Data for this review were identified by searches of PubMed and Medline with the terms “seronegative myasthenia” and “myasthenia acetylcholine receptor negative” with or without “SFEMG”, “jitter”, or “tensilon/edrophonium”. We also referred to our own files for publications about myasthenia gravis. Abstracts were included only when they related directly to otherwise unpublished work by the authors. Only papers published in English were reviewed.
ReviewSeronegative generalised myasthenia gravis: clinical features, antibodies, and their targets
Section snippets
Seropositive generalised MG
The clinical, pathophysiological, and therapeutic issues of seropositive MG have been reviewed elsewhere.1, 2 MG is the best-understood autoimmune disease of the nervous system, and one of the few conditions in which the effector mechanisms are thought to be entirely antibody-mediated. The antibodies are directed against AChR, which is exposed on the surface of the muscle membrane (figure 1), and lead to loss of AChRs, causing a defect in neuromuscular transmission with muscle weakness and
Seronegative MG
In the first comprehensive study of autoantibody status in patients with MG, Lindstrom and colleagues4 noted that AChR antibodies were not detectable in 13% of patients and suggested that they might have antibodies to another protein, or have a different form of the disease. seronegative MG is thus defined as generalised MG in which the diagnosis has been made on clinical, electrophysiological, and pharmacological grounds but in which AChR antibodies cannot be detected. The term Seronegative MG
Confirmation of a humoral factor
The response to plasma exchange in seronegative MG49, 50 and the transmission of the disorder from mother to child64 clearly indicates that there is a circulating serum factor, probably IgG. The disease has been transferred to mice by injection of both plasma and immunoglobulin preparation from patients with seronegative MG. The mice did not show any obvious symptoms of MG, but electrophysiological tests in vitro revealed a defect in neuromuscular transmission in most animals.49 One possible
Conclusions
There seem to be subtle differences between seronegative and seropositive MG, but these are difficult to quantify. The distinctions are based on studies in a few patients, in some of which there are concerns about diagnostic accuracy. Improvements in diagnostic accuracy in patients with seronegative MG is a high priority to facilitate clinical as well as experimental studies.
MG without AChR antibodies is proving to be heterogeneous. MuSK antibodies are found in about 40% of patients with
Search strategy and selection criteria
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Differential response to rituximab in anti-AChR and anti-MuSK positive myasthenia gravis patients: a single-center retrospective study
2020, Journal of the Neurological SciencesThe role of the laboratory in the expanding field of neuroimmunology: Autoantibodies to neural targets
2018, Journal of Immunological MethodsSeronegative myasthenia gravis associated with malignant thymoma
2017, Neuromuscular DisordersCitation Excerpt :MG is often associated with pathological abnormalities of the thymus gland, including thymoma. It has been accepted that patients with thymoma-associated myasthenia gravis have antibodies against AChR [1]. Recently, there have been three cases of benign thymoma-associated seronegative myasthenia gravis reported in the literature [2,3].
Detection methods for neural autoantibodies
2016, Handbook of Clinical NeurologyMuSK autoantibodies in myasthenia gravis detected by cell based assay - A multinational study
2015, Journal of Neuroimmunology