Go Ogawa

GM1/GalNAc-GD1a complex A target for pure motor Guillain-Barré syndrome

Background: GM1 and GalNAc-GD1a are located on the axolemma of the motor nerves and are believed to be the antigens associated with pure motor Guillain-Barré syndrome (GBS). Furthermore, GM1 and GalNAc-GD1a may exist nearby and colocalize on the axolemma. Ganglioside complex (GSC) antigens associated with GM1 or GalNAc-GD1a can be target antigens in pure motor GBS. We investigated GBS sera for antibodies to a GSC consisting of GM1 and GalNAc-GD1a (GM1/GalNAc-GD1a) and analyzed the clinical and electrophysiologic findings of patients with antibodies to GM1/GalNAc-GD1a. Methods: Sera from 224 patients with GBS were surveyed for antibodies to GSCs consisting of two of nine gangliosides (GM1, GM2, GM3, GD1a, GD3, GT1a, GT1b, GQ1b, and GalNAc-GD1a). We analyzed the clinical and electrophysiologic features of patients with IgG antibodies to the GM1/GalNAc-GD1a complex. Results: Ten patients with GBS had IgG antibodies to the GM1/GalNAc-GD1a complex. The clinical findings of the 10 patients with GBS were characterized by preserved sensory system and infrequent cranial nerve deficits. According to the criteria established by Hadden et al., electrodiagnostic studies showed a demyelinating pattern in four patients and axonal neuropathy pattern in two. Early motor conduction block at intermediate nerve segments was found in five patients. Conclusions: GM1 and GalNAc-GD1a may form a complex in the axolemma at nodes of Ranvier or paranodes of the motor nerves, and may be a target antigen in pure motor Guillain-Barré syndrome, especially in the form of acute motor conduction block neuropathy.

GD1b-specific antibody induces ataxia in Guillain-Barré syndrome

Background: Rabbit ataxic neuropathy and several case reports have suggested a close association of IgG anti-GD1b antibodies with ataxia in Guillain-Barré syndrome (GBS). However, about half of the patients with GBS having IgG anti-GD1b antibodies with no reactivities against other gangliosides (GD1b-mono IgG) do not exhibit ataxia. Antibodies specific to ganglioside complexes (GSCs) containing GD1b have been found in sera from some patients with GBS. Objective: To investigate whether the reactivities of anti-GD1b IgG to such complexes are different between ataxic and nonataxic patients. Methods: The authors examined sera from 17 patients with GBS (9 with ataxia and 8 without ataxia) who had GD1b-mono IgG, with the use of an ELISA in which wells were coated with a mixture of GD1b and each of nine gangliosides (GM1, GM2, GM3, GD1a, GD3, GT1a, GT1b, GQ1b, and GalNAc-GD1a). The binding activities of the anti-GD1b IgG antibodies against such mixture antigens were compared between ataxic and nonataxic patients. Results: The reactivities to antigens, such as GD1b combined with GD1a, GT1b, GQ1b, and GalNAc-GD1a, were significantly reduced in ataxic compared with nonataxic patients. Sera from all nonataxic patients had antibody activities to GSCs not containing GD1b. Conclusions: The addition of another ganglioside may cause conformational change of GD1b. Given the inhibition of the binding ability of the anti-GD1b IgG antibodies by such a conformational change, the anti-GD1b IgG antibodies in ataxic patients may interact closely with GD1b. IgG antibodies highly specific for GD1b may induce ataxia in Guillain-Barré syndrome. GLOSSARY: GBS = Guillain-Barré syndrome; GSCs = ganglioside complexes; OD = optical density.

Seasonal variation of multiple sclerosis exacerbations in Japan.

Abstract.Several reports have described the seasonal variation of multiple sclerosis (MS) attacks in the European countries and in the US. Some have insisted that attacks occurred more frequently in winter or spring. We investigated the possibility of a seasonal variation in the frequency of MS attacks among patients in Japan. A total of 172 MS exacerbations in 34 MS patients were analyzed retrospectively. Attacks were divided into two groups: opticospinal type and brain type. The 12 months of the year were assigned to 6 groups based on average monthly temperature. Of the 172 MS exacerbations, 123 were opticospinal type and 49 were brain type of attacks. The total number of attacks was significantly more frequent in the warmest (July and August) and coldest (January and February) months. The heat of summer in warmer, low latitude areas may be a risk factor for MS attacks.

Antibodies to ganglioside complexes consisting of asialo-GM1 and GQ1b or GT1a in Fisher and Guillain-Barré syndromes

To determine the epitopes of ganglioside complexes (GSCs) containing GQ1b or GT1a, we investigated their reactivity to GSCs consisting of asialo-GM1 (GA1) and GQ1b or GT1a using IgG anti-GQ1b- or anti-GT1a-positive sera. Nine anti-GQ1b-positive sera had higher activity to GA1/GQ1b than to GQ1b, only five of which reacted with GM1/GQ1b and GD1b/GQ1b. Five of 14 sera positive for GA1/GT1a and GM1/GT1a were negative for GA1/GQ1b and GM1/GQ1b. Sialic acids attached to the internal galactose of gangliotetraose can influence the reactivity of anti-GSC antibodies. Screening for antibodies to GSCs containing GA1 is useful for elucidation of the antibody-mediated pathophysiology.

An antibody to the GM1/GalNAc-GD1a complex correlates with development of pure motor Guillain-Barré syndrome with reversible conduction failure.

Antibodies to a ganglioside complex consisting of GM1 and GalNAc-GD1a (GM1/GalNAc-GD1a) are found in sera from patients with Guillain-Barré syndrome (GBS). To elucidate the clinical significance of anti-GM1/GalNAc-GD1a antibodies in GBS, clinical features of 58 GBS patients with IgG anti-GM1/GalNAc-GD1a antibodies confirmed by enzyme-linked immunosorbent assay and thin layer chromatography immunostaining were analyzed. Compared to GBS patients without anti-GM1/GalNAc-GD1a antibodies, anti-GM1/GalNAc-GD1a-positive patients more frequently had a preceding respiratory infection (n=38, 66%, p<0.01) and were characterized by infrequency of cranial nerve deficits (n=9, 16%, p<0.01) and sensory disturbances (n=26, 45%, p<0.01). Of the 28 anti-GM1/GalNAc-GD1a-positive patients for whom electrophysiological data were available, 14 had conduction blocks (CBs) at intermediate segments of motor nerves, which were not followed by evident remyelination. Eight of 10 bedridden cases were able to walk independently within one month after the nadir. These results show that the presence of anti-GM1/GalNAc-GD1a antibodies correlated with pure motor GBS characterized by antecedent respiratory infection, fewer cranial nerve deficits, and CBs at intermediate sites of motor nerves. The CB may be generated through alteration of the regulatory function of sodium channels in the nodal axolemma.

Clinical Features of Opticospinal Multiple Sclerosis with Anti-Aquaporin 4 Antibody

Background: We have followed 9 Japanese patients with opticospinal multiple sclerosis (OSMS), some of whom showed longitudinally extensive spinal cord lesions, deep sensory disturbances and resistance to treatment. We investigated the patients for anti-aquaporin 4 (AQP4) antibodies and related this to their neuroimaging, clinical and laboratory features. Methods: We studied the clinical course, neurological findings, cerebrospinal fluid (CSF), and electrophysiological findings, and determined the presence of anti-AQP4 antibody and human leukocyte antigen DPB1 and DRB1 alleles. Results: Five patients (56.6%) had anti-AQP4 antibody. Antibody-positive patients displayed female predominance, longitudinally extensive spinal cord lesions, higher frequency of exacerbations, severe disability, and higher cell counts and total protein content without IgG oligoclonal bands in the CSF. They also showed poor steroid responsiveness and poor therapeutic response to interferon β1b. Conclusions: The presence of anti-AQP4 antibodies correlates with clinical severity and poor prognosis in OSMS.