Effects of phospholipids on antiganglioside antibody reactivity in GBS

Exploratory factor analysis determines latent factors in Guillain-Barré syndrome

Exploratory factor analysis (EFA) has been developed as a powerful statistical procedure in psychological research. EFA's purpose is to identify the nature and number of latent constructs (= factors) underlying a set of observed variables. Since the research goal of EFA is to determine what causes the observed responses, EFA is ideal for hypothesis-based studies, such as identifying the number and nature of latent factors (e.g., cause, risk factors, etc.). However, the application of EFA in the biomedical field has been limited. Guillain-Barré syndrome (GBS) is peripheral neuropathy, in which the presence of antibodies to glycolipids has been associated with clinical signs. Although the precise mechanism for the generation of anti-glycolipid antibodies is unclear, we hypothesized that latent factors, such as distinct autoantigens and microbes, could induce different sets of anti-glycolipid antibodies in subsets of GBS patients. Using 55 glycolipid antibody titers from 100 GBS and 30 control sera obtained by glycoarray, we conducted EFA and extracted four factors related to neuroantigens and one potentially suppressive factor, each of which was composed of the distinct set of anti-glycolipid antibodies. The four groups of anti-glycolipid antibodies categorized by unsupervised EFA were consistent with experimental and clinical findings reported previously. Therefore, we proved that unsupervised EFA could be applied to biomedical data to extract latent factors. Applying EFA for other biomedical big data may elucidate latent factors of other diseases with unknown causes or suppressing/exacerbating factors, including COVID-19.

Cholesterol-added antigens can enhance antiglycolipid antibody activity: Application to antibody testing

We analysed the effect of adding cholesterol to glycolipid antigens on antibody activity with enzyme-linked immunosorbent assay in 123 subjects consisting of 96 patients with Guillain-Barré syndrome, 25 Miller Fisher syndrome, and two Bickerstaff brainstem encephalitis. The use of cholesterol-added GM1 antigens increased anti-GM1 activity in 11 out of 23 anti-GM1-positive patients and resulted in six out of 100 anti-GM1-negative patients becoming anti-GM1-positive. Enhancement of anti-GM1 activity by cholesterol addition was significantly associated with antecedent gastrointestinal infection. The use of cholesterol-added glycolipid antigens can increase the detection rate of anti-glycolipid antibodies and accurately evaluate the anti-glycolipid antibody activity in vivo.

Antiglycolipid antibodies in Guillain-Barré and Fisher syndromes: discovery, current status and future perspective

Guillain-Barré syndrome (GBS) and Fisher syndrome (FS) are acute autoimmune neuropathies, often preceded by an infection. Antiglycolipid antibody titres are frequently elevated in sera from the acute-phase patients. Particularly, IgG anti-GQ1b antibodies are positive in as high as 90% of FS cases and thus useful for diagnosis. The development of animal models of antiglycolipid antibody-mediated neuropathies proved that some of these antibodies are directly involved in the pathogenetic mechanisms by binding to the regions where the respective target glycolipid is specifically localised. Discovery of the presence of the antibodies that specifically recognise a new conformational epitope formed by two different gangliosides (ganglioside complex) in the acute-phase sera of some patients with GBS suggested the carbohydrate-carbohydrate interaction between glycolipids. This finding indicated the need for further research in basic glycobiological science. Antiglycolipid antibodies, in particular antigangliosides antibodies, are mostly detected in acute motor axonal neuropathy type of GBS and in FS, and less frequently in the acute inflammatory demyelinating polyneuropathy (AIDP) type of GBS or in central nervous system (CNS) diseases. In the future, the search for the putative antibodies in AIDP and those that might be present in CNS diseases should continue. In addition, more efficient standardisation of antiglycolipid antibody detection methods and use as biomarkers in daily clinical practice in neurology is needed.

Guillain-Barré Syndrome: A Variant Consisting of Facial Diplegia and Paresthesia with Left Facial Hemiplegia Associated with Antibodies to Galactocerebroside and Phosphatidic Acid

BACKGROUND A rare variant of Guillain-Barré syndrome (GBS) consists of facial diplegia and paresthesia, but an even more rare association is with facial hemiplegia, similar to Bell's palsy. This case report is of this rare variant of GBS that was associated with IgG antibodies to galactocerebroside and phosphatidic acid. CASE REPORT A 54-year-old man presented with lower left facial palsy and paresthesia of his extremities, following an upper respiratory tract infection. Physical examination confirmed lower left facial palsy and paresthesia of his extremities with hyporeflexia of his lower limbs and sensory loss of all four extremities. The differential diagnosis was between a variant of GBS and Bell's palsy. Following initial treatment with glucocorticoids followed by intravenous immunoglobulin (IVIG), his sensory abnormalities resolved. Serum IgG antibodies to galactocerebroside and phosphatidic acid were positive in this patient, but not other antibodies to glycolipids or phospholipids were found. Five months following discharge from hospital, his left facial palsy had improved. CONCLUSIONS A case of a rare variant of GBS is presented with facial diplegia and paresthesia and with unilateral facial palsy. This rare variant of GBS may which may mimic Bell's palsy. In this case, IgG antibodies to galactocerebroside and phosphatidic acid were detected.

Absence of lactobacilli containing glycolipids with the α-galactose epitope and the enhanced fucosylation of a receptor glycolipid GA1 in the digestive tracts of immune-deficient scid mice

The Lactobacillus species in the digestive tracts of immune-deficient scid mice was distinct from that in control mice, i.e. Lactobacillus murinus in scid and L. johnsonii in control mice, according to their 16S-rRNA, indicating that a symbiotic relationship between lactobacilli and a host is established under pressure from the immune system. The caecal and colonal contents rich in L. murinus of scid mice were loose with a strong sour smell, resulting in diarrhoea, and those with L. johnsonii in control mice included abundant solid materials. Lactobacillus glycolipids were revealed to be recognized by the immune system, and by TLC-immunostaining, LacTetH-DG (Galα1-6Galα1-6Galα1-2Glcα1-3'DG) of L. johnsonii was detected in the stomach, caecum and colon of control mice, but not in those of scid ones, in which fucosylation of a receptor GA1 for L. johnsonii was enhanced more than 4-fold compared with in the control mice. Thus, structural modification of receptor glycolipids was revealed to occur in the process of establishment of a symbiotic relationship between lactobacilli and a host. LacTetH-DG was also immunogenic to human, because of the presence of natural antibodies against it, and the antibody binding to it was comparable to that of blood group- and species-related glycosphingolipids.

Autoantibodies in neuroimmunological diseases; relevance of fine specificity

Autoantibodies are involved in the pathogenesis of several neuroimmunological diseases. Anti-neurofascin antibodies are detected in sera from some patients with multiple sclerosis and have been shown to induce axonal damage and exacerbation of experimental autoimmune encephalomyelitis. Recently, Lindner et al. reported a discrepancy between the activity of the anti-neurofascin antibodies in vivo and that in a cell-based assay. This may be due to the effects of antibody fine specificity and the local molecular environment of the target membrane on the reactivity of the autoantibodies, as reported in diseases such as Guillain-Barré syndrome. Thus, an assay system that better reflects the environment in vivo is needed to evaluate the pathogenetic roles of autoantibodies.

Antibodies to gangliosides and ganglioside complexes in Guillain-Barré syndrome and Fisher syndrome: mini-review

Antiganglioside antibodies play a pathogenic role in the pathophysiology of Guillain-Barré syndrome (GBS) and Fisher syndrome (FS). Antiganglioside antibody-mediated nerve injury is likely to result from nerve damage through complement activation or dysfunction of molecules such as voltage-gated sodium and calcium channels. Clustered epitopes of complexes of two gangliosides in the cell membrane can be targeted by serum antibodies in GBS and FS and may regulate the accessibility and avidity of antiganglioside antibodies. The glycolipid environment or the specific distribution of target gangliosides in the peripheral nervous system may also influence the pathogenic effect of antiganglioside antibodies in GBS and FS. Structural and functional analyses of glycoepitopes of ganglioside complexes in membranes will provide new vistas on antibody-antigen interaction in GBS and shed light on microdomain function mediated by carbohydrate-carbohydrate interactions, which may lead to novel treatments for GBS and FS.

Clinical and immunological spectrum of the Miller Fisher syndrome

The Miller Fisher syndrome (MFS), characterized by ataxia, areflexia, and ophthalmoplegia, was first recognized as a distinct clinical entity in 1956. MFS is mostly an acute, self-limiting condition, but there is anecdotal evidence of benefit with immunotherapy. Pathological data remain scarce. MFS can be associated with infectious, autoimmune, and neoplastic disorders. Radiological findings have suggested both central and peripheral involvement. The anti-GQ1b IgG antibody titer is most commonly elevated in MFS, but may also be increased in Guillain-Barré syndrome (GBS) and Bickerstaff's brainstem encephalitis (BBE). Molecular mimicry, particularly in relation to antecedent Campylobacter jejuni and Hemophilus influenzae infections, is likely the predominant pathogenic mechanism, but the roles of other biological factors remain to be established. Recent studies have demonstrated the presence of neuromuscular transmission defects in association with anti-GQ1b IgG antibody, both in vitro and in vivo. Collective findings from clinical, radiological, immunological, and electrophysiological techniques have helped to define MFS, GBS, and BBE as major disorders within the proposed spectrum of anti-GQ1b IgG antibody syndrome.

Anti-ganglioside complex antibodies associated with severe disability in GBS

Ganglioside complexes (GSCs) are known as target antigens in Guillain-Barré syndrome (GBS). To elucidate the clinical importance of the anti-GSC antibodies in GBS, we investigated serum antibodies to GSCs containing two of the gangliosides, GM1, GD1a, GD1b and GT1b, and analyzed clinical features of anti-GSC-positive GBS patients. Thirty-nine (17%) of 234 GBS patients had IgG anti-GSC antibodies. Anti-GSC-positive GBS had antecedent gastrointestinal infection and lower cranial nerve deficits more frequently than control GBS. The presence of antibody specificity to GD1a/GD1b and/or GD1b/GT1b was significantly associated with severe disability and a requirement for mechanical ventilation.