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Latov N, Brannagan TH, Sander HW, Gondim FDAA. Anti-MAG neuropathy: historical aspects, clinical-pathological correlations, and considerations for future therapeutical trials. ARQUIVOS DE NEURO-PSIQUIATRIA 2024; 82:1-7. [PMID: 38325389 PMCID: PMC10849826 DOI: 10.1055/s-0043-1777728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 11/21/2023] [Indexed: 02/09/2024]
Abstract
BACKGROUND Patients with anti-MAG neuropathy present with distal demyelinating polyneuropathy, IgM monoclonal gammopathy, and elevated titers of anti-MAG antibodies. OBJECTIVE This paper reviews what is known about the clinical presentation, course, pathophysiology, and treatment of anti-MAG neuropathy, with considerations for the design of therapeutic trials. METHODS A literature review of the medical and scientific literature related to anti-MAG neuropathy, and the design of therapeutic clinical trials in peripheral neuropathy. RESULTS Anti-MAG neuropathy can remain indolent for many years but then enter a progressive phase. Highly elevated antibody titers are diagnostic, but intermediate titers can also occur in chronic inflammatory demyelinating polyneuropathy (CIDP). The peripheral nerves can become inexcitable, thereby masking the demyelinating abnormalities. There is good evidence that the anti-MAG antibodies cause neuropathy. Reduction of the autoantibody concentration by agents that target B-cells was reported to result in clinical improvement in case series and uncontrolled trials, but not in controlled clinical trials, probably due to inadequate trial design. CONCLUSION We propose that therapeutic trials for anti-MAG neuropathy include patients with the typical presentation, some degree of weakness, highly elevated anti-MAG antibody titers, and at least one nerve exhibiting demyelinating range abnormalities. Treatment with one or a combination of anti-B-cell agents would aim at reducing the autoantibody concentration by at least 60%. A trial duration of 2 years may be required to show efficacy. The neuropathy impairment score of the lower extremities (NIS-LL) plus the Lower Limb Function (LLF) score would be a suitable primary outcome measure.
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Affiliation(s)
- Norman Latov
- Weil Medical College of Cornell University, Peripheral Neuropathy Center, New York, New York, United States.
| | - Thomas H. Brannagan
- Columbia University, Vagelos College of Physicians and Surgeons, Peripheral Neuropathy Center, Department of Neurology, New York, New York, United States.
| | - Howard W. Sander
- New York University, Department of Neurology, New York, New York, United States.
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Cornejo AC, Latov N. Time course of the autoantibody response to therapy in anti-MAG neuropathy: TWO case REPORTS. Heliyon 2024; 10:e28870. [PMID: 38601656 PMCID: PMC11004559 DOI: 10.1016/j.heliyon.2024.e28870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 03/12/2024] [Accepted: 03/26/2024] [Indexed: 04/12/2024] Open
Abstract
Background Anti-MAG neuropathy is a slowly progressive demyelinating neuropathy that can lead to disability. The neuropathy is thought to be caused by monoclonal IgM antibodies that target the Myelin Associated Glycoprotein (MAG) in peripheral nerves. Therapy is directed at lowering the autoantibody concentrations with B-cells depleting agents, most often rituximab, based on case series and uncontrolled trials reporting improvement. There are no FDA approved treatments for anti-MAG neuropathy, however, and two relatively short duration randomized controlled trials with rituximab failed to achieve their pre-specified primary endpoints. There is also little information regarding the number or duration of treatments that are required to effectively reduce the antibody concentrations. Case presentations We report the time course of the anti-MAG antibody response in two patients with anti-MAG neuropathy that were treated with rituximab for several years. A reduction of 50% in the anti-MAG IgM was seen after 19 and 58 months respectively, and of 70% after 74 or 104 months of treatment respectively. Titres remained low, without evidence of recurrence after the treatments were discontinued. Conclusion Therapy of anti-MAG neuropathy with rituximab may require repeat treatments over more than one year to achieve a significant reduction in autoantibody concentrations. These considerations should inform treatment decisions and the design of clinical trials.
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Affiliation(s)
| | - Norman Latov
- New York - Presbyterian/Weill Cornell Medicine, USA
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Stino AM, Elsheikh B, Allen JA. Anti-myelin-associated glycoprotein neuropathy: Where do we stand? Muscle Nerve 2023; 68:823-832. [PMID: 37602932 DOI: 10.1002/mus.27954] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 07/19/2023] [Accepted: 07/22/2023] [Indexed: 08/22/2023]
Abstract
Myelin-associated glycoprotein (MAG) is a transmembrane glycoprotein concentrated in periaxonal Schwann cell and oligodendroglial membranes of myelin sheaths that serves as an antigen for immunoglobulin M (IgM) monoclonal antibodies. Individuals who harbor anti-MAG antibodies classically develop a progressive autoimmune peripheral neuropathy characterized clinically by ataxia, distal sensory loss, and gait instability, and electrophysiologically by distally accentuated conduction velocity slowing. Although off-label immunotherapy is common, there are currently no proven effective disease-modifying therapeutics, and most patients experience slow accumulation of disability over years and decades. The typically slowly progressive nature of this neuropathy presents unique challenges when trying to find effective anti-MAG therapeutic agents. Drug development has also been hampered by the lack of validated outcome measures that can detect clinically meaningful changes in a reasonable amount of time as well as by the lack of disease activity biomarkers. In this invited review, we provide an update on the state of clinicometric outcome measures and disease activity biomarkers in anti-MAG neuropathy. We highlight the insensitivity of widely used existing clinicometric outcome measures such as the Inflammatory Neuropathy Cause and Treatment (INCAT) disability score as well as the INCAT sensory subscore in anti-MAG neuropathy, referencing the two previous negative randomized controlled clinical trials evaluating rituximab. We then discuss newly emerging candidate therapeutic agents, including tyrosine kinase inhibitors and enhanced B-cell-depleting agents, among others. We conclude with a practical approach to the evaluation and management of anti-MAG neuropathy patients.
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Affiliation(s)
- Amro Maher Stino
- Department of Neurology, Division of Neuromuscular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Bakri Elsheikh
- Department of Neurology, Division of Neuromuscular Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Jeffrey A Allen
- Department of Neurology, Division of Neuromuscular Medicine, University of Minnesota, Minneapolis, Minnesota, USA
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Castellani F, Visentin A, Schirinzi E, Salvalaggio A, Cacciavillani M, Candiotto C, Baratè C, Cellini A, Bertorelle R, Siciliano G, Trentin L, Briani C. Mutational Profile in 75 Patients With Anti-Myelin-Associated Glycoprotein Neuropathy: Clinical and Hematologic Therapy Response and Hints on New Therapeutic Targets. NEUROLOGY(R) NEUROIMMUNOLOGY & NEUROINFLAMMATION 2023; 10:10/4/e200122. [PMID: 37137530 PMCID: PMC10155778 DOI: 10.1212/nxi.0000000000200122] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 03/13/2023] [Indexed: 05/05/2023]
Abstract
BACKGROUND AND OBJECTIVES Neuropathy with antibodies to myelin-associated glycoprotein (MAG) is the most common paraproteinemic IgM neuropathy. Recently, the mutational profile of the MYD88 and CXCR4 genes has been included in the diagnostic workup of IgM monoclonal gammopathies. The objective of our study was to assess the prevalence of MYD88 L265P and CXCR4 S338X gene variants in patients with anti-MAG antibody neuropathy. Secondary aims were to evaluate possible correlations between the mutational profile and neuropathy severity, antibody titers, and treatment response. METHODS Seventy-five patients (47 men, mean age at molecular analysis 70.8 ± 10.2 years; mean disease duration 5.1 ± 4.9 years) with anti-MAG antibody neuropathy were recruited. Among them, 38 (50.7%) had IgM monoclonal gammopathy of undetermined significance, 29 (38.7%) Waldenstrom macroglobulinemia (WM), and 8 (10.6%) chronic lymphocytic leukemia/marginal zone lymphoma/hairy cell leukemia variant. Molecular analysis was performed on DNA from the bone marrow mononuclear cells in 55 of 75 patients and from peripheral mononuclear cells in 18 of 75 patients. Forty-five patients were treated with rituximab, 6 with ibrutinib, 2 with obinutuzumab-chlorambucil, and 3 with venetoclax-based therapy. All the patients were assessed with the Inflammatory Neuropathy Cause and Treatment (INCAT) Disability Scale, INCAT Sensory Sum Score, and MRC Sum Score at baseline and follow-up. We considered as responders, patients who improved by at least 1 point in 2 clinical scales. RESULTS Fifty patients (66.7%) carried the MYD88L265P variant, with a higher frequency in WM and naive patients (77.2% vs 33.3%, p = 0.0012). No patients harbored the CXCR4S338X variant. There were no significant differences in hematologic data (IgM levels, M protein, and anti-MAG antibody titers), neuropathy severity, or response to rituximab in MYD88-altered and MYD88 wild-type patients. Nine of 11 (81.8%) patients treated with novel targeted drug, according to the MYD88 status, responded to treatments. DISCUSSION MYD88L265P variant has a high prevalence (66.7%) in anti-MAG antibody neuropathy representing a potential effective mutational target for Bruton tyrosine kinase inhibitors. MYD88L265P variant, however, does not seem to be a prognostic factor of neuropathy severity or response to rituximab. In patients not responding or becoming refractory to rituximab, a tailored therapy with new effective target therapies should be considered.
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Affiliation(s)
- Francesca Castellani
- From the Department of Neurosciences (F.C., A.S., Chiara Briani), Neurology Unit, University of Padova; Hematology and Clinical Immunology Unit (A.V., A.C., L.T.), Department of Medicine, University of Padova; Department of Clinical and Experimental Medicine (E.S., G.S.), Neurological Clinic, University of Pisa; EMG Lab (M.C.), CEMES, Synlab Group, Padova; Immunology and Molecular Oncology (C.C., R.B.), Veneto Institute of Oncology IOV-IRCCS, Padova; and Department of Clinical and Experimental Medicine (Claudia Baratè), Section of Hematology, University of Pisa, Italy
| | - Andrea Visentin
- From the Department of Neurosciences (F.C., A.S., Chiara Briani), Neurology Unit, University of Padova; Hematology and Clinical Immunology Unit (A.V., A.C., L.T.), Department of Medicine, University of Padova; Department of Clinical and Experimental Medicine (E.S., G.S.), Neurological Clinic, University of Pisa; EMG Lab (M.C.), CEMES, Synlab Group, Padova; Immunology and Molecular Oncology (C.C., R.B.), Veneto Institute of Oncology IOV-IRCCS, Padova; and Department of Clinical and Experimental Medicine (Claudia Baratè), Section of Hematology, University of Pisa, Italy
| | - Erika Schirinzi
- From the Department of Neurosciences (F.C., A.S., Chiara Briani), Neurology Unit, University of Padova; Hematology and Clinical Immunology Unit (A.V., A.C., L.T.), Department of Medicine, University of Padova; Department of Clinical and Experimental Medicine (E.S., G.S.), Neurological Clinic, University of Pisa; EMG Lab (M.C.), CEMES, Synlab Group, Padova; Immunology and Molecular Oncology (C.C., R.B.), Veneto Institute of Oncology IOV-IRCCS, Padova; and Department of Clinical and Experimental Medicine (Claudia Baratè), Section of Hematology, University of Pisa, Italy
| | - Alessandro Salvalaggio
- From the Department of Neurosciences (F.C., A.S., Chiara Briani), Neurology Unit, University of Padova; Hematology and Clinical Immunology Unit (A.V., A.C., L.T.), Department of Medicine, University of Padova; Department of Clinical and Experimental Medicine (E.S., G.S.), Neurological Clinic, University of Pisa; EMG Lab (M.C.), CEMES, Synlab Group, Padova; Immunology and Molecular Oncology (C.C., R.B.), Veneto Institute of Oncology IOV-IRCCS, Padova; and Department of Clinical and Experimental Medicine (Claudia Baratè), Section of Hematology, University of Pisa, Italy
| | - Mario Cacciavillani
- From the Department of Neurosciences (F.C., A.S., Chiara Briani), Neurology Unit, University of Padova; Hematology and Clinical Immunology Unit (A.V., A.C., L.T.), Department of Medicine, University of Padova; Department of Clinical and Experimental Medicine (E.S., G.S.), Neurological Clinic, University of Pisa; EMG Lab (M.C.), CEMES, Synlab Group, Padova; Immunology and Molecular Oncology (C.C., R.B.), Veneto Institute of Oncology IOV-IRCCS, Padova; and Department of Clinical and Experimental Medicine (Claudia Baratè), Section of Hematology, University of Pisa, Italy
| | - Cinzia Candiotto
- From the Department of Neurosciences (F.C., A.S., Chiara Briani), Neurology Unit, University of Padova; Hematology and Clinical Immunology Unit (A.V., A.C., L.T.), Department of Medicine, University of Padova; Department of Clinical and Experimental Medicine (E.S., G.S.), Neurological Clinic, University of Pisa; EMG Lab (M.C.), CEMES, Synlab Group, Padova; Immunology and Molecular Oncology (C.C., R.B.), Veneto Institute of Oncology IOV-IRCCS, Padova; and Department of Clinical and Experimental Medicine (Claudia Baratè), Section of Hematology, University of Pisa, Italy
| | - Claudia Baratè
- From the Department of Neurosciences (F.C., A.S., Chiara Briani), Neurology Unit, University of Padova; Hematology and Clinical Immunology Unit (A.V., A.C., L.T.), Department of Medicine, University of Padova; Department of Clinical and Experimental Medicine (E.S., G.S.), Neurological Clinic, University of Pisa; EMG Lab (M.C.), CEMES, Synlab Group, Padova; Immunology and Molecular Oncology (C.C., R.B.), Veneto Institute of Oncology IOV-IRCCS, Padova; and Department of Clinical and Experimental Medicine (Claudia Baratè), Section of Hematology, University of Pisa, Italy
| | - Alessandro Cellini
- From the Department of Neurosciences (F.C., A.S., Chiara Briani), Neurology Unit, University of Padova; Hematology and Clinical Immunology Unit (A.V., A.C., L.T.), Department of Medicine, University of Padova; Department of Clinical and Experimental Medicine (E.S., G.S.), Neurological Clinic, University of Pisa; EMG Lab (M.C.), CEMES, Synlab Group, Padova; Immunology and Molecular Oncology (C.C., R.B.), Veneto Institute of Oncology IOV-IRCCS, Padova; and Department of Clinical and Experimental Medicine (Claudia Baratè), Section of Hematology, University of Pisa, Italy
| | - Roberta Bertorelle
- From the Department of Neurosciences (F.C., A.S., Chiara Briani), Neurology Unit, University of Padova; Hematology and Clinical Immunology Unit (A.V., A.C., L.T.), Department of Medicine, University of Padova; Department of Clinical and Experimental Medicine (E.S., G.S.), Neurological Clinic, University of Pisa; EMG Lab (M.C.), CEMES, Synlab Group, Padova; Immunology and Molecular Oncology (C.C., R.B.), Veneto Institute of Oncology IOV-IRCCS, Padova; and Department of Clinical and Experimental Medicine (Claudia Baratè), Section of Hematology, University of Pisa, Italy
| | - Gabriele Siciliano
- From the Department of Neurosciences (F.C., A.S., Chiara Briani), Neurology Unit, University of Padova; Hematology and Clinical Immunology Unit (A.V., A.C., L.T.), Department of Medicine, University of Padova; Department of Clinical and Experimental Medicine (E.S., G.S.), Neurological Clinic, University of Pisa; EMG Lab (M.C.), CEMES, Synlab Group, Padova; Immunology and Molecular Oncology (C.C., R.B.), Veneto Institute of Oncology IOV-IRCCS, Padova; and Department of Clinical and Experimental Medicine (Claudia Baratè), Section of Hematology, University of Pisa, Italy
| | - Livio Trentin
- From the Department of Neurosciences (F.C., A.S., Chiara Briani), Neurology Unit, University of Padova; Hematology and Clinical Immunology Unit (A.V., A.C., L.T.), Department of Medicine, University of Padova; Department of Clinical and Experimental Medicine (E.S., G.S.), Neurological Clinic, University of Pisa; EMG Lab (M.C.), CEMES, Synlab Group, Padova; Immunology and Molecular Oncology (C.C., R.B.), Veneto Institute of Oncology IOV-IRCCS, Padova; and Department of Clinical and Experimental Medicine (Claudia Baratè), Section of Hematology, University of Pisa, Italy
| | - Chiara Briani
- From the Department of Neurosciences (F.C., A.S., Chiara Briani), Neurology Unit, University of Padova; Hematology and Clinical Immunology Unit (A.V., A.C., L.T.), Department of Medicine, University of Padova; Department of Clinical and Experimental Medicine (E.S., G.S.), Neurological Clinic, University of Pisa; EMG Lab (M.C.), CEMES, Synlab Group, Padova; Immunology and Molecular Oncology (C.C., R.B.), Veneto Institute of Oncology IOV-IRCCS, Padova; and Department of Clinical and Experimental Medicine (Claudia Baratè), Section of Hematology, University of Pisa, Italy.
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Naum R, Gwathmey KG. Autoimmune polyneuropathies. HANDBOOK OF CLINICAL NEUROLOGY 2023; 195:587-608. [PMID: 37562888 DOI: 10.1016/b978-0-323-98818-6.00004-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
The autoimmune peripheral neuropathies with prominent motor manifestations are a diverse collection of unusual peripheral neuropathies that are appreciated in vast clinical settings. This chapter highlights the most common immune-mediated, motor predominant neuropathies excluding acute, and chronic inflammatory demyelinating polyradiculoneuropathy (AIDP and CIDP, respectively). Other acquired demyelinating neuropathies such as distal CIDP and multifocal motor neuropathy will be covered. Additionally, the radiculoplexus neuropathies, resulting from microvasculitis-induced injury to nerve roots, plexuses, and nerves, including diabetic and nondiabetic lumbosacral radiculoplexus neuropathy and neuralgic amyotrophy (i.e., Parsonage-Turner syndrome), will be included. Finally, the motor predominant peripheral neuropathies encountered in association with rheumatological disease, particularly Sjögren's syndrome and rheumatoid arthritis, are covered. Early recognition of these distinct motor predominant autoimmune neuropathies and initiation of immunomodulatory and immunosuppressant treatment likely result in improved outcomes.
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Affiliation(s)
- Ryan Naum
- Department of Neurology, Virginia Commonwealth University, Richmond, VA, United States
| | - Kelly Graham Gwathmey
- Neuromuscular Division, Department of Neurology, Virginia Commonwealth University, Richmond, VA, United States.
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Abstract
Autoimmune neuropathy may present acutely or with a more progressive and/or relapsing and remitting course. Acute inflammatory neuropathy or Guillain-Barré syndrome (GBS) has variable presentations but by far the most common is acute inflammatory demyelinating polyradiculoneuropathy which is characterized by rapidly progressive proximal and distal symmetric weakness, sensory loss, and depressed reflexes. The most common chronic autoimmune neuropathy is chronic inflammatory demyelinating polyradiculoneuropathy, which in its most typical form is clinically similar to acute inflammatory demyelinating polyradiculoneuropathy (proximal and distal symmetric weakness, sensory loss, and depressed reflexes) but differs in that onset is much more gradual, i.e., over at least 8 weeks. While the majority of GBS cases result from a postinfectious activation of the immune system, presumably in a genetically susceptible host, less is understood regarding the etiopathogenesis of chronic inflammatory demyelinating polyradiculoneuropathy. Both acute and chronic forms of these inflammatory neuropathies are driven by some combination of innate and adaptive immune pathways, with differing contributions depending on the neuropathy subtype. Both disorders are largely clinical diagnoses, but diagnostic tools are available to confirm the diagnosis, prognosticate, detect variant forms, and rule out mimics. Given the autoimmune underpinnings of both disorders, immunosuppressive and immunomodulating treatments are typically given in both diseases; however, they differ in their response to treatment.
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Affiliation(s)
- Caroline Miranda
- Department of Neurology, Columbia University, Vagelos College of Physicians and Surgeons, New York, NY, United States.
| | - Thomas H Brannagan
- Department of Neurology, Columbia University, Vagelos College of Physicians and Surgeons, New York, NY, United States
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Parisi M, Dogliotti I, Clerico M, Bertuzzo D, Benevolo G, Orsucci L, Schiavetti I, Cavallo R, Cavallo F, Ragaini S, Di Liberto A, Ferrante M, Bondielli G, Artusi CA, Drandi D, Lopiano L, Ferrero B, Ferrero S. Efficacy of rituximab in anti-myelin-associated glycoprotein demyelinating polyneuropathy: Clinical, hematological and neurophysiological correlations during 2 years of follow-up. Eur J Neurol 2022; 29:3611-3622. [PMID: 36083713 PMCID: PMC9825860 DOI: 10.1111/ene.15553] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/11/2022] [Accepted: 08/31/2022] [Indexed: 01/11/2023]
Abstract
BACKGROUND AND PURPOSE We evaluated the clinical and neurophysiological efficacy of rituximab (RTX) in a neurophysiologically homogeneous group of patients with monoclonal gammopathy and immunoglobulin M (IgM) anti-myelin-associated glycoprotein antibody (anti-MAG) demyelinating polyneuropathy. METHODS Twenty three anti-MAG-positive polyneuropathic patients were prospectively evaluated before and for 2 years after treatment with RTX 375 mg/m2 . The Inflammatory Neuropathy Cause and Treatment (INCAT) disability scale (INCAT-ds), modified INCAT sensory score (mISS), Medical Research Council sum score, Patients' Global Impression of Change scale were used, IgM levels were assessed and extensive electrophysiological examinations were performed before (T0) and 1 year (T1) and 2 years (T2) after RTX treatment. RESULTS At T1 and T2 there was a significant reduction from T0 both in mISS and in INCAT-ds, with a p value < 0.001 in the inferential Friedman's test overall analysis. Ulnar nerve Terminal Latency Index and distal motor latency significantly changed from T0 to T1 and in the overall analysis (p = 0.001 and p = 0.002), and ulnar nerve sensory nerve action potential (SNAP) amplitude was significantly increased at T2 from T1, with a p value < 0.001 in the overall analysis. Analysis of the receiver-operating characteristic curves showed that a 41.8% increase in SNAP amplitude in the ulnar nerve at T2 from T0 was a fair predictor of a mISS reduction of ≥2 points (area under the curve 0.85; p = 0.005; sensitivity: 90.9%, specificity: 83.3%). CONCLUSIONS This study suggests that RTX is effective in patients with clinically active demyelinating anti-MAG neuropathy over 2 years of follow-up, and that some neurophysiological variables might be useful for monitoring this efficacy.
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Affiliation(s)
- Mattia Parisi
- Department of NeurosciencesUniversity of TurinTurinItaly
| | - Irene Dogliotti
- Stem Cell Transplant UnitUniversity Hospital A.O.U. “Città della Salute e della Scienza di Torino”TurinItaly
| | - Michele Clerico
- Department of Molecular Biotechnologies and Health SciencesUniversity of TurinTurinItaly,SSD Myeloma Unit and Clinical Trial, University HaematologyA.O.U. "Città della Salute e della Scienza di Torino"TurinItaly
| | | | - Giulia Benevolo
- SSD Myeloma Unit and Clinical Trial, University HaematologyA.O.U. "Città della Salute e della Scienza di Torino"TurinItaly
| | - Lorella Orsucci
- Division of Hematology 2A.O.U. "Città della Salute e della Scienza di Torino"TurinItaly
| | - Irene Schiavetti
- Section of Biostatistics, Department of Health SciencesUniversity of GenoaGenoaItaly
| | - Roberto Cavallo
- Department of NeurologyOspedale San Giovanni BoscoTurinItaly
| | - Federica Cavallo
- Department of Molecular Biotechnologies and Health SciencesUniversity of TurinTurinItaly,SSD Myeloma Unit and Clinical Trial, University HaematologyA.O.U. "Città della Salute e della Scienza di Torino"TurinItaly
| | - Simone Ragaini
- Department of Molecular Biotechnologies and Health SciencesUniversity of TurinTurinItaly,SSD Myeloma Unit and Clinical Trial, University HaematologyA.O.U. "Città della Salute e della Scienza di Torino"TurinItaly
| | | | - Martina Ferrante
- Department of Molecular Biotechnologies and Health SciencesUniversity of TurinTurinItaly
| | - Giulia Bondielli
- Department of Molecular Biotechnologies and Health SciencesUniversity of TurinTurinItaly
| | | | - Daniela Drandi
- Department of Molecular Biotechnologies and Health SciencesUniversity of TurinTurinItaly
| | | | - Bruno Ferrero
- Department of NeurosciencesUniversity of TurinTurinItaly
| | - Simone Ferrero
- Department of Molecular Biotechnologies and Health SciencesUniversity of TurinTurinItaly,SSD Myeloma Unit and Clinical Trial, University HaematologyA.O.U. "Città della Salute e della Scienza di Torino"TurinItaly
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Polyneuropathy Associated with IgM Monoclonal Gammopathy; Advances in Genetics and Treatment, Focusing on Anti-MAG Antibodies. HEMATO 2022. [DOI: 10.3390/hemato3040045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
With increasing age, the chances of developing either MGUS or polyneuropathy increase as well. In some cases, there is a causative relationship between the IgM M-protein and polyneuropathy. In approximately half of these cases, IgM targets the myelin-associated glycoprotein (MAG). This results in chronic polyneuropathy with slowly progressive, predominantly sensory neurological deficits and distally demyelinating features in nerve conduction studies. Despite the disease being chronic and developing slowly, it can cause considerable impairment. We reviewed English medical publications between 1980 and May 2022 on IgM gammopathy-associated polyneuropathy, with special attention to studies addressing the pathophysiology or treatment of anti-MAG polyneuropathy. Treatment options have been limited to a temporizing effect of intravenous immunoglobulins in some patients and a more sustained effect of rituximab but in only 30 to 55 percent of patients. An increase in our knowledge concerning genetic mutations, particularly the MYD88L265P mutation, led to the development of novel targeted treatment options such as BTK inhibitors. Similarly, due to the increasing knowledge of the pathophysiology of anti-MAG polyneuropathy, new treatment options are emerging. Since anti-MAG polyneuropathy is a rare disease with diverse symptomatology, large trials with good outcome measures are a challenge.
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De Masi R, Orlando S. GANAB and N-Glycans Substrates Are Relevant in Human Physiology, Polycystic Pathology and Multiple Sclerosis: A Review. Int J Mol Sci 2022; 23:7373. [PMID: 35806376 PMCID: PMC9266668 DOI: 10.3390/ijms23137373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 06/22/2022] [Accepted: 06/28/2022] [Indexed: 11/29/2022] Open
Abstract
Glycans are one of the four fundamental macromolecular components of living matter, and they are highly regulated in the cell. Their functions are metabolic, structural and modulatory. In particular, ER resident N-glycans participate with the Glc3Man9GlcNAc2 highly conserved sequence, in protein folding process, where the physiological balance between glycosylation/deglycosylation on the innermost glucose residue takes place, according GANAB/UGGT concentration ratio. However, under abnormal conditions, the cell adapts to the glucose availability by adopting an aerobic or anaerobic regimen of glycolysis, or to external stimuli through internal or external recognition patterns, so it responds to pathogenic noxa with unfolded protein response (UPR). UPR can affect Multiple Sclerosis (MS) and several neurological and metabolic diseases via the BiP stress sensor, resulting in ATF6, PERK and IRE1 activation. Furthermore, the abnormal GANAB expression has been observed in MS, systemic lupus erythematous, male germinal epithelium and predisposed highly replicating cells of the kidney tubules and bile ducts. The latter is the case of Polycystic Liver Disease (PCLD) and Polycystic Kidney Disease (PCKD), where genetically induced GANAB loss affects polycystin-1 (PC1) and polycystin-2 (PC2), resulting in altered protein quality control and cyst formation phenomenon. Our topics resume the role of glycans in cell physiology, highlighting the N-glycans one, as a substrate of GANAB, which is an emerging key molecule in MS and other human pathologies.
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Affiliation(s)
- Roberto De Masi
- Complex Operative Unit of Neurology, “F. Ferrari” Hospital, Casarano, 73042 Lecce, Italy;
- Laboratory of Neuroproteomics, Multiple Sclerosis Centre, “F. Ferrari” Hospital, Casarano, 73042 Lecce, Italy
| | - Stefania Orlando
- Laboratory of Neuroproteomics, Multiple Sclerosis Centre, “F. Ferrari” Hospital, Casarano, 73042 Lecce, Italy
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10
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From Biology to Treatment of Monoclonal Gammopathies of Neurological Significance. Cancers (Basel) 2022; 14:cancers14061562. [PMID: 35326711 PMCID: PMC8946535 DOI: 10.3390/cancers14061562] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/06/2022] [Accepted: 03/15/2022] [Indexed: 12/23/2022] Open
Abstract
Monoclonal gammopathy and peripheral neuropathy are common diseases of elderly patients, and almost 10% of patients with neuropathy of unknown cause have paraprotein. However, growing evidence suggests that several hematological malignancies synthesize and release monoclonal proteins that damage the peripheral nervous system through different mechanisms. The spectrum of the disease varies from mild to rapidly progressive symptoms, sometimes affecting not only sensory nerve fibers, but also motor and autonomic fibers. Therefore, a multidisciplinary approach, mainly between hematologists and neurologists, is recommended in order to establish the correct diagnosis of monoclonal gammopathy of neurological significance and to tailor therapy based on specific genetic mutations. In this review, we summarize the spectrum of monoclonal gammopathies of neurological significance, their distinctive clinical and neurophysiological phenotypes, the most relevant pathophysiological events and new therapeutic approaches.
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Amaador K, Wieske L, Koel-Simmelink MJA, Kamp A, Jongerius I, de Heer K, Teunissen CE, Minnema MC, Notermans NC, Eftimov F, Kersten MJ, Vos JMI. Serum neurofilament light chain, contactin-1 and complement activation in anti-MAG IgM paraprotein-related peripheral neuropathy. J Neurol 2022; 269:3700-3705. [PMID: 35157138 PMCID: PMC9217848 DOI: 10.1007/s00415-022-10993-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 01/21/2022] [Accepted: 01/22/2022] [Indexed: 11/26/2022]
Abstract
Abstract
Introduction
In anti-myelin-associated glycoprotein IgM paraprotein-related peripheral neuropathy (anti-MAG PN), there is a lack of reliable biomarkers to select patients eligible for therapy and for evaluating treatment effects, both in routine practice and in clinical trials. Neurofilament light chain (NfL) and contactin-1 (CNTN1) can serve as markers of axonal and paranodal damage. Complement activation is involved in the pathogenesis in anti-MAG PN. We, therefore, hypothesized that serum NfL, CNTN1, C3b/c and C4b/c may function as biomarkers of disease activity in anti-MAG PN.
Methods
In this prospective cohort study, we included 24 treatment-naïve patients with anti-MAG PN (mean age 69 years, 57% male) that had IgM paraproteinemia, a high IgM MAG-antibody, and clinical diagnosis of anti-MAG PN by a neurologist specialized in peripheral nerve disorders. We measured serum NfL, CNTN1, C3b/c and C4b/c, reference values were based on healthy controls. As controls, 10 treatment-naïve patients with IgM Monoclonal gammopathy of undetermined significance (MGUS) or Waldenström’s Macroglobulinemia (mean age 69 years, 60% male) without signs of neuropathy were included (non-PN).
Results
NfL, CNTN1 levels in serum were mostly normal in anti-MAG PN patients and comparable to non-PN patients. C3b/c and C4b/c levels were normal in anti-MAG PN patients.
Conclusion
Our results do not support serum NfL, CNTN1, and C3b/c and C4b/c as potential biomarkers in anti-MAG PN, although we cannot exclude that subgroups or subtle abnormalities could be found in a much larger cohort with longitudinal follow-up.
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Affiliation(s)
- Karima Amaador
- Department of Hematology, Amsterdam UMC, University of Amsterdam, Cancer Center Amsterdam, LYMMCARE, Amsterdam, The Netherlands
| | - Luuk Wieske
- Department of Neurology and Neurophysiology, Amsterdam Neuroscience, Amsterdam UMC, Location AMC, Amsterdam, The Netherlands
| | - Marleen J A Koel-Simmelink
- Neurochemistry Laboratory, Department of Clinical Chemistry, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit, Amsterdam UMC, Location VU Medical Center, Amsterdam, The Netherlands
| | - A Kamp
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory, Amsterdam University Medical Centre, University of Amsterdam, Amsterdam, 1066CX, The Netherlands
| | - Ilse Jongerius
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory, Amsterdam University Medical Centre, University of Amsterdam, Amsterdam, 1066CX, The Netherlands
- Department of Pediatric Immunology, Rheumatology and Infectious Diseases, Emma Children's Hospital, Amsterdam UMC, Amsterdam, The Netherlands
| | - Koen de Heer
- Department of Hematology, Amsterdam UMC, University of Amsterdam, Cancer Center Amsterdam, LYMMCARE, Amsterdam, The Netherlands
- Department of Internal Medicine, Flevo Hospital, Almere, The Netherlands
| | - Charlotte E Teunissen
- Neurochemistry Laboratory, Department of Clinical Chemistry, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit, Amsterdam UMC, Location VU Medical Center, Amsterdam, The Netherlands
| | - Monique C Minnema
- Department of Hematology, University Medical Center Utrecht, University Utrecht, Utrecht, The Netherlands
| | - Nicolette C Notermans
- Department of Neurology, UMC Utrecht Brain Center, University Medical Center Utrecht, University Utrecht, Utrecht, The Netherlands
| | - Filip Eftimov
- Department of Neurology and Neurophysiology, Amsterdam Neuroscience, Amsterdam UMC, Location AMC, Amsterdam, The Netherlands
| | - Marie José Kersten
- Department of Hematology, Amsterdam UMC, University of Amsterdam, Cancer Center Amsterdam, LYMMCARE, Amsterdam, The Netherlands
| | - Josephine M I Vos
- Department of Hematology, Amsterdam UMC, University of Amsterdam, Cancer Center Amsterdam, LYMMCARE, Amsterdam, The Netherlands.
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Latov N. Immune mechanisms, the role of complement, and related therapies in autoimmune neuropathies. Expert Rev Clin Immunol 2021; 17:1269-1281. [PMID: 34751638 DOI: 10.1080/1744666x.2021.2002147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
INTRODUCTION Autoimmune neuropathies have diverse presentations and underlying immune mechanisms. Demonstration of efficacy of therapeutic agents that inhibit the complement cascade would confirm the role of complement activation. AREAS COVERED A review of the pathophysiology of the autoimmune neuropathies, to identify those that are likely to be complement mediated. EXPERT OPINION Complement mediated mechanisms are implicated in the acute and chronic neuropathies associated with IgG or IgM antibodies that target the Myelin Associated Glycoprotein (MAG) or gangliosides in the peripheral nerves. Antibody and complement mechanisms are also suspected in the Guillain-Barré syndrome and chronic inflammatory demyelinating neuropathy, given the therapeutic response to plasmapheresis or intravenous immunoglobulins, even in the absence of an identifiable target antigen. Complement is unlikely to play a role in paraneoplastic sensory neuropathy associated with antibodies to HU/ANNA-1 given its intracellular localization. In chronic demyelinating neuropathy with anti-nodal/paranodal CNTN1, NFS-155, and CASPR1 antibodies, myotonia with anti-VGKC LGI1 or CASPR2 antibodies, or autoimmune autonomic neuropathy with anti-gAChR antibodies, the response to complement inhibitory agents would depend on the extent to which the antibodies exert their effects through complement dependent or independent mechanisms. Complement is also likely to play a role in Sjogren's, vasculitic, and cryoglobulinemic neuropathies.
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Affiliation(s)
- Norman Latov
- Department of Neurology, Weill Cornell Medical College, New York, USA
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