Advances in neuroimmunological laboratory studies on neuromuscular diseases

The recent methodological advances in molecular biology, immunology, and genetics have clarified neuroimmunological problems in axonal Guillain-Barré syndrome, seronegative myasthenia gravis, paraneoplastic neurologic syndromes and many others. In addition to clinical and serological studies in peripheral neuropathies, the origins and measurement of anti-ganglioside antibodies and relationships to similar carbohydrate structures on infectious organisms are discussed in the context of molecular mimicry hypothesis, especially related with both the localization of relevant gangliosides in the nerve and clinical phenotypes. Major advances have been made in animal modeling of anti-ganglioside antibody-associated disease. An explanation for muscular weakness in 10-15% of patients with seronegative myasthenia gravis who lack autoantibodies to acetylcholine receptors(AchRs) appears to be the autoantibodies to muscle-specific receptor tyrosine kinase (MuSK). MuSK mediates agrin-induced clustering of AchRs during synapse formation. These autoantibodies to the extracellular domain of MuSK inhibit its function in tissue culture. Isoelectric focusing (IEF) and agar gel electrophoresis (AGE) are used to examine cerebrospinal fluid (CSF) and sera from patients with multiple sclerosis (MS). The CSF oligoclonal IgG bands (OB) are less frequently observed in Japanese MS patients compared with Caucasian patients. Few optic-spinal form of MS (OS-MS) was positive for OB by agarose gel electrophoresis, but IEF is more sensitive than AGE. Recent IEF data revealed some OS-MS patients were positive for OB. The neuroimmunological advances revealed the relationship between the neuroimmunological diseases and the putative autoantibodies as diagnostic markers, for example, HAM and hnRNP-A1, MSand anti-hnRNP-B1 antibody, opsoclonus-myoclonus syndrome and anti-GluRdelta2 antibody, Rasmussen encephalitis and anti-GluR3 antibody, paraneoplastic brainstem encephalitis and anti-Ma2 antibody, and so on.