This monocentric prospective study of patient suffering from Amyotrophic lateral sclerosis (ALS) aims to evaluate the prognosis and diagnostic potential of both Neurofilament-Light (Nf-L) and ...neuroinflammatory biomarkers in serum and CSF. Candidate markers levels were measured using multiplex method in serum of 60 ALS patients, 94 healthy controls of 43 patients suffering from Inflammatory Peripheral Neuropathies (IPN). A comparative CSF analysis was performed for 20 ALS and 17 IPN patients. Among the altered biomarkers, CSF Nf-L level remains the best marker of ALS severity, while serum levels correlate strongly with disease progression. The combination of Nf-L and ICAM-1 concentrations in the CSF and IFN-γ concentration in the serum differentiate ALS patients from IPN patients with improved sensibility and specificity relative to individual biomarkers. A cutoff value of 0.49 for the fitted values of these 3 biomarkers discriminate ALS from IPN patients with a specificity of 100% (78.20-100%) and a sensibility of 85.71% (57.19-98.22%) with an AUC of 0.99 ± 0.01. The measure of Nf-L and neuroinflammatory biomarkers in CSF and serum can be useful biomarkers panel in the differential diagnosis of ALS.
Chronic inflammatory demyelination polyneuropathy is a heterogeneous and treatable immune-mediated disorder that lacks biomarkers to support diagnosis. Recent evidence indicates that paranodal ...proteins (contactin 1, contactin-associated protein 1, and neurofascin-155) are the targets of autoantibodies in subsets of patients showing distinct clinical presentations. Here, we identified neurofascin-186 and neurofascin-140 as the main targets of autoantibodies in five patients presenting IgG reactivity against the nodes of Ranvier. Four patients displayed predominantly IgG4 antibodies, and one patient presented IgG3 antibodies that activated the complement pathway in vitro. These patients present distinct clinical features compared to those with anti-neurofascin-155 IgG4. Most patients had a severe phenotype associated with conduction block or decreased distal motor amplitude. Four patients had a subacute-onset and sensory ataxia. Two patients presented with nephrotic syndromes and one patient with an IgG4-related retroperitoneal fibrosis. Intravenous immunoglobulin and corticosteroids were effective in three patients, and one patient remitted following rituximab treatment. Clinical remission was associated with autoantibody depletion and with recovery of conduction block and distal motor amplitude suggesting a nodo-paranodopathy. Our data demonstrate that the pathogenic mechanisms responsible for chronic inflammatory demyelination polyneuropathy are broad and may include dysfunctions at the nodes of Ranvier in a subgroup of patients.
Introduction
IgG4 antibodies against neurofascin (Nfasc155 and Nfasc140/186), contactin (CNTN1) and contactin-associated protein (Caspr1) are described in specific subtypes of chronic inflammatory ...demyelinating polyradiculoneuropathy (CIDP). Our objective was to assess, in a real-life practice, the incidence, the clinical features and the response to treatment of these forms of CIDP.
Methods
1500 sera of patients suspected of having CIDP from France, Belgium and Switzerland were prospectively tested using a flow cytometry technique. The characteristics of patients with antibodies against the node of Ranvier were compared to 100 seronegative CIDP from our department.
Results
IgG4 antibodies against Nfasc155, CNTN1, and Caspr1 were, respectively, detected in 15 (prevalence 1%), 10 (0.7%) and 2 (0.2%) sera. Antibodies specific of the Nfasc140/186 were not detected.
All subjects with antibodies against the node of Ranvier fulfilled diagnostic criteria for CIDP.
CIDP with anti-Nfasc155 were younger, had more sensory ataxia and postural tremor than seronegative CIDP. CIDP with anti-CNTN1 had more frequent subacute onset and facial paralysis, commoner renal involvement with membranous glomerulonephritis and greater disability, than seronegative CIDP. CIDP with anti-Caspr1 had more frequent respiratory failure and cranial nerve involvement but not more neuropathic pain than seronegative CIDP. Intravenous immunoglobulins were ineffective in most seropositive patients. Rituximab produced dramatic improvement in disability and decreased antibodies titres in 13 seropositive patients (8 with anti-Nfasc155 and 5 with anti-CNTN1 antibodies).
Conclusions
Although rare, anti-paranodal antibodies are clinically valuable, because they are associated with specific phenotypes and therapeutic response.
Previous studies have described the clinical, serological and pathological features of patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and antibodies directed against ...the paranodal proteins neurofascin-155, contactin-1 (CNTN1), contactin-associated protein-1 (Caspr1), or nodal forms of neurofascin. Such antibodies are useful for diagnosis and potentially treatment selection. However, antibodies targeting Caspr1 only or the Caspr1/CNTN1 complex have been reported in few patients with CIDP. Moreover, it is unclear if these patients belong to the same pathophysiological subgroup. Using cell-based assays in routine clinical testing, we identified sera from patients with CIDP showing strong membrane reactivity when both CNTN1 and Caspr1 were co-transfected (but not when CNTN1 was transfected alone). Fifteen patients (10 male; aged between 40 and 75) with antibodies targeting Caspr1/CNTN1 co-transfected cells were enrolled for characterization. The prevalence of anti-Caspr1/CNTN1 antibodies was 1.9% (1/52) in the Sant Pau CIDP cohort, and 4.3% (1/23) in a German cohort of acute-onset CIDP. All patients fulfilled European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) definite diagnostic criteria for CIDP. Seven (47%) were initially diagnosed with Guillain-Barré syndrome due to an acute-subacute onset. Six (40%) patients had cranial nerve involvement, eight (53%) reported neuropathic pain and 12 (80%) ataxia. Axonal involvement and acute denervation were frequent in electrophysiological studies. Complete response to intravenous immunoglobulin was not observed, while most (90%) responded well to rituximab. Enzyme-linked immunosorbent assay (ELISA) and teased nerve fibre immunohistochemistry confirmed reactivity against the paranodal Caspr1/CNTN1 complex. Weaker reactivity against Caspr1 transfected alone was also detected in 10/15 (67%). Sera from 13 of these patients were available for testing by ELISA. All 13 samples reacted against Caspr1 by ELISA and this reactivity was enhanced when CNTN1 was added to the Caspr1 ELISA. IgG subclasses were also investigated by ELISA. IgG4 was the predominant subclass in 10 patients, while IgG3 was predominant in other three patients. In conclusion, patients with antibodies to the Caspr1/CNTN1 complex display similar serological and clinical features and constitute a single subgroup within the CIDP syndrome. These antibodies likely target Caspr1 primarily and are detected with Caspr1-only ELISA, but reactivity is optimal when CNTN1 is added to Caspr1 in cell-based assays and ELISA.
Membranous glomerulonephritis (MGN) is a common cause of nephrotic syndrome in adults, mediated by glomerular antibody deposition to an increasing number of newly recognised antigens. Previous case ...reports have suggested an association between patients with anti-contactin-1 (CNTN1)-mediated neuropathies and MGN. In an observational study we investigated the pathobiology and extent of this potential cause of MGN by examining the association of antibodies against CNTN1 with the clinical features of a cohort of 468 patients with suspected immune-mediated neuropathies, 295 with idiopathic MGN, and 256 controls. Neuronal and glomerular binding of patient IgG, serum CNTN1 antibody and protein levels, as well as immune-complex deposition were determined. We identified 15 patients with immune-mediated neuropathy and concurrent nephrotic syndrome (biopsy proven MGN in 12/12), and 4 patients with isolated MGN from an idiopathic MGN cohort, all seropositive for IgG4 CNTN1 antibodies. CNTN1-containing immune complexes were found in the renal glomeruli of patients with CNTN1 antibodies, but not in control kidneys. CNTN1 peptides were identified in glomeruli by mass spectroscopy. CNTN1 seropositive patients were largely resistant to first-line neuropathy treatments but achieved a good outcome with escalation therapies. Neurological and renal function improved in parallel with suppressed antibody titres. The reason for isolated MGN without clinical neuropathy is unclear. We show that CNTN1, found in peripheral nerves and kidney glomeruli, is a common target for autoantibody-mediated pathology and may account for between 1 and 2% of idiopathic MGN cases. Greater awareness of this cross-system syndrome should facilitate earlier diagnosis and more timely use of effective treatment.
Anti‐myelin‐associated glycoprotein (MAG) neuropathy is a disabling autoimmune peripheral neuropathy that is caused by circulating monoclonal IgM autoantibodies directed against the human natural ...killer‐1 (HNK‐1) epitope. This carbohydrate epitope is highly expressed on adhesion molecules such as MAG, a glycoprotein present in myelinated nerves. We previously showed the therapeutic potential of the glycopolymer poly(phenyl disodium 3‐O‐sulfo‐β‐d‐glucopyranuronate)‐(1→3)‐β‐d‐galactopyranoside (PPSGG) in selectively neutralizing anti‐MAG IgM antibodies in an immunological mouse model and ex vivo with sera from anti‐MAG neuropathy patients. PPSGG is composed of a biodegradable backbone that multivalently presents a mimetic of the HNK‐1 epitope. In this study, we further explored the pharmacodynamic properties of the glycopolymer and its ability to inhibit the binding of anti‐MAG IgM to peripheral nerves. The polymer selectively bound anti‐MAG IgM autoantibodies and prevented the binding of patients’ anti‐MAG IgM antibodies to myelin of non‐human primate sciatic nerves. Upon PPSGG treatment, neither activation nor inhibition of human and murine peripheral blood mononuclear cells nor alteration of systemic inflammatory markers was observed in mice or ex vivo in human peripheral blood mononuclear cells. Intravenous injections of PPSGG to mice immunized against the HNK‐1 epitope removed anti‐MAG IgM antibodies within less than 1 hr, indicating a fast and efficient mechanism of action as compared to a B‐cell depletion with anti‐CD20. In conclusion, these observations corroborate the therapeutic potential of PPSGG for an antigen‐specific treatment of anti‐MAG neuropathy.
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Anti‐MAG (myelin‐associated glycoprotein) neuropathy is a disabling autoimmune peripheral neuropathy that is caused by circulating monoclonal IgM autoantibodies directed against the HNK‐1 (human natural killer‐1) epitope. This glycoepitope is highly expressed on adhesion molecules such as MAG and is localized mainly in paranodal loops and Schmidt–Lantermann incisures of the peripheral nervous system. The glycopolymer PPSGG selectively bound anti‐MAG IgM autoantibodies and prevented the binding of patients’ autoantibodies to myelin of primate sciatic nerves in the IFA (indirect fluorescents assay) anti‐MAG IgM assay (right panel). These findings corroborate the therapeutic potential of PPSGG for an antigen‐specific treatment of anti‐MAG neuropathy.
Read the Editorial Highlight for this article on page 465.
The aim of the research is to study the human leukocyte antigen (HLA) class II allele frequencies in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) associated with anti-neurofascin ...155 (NF155) antibodies.
Thirteen anti-NF155+ and 35 anti-NF155 negative (anti-NF155neg) CIDP patients were included in a case-control study. The frequencies of the DRB1 HLA allele were analyzed in all patients while DQ frequencies were only studied in patients sharing the DRB1*15 allele. In silico HLA-peptide binding and NF155 antigenicity, predictions were performed to analyze overlap between presented peptides and antigenic regions.
DRB1*15 alleles (DRB1*15:01 and DRB1*15:02) were present in 10 out of 13 anti-NF155+ CIDP patients and in only 5 out of 35 anti-NF155neg CIDP patients (77 vs 14%; OR = 20, CI = 4.035 to 99.13). DRB1*15 alleles appeared also in significantly higher proportions in anti-NF155+ CIDP than in normal population (77 vs 17%; OR = 16.9, CI = 4.434 to 57.30). Seven anti-NF155+ CIDP patients (53%) and 5 anti-NF155neg CIDP patients had the DRB1*15:01 allele (OR = 7, p = 0.009), while 3 anti-NF155+ CIDP patients and none of the anti-NF155neg CIDP patients had the DRB1*15:02 allele (OR = 23.6, p = 0.016). In silico analysis of the NF155 peptides binding to DRB1*15 alleles showed significant overlap in the peptides presented by the 15:01 and 15:02 alleles, suggesting functional homology.
DRB1*15 alleles are the first strong risk factor associated to a CIDP subset, providing additional evidence that anti-NF155+ CIDP patients constitute a differentiated disease within the CIDP syndrome.
ABSTRACT
Introduction: The diagnostic sensitivity of repetitive nerve stimulation (RNS) in patients with myasthenia gravis (MG) varies as a function of the number of muscles or the choice of muscles ...studied. Methods: By exploring 12 muscles bilaterally, we evaluated the global sensitivity of RNS at rest, the sensitivity in different clinical forms, and the sensitivity of different combinations of muscles studied. Results: The global sensitivity of RNS was 82%, and specificity was 100%. The sensitivity in the MG subgroups was as follows: ocular (O) = 67%; oculobulbar (OB) = 86%; and generalized (G) = 89%. The most sensitive muscles were the anconeus in group O, orbicularis oculi (OO) or nasalis in group OB, and the trapezius in group G. Maximum sensitivity was obtained by exploring OO, trapezius, and anconeus bilaterally. Conclusions: We recommend bilateral exploration of at least 3 muscles, a facial muscle, trapezius, and anconeus. Muscle Nerve 55: 532–538, 2017
Abstract Antibodies against complexes of GM1:GalC are detected in multifocal motor neuropathy. Previous studies used different techniques, explaining disparities in the results. Antibodies against ...GM1 and GM1:GalC with different proportions of GalC were measured with both glycoarray and ELISA in 20 multifocal motor neuropathies, and 45 controls. The 1:5 ratio and the 1:1 ratio of GM1:GalC (weight ratio) were respectively the most effective for glycoarray and for ELISA. Testing for anti-GM1:GalC antibodies increased the sensitivity from 40% with anti-GM1 antibodies to 65% with array and 60% with ELISA without loss in specificity (above 91%). Anti-GM1:GalC antibodies are effective biological tools to diagnose multifocal motor neuropathy.
Highlights • We describe the largest series of co-occurence of ALS and myasthenia gravis. • This association is rare and requires strict diagnostic criteria. • It may be triggered by a dysfunction of ...the adaptive immune system in both disorders. • False positivity for anti-AChR antibodies is encountered in some ALS patients. • Transient response to acetylcholinesterase inhibitors is also possible in ALS.
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