Anti-ganglioside antibodies in amyotrophic lateral sclerosis revisited

The presence and clinical significance of autoantibodies in amyotrophic lateral sclerosis: a narrative review

Amyotrophic lateral sclerosis (ALS) is a debilitating and rapidly fatal neurodegenerative disease, which is characterized by the selective loss of the upper and lower motor neurons. The pathogenesis of ALS remains to be elucidated and has been connected to genetic, environmental and immune conditions. Evidence from clinical and experimental studies has suggested that the immune system played an important role in ALS pathophysiology. Autoantibodies are essential components of the immune system. Several autoantibodies directed at antigens associated with ALS pathogenesis have been identified in the serum and/or cerebrospinal fluid of ALS patients. The aim of this review is to summarize the presence and clinical significance of autoantibodies in ALS.

Diagnostic value of neurofilaments in differentiating motor neuron disease from multifocal motor neuropathy

OBJECTIVE

To evaluate the performance of serum neurofilament light chain (NfL) and cerebrospinal fluid (CSF) phosphorylated neurofilament heavy chain (pNfH) as diagnostic biomarkers for the differentiation between motor neuron disease (MND) and multifocal motor neuropathy (MMN).

METHODS

This retrospective, monocentric study included 16 patients with MMN and 34 incident patients with MND. A subgroup of lower motor neuron (MN) dominant MND patients (n = 24) was analyzed separately. Serum NfL was measured using Ella automated immunoassay, and CSF pNfH was measured using enzyme-linked immunosorbent assay. Area under the curve (AUC), optimal cutoff values (Youden's index), and correlations with demographic characteristics were calculated.

RESULTS

Neurofilament concentrations were significantly higher in MND compared to MMN (p < 0.001), and serum NfL and CSF pNfH correlated strongly with each other (Spearman's rho 0.68, p < 0.001). Serum NfL (AUC 0.946, sensitivity and specificity 94%) and CSF pNfH (AUC 0.937, sensitivity 90.0%, specificity 100%) performed excellent in differentiating MND from MMN. Optimal cutoff values were ≥ 44.15 pg/mL (serum NfL) and ≥ 715.5 pg/mL (CSF pNfH), respectively. Similar results were found when restricting the MND cohort to lower MN dominant patients. Only one MMN patient had serum NfL above the cutoff. Two MND patients presented with neurofilament concentrations below the cutoffs, both featuring a slowly progressive disease.

CONCLUSION

Neurofilaments are valuable supportive biomarkers for the differentiation between MND and MMN. Serum NfL and CSF pNfH perform similarly well and elevated neurofilaments in case of diagnostic uncertainty underpin MND diagnosis.

Miller-Fisher syndrome with positive anti-GD1b and anti-GM1 antibodies combined with multiple autoimmune antibodies: A case report

RATIONALE

Anti-ganglioside antibodies (AGA) play an essential role in the development of Miller-Fisher syndrome (MFS). The positive rate of ganglioside antibodies was exceptionally high in MFS, especially anti-GQ1b antibodies. However, the presence of other ganglioside antibodies does not exclude MFS.

PATIENT CONCERNS

We present a 48-year-old male patient who suddenly developed dizziness, visual rotation, nausea, and vomiting accompanied by unsteady gait and diplopia for 3 days before presentation to our clinic.

DIAGNOSES

On physical examination, the patient's right eye could not fully move to the right side and horizontal nystagmus was found. Coordination was also impaired in the upper and lower extremities with dysmetria and dysdiadochokinesia. The electromyography and cerebrospinal fluid examination results were normal. The serum anti-GQlb antibody test results were negative. However, serum anti-GD1b IgM and anti-GM1 IgM antibodies were positive. Meanwhile, the anti-thyroid peroxidase antibody was >600.00 IU/mL (0.00-34.00), and the anti-SS-A/Ro52 antibody was positive. He was diagnosed with MFS.

INTERVENTIONS

The patient received IVIg treatment for 5 days (0.4 g/kg/day) from day 2 to day 6 of hospitalization. On the 7th day of admission, the patient was administered intravenous methylprednisolone (500 mg/day), which was gradually reduced.

OUTCOMES

The patient's symptoms improved after treatment with immunoglobulins and hormones.

LESSONS

We report a case of MFS with positive anti-GD1b and anti-GM1 antibodies combined with multiple autoimmune antibodies. Positive ganglioside antibodies may be used as supporting evidence for the diagnosis; however, the diagnosis of MFS is more dependent on clinical symptoms.

Ganglioside GM1 and the Central Nervous System

GM1 is one of the major glycosphingolipids (GSLs) on the cell surface in the central nervous system (CNS). Its expression level, distribution pattern, and lipid composition are dependent upon cell and tissue type, developmental stage, and disease state, which suggests a potentially broad spectrum of functions of GM1 in various neurological and neuropathological processes. The major focus of this review is the roles that GM1 plays in the development and activities of brains, such as cell differentiation, neuritogenesis, neuroregeneration, signal transducing, memory, and cognition, as well as the molecular basis and mechanisms for these functions. Overall, GM1 is protective for the CNS. Additionally, this review has also examined the relationships between GM1 and neurological disorders, such as Alzheimer's disease, Parkinson's disease, GM1 gangliosidosis, Huntington's disease, epilepsy and seizure, amyotrophic lateral sclerosis, depression, alcohol dependence, etc., and the functional roles and therapeutic applications of GM1 in these disorders. Finally, current obstacles that hinder more in-depth investigations and understanding of GM1 and the future directions in this field are discussed.

Ceramide and Sphingosine-1-Phosphate in Neurodegenerative Disorders and Their Potential Involvement in Therapy

Neurodegenerative disorders (ND) are progressive diseases of the nervous system, often without resolutive therapy. They are characterized by a progressive impairment and loss of specific brain regions and neuronal populations. Cellular and animal model studies have identified several molecular mechanisms that play an important role in the pathogenesis of ND. Among them are alterations of lipids, in particular sphingolipids, that play a crucial role in neurodegeneration. Overall, during ND, ceramide-dependent pro-apoptotic signalling is promoted, whereas levels of the neuroprotective spingosine-1-phosphate are reduced. Moreover, ND are characterized by alterations of the metabolism of complex sphingolipids. The finding that altered sphingolipid metabolism has a role in ND suggests that its modulation might provide a useful strategy to identify targets for possible therapies. In this review, based on the current literature, we will discuss how bioactive sphingolipids (spingosine-1-phosphate and ceramide) are involved in some ND (Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis) and their possible involvement in therapies.

Amyotrophic lateral sclerosis mimics

Amyotrophic lateral sclerosis (ALS) is the most common adult-onset motor neuron disorder characterized by progressive degeneration of cortical, bulbar, and spinal motor neurons. When a patient presents with a progressive upper and/or lower motor syndrome, clinicians must pay particular attention to any atypical features in the history and/or clinical examination suggesting an alternate diagnosis, as up to 10% percent of patients initially diagnosed with ALS have a mimic of ALS. ALS is a clinical diagnosis and requires the exclusion of other disorders that may have similar presentations but a more favorable prognosis or an effective therapy. Because there is currently no specific diagnostic biomarker that is sensitive or specific for ALS, understanding the spectrum of clinical presentations of ALS and its mimics is paramount. While true mimics of ALS are rare, the clinician must correctly identify these disorders to avoid the misdiagnosis of ALS and to initiate effective treatment where available.

Impact of antecedent infections on the antibodies against gangliosides and ganglioside complexes in guillain-barré syndrome: A correlative study

Background and Aims:

Guillain-Barré Syndrome (GBS), an immune-mediated neuropathy, is characterized by antibodies against gangliosides/ganglioside complexes (GSCs) of peripheral nerves. Antecedent infections have been reported to induce antibodies that cross-react with the host gangliosides and thereby have a pivotal role in conferring an increased risk for developing GBS. Data pertaining to the impact of various antecedent infections, particularly those prevalent in tropical countries like India on the ganglioside/GSC antibodies is sparse. We aimed at exploring the association between six antecedent infections and the profile of ganglioside/GSC antibodies in GBS.

Methods:

Patients with GBS (n = 150) and healthy controls (n = 50) were examined for the serum profile of antibodies against GM1, GM2, GD1a, GD1b, GT1b, and GQ1b and their GSCs by ELISA. These antibodies were correlated with immunoreactivities against Campylobacter jejuni, Japanese encephalitis (JE), dengue, influenza, zika, and chikungunya infections.

Results:

The frequencies of antibodies against six single gangliosides (P < 0.001) and their GSCs (P = 0.039) were significantly higher in patients as compared to controls. Except for GT1b-antibody which was more frequent in axonal GBS, none of the other ganglioside/GSC antibodies correlated with the electrophysiological subtypes of GBS. Antecedent JE infection was significantly associated with increased frequency of antibodies against GD1a, GD1b, GT1b, and GQ1b. Antibodies against GSCs were not influenced by the antecedent infections.

Interpretation:

This study for the first time shows an association between antecedent JE infection and ganglioside antibodies in GBS. This finding reinforces the determining role of antecedent infections on ganglioside antibody responses and the subsequent immunological processes in GBS.

Amyotrophic lateral sclerosis in a patient who recovered from Miller Fisher Syndrome: The role of GQ1b antibody revisited

Miller Fisher Syndrome (MFS), a variant of Guillain Barre Syndrome (GBS), and amyotrophic lateral sclerosis (ALS) are two rare neuromuscular diseases that are usually unrelated. While ganglioside antibodies have a common relation with MFS and GBS, they have also been found in association, albeit less commonly, with ALS. A patient experiencing MFS and then ALS in tandem has never been documented. We discuss a case demonstrating these findings, with GQ1b elevated on both occasions. The pathophysiologic role of GQ1b is explored.

The Involvement of Lactosylceramide in Central Nervous System Inflammation Related to Neurodegenerative Disease

Neurodegenerative diseases are a class of slow-progressing terminal illnesses characterized by neuronal lesions, such as multiple sclerosis [MS, Alzheimer’s disease (AD), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS)]. Their incidence increases with age, and the associated burden on families and society will become increasingly more prominent with aging of the general population. In recent years, there is growing studies have shown that lactosylceramide (LacCer) plays a crucial role in the progression of neurodegeneration, although these diseases have different pathogenic mechanisms and etiological characteristics. Based on latest research progress, this study expounds the pathogenic role of LacCer in driving central nervous system (CNS) inflammation, as well as the role of membrane microstructure domain (lipid rafts) and metabolite gangliosides, and discusses in detail their links with the pathogenesis of neurodegenerative diseases, with a view to providing new strategies and ideas for the study of pathological mechanisms and drug development for neurodegenerative diseases in the future.

Sporadic Amyotrophic Lateral Sclerosis Due to a FUS P525L Mutation with Asymmetric Muscle Weakness and Anti-ganglioside Antibodies

Amyotrophic lateral sclerosis (ALS) due to a fused in sarcoma (FUS) P525L mutation is characterized by a rapidly progressive course. Multifocal motor neuropathy (MMN) may resemble ALS in early stage and is associated with anti-ganglioside antibodies. A 38-year-old woman was admitted to our hospital because of progressive muscle weakness in the right limbs. She had mild mental retardation and minor deformities. Initially, we suspected MMN given the asymmetric muscle weakness and detection of anti-ganglioside antibodies. However, physical and electrophysiological tests did not support MMN, instead suggesting ALS. We confirmed a heterozygous P525L mutation and finally diagnosed this case as ALS due to an FUS mutation.

Very Early Involvement of Innate Immunity in Peripheral Nerve Degeneration in SOD1-G93A Mice

Recent preclinical and clinical evidence suggest that immune system has a role in the progression and prognosis of Amyotrophic Lateral Sclerosis (ALS), but the identification of a clear mechanism and immune players remains to be elucidated. Here, we have investigated, in 30 and 60 days (presymptomatic) and 120 days (symptomatic) old SOD1-G93A mice, systemic, peripheral, and central innate and adaptive immune and inflammatory response, correlating it with the progression of the neurodegeneration in neuromuscular junction, sciatic nerves, and spinal cord. Surprisingly, we found a very initial (45-60 days) presence of IgG in sciatic nerves together with a gradual enhancement of A20/TNFAIP3 (protein controlling NF-κB signalling) and a concomitantly significant increase and activation of circulating mast cells (MCs) as well as MCs and macrophages in sciatic nerve and an enhancement of IL-6 and IL-10. This immunological frame coincided with a myelin aggregation. The 30-60 days old SOD1-G93A mice didn't show real elements of neuroinflammation and neurodegeneration in spinal cord. In 120 days old mice macrophages and monocytes are widely diffused in sciatic nerves, peripheral neurodegeneration reaches the tip, high circulating levels of TNFα and IL-2 were found and spinal cord exhibits clear signs of neural damage and infiltrating immune cells. Our results underpin a clear immunological disorder at the origin of ALS axonopathy, in which MCs are involved in the initiation and sustaining of inflammatory events. These data cannot be considered a mere epiphenomenon of motor neuron degeneration and reveal new potential selective immune targets in ALS therapy.

Gangliosides in the Brain: Physiology, Pathophysiology and Therapeutic Applications

Gangliosides are glycosphingolipids highly abundant in the nervous system, and carry most of the sialic acid residues in the brain. Gangliosides are enriched in cell membrane microdomains ("lipid rafts") and play important roles in the modulation of membrane proteins and ion channels, in cell signaling and in the communication among cells. The importance of gangliosides in the brain is highlighted by the fact that loss of function mutations in ganglioside biosynthetic enzymes result in severe neurodegenerative disorders, often characterized by very early or childhood onset. In addition, changes in the ganglioside profile (i.e., in the relative abundance of specific gangliosides) were reported in healthy aging and in common neurological conditions, including Huntington's disease (HD), Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), stroke, multiple sclerosis and epilepsy. At least in HD, PD and in some forms of epilepsy, experimental evidence strongly suggests a potential role of gangliosides in disease pathogenesis and potential treatment. In this review, we will summarize ganglioside functions that are crucial to maintain brain health, we will review changes in ganglioside levels that occur in major neurological conditions and we will discuss their contribution to cellular dysfunctions and disease pathogenesis. Finally, we will review evidence of the beneficial roles exerted by gangliosides, GM1 in particular, in disease models and in clinical trials.

Physiology of gangliosides and the role of antiganglioside antibodies in human diseases

Gangliosides are structurally and functionally polymorphic sialic acid containing glycosphingolipids that are widely distributed in the human body. They play important roles in protecting us against immune attacks, yet they can become targets for autoimmunity and act as receptors for microbes, like the influenza viruses, and toxins, such as the cholera toxin. The expression patterns of gangliosides vary in different tissues, during different life periods, as well as in different animals. Antibodies against gangliosides (AGA) can target immune attack e.g., against neuronal cells and neutralize their complement inhibitory activity. AGAs are important especially in acquired demyelinating immune-mediated neuropathies, like Guillain-Barré syndrome (GBS) and its variant, the Miller-Fisher syndrome (MFS). They can emerge in response to different microbial agents and immunological insults. Thereby, they can be involved in a variety of diseases. In addition, antibodies against GM3 were found in the sera of patients vaccinated with Pandemrix®, who developed secondary narcolepsy, strongly supporting the autoimmune etiology of the disease.

Recommendations for cerebrospinal fluid analysis

Diseases of the central nervous system (CNS) mean for the human organism a potentially dangerous situation. An investigation of cerebrospinal fluid (CSF) provides important information about a character of CNS impairment in the decision-making diagnostic and therapeutic algorithm. The authors present a brief overview of available cerebrospinal fluid assays, shortened indication criteria, a recommended algorithm of CSF assessment in different suspected diseases, and a view of the external quality system. The whole portfolio of obtainable CSF methodology is further subdivided according to the adequate choice into the first and inevitable basic routine panel, and following complicated analyses of highly specialized character. The basic panel is considered for standard laboratories, the complete specialized assessment should be provided by a super-consulting laboratory.

Novel autoantibodies against the proteasome subunit PSMA7 in amyotrophic lateral sclerosis

OBJECTIVE

To identify autoantibodies using sera from ALS patients and elucidate their roles in disease pathology.

METHODS

An immunological screening was performed with a phage expression library SEREX method using sera from 3 ALS patients to identify ALS-related autoantibodies. Levels of antibodies identified by SEREX were measured in 33 ALS patients and 30 normal controls (NCs) by AlphaLISA using recombinant non-full-length proteins. The results were then validated by ELISA using full-length proteins in 71 ALS patients, 30 NCs and 34 disease controls (DCs). The relationship between the titres and clinical profiles of ALS patients were examined.

RESULTS

Four autoantibodies identified by SEREX were proteasome subunit alpha type 7 (PSMA7), vimentin, hydroxymethylbilane synthase and TBC1 domain family member 2 (TBC1D2). AlphaLISA revealed that only the anti-PSMA7 and anti-TBC1D2 levels were significantly different between the ALS and NCs groups. ELISA showed that only the levels of antibody against PSMA7, involved in protein degradation by the ubiquitin-proteasome pathway (UPP), were higher in the ALS group than both the NC (P < .01) and DC (P = .034) groups. Anti-PSMA7 levels tended to be negatively correlated with the logarithm of disease duration (P = .052) and were significantly positively correlated with the logarithm of creatine kinase levels (P = .011). The anti-PSMA7 antibody levels were different between patients with and without dysphagia (P < .01).

CONCLUSIONS

Serum anti-PSMA7 antibody might be a disease-promoting factor in early-stage ALS and might be a biomarker of ALS. Anti-PSMA7 autoantibody might contribute to the pathogenesis of ALS, possibly via its role in the UPP.

Neuromuscular Junction Dismantling in Amyotrophic Lateral Sclerosis

Neuromuscular junction assembly and plasticity during embryonic, postnatal, and adult life are tightly regulated by the continuous cross-talk among motor nerve endings, muscle fibers, and glial cells. Altered communications among these components is thought to be responsible for the physiological age-related changes at this synapse and possibly for its destruction in pathological states. Neuromuscular junction dismantling plays a crucial role in the onset of Amyotrophic Lateral Sclerosis (ALS). ALS is characterized by the degeneration and death of motor neurons leading to skeletal muscle denervation, atrophy and, most often, death of the patient within five years from diagnosis. ALS is a non-cell autonomous disease as, besides motor neuron degeneration, glial cells, and possibly muscle fibers, play a role in its onset and progression. Here, we will review the recent literature regarding the mechanisms leading to neuromuscular junction disassembly and muscle denervation focusing on the role of the three players of this peripheral tripartite synapse.

Amyotrophic lateral sclerosis: moving towards a new classification system

Amyotrophic lateral sclerosis is a progressive adult-onset neurodegenerative disease that primarily affects upper and lower motor neurons, but also frontotemporal and other regions of the brain. The extent to which each neuronal population is affected varies between individuals. The subsequent patterns of disease progression form the basis of diagnostic criteria and phenotypic classification systems, with considerable overlap in the clinical terms used. This overlap can lead to confusion between diagnosis and phenotype. Formal classification systems such as the El Escorial criteria and the International Classification of Diseases are systematic approaches but they omit features that are important in clinical management, such as rate of progression, genetic basis, or functional effect. Therefore, many neurologists use informal classification approaches that might not be systematic, and could include, for example, anatomical descriptions such as flail-arm syndrome. A new strategy is needed to combine the benefits of a systematic approach to classification with the rich and varied phenotypic descriptions used in clinical practice.

Detection of Naturally Occurring Human Antibodies Against Gangliosides by ELISA

Gangliosides are sialic acid-containing glycolipids that have been considered attractive targets for cancer immunotherapy, based on the qualitative and quantitative changes they suffer during malignant transformation and due to their importance for tumor biology. Natural antibodies against gangliosides have been detected not only in cancer patients but also in healthy donors. The presence of these antibodies can be used as diagnostic or prognostic factor. However, these responses are difficult to detect because anti-ganglioside antibodies are usually of IgM isotype and low affinity. Enzyme Linked Immunosorbent Assay (ELISA) is an immunoassay based on the specific binding of antibodies to antigens bound to a solid phase. These antigens can be glycolipids like gangliosides. An enzyme linked to the last reactant allows the detection of specific binding through the development of color after the addition of a suitable substrate. ELISA combines the specificity of antibodies with the sensitivity of enzyme reactions. The ELISA method described herein can be used to detect antibody responses against gangliosides not only related to cancer but also to autoimmune diseases and infections, both in healthy donors, and patients, untreated or receiving specific immunotherapy.

Serum and CSF GQ1b antibodies in isolated ophthalmologic syndromes

OBJECTIVE

To establish the sensitivity and specificity of serum and CSF antibodies targeting the gangliosides GQ1b (GQ1bAb) in isolated ophthalmologic syndromes, such as acute ophthalmoplegia (AO) and optic neuritis (ON), caused by disorders other than Miller-Fisher syndrome (MFS).

METHODS

We measured serum and CSF GQ1bAb in patients with MFS and with AO or ON caused by other disorders than MFS.

RESULTS

Twenty-one patients with AO (21 serum, 9 CSF), 13 with ON (13 serum, 13 CSF), and 12 with MFS (12 serum, 10 CSF) were included in the study. There were no significant differences in age, sex, and CSF findings between the AO and MFS groups. Elevated serum GQ1b titers occurred in 11 of 12 patients with MFS but in only 1 of the 34 patients without MFS. Sensitivity was 92% (95% confidence interval [CI] 62%-100%) and specificity 97% (95% CI 85%-100%). In CSF, GQ1bAb were identified in 2 of 10 patients with MFS but in none with other disorders. Sensitivity was 20% (95% CI 2%-56%) and specificity 100% (95% CI 85%-100%).

CONCLUSIONS

Increased serum GQ1bAb are highly specific for MFS. Measurement of GQ1bAb in CSF does not improve diagnosis.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that serum GQ1bAb accurately distinguish MFS from other disorders (sensitivity 92%, 95% CI 62%-100%; specificity 97%, 95% CI 85%-100%).

Quantitative GSL-glycome analysis of human whole serum based on an EGCase digestion and glycoblotting method

Glycosphingolipids (GSLs) are lipid molecules linked to carbohydrate units that form the plasma membrane lipid raft, which is clustered with sphingolipids, sterols, and specific proteins, and thereby contributes to membrane physical properties and specific recognition sites for various biological events. These bioactive GSL molecules consequently affect the pathophysiology and pathogenesis of various diseases. Thus, altered expression of GSLs in various diseases may be of importance for disease-related biomarker discovery. However, analysis of GSLs in blood is particularly challenging because GSLs are present at extremely low concentrations in serum/plasma. In this study, we established absolute GSL-glycan analysis of human serum based on endoglycoceramidase digestion and glycoblotting purification. We established two sample preparation protocols, one with and the other without GSL extraction using chloroform/methanol. Similar amounts of GSL-glycans were recovered with the two protocols. Both protocols permitted absolute quantitation of GSL-glycans using as little as 20 μl of serum. Using 10 healthy human serum samples, up to 42 signals corresponding to GSL-glycan compositions could be quantitatively detected, and the total serum GSL-glycan concentration was calculated to be 12.1-21.4 μM. We further applied this method to TLC-prefractionated serum samples. These findings will assist the discovery of disease-related biomarkers by serum GSL-glycomics.