophy was associated with high levels of inflammatory cytokines: tumor necrosis factor, interleukin (IL)-6, and reactive oxygen species. In the presence of anti-SRP or anti-HMGCR Abs, mechanisms involved in muscle regeneration were also impaired due to a defect of myoblast fusion. This defect was associated with a decreased production of IL-4 and IL-13. The addition of IL-4 and/or IL-13 totally rescued fusion capacity.

Interpretation: These data show that molecular mechanisms of atrophy and regeneration are affected and contribute to loss of muscle function occurring in IMNM. This emphasizes the potential interest of targeted therapies addressing these mechanisms. Ann Neurol 2017;81:538-548.
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http://dx.doi.org/10.1002/ana.24902DOI Listing
April 2017

High risk of cancer in autoimmune necrotizing myopathies: usefulness of myositis specific antibody.

Brain 2016 08 17;139(Pt 8):2131-5. Epub 2016 Apr 17.

1 Département de Médecine Interne et Immunologie Clinique, Hôpital Pitié-Salpêtrière, DHU I2B, AP-HP, Paris, France 2 INSERM U974, UPMC Sorbonne Universités, Paris, France.

Cancer can occur in patients with inflammatory myopathies. This association is mainly observed in dermatomyositis, and myositis-specific antibodies have allowed us to delineate patients at an increased risk. Malignancy is also reported in patients with necrotizing autoimmune myopathies, but the risk remains elusive. Anti-signal recognition particle or anti-HMGCR antibodies have been specifically associated with necrotizing autoimmune myopathies. We aimed at screening the incidence of cancer in necrotizing autoimmune myopathies. A group of patients (n = 115) with necrotizing autoimmune myopathies with or without myositis-specific antibodies was analysed. Malignancy occurred more frequently in seronegative necrotizing autoimmune myopathies patients and in HMGCR-positive patients compared to anti-signal recognition particle positive patients. Synchronous malignancy was diagnosed in 21.4% and 11.5% of cases, respectively, and incidence of cancer was higher compared to the general population in both groups. No specific type of cancer was predominant. Patients suffering from a synchronous cancer had a decreased median survival time. Cancer screening is necessary in seronegative necrotizing autoimmune myopathies and in HMGCR-positive patients but not in anti-signal recognition particle-positive patients.
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http://dx.doi.org/10.1093/brain/aww054DOI Listing
August 2016

Efficacy of Rituximab in Refractory Inflammatory Myopathies Associated with Anti- Synthetase Auto-Antibodies: An Open-Label, Phase II Trial.

PLoS One 2015 5;10(11):e0133702. Epub 2015 Nov 5.

Département de Médecine Interne et Immunologie Clinique, Centre de Référence des Pathologies Neuromusculaires Paris Est, UPMC, APHP, INSERM, UMR 974, DHU i2B, Hôpital Pitié-Salpêtrière, Paris, France.

Objective: Anti-synthetase syndrome (anti-SS) is frequently associated with myositis and interstitial lung disease (ILD). We evaluated prospectively, in a multicenter, open-label, phase II study, the efficacy of rituximab on muscle and lung outcomes.

Methods: Patients were enrolled if they were refractory to conventional treatments (prednisone and at least 2 immunosuppressants). They received 1 g of rituximab at D0, D15, and M6. The primary endpoint was muscular improvement based on manual muscular testing (MMT10, Kendall score in 10 muscles) at M12. Secondary endpoints were normalization of creatine kinase (CK) level, ILD improvement based on forced vital capacity and/or diffuse capacity for carbon monoxide, and number and/or doses of associated immunosuppressants.

Results: Twelve patients were enrolled, and 10 completed the study. Only 2 patients presented an improvement of at least 4 points on at least two muscle groups (primary end-point). Overall, seven patients had an increase of at least 4 points on MMT10. CK level decreased from 399 IU/L (range, 48-11,718) to 74.5 IU/L (range, 40-47,857). Corticosteroid doses decreased from 52.5 mg/d (range, 10-70) to 9 mg/d (range, 7-65) and six patients had a decrease in the burden of their associated immunosuppressants. At baseline, all 10 patients presented with ILD. At M12, improvement of ILD was observed in 5 out of the 10 patients, stabilization in 4, and worsening in 1.

Conclusions: This pilot study of rituximab treatment in patients with refractory anti-SS provided data on evolution of muscular and pulmonary parameters. Rituximab should now be evaluated in a larger, controlled study for this homogenous group of patients.

Trial Registration: Clinicaltrials.gov NCT00774462.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0133702PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4634756PMC
June 2016

Oral-tolerization Prevents Immune Responses and Improves Transgene Persistence Following Gene Transfer Mediated by Adeno-associated Viral Vector.

Mol Ther 2016 Feb 12;24(1):87-95. Epub 2015 Aug 12.

Inserm, U905, Rouen, France.

Gene therapy represents a feasible strategy to treat inherited monogenic diseases and intramuscular (i.m.) injection of recombinant adeno-associated viral (AAV) vector is now recognized as a convenient and safe method of gene transfer. However, this approach is hampered by immune responses directed against the vector and against the transgenic protein. We used here to reproduce this situation a mouse model where robust immune responses are induced following injection of an AAV vector coding for an immunogenic transgenic protein. We show that prophylactic oral administration of the immunogenic protein before AAV-mediated gene transfer completely prevented antibody formation and cytotoxic CD8(+) T-cell response. Consistently, prophylactic oral-tolerization considerably improved long-term transgene persistence and expression. Mechanistically, inhibition of the cytotoxic immune response involved abortive proliferation of antigen-specific cytotoxic CD8(+) T cells, upregulation of the PD-1 immunoregulatory molecule, downregulation of the Bcl-2 antiapoptotic factor, and their deletion in the context of AAV-mediated gene transfer. Hence, gene therapy may represent an ideal situation where oral-tolerization can be adopted before or at the same time as vector injection to efficiently prevent deleterious immune responses directed against the transgenic protein.
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http://dx.doi.org/10.1038/mt.2015.146DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4754539PMC
February 2016

Infliximab improves endothelial dysfunction in a mouse model of antiphospholipid syndrome: Role of reduced oxidative stress.

Vascul Pharmacol 2015 Aug 11;71:93-101. Epub 2015 Apr 11.

Rouen University Hospital, Department of Internal Medicine, Rouen France; University of Rouen, Institute for Research and Innovation in Biomedicine, Rouen, France.

Antiphospholipid syndrome (APS), induces endothelial dysfunction, oxidative stress and systemic inflammation that may be mediated by TNFα. Thus, we investigated the possible protective effect of the anti-TNFα antibody infliximab (5μg/g) on endothelial function in a mouse APS model (induced by injection of purified human anti-β2GP1-IgG). Seven days after anti-β2GPI-IgG injection, we observed an increase in plasma sVCAM-1 and sE-selectin levels and in aortic mRNA expression of VCAM-1 and E-selectin. This was associated with a decreased endothelium-dependent relaxation of isolated mesenteric arteries to acetylcholine, together with decreased mesenteric eNOS mRNA expression and increased eNOS uncoupling, accompanied by increased iNOS and gp91phox mRNA and increased left ventricular GSH/GSSH ratio. Infliximab significantly improved the NO-mediated relaxing responses to acetylcholine, and induced a decrease in iNOS and gp91phox mRNA expression. The õpro-adhesive and pro-coagulant phenotypes induced by the anti-β2GP1-IgG were also reversed. This study provides the first evidence that TNFα antagonism improves endothelial dysfunction in APS and suggests that endothelial dysfunction is mediated by TNFα and oxidative stress. Therefore, infliximab may be of special relevance in clinical practice.
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http://dx.doi.org/10.1016/j.vph.2015.03.014DOI Listing
August 2015

Chromosomal instability but lack of transformation in human myoblast preparations.

Cell Transplant 2014 ;23(12):1475-87

Inserm, U905, Rouen, France.

Genetic alterations have recently been described as emerging during the culture of embryonic stem cells or induced pluripotent stem cells, raising concerns about their safety in future clinical use. Myoblasts are adult stem cells with important therapeutic potential that have been used in clinical trials for almost 20 years, but their genome integrity has not yet been established. Here we produced 10 human myoblast preparations and investigated their genomic stability. At the third passage, half of the preparations had a normal karyotype and half showed one to four alterations/30 metaphases. Chromosome 2 trisomy was found in 1-2/30 metaphases and/or 2/100 nuclei by FISH in 3/10 samples, and there was no other recurrent anomaly. When prolonging cultures, these erratic abnormalities were never associated with a growth advantage. Cellular senescence was manifested in all samples by growth arrest before passage 15. Expression of TERT was always negative. Molecular analysis of individual p53 transcripts did not reveal tumorigenic mutations. CGH array (10 samples) and exome sequencing (one sample) failed to detect copy number variations or accumulation of mutations, respectively. Myoblasts did not grow either in soft agar or in vivo after injection in immunodeficient mice. Hence, occasional genomic abnormalities may occur during myoblast culture but are not associated with risk of transformation.
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http://dx.doi.org/10.3727/096368913X670192DOI Listing
September 2015

Role of Toll-like receptors 2 and 4 in mediating endothelial dysfunction and arterial remodeling in primary arterial antiphospholipid syndrome.

Arthritis Rheumatol 2014 Nov;66(11):3210-20

Rouen University Hospital, INSERM U1096, University of Rouen, and Centre d'Investigation Clinique, INSERM 1404, Rouen, France.

Objective: To assess the role of Toll-like receptors (TLRs) in antiphospholipid antibody (aPL)-mediated vascular abnormalities in patients with primary arterial antiphospholipid syndrome (APS).

Methods: Forty-eight subjects participated in the study. Arterial function and structure and TLR pathway activation were determined in patients with primary arterial APS and matched controls. The pathogenic effects of aPL isolated from patients were assessed in wild-type (WT) and TLR-knockout mice.

Results: APS patients had endothelial dysfunction, arterial stiffening, and hypertrophy, as evidenced by decreased brachial artery endothelium-dependent flow-mediated dilation (FMD) and increased aortic pulse wave velocity and carotid intima-media thickness (IMT), as compared with controls. Plasma samples from APS patients revealed decreased nitric oxide (NO) availability and a pro-oxidative, proinflammatory, and prothrombotic state illustrated by a decrease in nitrite and an increase in lipid peroxidation, tumor necrosis factor α levels, and tissue factor (TF) levels. Furthermore, TLR pathway activation was found in APS patients with increased TLR-2 and TLR-4 messenger RNA expression and increased protein levels of the activated TLR transduction protein interleukin-1 receptor-associated kinase 1 in peripheral blood mononuclear cells. Moreover, agonist-stimulated cell-surface expression of TLR-2 and TLR-4 in circulating monocytes was higher in APS patients than in controls. These changes were positively associated with IMT and negatively associated with FMD. Finally, aPL injection decreased mesenteric endothelium-dependent relaxation and increased TF expression in WT mice but not in TLR-2- or TLR-4-knockout mice.

Conclusion: This translational study supports the notion that TLR-2 and TLR-4 play a role in mediating vascular abnormalities in patients with primary arterial APS. TLRs thus constitute a promising pharmacologic target for preventing cardiovascular complications in APS.
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http://dx.doi.org/10.1002/art.38785DOI Listing
November 2014

Anti-HMGCR autoantibodies in European patients with autoimmune necrotizing myopathies: inconstant exposure to statin.

Medicine (Baltimore) 2014 May;93(3):150-157

From the AP-HP, Hôpital Pitié-Salpêtrière, Department of Internal Medicine 1 and Inflammation-Immunopathology-Biotherapy Department (I2B), East Paris Neuromuscular Diseases Reference Center, Inserm U974, Université Pierre et Marie Curie, Paris 6, Paris (YA, AR, SH, O. Benveniste); Inserm, U905, Immunology Department, Normandie Univ, IRIB and Rouen University Hospital (LD, FJ, JM, O. Boyer); AP-HP, Hôpital Pitié-Salpêtrière, Department of Immunochemistry, Université Pierre et Marie Curie, Paris 6, Paris (JLC, LM); AP-HP, Hôpital Pitié-Salpêtrière, Institute of Myology, Unite de Morphologie Musculaire, CNRS-UMR7215, Paris (NBR); AP-HP, Hôpital Pitié-Salpêtrière, Department of Neuropathology, Université Pierre et Marie Curie, Paris 6, Paris (TM, OD); AP-HP, Hôpital Pitié-Salpêtrière, Department of Neurology, East Paris Neuromuscular Diseases Reference Center, Université Pierre et Marie Curie, Paris 6, Paris (AB, PL, TS, BE); AP-HP, Hôpital Cochin Centre de Référence Maladies Auto-Immunes et Systémiques Rares, Service de Médecine Interne Pôle Médecine, Université René Descartes Paris V, Paris (NCC, BT); APHM, Hôpital la Timone, Centre de Référence des Maladies Neuromusculaires, Marseille (ECS); Clermont-Ferrand University Hospital, Department of Rheumatology, Clermont-Ferrand (AT); AP-HP, Hôpital Necker, Department of Paediatric Rheumatology, Paris (BBM); AP-HP, Hôpital Bicêtre, Department of Paediatric Rheumatology, Kremlin-Bicêtre, Paris (IKP); CHU Strasbourg, Department of Rheumatology, Strasbourg (JS); Hôpital Pitié-Salpêtrière, Institute of Myology, Paris (LS); AP-HP, Hôpital Jean Verdier, Department of Internal Medicine, La Seine-Saint-Denis (OF); AP-HP, Hôpital Avicenne, Department of Internal Medicine, Bobigny (CL); CHRU Tours, Department of Internal Medicine, Tours (ED); Fondation A. de Rothschild, Department of Neurology, Paris (RDP); AP-HP, Hôpital Bichat, Department of Internal Medicine, Paris (AD); CHU Rennes, Department of Neurology, Rennes (DM); Centre Hospitalier de la Region d'Annecy, Department of Internal Medicine, Annecy (CM); Hôpital Pierre Oudot, Department of Internal Medicine, Bourgouin (MR); Hôpital du Haut Levêque, Department of Neurology, Bordeaux (XF); CHU Rennes, Department of Internal Medicine, Rennes (SB, BG); CHU Fort de France, Department of Neurology, Fort de France (RM); AP-HP, Hôpital Pitié-Salpêtrière, Departement Hospitalo-Universitaire I2B, UPMC Univ Paris 06, UMR 7211, INSERM, UMRS 959, Department of Internal Medicine 2, Paris (PC, LA); France.

Necrotizing autoimmune myopathy (NAM) is a group of acquired myopathies characterized by prominent myofiber necrosis with little or no muscle inflammation. Recently, researchers identified autoantibodies (aAb) against 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) in patients with NAM, especially in statin-exposed patients. Here we report what is to our knowledge the first European cohort of patients with NAM.The serum of 206 patients with suspicion of NAM was tested for detection of anti-HMGCR aAb using an addressable laser bead immunoassay. Forty-five patients were found to be anti-HMGCR positive. Their mean age was 48.9 ± 21.9 years and the group was predominantly female (73.3%). Statin exposure was recorded in 44.4% of patients. Almost all patients had a muscular deficit (97.7%), frequently severe (Medical Research Council [MRC] 5 ≤3 in 75.5%). Subacute onset (<6 mo) was noted for most of them (64.4%). Nevertheless, 3 patients (6.6%) had a slowly progressive course over more than 10 years. Except for weight loss (20%), no extramuscular sign was observed. The mean CK level was high (6941 ± 8802 IU/L) and correlated with muscle strength evaluated by manual muscle testing (r = -0.37, p = 0.03). Similarly, anti-HMGCR aAb titers were correlated with muscular strength (r = -0.31; p = 0.03) and CK level (r = 0.45; p = 0.01). Mean duration of treatment was 34.1 ± 40.8 months, and by the end of the study no patient had been able to stop treatment.This study confirms the observation and description of anti-HMGCR aAb associated with NAM. The majority of patients were statin naive and needed prolonged treatments. Some patients had a dystrophic-like presentation. Anti-HMGR aAb titers correlated with CK levels and muscle strength, suggesting their pathogenic role.
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http://dx.doi.org/10.1097/MD.0000000000000028DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4632910PMC
May 2014

Serum levels of anti-SRP54 antibodies reflect disease activity of necrotizing myopathy in a child treated effectively with combinatorial methylprednisolone pulses and plasma exchanges followed by intravenous cyclophosphamide.

Mod Rheumatol 2014 May 7;24(3):529-31. Epub 2014 Feb 7.

Department of Pediatrics, Yokohama City University , Kanazawaku, Yokohama , Japan.

We describe the effectiveness of combinatorial therapy with plasma exchanges and methylprednisolone pulses followed by intravenous cyclophosphamide in a young girl with anti-signal recognition particle 54 (SRP54) antibody-associated myopathy. We also use a newly described quantitative assay to demonstrate the close association between the titers of anti-SRP54 antibodies and disease activity. This is the first report of a pediatric patient indicating that the serum levels of anti-SRP54 antibodies are also beneficial for monitoring the disease activity of progressive necrotizing myopathy.
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http://dx.doi.org/10.3109/14397595.2013.852852DOI Listing
May 2014

Exploring necrotizing autoimmune myopathies with a novel immunoassay for anti-3-hydroxy-3-methyl-glutaryl-CoA reductase autoantibodies.

Arthritis Res Ther 2014 Feb 3;16(1):R39. Epub 2014 Feb 3.

Introduction: Necrotizing autoimmune myopathies (NAM) have recently been defined as a distinct group of severe acquired myopathies, characterized by prominent myofiber necrosis without significant muscle inflammation. Because of the lack of appropriate biomarkers, these diseases have been long misdiagnosed as atypical forms of myositis. NAM may be associated to autoantibodies directed against signal recognition particle (SRP) or 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGCR). The objective of this work was to quantify anti-HMGCR autoantibodies in patients with suspicion of NAM through the development of a new addressable laser bead immunoassay (ALBIA).

Methods: Recombinant HMGCR C-domain was bound to fluorescent beads. After incubation with serum, autoantibodies were revealed using class- or subclass-specific anti-human immunoglobulin G (IgG) antibodies. Anti-HMGCR levels were assayed in 150 patients with suspicion of NAM, 142 controls with different inflammatory/autoimmune diseases and 100 healthy donors. Inhibition with free recombinant HMGCR and immunoprecipitation experiments confirmed test specificity. Reproducibility and repeatability were determined from sera with various levels of anti-HMGCR autoantibodies. A multiplex assay (ALBIA-NAM) was also developed to permit the simultaneous quantification of anti-HMGCR and anti-signal recognition particle autoantibodies.

Results: No controls scored positive. Of 150 patients with suspicion of NAM, 24% were positive for anti-HMGCR autoantibodies with levels ranging from 24 to 2,656 AU/mL. Anti-HMGCR positivity could be associated to a cytoplasmic pattern in immunofluorescence assay on HEp-2 cells. Anti-HMGCR-positive patients had high creatine kinase (CK) levels (mean 6,630 IU/L) and only 40% of them had been exposed to statins. Multiplex ALBIA-NAM was equally as effective as monoplex anti-HMGCR and anti-SRP ALBIA.

Conclusions: Both monoplex ALBIA-HMGCR and multiplex ALBIA-NAM reliably detect and quantify anti-HMGCR autoantibodies. A positive result allows ascribing patients with a necrotizing myopathy to an autoimmune form. Anti-HMGCR autoantibodies may be found in patients who have not taken statins.
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http://dx.doi.org/10.1186/ar4468DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3979083PMC
February 2014

Restoration of anal sphincter function after myoblast cell therapy in incontinent rats.

Cell Transplant 2015 18;24(2):277-86. Epub 2013 Oct 18.

Inserm, U905, Rouen, France.

Fecal incontinence (FI) remains a socially isolating condition with profound impact on quality of life for which autologous myoblast cell therapy represents an attractive treatment option. We developed an animal model of FI and investigated the possibility of improving sphincter function by intrasphincteric injection of syngeneic myoblasts. Several types of anal cryoinjuries were evaluated on anesthetized Fischer rats receiving analgesics. The minimal lesion yielding sustainable anal sphincter deficiency was a 90° cryoinjury of the sphincter, repeated after a 24-h interval. Anal sphincter pressure was evaluated longitudinally by anorectal manometry under local electrostimulation. Myoblasts were prepared using a protocol mimicking a clinical-grade process and further transduced with a GFP-encoding lentiviral vector before intrasphincteric injection. Experimental groups were uninjured controls, cryoinjured + PBS, and cryoinjured + myoblasts (different doses or injection site). Myoblast injection was well tolerated. Transferred myoblasts expressing GFP integrated into the sphincter and differentiated in situ into dystrophin-positive mature myofibers. Posttreatment sphincter pressures increased over time. At day 60, pressures in the treated group were significantly higher than those of PBS-injected controls and not significantly different from those of normal rats. Longitudinal follow-up showed stability of the therapeutic effect on sphincter function over a period of 6 months. Intrasphincteric myoblast injections at the lesion borders were equally as effective as intralesion administration, but an injection opposite to the lesion was not. These results provide proof of principle for myoblast cell therapy to treat FI in a rat model. This strategy is currently being evaluated in humans in a randomized double-blind placebo-controlled clinical trial.
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http://dx.doi.org/10.3727/096368913X674053DOI Listing
November 2015

Immune-mediated myopathy related to anti 3-hydroxy-3-methylglutaryl-coenzyme A reductase antibodies as an emerging cause of necrotizing myopathy induced by statins.

Joint Bone Spine 2014 Jan 13;81(1):79-82. Epub 2013 Aug 13.

CHU Clermont-Ferrand, Department of Rheumatology, Hôpital Gabriel-Montpied, 63003 Clermont-Ferrand, France. Electronic address:

Immune-mediated necrotizing myopathy (IMNM) associated with statin use and anti 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) antibody is a new and emerging entity that supports a link between statin use and IMNM and raises the questions of distinct clinical phenotypes and treatment strategy. We describe the clinical and histopathological characteristics of a patient and discuss the spectrum of IMNM and statin-induced myopathies. A 65-year-old man was suffering from proximal muscle weakness and elevated CK levels, following exposure to statin therapy. The symptoms worsened despite discontinuation of the drug. At that point, no myositis-specific or -associated antibodies were detected. Malignancy screening did not reveal abnormalities. Muscle biopsy demonstrated a predominantly necrotizing myopathy with minimal lymphocytic infiltrates, MHC class I expression in necrotic muscle fibers, and complement deposition on scattered non-necrotic muscle fibers. Muscle protein analysis by western blot was normal. The patient did not improve with steroid and methotrexate and required monthly intravenous immunoglobulin (IVIG) therapy. Muscle strength gradually improved, CK levels normalized and IVIG were stopped 1 year later. Screening for anti-HMGCR antibodies, not available at the time of presentation, was highly positive. Identification of anti-HMGCR antibodies in statin-exposed patients with myopathy appears to be helpful both for differential diagnosis and for treatment strategy. In patients who did not improve after discontinuation of the statin treatment, a muscle biopsy should be performed as well as screening for anti-HMGCR antibodies. Patients with this disorder require aggressive immunosuppressive treatment.
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http://dx.doi.org/10.1016/j.jbspin.2013.06.008DOI Listing
January 2014

Overexpression of MHC class I in muscle of lymphocyte-deficient mice causes a severe myopathy with induction of the unfolded protein response.

Am J Pathol 2013 Sep 12;183(3):893-904. Epub 2013 Jul 12.

National Institute of Health and Medical Research (INSERM), U905, Rouen, France.

Muscle fibers do not normally express major histocompatibility complex class I (MHC-I) molecules, and their reexpression is a hallmark of inflammatory myopathies. It has been shown in mice that overexpression of MHC-I induces a poorly inflammatory myositis accompanied by the unfolded protein response (UPR), but it is unclear whether it is attributable to T-cell-mediated MHC-I-dependent immune responses or to MHC-I forced expression per se. Indeed, besides presenting antigenic peptides to CD8(+) T cells, MHC-I may also possibly exert nonimmunologic, yet poorly understood pathogenic effects. Thus, we investigated the pathogenicity of MHC-I expression in muscle independently of its immune functions. HT transgenic mice that conditionally overexpress H-2K(b) in muscle were bred to an immunodeficient Rag2(-/-) background. The muscle proteome was analyzed by label-free high-resolution protein quantitation and Western blot. Despite the absence of adaptive immunity, HT Rag2(-/-) mice developed a very severe myopathy associated with the cytoplasmic accumulation of H-2K(b) molecules. The UPR was manifest by up-regulation of characteristic proteins. In humans, we found that HLA class I molecules not only were expressed at the sarcolemma but also could accumulate intracellularly in some patients with inclusion body myositis. Accordingly, the UPR was triggered as a function of the degree of HLA accumulation in myofibers. Hence, reexpression of MHC-I in normally negative myofibers exerts pathogenic effects independently of its immune function.
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http://dx.doi.org/10.1016/j.ajpath.2013.06.003DOI Listing
September 2013

Potential of olfactory ensheathing cells from different sources for spinal cord repair.

PLoS One 2013 24;8(4):e62860. Epub 2013 Apr 24.

UPRES EA 3830, Institute for Research and Innovation in Biomedicine, University of Rouen, Rouen, Normandy, France.

Spinal cord injury (SCI) induces a permanent disability in patients. To this day no curative treatment can be proposed to restore lost functions. Therefore, extensive experimental studies have been conducted to induce recovery after SCI. One of the most promising therapies is based on the use of olfactory ensheathing cells (OECs). OECs can be obtained from either the olfactory bulbs (OB-OECs) or from olfactory mucosa (OM-OECs), involving a less invasive approach for autotransplantation. However the vast majority of experimental transplantations have been focusing on OB-OECs although the OM represents a more accessible source of OECs. Importantly, the ability of OM-OECs in comparison to OB-OECs to induce spinal cord recovery in the same lesion paradigm has never been described. We here present data using a multiparametric approach, based on electrophysiological, behavioral, histological and magnetic resonance imaging experiments on the repair potential of OB-OECs and OM-OECs from either primary or purified cultures after a severe model of SCI. Our data demonstrate that transplantation of OECs obtained from OB or OM induces electrophysiological and functional recovery, reduces astrocyte reactivity and glial scar formation and improves axonal regrowth. We also show that the purification step is essential for OM-OECs while not required for OB-OECs. Altogether, our study strongly indicates that transplantation of OECs from OM represents the best benefit/risk ratio according to the safety of access of OM and the results induced by transplantations of OM-OECs. Indeed, purified OM-OECs in addition to induce recovery can integrate and survive up to 60 days into the spinal cord. Therefore, our results provide strong support for these cells as a viable therapy for SCI.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0062860PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3634744PMC
December 2013

Alternative splicing of the N-terminal cytosolic and transmembrane domains of P2X7 controls gating of the ion channel by ADP-ribosylation.

PLoS One 2012 27;7(7):e41269. Epub 2012 Jul 27.

Institute of Immunology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

P2X7 is a homotrimeric ion channel with two transmembrane domains and a large extracellular ATP-binding domain. It plays a key role in the response of immune cells to danger signals released from cells at sites of inflammation. Gating of murine P2X7 can be induced by the soluble ligand ATP, as well as by NAD(+)-dependent ADP-ribosylation of arginine 125, a posttranslational protein modification catalyzed by the toxin-related ecto-enzymes ART2.1 and ART2.2. R125 is located at the edge of the ligand-binding crevice. Recently, an alternative splice variant of P2X7, designated P2X7(k), was discovered that differs from the previously described variant P2X7(a) in the N-terminal 42 amino acid residues composing the first cytosolic domain and most of the Tm1 domain. Here we compare the two splice variants of murine P2X7 with respect to their sensitivities to gating by ADP-ribosylation in transfected HEK cells. Our results show that the P2X7(k) variant is sensitive to activation by ADP-ribosylation whereas the P2X7(a) variant is insensitive, despite higher cell surface expression levels. Interestingly, a single point mutation (R276K) renders the P2X7(a) variant sensitive to activation by ADP-ribosylation. Residue 276 is located at the interface of neighboring subunits approximately halfway between the ADP-ribosylation site and the transmembrane domains. Moreover, we show that naive and regulatory T cells preferentially express the more sensitive P2X7(k) variant, while macrophages preferentially express the P2X7(a) variant. Our results indicate that differential splicing of alternative exons encoding the N-terminal cytosolic and transmembrane domains of P2X7 control the sensitivity of different immune cells to extracellular NAD(+) and ATP.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0041269PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3407210PMC
March 2013

Improved Immunological Tolerance Following Combination Therapy with CTLA-4/Ig and AAV-Mediated PD-L1/2 Muscle Gene Transfer.

Front Microbiol 2011 29;2:199. Epub 2011 Sep 29.

INSERM U905, Faculty of Medicine and Pharmacy Rouen, France.

Initially thought as being non-immunogenic, recombinant AAVs have emerged as efficient vector candidates for treating monogenic diseases. It is now clear however that they induce potent immune responses against transgene products which can lead to destruction of transduced cells. Therefore, developing strategies to circumvent these immune responses and facilitate long-term expression of transgenic therapeutic proteins is a main challenge in gene therapy. We evaluated herein a strategy to inhibit the undesirable immune activation that follows muscle gene transfer by administration of CTLA-4/Ig to block the costimulatory signals required early during immune priming and by using gene transfer of PD-1 ligands to inhibit T cell functions at the tissue sites. We provide the proof of principle that this combination immunoregulatory therapy targeting two non-redundant checkpoints of the immune response, i.e., priming and effector functions, can improve persistence of transduced cells in experimental settings where cytotoxic T cells escape initial blockade. Therefore, CTLA-4/Ig plus PD-L1/2 combination therapy represents a candidate approach to circumvent the bottleneck of immune responses directed toward transgene products.
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http://dx.doi.org/10.3389/fmicb.2011.00199DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3202221PMC
November 2011

Correlation of anti-signal recognition particle autoantibody levels with creatine kinase activity in patients with necrotizing myopathy.

Arthritis Rheum 2011 Jul;63(7):1961-71

Université Pierre et Marie Curie, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France.

Objective: Anti-signal recognition particle (anti-SRP) autoantibodies are associated with severe acquired necrotizing myopathies. The role of these autoantibodies remains elusive, and the evolution of anti-SRP levels over time is unknown. In this study, we developed an addressable laser bead immunoassay (ALBIA) technique to investigate a correlation between anti-SRP levels, serum creatine kinase (CK) levels, and muscle strength in patients with necrotizing myopathy.

Methods: The diagnostic value of the ALBIA assay was determined by comparing serum levels of anti-SRP autoantibodies in 31 anti-SRP immunodot-positive patients to those in 190 healthy blood donors and 199 control patients with different inflammatory/autoimmune conditions or polyclonal hypergammaglobulinemia. Among the 31 anti-SRP-positive patients, serum samples from 8 patients were monitored over time for levels of anti-SRP autoantibodies and levels of CK (determined at least 3 times, consecutively, over a mean followup period of 783 days). The relationship between levels of anti-SRP autoantibodies and levels of CK was tested using a linear mixed model.

Results: The assay yielded positive results for anti-SRP in all anti-SRP immunodot-positive serum samples tested, while all control sera tested negative. The 8 anti-SRP-positive patients who were followed up longitudinally were found to have normalized CK levels and improved muscle strength. There was a striking correlation between the degree of myolysis, as measured by CK levels, in patients receiving therapy and the anti-SRP54 autoantibody levels in these same patients (P = 0.002).

Conclusion: Anti-SRP-positive myositis appears to be one of the few autoimmune diseases in which specific autoantibody levels are correlated with surrogate disease activity markers. These results reveal the usefulness of monitoring anti-SRP autoantibody levels in patients receiving therapy, and may also suggest a possible pathogenic role for anti-SRP autoantibodies in the necrotizing myopathies.
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http://dx.doi.org/10.1002/art.30344DOI Listing
July 2011

Transplantation of olfactory ensheathing cells promotes axonal regeneration and functional recovery of peripheral nerve lesion in rats.

Muscle Nerve 2011 Apr 8;43(4):543-51. Epub 2011 Feb 8.

Experimental Surgery Laboratory, Groupe de Recherche sur le Handicap Ventilatoire, UPRES EA 3830, European Institute for Peptide Research (IFRMP 23), Institute for Medical Research, Faculty of Medicine and Pharmacy, University of Rouen, 22 Boulevard Gambetta, 76183 Rouen, France.

Introduction: Olfactory ensheathing cells (OECs) hold promise for cell therapy because they may promote regeneration of the central nervous system. However, OECs have been less studied after peripheral nerve injury (PNI). The purpose of this investigation was to determine the effect of OEC transplantation on a severe sciatic nerve (SN) lesion.

Methods: OECs were injected in rats after section and 2-cm resection of the SN.

Results: Three months after therapy, muscle strength and morphometric studies showed complete restoration of the contractile properties of the gastrocnemius and complete repair of the SN. Immunohistochemistry and RT-PCR studies indicated an increase in the presence of neurotrophic factors. Interestingly, tracking of green fluorescent protein (GFP)-positive OECs showed that no OECs were present in the SN.

Discussion: Our results demonstrate that, after severe PNI, OECs have remarkable potential for nerve regeneration by creating a favorable microenvironment.
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http://dx.doi.org/10.1002/mus.21907DOI Listing
April 2011

Role of toll-like receptor 4 in the inflammation reaction surrounding silicone prosthesis.

Acta Biomater 2011 May 25;7(5):2047-52. Epub 2011 Jan 25.

Department of Plastic and Reconstructive Surgery, Rouen University Hospital, Rouen, France.

The inflammation which occurs around the silicone prosthesis is a complex process that can provoke the failure of the device and compromise the health of the implanted patient. Toll-like receptors (TLRs), which are transmembrane proteins, are now known to act in the innate immune response and in endogenous inflammation. The aim of our study was to assess the role of TLR4 in the foreign body reaction to a silicone shell prosthesis. Disks of shell silicone prosthesis were implanted in the subcutaneous tissue of C57BL6-TLR4-/- and C57BL6-WT mice. At day 14, inflammatory cell infiltrate and vessel sections around the prosthesis were less numerous in TLR4-/- than in WT mice. A histomorphometric analysis showed that the capsule around the implant was 1.96-fold less thick in depleted TLR4 than in wild-type mice. In addition, vascular endothelial growth factor and transforming growth factor 1 were underexpressed in the surrounding tissue of the prosthesis in TLR4-/- mice. Our study suggests, from this foreign body response model against silicone in mice, that TLR4 plays a key role in the reaction process around silicone implants.
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http://dx.doi.org/10.1016/j.actbio.2011.01.030DOI Listing
May 2011

Comparative gene expression profiling of olfactory ensheathing cells from olfactory bulb and olfactory mucosa.

Glia 2010 Oct;58(13):1570-80

Experimental Surgery Laboratory, European Institute for Peptide Research (IFRMP 23), University of Rouen, 22 boulevard Gambetta, 76183 Rouen, France.

Olfactory ensheathing cells (OEC) have the ability to promote regeneration in the nervous system. Hence, they hold promise for cell therapy. Most of the experimental studies have investigated the role of OECs taken from olfactory bulb (OB). However, for a clinical human application, olfactory mucosa (OM) seems to be the only acceptable source for OECs. Many studies have compared the distinct ability of OECs from OB and OM to improve functional nerve regeneration after lesion of the nervous system. Nevertheless, the two populations of OECs may differ in several points, which might affect all fate after transplantation in vivo. We report here the first study which compares gene expression profiling between these two populations of OECs. It appears that OB-OECs and OM-OECs display distinct gene expression pattern, which suggest that they may be implicated in different physiological processes. Notably, OM-OECs overexpress genes characteristic of wound healing and regulation of extra cellular matrix. In contrast, OB-OECs gene profile suggests a prominent role in nervous system development. Hence, OB-OECs and OM-OECs fundamentally differ in their gene expression pattern, which may represent a crucial point for future clinical application.
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http://dx.doi.org/10.1002/glia.21030DOI Listing
October 2010

Cutting edge: CD4-independent development of functional FoxP3+ regulatory T cells.

J Immunol 2009 Oct;183(7):4182-6

INSERM, Unité 905, Rouen, France; University of Rouen, Institut Fédératif de Recherches Multidisciplinaires sur les Peptides, Institute for Biomedical Research, F-76000 Rouen, France.

The CD4 coreceptor is mandatory for the differentiation and function of conventional MHC class II-restricted T cells, but little is known about its contribution in regulatory T cells (Tregs). We thus investigated the Treg compartment in mice lacking CD4. CD3+CD8-FoxP3+ cells were readily detected in the periphery of CD4(-/-) mice, where their percentages were even increased as compared with wild-type animals. These cells had a classical CD25+CD152+GITR+ Treg phenotype, were enriched in memory-type Tregs, and displayed a diversified TCR repertoire. Functionally, CD4(-/-) Tregs were equally as suppressive as CD4(+/+) Tregs in vitro as well as in vivo. Hence, the CD4 coreceptor is dispensable for the generation and function of FoxP3+ Tregs. Furthermore, CD3+CD8-FoxP3+ Tregs were also found to develop in the absence of both CD4 and MHC-II molecules, demonstrating that the generation of Tregs can occur independently of MHC-II recognition.
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http://dx.doi.org/10.4049/jimmunol.0901678DOI Listing
October 2009

Detection and characterization of anti-envoplakin linker autoantibodies in paraneoplastic pemphigus using specific bead-based assay.

Clin Immunol 2008 Nov 14;129(2):304-12. Epub 2008 Sep 14.

Inserm, U905, Institut Fédératif de Recherche 23, Rouen, F-76183 France.

Paraneoplastic pemphigus (PNP) is characterized by an autoantibody response directed against desmosomal antigens, desmogleins and plakin's proteins, i.e., periplakin and envoplakin. Notably, PNP antibodies were shown to recognize major epitopes located in the linker subdomain of human envoplakin and thus, may constitute a diagnostic marker of PNP. In this study, a recombinant envoplakin-linker subdomain (rENV-L) was produced and used to develop a specific bead-based assay to determine the prevalence and titers of anti-rENV-L antibodies in patients with different types of autoimmune bullous skin diseases. Sera from 33 PNP, 41 pemphigus vulgaris, 46 pemphigus foliaceus, 24 bullous pemphigoid and 74 normal subjects were analyzed by rENV-L bead-based assay: 23/33 (69.7%) PNP, 2/24 (8.3%) bullous pemphigoid and 4/74 (5.4%) healthy control sera showed IgG reactivity against rENV-L. For PNP, the sensitivity and specificity of the assay were 69.7% and 94.6%, respectively. Among the PNP sera reacting with envoplakin and periplakin by immunoblot analysis, 80.8% contained anti-rENV-L antibodies. Finally, we showed that an anti-rENV-L mAb that recognizes both envoplakin and periplakin gave the same fluorescence pattern on rat bladder sections than PNP sera. Thus, anti-rENV-L antibodies constitute a useful diagnostic marker of PNP and our bead-based assay, notably combined with other epidermal autoantigens, a useful tool to diagnose PNP.
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http://dx.doi.org/10.1016/j.clim.2008.07.021DOI Listing
November 2008

Immunogenetics of pemphigus: an update.

Autoimmunity 2006 Nov;39(7):531-9

Faculté de Médicine et de Pharmacie, INSERM U519, Université de Rouen, Rouen, France.

Pemphigus are rare but informative models of organ-specific autoimmune diseases, resulting from the interplay of environmental, genetic and stochastic factors. There are many arguments to consider that pemphigus have a genetic basis involving, as many other autoimmune diseases, several different genes with additive or synergistic effects. So far, the unique strategy used to identify the contributive loci has been direct analysis of candidate genes through conventional case-control association studies. The major histocompatibility complex in particular the class II locus was demonstrated to be associated with pemphigus with a high rate of replicability. The progresses in the understanding of pemphigus physiopathology and the development of new molecular tools offer new perspectives to unveiled the genetic basis of this group of autoimmune blistering diseases, as shown by recent studies of candidate genes expressed at different levels of the autoimmune process.
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http://dx.doi.org/10.1080/08916930600971497DOI Listing
November 2006