IgM anti-GM1 Antibodies Research Articles

Multifocal motor neuropathy in Japan: A nationwide survey on prevalence, clinical profiles, and treatment.

Multifocal motor neuropathy (MMN) is a rare disease for which epidemiological and clinical data are limited. We conducted a nationwide survey to determine disease prevalence, incidence, clinical profile, and current treatment status in Japan. A nationwide survey was conducted in 2021 using an established epidemiological method. Questionnaires were sent to all neurology and pediatric neurology departments in Japan. An initial questionnaire was administered to determine the number of patients with and incidence of MMN. A second questionnaire was administered to collect detailed clinical information. The European Federation of Neurological Societies/Peripheral Nerve Society 2010 guidelines were used as diagnostic criteria. The estimated number of patients with MMN was 507. The estimated prevalence was 0.40 per 100,000 individuals. Detailed clinical profiles were available for 120 patients. The male-to-female ratio was 2.3:1 and the median onset age was 42 years. The median disease duration at diagnosis was 25 months. Most patients presented with upper limb-dominant muscle weakness. Motor nerve conduction blocks were found in 62% of patients and positive anti-GM1 IgM antibody results in 54%. A total of 117 (98%) patients received immunoglobulin therapy, and 91% of them showed improvement. At the time of the last visit (median, 82 months from treatment initiation), 89 (74%) patients were receiving maintenance immunoglobulin therapy. A slight progression of neurological deficits was observed during follow-up. Most patients with MMN in Japan received induction and maintenance immunoglobulin therapies, which appear to suppress long-term disease progression.

Autoantibodies in Chronic Immune-Mediated Demyelinating Polyneuropathy

Autoantibodies against nodal and paranodal proteins, such as neurofascin 140/186, neurofascin 155, contactin 1, and contactin-associated protein 1, have been identified in subsets of patients with chronic inflammatory demyelinating polyneuropathy. Their distinctive characteristics including poor response to immunoglobulin led to the establishment of a new disease entity called "autoimmune nodopathies." IgM monoclonal antibodies against myelin-associated glycoproteins cause intractable sensory-dominant demyelinating polyneuropathy. IgM anti-GM1 and IgG anti-LM1 antibodies are associated with multifocal motor neuropathy and chronic inflammatory demyelinating polyneuropathy, respectively. Monoclonal IgM against disialosyl ganglioside epitopes induces chronic ataxic neuropathy with ophthalmoplegia and cold agglutinin.

Multifocal motor neuropathy is not associated with altered innate immune responses to endotoxin

ObjectiveAntibody- and complement-mediated peripheral nerve inflammation are central in the pathogenesis of MMN. Here, we studied innate immune responses to endotoxin in patients with MMN and controls to further our understanding of MMN risk factors and disease modifiers. MethodsWe stimulated whole blood of 52 patients with MMN and 24 controls with endotoxin and collected plasma. With a multiplex assay, we determined levels of the immunoregulating proteins IL-1RA, IL-1β, IL-6, IL-10, IL-21, TNF-α, IL-8 and CD40L in unstimulated and LPS-stimulated plasma. We compared baseline and stimulated protein levels between patients and controls and correlated concentrations to clinical parameters. ResultsProtein level changes after stimulation were comparable between groups (p > 0.05). IL-1RA, IL-1β, IL-6 and IL-21 baseline concentrations showed a positive correlation with monthly IVIg dosage (all corrected p-values < 0.016). Patients with anti-GM1 IgM antibodies showed a more pronounced IL-21 increase after stimulation (p 0.048). ConclusionsAltered endotoxin-induced innate immune responses are unlikely to be a susceptibility factor for MMN.

High and Persistent Anti-GM1 Antibody Titers Are Associated With Poor Clinical Recovery in Guillain-Barré Syndrome.

Guillain-Barré syndrome (GBS) is an acute immune-mediated polyradiculoneuropathy that may follow a preceding infection inducing a cross-reactive antibody response to glycosphingolipids in peripheral nerves. The immune response in GBS is considered to be short lasting, explaining its monophasic clinical course. However, the disease course varies between patients, and residual deficits frequently occur. The duration of the antibody response has not been defined extensively in GBS, and the persistence of these antibodies may impair clinical recovery. The aim of this study was to determine the titer course of serum antibody titers to the ganglioside GM1 in relation to clinical course and outcome in patients with GBS. Acute-phase sera from patients with GBS included in previous therapeutic trials were screened for anti-GM1 IgG and IgM antibodies in ELISA. Anti-GM1 antibody titers were determined in sera collected at entry and during a 6-month follow-up. Clinical course and outcomes were compared between groups based on the titer course. Anti-GM1 antibodies were detected in 78 (20.7%) of 377 included patients. The anti-GM1 IgG and IgM antibody titer course was highly variable between patients. A subset of anti-GM1-positive patients had persistent anti-GM1 antibodies at 3 months (n = 27/43 [62.8%]) and 6 months (n = 19/41 [46.3%]). Patients with a high anti-GM1 IgG and IgM titer at entry recovered more slowly and less complete than anti-GM1-negative patients (IgG: p = 0.015, IgM: p = 0.03). High vs low IgG titers were independently associated with poor outcome after correcting for known prognostic factors (p = 0.046). Among patients with a high anti-GM1 IgG titer at entry, a slow titer decline was associated with poor outcome at 4 weeks (p = 0.003) and 6 months (p = 0.032). Persistent high IgG titers at 3 and 6 months were associated with poor outcome at 6 months (3 months: p = 0.022, 6 months: p = 0.004). High anti-GM1 IgG and IgM antibody titers at entry and persistent high anti-GM1 IgG antibody titers are associated with poor outcome in patients with GBS. Antibody persistency indicates ongoing antibody production long after the acute disease state in GBS. Further research is required to determine whether antibody persistency interferes with nerve recovery and is a target for treatments.

Safety, Efficacy, And Pharmacokinetics of Argx-117 in Adults With Multifocal Motor Neuropathy: A Global, Multicenter, Placebo Controlled Phase 2 Study (Arda)

Objective To report the study design of a Phase 2, multicenter, randomized, placebo controlled, parallel-group study (ARDA, NCT05225675) will assess the safety, efficacy, PK, and PD of ARGX-117 in adults with MMN. Background Multifocal motor neuropathy (MMN) is a chronic, immune-mediated neuropathy characterized by progressive asymmetric weakness predominantly affecting the distal upper limbs. MMN is often associated with anti-GM1 IgM antibodies targeting the axolemma at the node of Ranvier, leading to activation of the classical complement pathway which drives subsequent damage to the axon. IVIg is the only proven effective therapy. ARGX-117 is a novel monoclonal antibody that inhibits complement factor 2 (C2). Using an in vitro model for MMN, ARGX-117 was shown to block IgM-mediated classical pathway complement activation on both motor neurons and Schwann cells. ARGX-117 is being studied in adults with MMN in a Phase 2, multicenter, randomized, placebo controlled, parallel-group study. Design/Methods Forty-eight participants will be recruited and assigned to one of two dosing cohorts (24 participants each) and randomized 2:1 within each cohort to receive either ARGX-117 or placebo. Key inclusion criteria include: diagnosis of probable or definite MMN per 2010 EFNS/PNS guidelines, stable IVIg regimen, and IVIg treatment dependency. The primary objective is safety based on adverse event monitoring and other safety assessments. Secondary objectives include assessment of efficacy measured as strength and functional disability, pharmacokinetics, pharmacodynamics (C2 and CH50), and immunogenicity of ARGX-117. After completing the 16-week treatment period, participants may enroll in an open-label extension study, or enter the safety follow-up period. Results This ongoing phase 2 study will assess the safety and efficacy of ARGX-117 in participants with MMN. Conclusions The results of this study will inform and direct future studies of ARGX-117 in this patient population.

Mixed IgG and IgM anti-GM1 ganglioside antibody positive multifocal motor neuropathy with severe secondary axonal loss in a Filipino female

Approximately 40% of patients with multifocal motor neuropathy had anti-GM1 IgM antibodies, while only 1 out of 88 patients had anti-GM1 IgG antibodies. Unlike its predominantly demyelinating IgM counterpart, the anti-GM1 IgG antibody is often seen in the axonal variant of Guillain Barre syndrome. As it affects axons, it is also associated with worse prognosis. We report here a 58-year-old woman who was admitted for 3 months history of progressive asymmetric weakness, initially involving the right-hand extensors, eventually affecting the contralateral side and the lower extremities. The electrodiagnostic examination revealed multifocal pure motor demyelinating neuropathy with severe axonal loss. On nerve ultrasound, the axons were small in non-compressive areas. The extremely elevated anti-GM1 IgM titer (1:51,200, nv&lt;1:800) was consistent with the diagnosis of MMN. Her anti-GM1 IgG antibodies (1: 12,800, nv&lt;1:800) was also elevated. In conclusion, the presence of concomitant anti-GM IgG and anti-GM1 IgM may lead to an MMN with more severe axonal loss.

Chronic inflammatory demyelinating polyneuropathy and psoriasis comorbidity with significantly alleviated in symptoms after secukinumab: case report

BackgroundChronic inflammatory demyelinating polyneuropathy (CIDP) is an autoimmune disease that involves damage to the peripheral nervous system. The course of the disease can progress for more than 8 weeks, with frequent incidences of relapse-remission courses. This article reported a rare combination of CIDP with fluctuating symptoms, recurrence-remission, and comorbidity with psoriasis.Case presentationA 29-year-old male patient with repeated limb weakness and numbness was admitted to the hospital several times in the past six months. He had a history of psoriasis for 6 years, and the medications (clobetasol propionate ointment and calcipotriol ointment) treated for psoriasis were discontinued 1 year ago. During the hospitalization, repeated intravenous injections of human immunoglobulin G (IVIg), immunoadsorption, and secukinumab were performed. Nerve electrophysiology tests, ganglioside autoantibody spectrum tests, and clinical MRC muscle strength scores were performed on a regular basis to confirm the diagnosis of CIDP. The patient was regularly followed up.ResultsAfter repeated rounds of human IVIg and immunoadsorption, the patient’s MRC score was increased by ≥ 6 points. The first ganglioside autoantibody spectrum test showed anti-GQ1b IgG ( +) and anti-GM1 IgM ( +) antibodies, and all were negative after re-examination. Finally, the patient was treated with the IL-17A inhibitor secukinumab for psoriasis. During 7 months of follow-up, the CIDP and psoriasis symptoms are relatively stable.ConclusionCombination of IVIg and immunoadsorption was highly effective in treating CIDP complicated with psoriasis. The clinical manifestations of CIDP are diverse. When relapse-remission occurs in the course of the disease, it is necessary to clarify whether it is combined with other autoimmune diseases and should control the autoimmune diseases as soon as possible.

Facial Diplegia as the Sole Manifestation of Post-Vaccination Guillain-Barre Syndrome: A Case Report and Literature Review.

Recently, a large study concluded that certain brands of vaccines may increase the risk of Bell's palsy and Guillain Barre Syndrome (GBS). As to whether vaccination after COVID-19 modify the risk of Bell's palsy or GBS has not yet been studied. Here we report a 35years old COVID-19 survivor whom in less than 2weeks after his second dose of inactivated SARS-CoV2 vaccine, developed bilateral facial nerve paralysis. In addition, he had hyperacusis, dysgeusia and decreased lacrimation without any signs of sensory and motor deficits in the limbs. His limb nerve conduction study (NCS) was unremarkable in contrast to bilaterally abnormal facial NCS and blink reflexes. Although he had negative anti-GM1 IgG and IgM antibodies, he has marked albuminocytologic dissociation, classic of acute inflammatory demyelinating polyneuropathy. To date, there were no similar case reports which published the occurrence of facial diplegia as sole manifestation of GBS in a post COVID-19 patient who recently completed vaccination. We believe that molecular mimicry, induced by magnified immune response from both COVID-19 and vaccination may have caused the symptom.

Classical Complement Pathway Inhibition in a "Human-On-A-Chip" Model of Autoimmune Demyelinating Neuropathies.

Chronic autoimmune demyelinating neuropathies are a group of rare neuromuscular disorders with complex, poorly characterized etiology. Here we describe a phenotypic, human-on-a-chip (HoaC) electrical conduction model of two rare autoimmune demyelinating neuropathies, chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN), and explore the efficacy of TNT005, a monoclonal antibody inhibitor of the classical complement pathway. Patient sera was shown to contain anti-GM1 IgM and IgG antibodies capable of binding to human primary Schwann cells and induced pluripotent stem cell derived motoneurons. Patient autoantibody binding was sufficient to activate the classical complement pathway resulting in detection of C3b and C5b-9 deposits. A HoaC model, using a microelectrode array with directed axonal outgrowth over the electrodes treated with patient sera, exhibited reductions in motoneuron action potential frequency and conduction velocity. TNT005 rescued the serum-induced complement deposition and functional deficits while treatment with an isotype control antibody had no rescue effect. These data indicate that complement activation by CIDP and MMN patient serum is sufficient to mimic neurophysiological features of each disease and that complement inhibition with TNT005 was sufficient to rescue these pathological effects and provide efficacy data included in an investigational new drug application, demonstrating the model's translational potential.

Serum antiganglioside antibodies in patients with autoimmune limbic encephalitis.

Ganglioside antibodies are identified not only in patients with inflammatory neuropathies but also several central nervous system disorders and paraneoplastic neuropathies. Our aim was to investigate whether ganglioside antibodies are found in autoimmune encephalitis patients and may function as a diagnostic and prognostic biomarker. Sera and cerebrospinal fluid (CSF) samples of 33 patients fulfilling the criteria for probable autoimmune encephalitis were collected within the first week of clinical manifestation. None of the patients had evident symptoms and findings of peripheral polyneuropathy. Well-characterized antineuronal and paraneoplastic antibodies were investigated in sera and CSF and antiganglioside (antiGM1, GM2, GM3, GD1a, GD1b, GT1b, and GQ1b) IgG and IgM antibodies were measured in sera using commercial immunoblots. Twenty-eight of 33 autoimmune encephalitis patients displayed antibodies against neuronal surface or onco-neural antigens with N-methyl-D-aspartate receptor (NMDAR), glutamic acid decarboxylase (GAD) and Hu antibodies being the most prevalent. While no antiganglioside IgG antibodies were found, 4 patients (2 anti-NMDAR+, 1 anti-GAD+ and 1 antibody negative) with autoimmune limbic encephalitis displayed anti-GM1, anti-GM2, anti-GM3 or anti-GQ1b IgM antibodies. There was no apparent association between antiganglioside positivity and clinical and demographic features. Serum ganglioside IgM antibodies may infrequently emerge during the clinical course of autoimmune limbic encephalitis without evident polyneuropathy. Absence of the IgG response suggests that these antibodies might have developed as a hyperacute immune response to neuro-axonal destruction. Nevertheless, potential impact of ganglioside antibodies on axonal degeneration and neuronal loss in limbic encephalitis pends to be further investigated.

Anti-GM1 IgM antibody positive axonal variant of Guillain-Barre-syndrome in a pediatric patient with dengue fever

IntroductionWhile children of all ages may be affected by Guillain-Barre-Syndrome (GBS), there are no reports of Dengue Fever (DF) as the preceding or concurrent infection in this age group. In addition, the presence of anti-GM1 IgM antibody, commonly seen in Multifocal Motor Neuropathy, is rarely encountered in both axonal and demyelinating variants of GBS. Moreover, only few neuromuscular ultrasound findings of the axonal variant in children were reported in the literature. CaseHere we present a nine-year-old female who developed the classic signs, symptoms and neurophysiologic findings of axonal type of GBS during DF. She had elevated anti-GM1 IgM antibody atypical of this variant and diffusely enlarged nerves via neuromuscular ultrasound. ConclusionIn a pediatric patient with DF and acute flaccid paralysis, GBS should always be one of the considerations. Although rare, anti-ganglioside GM1 IgM antibody can still be found in axonal variant of GBS.

A case of monofocal motor neuropathy with GM1 and GD1b antibodies improved with intravenous immunoglobulin

Multifocal motor neuropathy is a purely motor neuropathy with a probably dysimmune pathogenesis, supported by the presence of anti-GM1 IgM antibodies in about half of the cases. Single nerve involvement allows for diagnosis of possible multifocal motor neuropathy. We present the case of a middle age man presenting with progressive weakness and hypotrophy in the left leg and difficulty in walking, in which we have diagnosed a dysimmune mononeuropathy. Treatment with IVIg was performed with substantial improvement. Although only one nerve is involved, early diagnosis of dysimmune mononeuropathy is important to start IVIg treatment that is often decisive.

Co-occurrence of Guillain-Barré Syndrome and Acute Disseminated Encephalomyelitis with Dual Positive of Anti-GT1a and Anti-GM1 Antibodies

Acute disseminated encephalomyelitis (ADEM) and Guillain-Barré syndrome (GBS) are both rare post-infectious neurological disorders. The co-existence of these conditions has often been reported despite of low incidence. We describe a 20-year-old male, who presented with acute flaccid paralysis and encephalopathy. The patient showed reversible MRI lesions suggesting ADEM. This case showed anti-GT1a IgG and anti-GM1 IgM antibodies positivity. We suggest that certain immunogenicity within central and peripheral nervous system may share a common autoimmune process during the disease course. Key Words: Acute disseminated encephalomyelitis, Guillain-Barré syndrome, Gangliosides

Neutropenia Following Intravenous Immunoglobulin Administration in a Patient with Multifocal Motor Neuropathy with Conduction Block

Intravenous immunoglobulin (IVIG) is the treatment of choice in patients with multifocal motor neuropathy with conduction block (MMNCB). Although IVIG is considered generally safe, neutropenia following IVIG infusion has been recognized as a rare hematologic side effect. Herein we report a patient with MMNCB who developed severe neutropenia following IVIG administration. A 41 year old woman presented with progressive weakness of her left lower extremity with frequent muscle cramps. Nerve conduction study revealed marked conduction blocks on right ulnar and right tibial nerves. Serum IgM anti-GM1 antibody was detected. Neutrophil count decreased from day 2 and recovered after 2 weeks following IVIG infusion. To our knowledge, neutropenia following IVIG infusion in MMNCB has never been discussed apart, although it can be an important clinical issue especially for patients with MMNCB.

Anti-sulfatide reactivity in patients with celiac disease

Objective: To explore a possible significance of the presence of anti-ganglioside and anti-sulfatide antibodies in sera of adult patients with celiac disease (CD) in different clinical scenario.Methods: We selected 22 adult patients with newly diagnosed CD and 20 age–sex matched non-CD controls. Patients’ serum was tested – before and after at least 6 months on a gluten-free diet (GFD) – for anti-GM1, GM2, GM3, GD1a, GD1b, GD3, GT1a, GT1b, GQ1b and sulfatide IgM, IgG and IgA auto-antibodies, by means of a dot blot technique and enzyme-linked immunosorbent assay (ELISA).Results: We found the presence of auto-antibodies in untreated patients. In particular, anti-sulfatide IgG antibodies were present in 8 (36%) patients independently of the presence of neurological symptoms. Anti-sulfatide IgA antibodies were present in 3 (19%) patients. During GFD, anti-sulfatide IgG disappeared in all the patients, whereas IgA were observed in 2 patients. Anti-sulfatide, anti-GM1 and anti-GM2 IgM antibodies were also observed in 2 patients on a GFD. All the other auto-antibodies were absent and no demographic or clinical parameters were associated. Non-CD controls did not present any auto-antibody.Conclusions: We found anti-sulfatide IgG antibodies in CD patients on a gluten-containing diet. Anti-sulfatide IgA antibodies persisted during GFD together with the occurrence of other IgM auto-antibodies. These data suggest a possible link between gluten and IgG auto-antibodies.

Polyclonal IgM and IgA block in vitro complement deposition mediated by anti-ganglioside antibodies in autoimmune neuropathies

Intravenous immunoglobulin (IVIG), consisting of IgG, is the first-line treatment for Guillain–Barré syndrome and multifocal motor neuropathy. IgG, but neither IgM nor IgA, has been demonstrated in vitro to inhibit complement deposition mediated by anti-ganglioside autoantibodies in sera from patients with both conditions. The objective of this study is to investigate the in vitro effectiveness of IgM and IgA in inhibiting complement deposition to ganglioside/anti-ganglioside antibody complexes. Serum samples were obtained from patients with multifocal motor neuropathy associated with anti-GM1 IgM antibodies, Guillain–Barré syndrome associated with anti-GM1 IgG antibodies and Miller Fisher syndrome associated with anti-GQ1b IgG antibodies. Inhibition of complement deposition using different immunoglobulin preparations was measured by enzyme-linked immunosorbent assay. IgM/A-enriched IVIG and immunoglobulin isotypes (polyclonal IgM and IgA) showed higher potential in inhibiting complement deposition than standard IVIG. Although the safety concerns about the use of IgM and IgA for an immunotherapy still remain, IgM and IgA may serve as an alternative immunotherapy in those anti-ganglioside antibody-mediated neuropathies.

Human immune globulin infusion in the management of multifocal motor neuropathy.

Multifocal motor neuropathy (MMN) is a debilitating and rare disease causing profound weakness with minimal to no sensory symptoms. Conduction block is frequently seen on electrodiagnostic testing. An immune-mediated pathology is suspected though the exact underlying pathophysiology has yet to be elucidated. The presence of anti-GM1 ganglioside IgM antibodies coupled with favorable response to intravenous and subcutaneous immunoglobulins supports a complement-mediated mechanism which leads to destruction of nerve tissue with probable predilection to the nodes of Ranvier. High-dose immunoglobulin currently is the only treatment with proven efficacy for MMN patients. Unfortunately, many patients experience decreased responsiveness to immunoglobulins over time, requiring higher and more frequent dosing. In this review, we will focus on the pharmacology, efficacy, safety, and tolerability of intravenous and subcutaneous immune globulin infusion for treatment of MMN.

Complement activity is associated with disease severity in multifocal motor neuropathy

Objective:To investigate whether high innate activity of the classical and lectin pathways of complement is associated with multifocal motor neuropathy (MMN) and whether levels of innate complement activity or the potential of anti-GM1 antibodies to activate the complement system correlate with disease severity.Methods:We performed a case-control study including 79 patients with MMN and 79 matched healthy controls. Muscle weakness was documented with Medical Research Council scale sum score and axonal loss with nerve conduction studies. Activity of the classical and lectin pathways of complement was assessed by ELISA. We also determined serum mannose-binding lectin (MBL) concentrations and polymorphisms in the MBL gene (MBL2) and quantified complement-activating properties of anti-GM1 IgM antibodies by ELISA.Results:Activity of the classical and lectin pathways, MBL2 genotypes, and serum MBL concentrations did not differ between patients and controls. Complement activation by anti-GM1 IgM antibodies was exclusively mediated through the classical pathway and correlated with antibody titers (p < 0.001). Logistic regression analysis showed that both high innate activity of the classical pathway of complement and high complement-activating capacity of anti-GM1 IgM antibodies were significantly associated with more severe muscle weakness and axonal loss.Conclusion:High innate activity of the classical pathway of complement and efficient complement-activating properties of anti-GM1 IgM antibodies are determinants of disease severity in patients with MMN. These findings underline the importance of anti-GM1 antibody–mediated complement activation in the pathogenesis and clinical course of MMN.

Cytokine profiles in multifocal motor neuropathy and progressive muscular atrophy

Multifocal motor neuropathy (MMN) and progressive muscular atrophy (PMA) are associated with IgM monoclonal gammopathy or the presence IgM anti-GM1-antibodies. To further investigate the pathophysiology of MMN and PMA we determined concentrations of 16 mainly B-cell associated inflammatory markers in serum from 25 patients with MMN, 55 patients with PMA, 25 patients with amyotrophic lateral sclerosis (ALS) and 50 healthy controls. Median serum concentrations of the 16 tested cytokines and chemokines were not significantly increased in patients with MMN or patients with PMA, irrespective of the presence of IgM monoclonal gammopathy or high IgM anti-GM1 antibodies. These results argue against a systemic B-cell mediated immune response underlying the pathogenesis of MMN and PMA.

The Diagnostic Utility of Determining Anti-GM1: GalC Complex Antibodies in Multifocal Motor Neuropathy: A Validation Study.

Background: Multifocal motor neuropathy (MMN) is associated with IgM antibodies to GM1 ganglioside. The importance of the lipid milieu that might facilitate or inhibit antibody binding to GM1 in immunoassays is well recognised. Existing studies, using a range of different approaches, generally concur that anti-GM1 IgM antibody detection rates are improved by the addition of galactocerebroside (GalC) to the GM1 assay.Objective: The current study sought to formally evaluate the clinical utility of the GM1:GalC complex assay in the diagnosis of MMN.Methods: Anti-GM1 and -GM1:GalC antibodies were examined using ELISA and glycoarray (dot blot) in a fully blinded study design, consisting of 100 MMN patients, 100 ALS cases and 100 healthy controls.Results: The detection of anti-GM1 Abs using glycoarray was 67% sensitive and 85% specific. The addition of GalC to GM1, (1:1 weight to weight ratio), increased the sensitivity to 81% , whilst dropping specificity to 80% . Increasing the GalC content to a 1:5 ratio (or higher) further decreased specificity, and in doing so limited the usefulness of the GM1:GalC assay to the level of GM1 alone. The addition of GalC to the ELISA method also significantly increased sensitivity compared with GM1 alone, albeit with a significant decrease in specificity.Conclusions: This study indicates that the GM1:GalC assay is an advantageous assay adaptation for detecting anti-GM1 antibodies in MMN, using either glycoarray or ELISA, and warrants introduction into clinical diagnostic practice.