TY - JOUR A1 - Doppler, Kathrin A1 - Appeltshauser, Luise A1 - Krämer, Heidrun H. A1 - King Man Ng, Judy A1 - Meinl, Edgar A1 - Villmann, Carmen A1 - Brophy, Peter A1 - Dib-Hajj, Sulayman D. A1 - Waxman, Stephen G. A1 - Weishaupt, Andreas A1 - Sommer, Claudia T1 - Contactin-1 and Neurofascin-155/-186 Are Not Targets of Auto-Antibodies in Multifocal Motor Neuropathy JF - PLoS One N2 - Multifocal motor neuropathy is an immune mediated disease presenting with multifocal muscle weakness and conduction block. IgM auto-antibodies against the ganglioside GM1 are detectable in about 50% of the patients. Auto-antibodies against the paranodal proteins contactin-1 and neurofascin-155 and the nodal protein neurofascin-186 have been detected in subgroups of patients with chronic inflammatory demyelinating polyneuropathy. Recently, auto-antibodies against neurofascin-186 and gliomedin were described in more than 60% of patients with multifocal motor neuropathy. In the current study, we aimed to validate this finding, using a combination of different assays for auto-antibody detection. In addition we intended to detect further auto-antibodies against paranodal proteins, specifically contactin-1 and neurofascin-155 in multifocal motor neuropathy patients’ sera. We analyzed sera of 33 patients with well-characterized multifocal motor neuropathy for IgM or IgG anti-contactin-1, anti-neurofascin-155 or -186 antibodies using enzyme-linked immunosorbent assay, binding assays with transfected human embryonic kidney 293 cells and murine teased fibers. We did not detect any IgM or IgG auto-antibodies against contactin-1, neurofascin-155 or -186 in any of our multifocal motor neuropathy patients. We conclude that auto-antibodies against contactin-1, neurofascin-155 and -186 do not play a relevant role in the pathogenesis in this cohort with multifocal motor neuropathy. KW - motor proteins KW - enzyme-linked immunoassays KW - binding analysis KW - neuropathy KW - nerve fibers KW - cell binding assay KW - antibodies KW - enzyme assays Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-126156 VL - 10 IS - 7 ER - TY - JOUR A1 - Doppler, Kathrin A1 - Schuster, Yasmin A1 - Appeltshauser, Luise A1 - Biko, Lydia A1 - Villmann, Carmen A1 - Weishaupt, Andreas A1 - Werner, Christian A1 - Sommer, Claudia T1 - Anti-CNTN1 IgG3 induces acute conduction block and motor deficits in a passive transfer rat model JF - Journal of Neuroinflammation N2 - Background: Autoantibodies against the paranodal protein contactin-1 have recently been described in patients with severe acute-onset autoimmune neuropathies and mainly belong to the IgG4 subclass that does not activate complement. IgG3 anti-contactin-1 autoantibodies are rare, but have been detected during the acute onset of disease in some cases. There is evidence that anti-contactin-1 prevents adhesive interaction, and chronic exposure to anti-contactin-1 IgG4 leads to structural changes at the nodes accompanied by neuropathic symptoms. However, the pathomechanism of acute onset of disease and the pathogenic role of IgG3 anti-contactin-1 is largely unknown. Methods: In the present study, we aimed to model acute autoantibody exposure by intraneural injection of IgG of patients with anti-contacin-1 autoantibodies to Lewis rats. Patient IgG obtained during acute onset of disease (IgG3 predominant) and IgG from the chronic phase of disease (IgG4 predominant) were studied in comparison. Results: Conduction blocks were measured in rats injected with the “acute” IgG more often than after injection of “chronic” IgG (83.3% versus 35%) and proved to be reversible within a week after injection. Impaired nerve conduction was accompanied by motor deficits in rats after injection of the “acute” IgG but only minor structural changes of the nodes. Paranodal complement deposition was detected after injection of the “acute IgG”. We did not detect any inflammatory infiltrates, arguing against an inflammatory cascade as cause of damage to the nerve. We also did not observe dispersion of paranodal proteins or sodium channels to the juxtaparanodes as seen in patients after chronic exposure to anti-contactin-1. Conclusions: Our data suggest that anti-contactin-1 IgG3 induces an acute conduction block that is most probably mediated by autoantibody binding and subsequent complement deposition and may account for acute onset of disease in these patients. This supports the notion of anti-contactin-1-associated neuropathy as a paranodopathy with the nodes of Ranvier as the site of pathogenesis. KW - complement deposition KW - paranodopathy KW - anti-contactin-1 KW - CIDP KW - passive transfer KW - autoantibody Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-200476 VL - 16 IS - 73 ER - TY - JOUR A1 - Stengel, Helena A1 - Vural, Atay A1 - Brunder, Anna-Michelle A1 - Heinius, Annika A1 - Appeltshauser, Luise A1 - Fiebig, Bianca A1 - Giese, Florian A1 - Dresel, Christian A1 - Papagianni, Aikaterini A1 - Birklein, Frank A1 - Weis, Joachim A1 - Huchtemann, Tessa A1 - Schmidt, Christian A1 - Körtvelyessy, Peter A1 - Villmann, Carmen A1 - Meinl, Edgar A1 - Sommer, Claudia A1 - Leypoldt, Frank A1 - Doppler, Kathrin T1 - Anti–pan-neurofascin IgG3 as a marker of fulminant autoimmune neuropathy JF - Neurology: Neuroimmunology & Neuroinflammation N2 - Objective To identify and characterize patients with autoantibodies against different neurofascin (NF) isoforms. Methods Screening of a large cohort of patient sera for anti-NF autoantibodies by ELISA and further characterization by cell-based assays, epitope mapping, and complement binding assays. Results Two different clinical phenotypes became apparent in this study: The well-known clinical picture of subacute-onset severe sensorimotor neuropathy with tremor that is known to be associated with IgG4 autoantibodies against the paranodal isoform NF-155 was found in 2 patients. The second phenotype with a dramatic course of disease with tetraplegia and almost locked-in syndrome was associated with IgG3 autoantibodies against nodal and paranodal isoforms of NF in 3 patients. The epitope against which these autoantibodies were directed in this second phenotype was the common Ig domain found in all 3 NF isoforms. In contrast, anti–NF-155 IgG4 were directed against the NF-155–specific Fn3Fn4 domain. The description of a second phenotype of anti–NF-associated neuropathy is in line with some case reports of similar patients that were published in the last year. Conclusions Our results indicate that anti–pan-NF-associated neuropathy differs from anti–NF-155-associated neuropathy, and epitope and subclass play a major role in the pathogenesis and severity of anti–NF-associated neuropathy and should be determined to correctly classify patients, also in respect to possible differences in therapeutic response. KW - neurology Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-202462 VL - 6 IS - 5 ER - TY - JOUR A1 - Rauschenberger, Vera A1 - von Wardenburg, Niels A1 - Schaefer, Natascha A1 - Ogino, Kazutoyo A1 - Hirata, Hiromi A1 - Lillesaar, Christina A1 - Kluck, Christoph J. A1 - Meinck, Hans‐Michael A1 - Borrmann, Marc A1 - Weishaupt, Andreas A1 - Doppler, Kathrin A1 - Wickel, Jonathan A1 - Geis, Christian A1 - Sommer, Claudia A1 - Villmann, Carmen T1 - Glycine Receptor Autoantibodies Impair Receptor Function and Induce Motor Dysfunction JF - Annals of Neurology N2 - Objective Impairment of glycinergic neurotransmission leads to complex movement and behavioral disorders. Patients harboring glycine receptor autoantibodies suffer from stiff‐person syndrome or its severe variant progressive encephalomyelitis with rigidity and myoclonus. Enhanced receptor internalization was proposed as the common molecular mechanism upon autoantibody binding. Although functional impairment of glycine receptors following autoantibody binding has recently been investigated, it is still incompletely understood. Methods A cell‐based assay was used for positive sample evaluation. Glycine receptor function was assessed by electrophysiological recordings and radioligand binding assays. The in vivo passive transfer of patient autoantibodies was done using the zebrafish animal model. Results Glycine receptor function as assessed by glycine dose–response curves showed significantly decreased glycine potency in the presence of patient sera. Upon binding of autoantibodies from 2 patients, a decreased fraction of desensitized receptors was observed, whereas closing of the ion channel remained fast. The glycine receptor N‐terminal residues \(^{29}\)A to \(^{62}\)G were mapped as a common epitope of glycine receptor autoantibodies. An in vivo transfer into the zebrafish animal model generated a phenotype with disturbed escape behavior accompanied by a reduced number of glycine receptor clusters in the spinal cord of affected animals. Interpretation Autoantibodies against the extracellular domain mediate alterations of glycine receptor physiology. Moreover, our in vivo data demonstrate that the autoantibodies are a direct cause of the disease, because the transfer of human glycine receptor autoantibodies to zebrafish larvae generated impaired escape behavior in the animal model compatible with abnormal startle response in stiff‐person syndrome or progressive encephalitis with rigidity and myoclonus patients. KW - glycine receptor autoantibodies KW - behavioral disorders KW - neurology Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-216005 VL - 88 IS - 3 SP - 544 EP - 561 ER - TY - JOUR A1 - Hartmannsberger, Beate A1 - Doppler, Kathrin A1 - Stauber, Julia A1 - Schlotter-Weigel, Beate A1 - Young, Peter A1 - Sereda, Michael W. A1 - Sommer, Claudia T1 - Intraepidermal nerve fiber density as biomarker in Charcot-Marie-Tooth disease 1A JF - Brain Communications N2 - Charcot–Marie–Tooth disease type 1A, caused by a duplication of the gene peripheral myelin protein 22 kDa, is the most frequent subtype of hereditary peripheral neuropathy with an estimated prevalence of 1:5000. Patients suffer from sensory deficits, muscle weakness and foot deformities. There is no treatment approved for this disease. Outcome measures in clinical trials were based mainly on clinical features but did not evaluate the actual nerve damage. In our case–control study, we aimed to provide objective and reproducible outcome measures for future clinical trials. We collected skin samples from 48 patients with Charcot–Marie–Tooth type 1A, 7 patients with chronic inflammatory demyelinating polyneuropathy, 16 patients with small fibre neuropathy and 45 healthy controls. To analyse skin innervation, 40-µm cryosections of glabrous skin taken from the lateral index finger were double-labelled by immunofluorescence. The disease severity of patients with Charcot–Marie–Tooth type 1A was assessed by the Charcot–Marie–Tooth neuropathy version 2 score, which ranged from 3 (mild) to 27 (severe) and correlated with age (P < 0.01, R = 0.4). Intraepidermal nerve fibre density was reduced in patients with Charcot–Marie–Tooth type 1A compared with the healthy control group (P < 0.01) and negatively correlated with disease severity (P < 0.05, R = −0.293). Meissner corpuscle (MC) density correlated negatively with age in patients with Charcot–Marie–Tooth type 1A (P < 0.01, R = −0.45) but not in healthy controls (P = 0.07, R = 0.28). The density of Merkel cells was reduced in patients with Charcot–Marie–Tooth type 1A compared with healthy controls (P < 0.05). Furthermore, in patients with Charcot–Marie–Tooth type 1A, the fraction of denervated Merkel cells was highly increased and correlated with age (P < 0.05, R = 0.37). Analysis of nodes of Ranvier revealed shortened paranodes and a reduced fraction of long nodes in patients compared with healthy controls (both P < 0.001). Langerhans cell density was increased in chronic inflammatory demyelinating polyneuropathy, but not different in Charcot–Marie–Tooth type 1A compared with healthy controls. Our data suggest that intraepidermal nerve fibre density might be used as an outcome measure in Charcot–Marie–Tooth type 1A disease, as it correlates with disease severity. The densities of Meissner corpuscles and Merkel cells might be an additional tool for the evaluation of the disease progression. Analysis of follow-up biopsies will clarify the effects of Charcot–Marie–Tooth type 1A disease progression on cutaneous innervation. KW - Charcot–Marie–Tooth disease type 1A KW - skin punch biopsy KW - intraepidermal nerve fibre density KW - Merkel cell density KW - reproducible outcome measure Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-229538 VL - 2 IS - 1 ER - TY - JOUR A1 - Appeltshauser, Luise A1 - Brunder, Anna-Michelle A1 - Heinius, Annika A1 - Körtvélyessy, Peter A1 - Wandinger, Klaus-Peter A1 - Junker, Ralf A1 - Villmann, Carmen A1 - Sommer, Claudia A1 - Leypoldt, Frank A1 - Doppler, Kathrin T1 - Antiparanodal antibodies and IgG subclasses in acute autoimmune neuropathy JF - Neurology: Neuroimmunology & Neuroinflammation N2 - Objective To determine whether IgG subclasses of antiparanodal autoantibodies are related to disease course and treatment response in acute- to subacute-onset neuropathies, we retrospectively screened 161 baseline serum/CSF samples and 66 follow-up serum/CSF samples. Methods We used ELISA and immunofluorescence assays to detect antiparanodal IgG and their subclasses and titers in serum/CSF of patients with Guillain-Barre syndrome (GBS), recurrent GBS (R-GBS), Miller-Fisher syndrome, and acute- to subacute-onset chronic inflammatory demyelinating polyradiculoneuropathy (A-CIDP). We evaluated clinical data retrospectively. Results We detected antiparanodal autoantibodies with a prevalence of 4.3% (7/161), more often in A-CIDP (4/23, 17.4%) compared with GBS (3/114, 2.6%). Longitudinal subclass analysis in the patients with GBS revealed IgG2/3 autoantibodies against Caspr-1 and against anti-contactin-1/Caspr-1, which disappeared at remission. At disease onset, patients with A-CIDP had IgG2/3 anti-Caspr-1 and anti-contactin-1/Caspr-1 or IgG4 anti-contactin-1 antibodies, IgG3 being associated with good response to IV immunoglobulins (IVIg). In the chronic phase of disease, IgG subclass of one patient with A-CIDP switched from IgG3 to IgG4. Conclusion Our data (1) confirm and extend previous observations that antiparanodal IgG2/3 but not IgG4 antibodies can occur in acute-onset neuropathies manifesting as monophasic GBS, (2) suggest association of IgG3 to a favorable response to IVIg, and (3) lend support to the hypothesis that in some patients, an IgG subclass switch from IgG3 to IgG4 may be the correlate of a secondary progressive or relapsing course following a GBS-like onset. KW - Guillain-Barre-Syndrome KW - inflammatory demyelinating polyradiculoneuropathy KW - musk myasthenia gravis KW - periperal nerve KW - neurofascin KW - autoantibodies KW - ontactin 1 KW - biopsies KW - binding KW - switch Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-230079 VL - 7 IS - 5 ER - TY - JOUR A1 - Kuzkina, Anastasia A1 - Bargar, Connor A1 - Schmitt, Daniela A1 - Rößle, Jonas A1 - Wang, Wen A1 - Schubert, Anna-Lena A1 - Tatsuoka, Curtis A1 - Gunzler, Steven A. A1 - Zou, Wen-Quan A1 - Volkmann, Jens A1 - Sommer, Claudia A1 - Doppler, Kathrin A1 - Chen, Shu G. T1 - Diagnostic value of skin RT-QuIC in Parkinson's disease: a two-laboratory study JF - NPJ Parkinson's Disease N2 - Skin alpha-synuclein deposition is considered a potential biomarker for Parkinson's disease (PD). Real-time quaking-induced conversion (RT-QuIC) is a novel, ultrasensitive, and efficient seeding assay that enables the detection of minute amounts of alpha-synuclein aggregates. We aimed to determine the diagnostic accuracy, reliability, and reproducibility of alpha-synuclein RT-QuIC assay of skin biopsy for diagnosing PD and to explore its correlation with clinical markers of PD in a two-center inter-laboratory comparison study. Patients with clinically diagnosed PD (n = 34), as well as control subjects (n = 30), underwent skin punch biopsy at multiple sites (neck, lower back, thigh, and lower leg). The skin biopsy samples (198 in total) were divided in half to be analyzed by RT-QuIC assay in two independent laboratories. The a-synuclein RT-QuIC assay of multiple skin biopsies supported the clinical diagnosis of PD with a diagnostic accuracy of 88.9% and showed a high degree of inter-rater agreement between the two laboratories (92.2%). Higher alpha-synuclein seeding activity in RT-QuIC was shown in patients with longer disease duration and more advanced disease stage and correlated with the presence of REM sleep behavior disorder, cognitive impairment, and constipation. The alpha-synuclein RT-QuIC assay of minimally invasive skin punch biopsy is a reliable and reproducible biomarker for Parkinson's disease. Moreover, alpha-synuclein RT-QuIC seeding activity in the skin may serve as a potential indicator of progression as it correlates with the disease stage and certain non-motor symptoms. KW - diagnostic markers KW - Parkinson's disease Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-260451 VL - 7 IS - 1 ER - TY - JOUR A1 - Sommer, Claudia A1 - Carroll, Antonia S. A1 - Koike, Haruki A1 - Katsuno, Masahisa A1 - Ort, Nora A1 - Sobue, Gen A1 - Vucic, Steve A1 - Spies, Judith M. A1 - Doppler, Kathrin A1 - Kiernan, Matthew C. T1 - Nerve biopsy in acquired neuropathies JF - Journal of the Peripheral Nervous System N2 - A diagnosis of neuropathy can typically be determined through clinical assessment and focused investigation. With technological advances, including significant progress in genomics, the role of nerve biopsy has receded over recent years. However, making a specific and, in some cases, tissue-based diagnosis is essential across a wide array of potentially treatable acquired peripheral neuropathies. When laboratory investigations do not suggest a definitive diagnosis, nerve biopsy remains the final step to ascertain the etiology of the disease. The present review highlights the utility of nerve biopsy in confirming a diagnosis, while further illustrating the importance of a tissue-based diagnosis in relation to treatment strategies, particularly when linked to long-term immunosuppressive therapies, KW - inflammatory neuropathy KW - nerve biopsy KW - nerve tumor KW - neuroleukemiosis Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259555 VL - 26 IS - S2 ER - TY - JOUR A1 - Ben-Kraiem, Adel A1 - Sauer, Reine-Solange A1 - Norwig, Carla A1 - Popp, Maria A1 - Bettenhausen, Anna-Lena A1 - Atalla, Mariam Sobhy A1 - Brack, Alexander A1 - Blum, Robert A1 - Doppler, Kathrin A1 - Rittner, Heike Lydia T1 - Selective blood-nerve barrier leakiness with claudin-1 and vessel-associated macrophage loss in diabetic polyneuropathy JF - Journal of Molecular Medicine N2 - Diabetic polyneuropathy (DPN) is the most common complication in diabetes and can be painful in up to 26% of all diabetic patients. Peripheral nerves are shielded by the blood-nerve barrier (BNB) consisting of the perineurium and endoneurial vessels. So far, there are conflicting results regarding the role and function of the BNB in the pathophysiology of DPN. In this study, we analyzed the spatiotemporal tight junction protein profile, barrier permeability, and vessel-associated macrophages in Wistar rats with streptozotocin-induced DPN. In these rats, mechanical hypersensitivity developed after 2 weeks and loss of motor function after 8 weeks, while the BNB and the blood-DRG barrier were leakier for small, but not for large molecules after 8 weeks only. The blood-spinal cord barrier remained sealed throughout the observation period. No gross changes in tight junction protein or cytokine expression were observed in all barriers to blood. However, expression of Cldn1 mRNA in perineurium was specifically downregulated in conjunction with weaker vessel-associated macrophage shielding of the BNB. Our results underline the role of specific tight junction proteins and BNB breakdown in DPN maintenance and differentiate DPN from traumatic nerve injury. Targeting claudins and sealing the BNB could stabilize pain and prevent further nerve damage. KW - macrophages KW - neuropathy KW - barrier KW - pain Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-265237 VL - 99 IS - 9 ER - TY - JOUR A1 - Brumberg, Joachim A1 - Kuzkina, Anastasia A1 - Lapa, Constantin A1 - Mammadova, Sona A1 - Buck, Andreas A1 - Volkmann, Jens A1 - Sommer, Claudia A1 - Isaias, Ioannis U. A1 - Doppler, Kathrin T1 - Dermal and cardiac autonomic fiber involvement in Parkinson's disease and multiple system atrophy JF - Neurobiology of Disease N2 - Pathological aggregates of alpha-synuclein in peripheral dermal nerve fibers can be detected in patients with idiopathic Parkinson's disease and multiple system atrophy. This study combines skin biopsy staining for p-alpha-synuclein depositions and radionuclide imaging of the heart with [\(^{123}\)I]-metaiodobenzylguanidine to explore peripheral denervation in both diseases. To this purpose, 42 patients with a clinical diagnosis of Parkinson's disease or multiple system atrophy were enrolled. All patients underwent a standardized clinical workup including neurological evaluation, neurography, and blood samples. Skin biopsies were obtained from the distal and proximal leg, back, and neck for immunofluorescence double labeling with anti-p-alpha-synuclein and anti-PGP9.5. All patients underwent myocardial [\(^{123}\)I]-metaiodobenzylguanidine scintigraphy. Dermal p-alpha-synuclein was observed in 47.6% of Parkinson's disease patients and was mainly found in autonomic structures. 81.0% of multiple system atrophy patients had deposits with most of cases in somatosensory fibers. The [\(^{123}\)I]-metaiodobenzylguanidine heart-to-mediastinum ratio was lower in Parkinson's disease than in multiple system atrophy patients (1.94 +/- 0.63 vs. 2.91 +/- 0.96; p < 0.0001). Irrespective of the diagnosis, uptake was lower in patients with than without p-alpha-synuclein in autonomic structures (1.42 +/- 0.51 vs. 2.74 +/- 0.83; p < 0.0001). Rare cases of Parkinson's disease with p-alpha-synuclein in somatosensory fibers and multiple system atrophy patients with deposits in autonomic structures or both fiber types presented with clinically overlapping features. In conclusion, this study suggests that alpha-synuclein contributes to peripheral neurodegeneration and mediates the impairment of cardiac sympathetic neurons in patients with synucleinopathies. Furthermore, it indicates that Parkinson's disease and multiple system atrophy share pathophysiologic mechanisms of peripheral nervous system dysfunction with a clinical overlap. KW - peripheral nervous system KW - Parkinson's disease KW - skin biopsy KW - MIBG scintigraphy KW - multiple system atrophy Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-260061 VL - 153 ER -