Laurent Magy

Centre Hospitalier Universitaire de Limoges, Limages, Limousin, France

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Publications (105)287.32 Total impact

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    ABSTRACT: Small-fiber neuropathy was induced in young adult mice by intraperitoneal injection of resiniferatoxin (RTX), a TRPV1 agonist. At day 7, RTX induced significant thermal and mechanical hypoalgesia. At day 28, mechanical and thermal nociception were restored. No nerve degeneration in skin was observed and unmyelinated nerve fiber morphology and density in sciatic nerve were unchanged. At day 7, substance P (SP) was largely depleted in dorsal root ganglia (DRG) neurons, although calcitonin gene-related peptide (CGRP) was only moderately depleted. Three weeks after, SP and CGRP expression was restored in DRG neurons. At the same time, CGRP expression remained low in intraepidermal nerve fibers (IENFs) whereas SP expression had improved. In summary, RTX induced in our model a transient neuropeptide depletion in sensory neurons without nerve degeneration. We think this model is valuable as it brings the opportunity to study functional nerve changes in the very early phase of small fiber neuropathy. Moreover, it may represent a useful tool to study the mechanisms of action of therapeutic strategies to prevent sensory neuropathy of various origins.
    Neuroscience Letters 05/2014; · 2.03 Impact Factor
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    ABSTRACT: Charcot-Marie-Tooth type 1A (CMT1A) and hereditary neuropathy with liability to pressure palsies (HNPP) are both autosomal-dominant disorders linked to peripheral myelin anomalies. CMT1A is associated with a Peripheral Myelin Protein 22 (PMP22) duplication, whereas HNPP is due to a PMP22 deletion on chromosome 17. In spite of this crucial difference, we report three observations of patients with the 1.4 megabase CMT1A duplication and atypical presentation (electrophysiological, clinical or pathological): a 10 year-old girl with tomaculous lesions on nerve biopsy; a 26 year-old woman with recurrent paresthesiae and block conduction on the electrophysiological study; a 46 year-old woman with transient recurrent nerve palsies mimicking HNPP. These observations highlight the wide spectrum of CMT1A and the overlap between CMT1A and HNPP (both linked to the PMP22 gene), and finally illustrate the complexity of the genotype-phenotype correlations in Charcot-Marie-Tooth diseases.
    Neuromuscular Disorders 04/2014; · 3.46 Impact Factor
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    ABSTRACT: The association of Charcot-Marie-Tooth (CMT) disease with renal dysfunction is uncommon but has long been recognized in several families. Recently, mutations in the INF2 gene, which encodes inverted formin-2, were identified in patients with focal segmental glomerulosclerosis and a dominant intermediate form of CMT (CMTDIE, OMIM #614455). We describe the pathologic lesions of nerve biopsies from 6 patients with INF2-related CMTDIE. There were 4 females and 2 males; ages were from 12 to 47 years; durations between neuropathy onset and biopsy were from 2 to 37 years. Clinical phenotypes were similar to those seen in other forms of CMT disease, but there was always an associated proteinuria (and later renal failure). Motor median nerve conduction velocities were in the range of intermediate CMT disease. Pathologic lesions suggested chronic demyelination and remyelination associated with progressive axonal loss. By electron microscopy, we observed unusual whorl-like proliferations of flattened Schwann cell cytoplasm and anomalies of unmyelinating Schwann cell cytoplasm with supernumerary elongated extensions similar to those described in CMT4C. We also observed abnormal accumulation of β-actin in the cytoplasm of Schwann cells. Our results suggest that these lesions reflect a global disorder of the actin cytoskeleton in Schwann cells and that CMTDIE is the first peripheral nerve disorder associated with a Schwann cell actinopathy.
    Journal of neuropathology and experimental neurology. 01/2014;
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    ABSTRACT: Charcot-Marie-Tooth type 1A (CMT1A) and hereditary neuropathy with liability to pressure palsies (HNPP) are both autosomal-dominant disorders linked to peripheral myelin anomalies. CMT1A is associated with a Peripheral Myelin Protein 22 (PMP22) duplication, whereas HNPP is due to a PMP22 deletion on chromosome 17. In spite of this crucial difference, we report three observations of patients with the 1.4 megabase CMT1A duplication and atypical presentation (electrophysiological, clinical or pathological): a10 year-old girl with tomaculous lesions on nerve biopsy; a 26 year-old woman with recurrent paresthesiae, bilateral calves hypertrophy and block conduction on the electrophysiological study; a 46 year-old woman with transient recurrent nerve palsies mimicking HNPP. These observations highlight the wide spectrum of CMT1A and the overlap between CMT1A and HNPP (both linked to the PMP22 gene), and finally illustrate the complexity of the genotype-phenotype correlations in Charcot-Marie-Tooth diseases.
    Neuromuscular Disorders 01/2014; · 3.46 Impact Factor
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    ABSTRACT: Chediak-Higashi syndrome is a rare autosomal recessive disease characterized by partial oculocutaneous albinism, recurrent pyogenic infections and the presence of giant granules in many cells such as leucocytes (hallmark of the disease). Neurological symptoms are rare. We describe two sisters who presented the same phenotype of slowly progressive motor neuronopathy (with Babinski sign in one patient); biopsy of the sural nerve showed an abnormal endoneurial accumulation of lipofuscin granules. We discuss these two observations and compare them with the few case reports of neuropathy in Chediak-Higashi syndrome.
    Journal of the Neurological Sciences. 01/2014;
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    ABSTRACT: The diagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP) is based on a set of clinical and neurophysiological parameters. However, in clinical practice, CIDP remains difficult to diagnose in atypical cases. In the present study, 32 experts from 22 centers (the French CIDP study group) were asked individually to score four typical, and seven atypical, CIDP observations (TOs and AOs, respectively) reported by other physicians, according to the Delphi method. The diagnoses of CIDP were confirmed by the group in 96.9 % of the TO and 60.1 % of the AO (p < 0.0001). There was a positive correlation between the consensus of CIDP diagnosis and the demyelinating features (r = 0.82, p < 0.004). The European CIDP classification was used in 28.3 % of the TOs and 18.2 % of the AOs (p < 0.002). The French CIDP study group diagnostic strategy was used in 90 % of the TOs and 61 % of the AOs (p < 0.0001). In 3 % of the TOs and 21.6 % of the AOs, the experts had difficulty determining a final diagnosis due to a lack of information. This study shows that a set of criteria and a diagnostic strategy are not sufficient to reach a consensus for the diagnosis of atypical CIDP in clinical practice.
    Journal of Neurology 12/2013; 260(12):3015. · 3.58 Impact Factor
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    ABSTRACT: The diagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP) is based on a set of clinical and neurophysiological parameters. However, in clinical practice, CIDP remains difficult to diagnose in atypical cases. In the present study, 32 experts from 22 centers (the French CIDP study group) were asked individually to score four typical, and seven atypical, CIDP observations (TOs and AOs, respectively) reported by other physicians, according to the Delphi method. The diagnoses of CIDP were confirmed by the group in 96.9 % of the TO and 60.1 % of the AO (p < 0.0001). There was a positive correlation between the consensus of CIDP diagnosis and the demyelinating features (r = 0.82, p < 0.004). The European CIDP classification was used in 28.3 % of the TOs and 18.2 % of the AOs (p < 0.002). The French CIDP study group diagnostic strategy was used in 90 % of the TOs and 61 % of the AOs (p < 0.0001). In 3 % of the TOs and 21.6 % of the AOs, the experts had difficulty determining a final diagnosis due to a lack of information. This study shows that a set of criteria and a diagnostic strategy are not sufficient to reach a consensus for the diagnosis of atypical CIDP in clinical practice
    Journal of Neurology 12/2013; 260(12):3015. · 3.58 Impact Factor
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    ABSTRACT: Up to 68% of patients with primary Sjögren's syndrome (pSS) undergo neurological complications, and evidence for distinct immunological subgroups is emerging. We sought to determine systemic and immunological profiles associated with neurological manifestations. 420 patients fulfilling the 2002 American-European pSS criteria were retrospectively analyzed. Neurological manifestations were diagnosed through clinical, biological, electrophysiological, and imaging findings. Biographical, clinical, and laboratory data were compared. Within 93 (22%) patients with neurological manifestations, peripheral and central nervous systems were involved in 66% and 44%, respectively. Raynaud's phenomenon, cutaneous vasculitis, renal involvement, and cryoglobulinemia were associated with sensorimotor neuropathy and mononeuritis multiplex (p<0.05). Conversely, pure sensory neuropathy occurred without extraglandular manifestation, and without anti-Ro/SSA antibodies (p<0.05). All neurological manifestations were associated with increased use of corticosteroids and immunosuppressive drugs (p<0.05). In pSS, patients with sensorimotor neuropathies and pure sensory neuropathies have distinct extraglandular and immunological profiles.
    European Journal of Internal Medicine 10/2013; · 2.05 Impact Factor
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    ABSTRACT: Charcot-Marie-Tooth (CMT) disease is a heterogeneous condition with a large number of clinical, electrophysiological and pathological phenotypes. More than 40 genes are involved. We report a child of gypsy origin with an autosomal recessive demyelinating phenotype. Clinical data, familial history, and electrophysiological studies were in favor of a CMT4 sub-type. The characteristic N-Myc downstream-regulated gene 1 (NDRG1) mutation responsible for this CMT4D phenotype was confirmed: p.R148X. The exact molecular function of the NDRG1 protein has yet to be elucidated.
    Journal of the Peripheral Nervous System 09/2013; 18(3):261-5. · 2.57 Impact Factor
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    ABSTRACT: OBJECTIVE: To determine whether rituximab 375 mg/m(2) was efficacious in patients with immunoglobulin M (IgM) anti-myelin-associated glycoprotein antibody demyelinating neuropathy (IgM anti-MAG demyelinating neuropathy). METHODS: Fifty-four patients with IgM anti-MAG demyelinating neuropathy were enrolled in this randomized, double-blind, placebo-controlled trial. The inclusion criteria were inflammatory neuropathy cause and treatment (INCAT) sensory score (ISS) ≥4 and visual analog pain scale >4 or ataxia score ≥2. The primary outcome was mean change in ISS at 12 months. RESULTS: Twenty-six patients were randomized to a group receiving 4 weekly infusions of 375 mg/m(2) rituximab, and 28 patients to placebo. Intention-to-treat analysis, with imputation of missing ISS values by the last observation carried forward method, showed a lack of mean change in ISS at 12 months, 1.0 ± 2.7 in the rituximab group, and 1.0 ± 2.8 in the placebo group. However, changes were observed, in per protocol analysis at 12 months, for the number of patients with an improvement of at least 2 points in the INCAT disability scale (p = 0.027), the self-evaluation scale (p = 0.016), and 2 subscores of the Short Form-36 questionnaire. CONCLUSIONS:Although primary outcome measures provide no evidence to support the use of rituximab in IgM anti-MAG demyelinating neuropathy, there were improvements in several secondary outcomes in per protocol analysis. LEVEL OF EVIDENCE: This study provides Class I evidence that rituximab is ineffective in improving ISS in patients with IgM anti-MAG demyelinating neuropathy.
    Neurology 07/2013; 80(24):2217. · 8.25 Impact Factor
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    ABSTRACT: CD4(+)CD25(+)FoxP3(+) regulatory T cells (Tregs) play a critical role in the maintenance of immune tolerance. Intravenous immunoglobulin (IVIg), a therapeutic preparation of normal pooled human IgG, expands Tregs in various experimental models and in patients. However, the cellular and molecular mechanisms by which IVIg expands Tregs is relatively unknown. As Treg expansion in the periphery requires signaling by antigen presenting cells such as dendritic cells (DC) and that IVIg has been demonstrated to modulate DC functions, we hypothesized that IVIg induces distinct signaling events in DC that subsequently mediate Treg expansion. We demonstrate that IVIg expands Tregs via induction of cyclooxygenase (COX)-2-dependent prostaglandin E2 (PGE2) in human DC. However, co-stimulatory molecules of DC such as programmed death ligands, OX40 ligand and inducible T-cell costimulator ligands were not implicated. Inhibition of PGE2 synthesis by COX-2 inhibitors prevented IVIg-mediated Treg expansion in vitro and significantly diminished IVIg-mediated Treg expansion in vivo and protection from disease in experimental autoimmune encephalomyelitis model. IVIg-mediated COX-2 expression, PGE2 production and Treg expansion were mediated in part via interaction of IVIg and F(ab')2 fragments of IVIg with DC-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN). Our results thus uncover novel cellular and molecular mechanism by which IVIg expands Tregs.
    Blood 07/2013; · 9.78 Impact Factor
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    ABSTRACT: The occurrence of corticosteroid-induced hepatitis is a rare event that has been recently described in the literature. We report the case of an acute cytolytic hepatitis in a patient treated with methylprednisolone for multiple sclerosis associated with an autoimmune thyroid dysfunction. After ruling out other etiologies, we concluded that the acute liver injury was due to steroids, and we analyzed the specific circumstances in the literature where methylprednisolone may have been responsible for acute hepatitis.
    Gastroentérologie Clinique et Biologique 01/2013; · 0.80 Impact Factor
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    ABSTRACT: Endoneurial fibroblast-like cells (EFLCs) have been described for more than 60 years, but the embryology, functions, and pathology of these cells are not well defined. Several hypotheses of their origin have been proposed. A previous study suggesting that they were of neural crest origin is supported by our data in humans. This lineage might account for EFLCs having multiple biologic functions and involvement in pathological processes. Here, we review what is known about the origin; functions in collagen synthesis, phagocytosis, inflammatory responses, and immune surveillance; and the pathological alterations of EFLCs based on the literature and on our personal observations.
    Journal of Neuropathology and Experimental Neurology 11/2012; 71(11):938-47. · 4.35 Impact Factor
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    ABSTRACT: Transthyretin familial amyloid polyneuropathy (TTRFAP) is an autosomal dominant neuropathy that is fatal within about 10 years after symptom onset. TTRFAP is observed worldwide, albeit with a higher frequency of the most common variant, Val30met, in Portugal, Sweden and Japan. Various phenotypic differences are observed. TTRFAP should be considered in patients with a progressive axonal polyneuropathy of unknown origin, especially when associated with autonomic nervous system dysfunction. A positive family history is found in most cases when onset begins around 30 years of age, while late-onset FAP is often sporadic and may be confused with chronic inflammatory demyelinating polyneuropathy. Nerve biopsy is often used to confirm the presence of extracellular amyloid deposits in interstitial tissue of the endoneurial space, although amyloid can also befound in muscle, salivary gland and abdominal fat. It is important to stress that biopsy negativity does not rule out amyloidosis. Genetic testing for TTR gene mutations should be performed in case of progressive length-dependent axonal polyneuropathy predominantly involving small nerve fibers.
    Bulletin de l'Académie nationale de médecine 10/2012; 196(7):1321-9; discussion 1329-31. · 0.16 Impact Factor
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    ABSTRACT: Peripheral neuropathy is a common neurological disorder that can be associated with a wide range of conditions, including rheumatic disease. Although the association of the two disorders can be coincidental, an underlying pathogenic link can occur in many instances, which can affect treatment options. The presentation of peripheral neuropathy can be multifaceted, an important consideration when recognizing the condition and optimizing diagnosis. Furthermore, understanding the diagnostic strategy will help physicians treating patients with rheumatic disease who develop peripheral neuropathy. Finally, although available treatment options have greatly reduced the risk of patients with inflammatory disorders developing systemic complications, among which includes peripheral neuropathy, new therapeutic agents can trigger toxic or immune-mediated neuropathies and treatment will need to be adjusted accordingly. In this Review, we will discuss the general approach for diagnosing patients with peripheral neuropathy, and detail the presentation, pathophysiological features and general rules of treatment of patients with peripheral neuropathy in the context of rheumatic disease.
    Nature Reviews Rheumatology 08/2012; 8(10):599-609. · 9.75 Impact Factor
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    ABSTRACT: Primary Sjögren's syndrome (pSS) is an autoimmune inflammatory disorder characterized by lymphocytic infiltration of exocrine glands, mainly the lacrimal and salivary glands leading to a chronic sicca syndrome. However, extraglandular organ systems may frequently be involved, including both central and peripheral nervous systems. Clinically significant neurologic manifestations affect approximately 20% of patients and may be the first manifestation of the disease in at least 25% of the cases. The spectrum of pSS-related neuropathies is wide including sensory neuropathies, neuronopathies, sensory-motor neuropathies, mononeuritis multiplex related to vasculitis… Central nervous system involvement is composed by multiple sclerosis-like manifestations including acute and chronic myelopathies and by more diffuse manifestations (cognitive dysfunction, subacute aseptic meningitis, encephalopathy, psychiatric symptoms, chorea, seizures…). The diagnosis and treatment of such pSS-related manifestations must be optimized in order to avoid severe disability.
    La Presse Médicale 07/2012; 41(9 Pt 2):e485-93. · 0.87 Impact Factor
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    ABSTRACT: BACKGROUND Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a central nervous system inflammatory disease. OBJECTIVE To describe the disease course of CLIPPERS. DESIGN A nationwide study was implemented to collect clinical, magnetic resonance imaging, cerebrospinal fluid, and brain biopsy specimen characteristics of patients with CLIPPERS. SETTING Academic research. PATIENTS Twelve patients with CLIPPERS. MAIN OUTCOME MEASURES The therapeutic management of CLIPPERS was evaluated. RESULTS Among 12 patients, 42 relapses were analyzed. Relapses lasted a mean duration of 2.5 months, manifested frequent cerebellar ataxia and diplopia, and were associated with a mean Expanded Disability Status Scale (EDSS) score of 4. Besides typical findings of CLIPPERS, magnetic resonance imaging showed brainstem mass effect in 5 patients, extensive myelitis in 3 patients, and closed ring enhancement in 1 patient. Inconstant oligoclonal bands were found on cerebrospinal fluid investigation in 4 patients, with an increased T-cell ratio of CD4 to CD8. Among 7 available brain biopsy specimens, staining was positive for perivascular CD4 T lymphocytes in 5 samples. Thirty-eight of 42 relapses were treated with pulse corticosteroid therapy, which led to improvement, with a mean residual EDSS score of 1.9 (range, 0-7). In 1 patient with untreated relapses, scores on the EDSS progressively increased to a score of 10 at death. Among 5 patients without long-term corticosteroid therapy, the mean annualized relapse rate was 0.5 (range, 0.25-2.8). Among 7 patients taking oral corticosteroids, no relapses occurred in those whose daily dose was 20 mg or higher. No progressive course of CLIPPERS was observed. Four patients with a final EDSS score of 4 or higher had experienced previous severe relapses (EDSS score, ≥5) and brainstem and spinal cord atrophy. CONCLUSIONS CLIPPERS is a relapsing-remitting disorder without progressive forms. Long-term disability is correlated with the severity of previous relapses. Further studies are needed to confirm that prolonged corticosteroid therapy prevents further relapses.
    Archives of neurology 07/2012; 69(7):847-55. · 7.58 Impact Factor
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    ABSTRACT: Polyneuropathy is a common presenting component of POEMS syndrome whose symptoms are attributed to an overproduction of vascular endothelial growth factor (VEGF). We report two female patients with POEMS syndrome presenting as a severe predominantly axonal neuropathy. A nerve biopsy was performed for these patients; pathological data confirmed unusual numerous acute axonal lesions associated with other classical signs of POEMS syndrome. POEMS syndrome is usually associated with demyelinating neuropathy (and secondary axonal loss); however, prominent axonal neuropathy (with acute axonal lesions on nerve biopsy) can also be observed in this disease. These observations illustrate the heterogeneity of peripheral nervous system involvement in POEMS syndrome.
    Journal of the neurological sciences 02/2012; 313(1-2):185-8. · 2.32 Impact Factor
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    ABSTRACT: Amyloid neuropathy is a rare peripheral neuropathy that classically presents as a progressive sensory neuropathy with prominent autonomic involvement. We describe 5 patients with amyloid neuropathy (familial amyloid polyneuropathy or acquired amyloidosis) who were initially mistaken to have chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) based on history, clinical examination, electrodiagnostic studies, and cerebrospinal fluid (CSF) analysis. The diagnosis of CIDP had been retained on clinical and electrophysiological grounds for all patients, but we observed no improvement after immunomodulatory treatment. Nerve biopsy confirmed amyloid deposits in nerves, and molecular genetic analysis showed a mutation of the transthyretin (V30M) gene for 3 patients; the 2 other patients had acquired amyloidosis. This report emphasizes the need to look for an alternative diagnosis in CIDP patients who do not respond to treatment and to look carefully for symptoms or signs of autonomic involvement in such patients.
    Muscle & Nerve 01/2012; 45(1):26-31. · 2.31 Impact Factor
  • Laurent Magy
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    ABSTRACT: Polyvalent immunoglobulins have been used for more than 20 years in immune-mediated disorders and humoral immunodeficiency Their use has gradually increased, leading regulatory authorities to issue guidelines on the indications of these costly treatments. Neurological diseases, including autoimmune neuromuscular disorders such as acute and chronic polyradiculoneuropathies and multifocal motor neuropathy, are the main indications of intravenous immunoglobulins. Most patients with these diseases will need long-term maintenance therapy Further research is needed to optimize the use of polyvalent immunoglobulins and to find alternative treatments.
    Bulletin de l'Académie nationale de médecine 01/2012; 196(1):49-60; discussion 61. · 0.16 Impact Factor

Publication Stats

594 Citations
287.32 Total Impact Points

Institutions

  • 2003–2013
    • Centre Hospitalier Universitaire de Limoges
      • Department of Neurology
      Limages, Limousin, France
  • 2012
    • Centre Léon Bérard
      Lyons, Rhône-Alpes, France
    • Université de Poitiers
      Poitiers, Poitou-Charentes, France
  • 2001–2012
    • University of Limoges
      Limages, Limousin, France