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Anti-GQ1b IgG antibodies have been often detected in the serum of patients with Miller Fisher syndrome or Guillain-Barré syndrome with ophthalmoplegia. These antibodies may participate in the development of ophthalmoplegia. Our patient with acute demyelinating polyradiculoneuropathy had no ophthalmoplegia despite having anti-GQ1b and anti-GT1a IgG antibodies in her serum.
An 80 year old woman was admitted because of weakness of her limbs. Ten days before admission to our hospital, after a common cold, she developed difficulty standing and paraesthesia in her lower legs. Within a few days, walking and prolonged sitting were nearly impossible and her arms became weak. On the day of admission, she developed dysphagia. There was no diplopia or ptosis at any time.
Her ocular and facial muscles were normal. She had difficulty in drinking water. Her limbs were weak (upper limbs MRC grade 3/5 and lower limbs 2 to 3/5). Deep reflexes were diminished or abolished. Pathological reflexes were not elicited. Superficial and deep sensation were abnormal below the knees. Stool culture was negative forCampylobacter jejuni. The CSF contained 159 mg protein/dl and no cells.
The right tibial motor nerve conduction velocity (MCV) was slow and the peroneal nerve did not respond. The median and ulnar nerves showed delayed distal latencies. Slowing of sensory nerve conduction velocity (SCV) was found only in the median nerve. F waves could not be elicited from the median and tibial nerves. A sural nerve biopsy on the 24th day showed loss of myelinated fibres without cell infiltration.
Dysphagia disappeared on the 27th day. Strength in her upper limbs recovered to MRC grade 4/5 a week later. One month after admission, she could walk with a little help. The protein concentrations in her CSF were 82 and 57 mg/dl after a month and four months respectively. Three months later, the median and tibial MCVs were still slow and could not be elicited in the peroneal nerve. The distal and F wave latencies in both the median and ulnar nerves were delayed. F waves could not be elicited in the peroneal or tibial nerves. Median SCV did not improve. The patient was discharged with no disability in activities of daily life four months after admission.
The patient’s serum was tested at intervals for antiganglioside antibody activities by enzyme linked immunosorbent assay (ELISA).1 GM1a, GM2, GM3, GD1a, GD1b, GT1a, GT1b, and GQ1b were prepared from bovine brain.2 The antigenic solution contained 20 pmol/50 μl of each ganglioside. Each patient’s serum was tested in triplicate at 1:100 dilution, and binding detected with horse radish peroxidase conjugated goat antihuman IgM or IgG antibody (Jackson Immunoresearch Laboratories, Inc, West Grove, PA, USA) at 1:1000 dilution. On admission, the serum reacted with both GQ1b and GT1a at a dilution of 1:3200. These two antibody activities, expressed as optical densities, fell to 1/2 in parallel with her improvement, but they could still be detected in her last blood sample (at 16 weeks). IgG antibodies against the other gangliosides were not detected at any time, nor were IgM antibodies to any ganglioside detected.
To determine whether these two antibodies react independently with each ganglioside or react with a common epitope sharing with GQ1b and GT1a, an absorption study was performed using GQ1b or GT1a coated polystyrene beads as described previously.1 The titre of anti-GQ1b IgG antibody decreased when preincubated with GT1a coated polystyrene beads, and vice versa for the anti-GT1a IgG antibody. Based on these results, we hypothesised that these antibodies reacted with a common epitope sharing GQ1b and GT1a.
Chiba et al 3 found anti-GQ1b IgG antibodies in patients with Miller Fisher syndrome and also with Guillain-Barré syndrome with ophthalmoplegia. They showed immunochemically that GQ1b was rich in the paranodal regions of the human oculomotor, trochlear, and abducens nerves. These anti-GQ1b IgG antibodies also reacted with GT1a. Yuki et al 4 found anti-GQ1b IgG antibodies in eight patients with acute paresis of the extraocular muscles but without ataxia. These results suggested that anti-GQ1b IgG antibodies had a part in the development of ophthalmoplegia. We have also detected anti-GQ1b and anti-GT1a IgG antibodies in six patients with Miller Fisher syndome and two with Guillain-Barré syndrome accompanied by ophthalmoplegia.We also found that these antibodies reacted with a common epitope sharing GQ1b and GT1a (unpublished data). Kimuraet al 5 have already reported a patient with acute relapsing sensory dominant polyneuropathy without ophthalmoplegia who had an anti-GQ1b IgG antibody which did not react with GT1a. Further clarification of the relation between anti-GQ1b IgG antibody and the development of ophthalmoplegia in Miller Fisher syndrome or Guillain-Barré syndrome is required.
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