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Suppression of ongoing experimental myasthenia by oral treatment with an acetylcholine receptor recombinant fragment.

Myasthenia gravis (MG) is an autoimmune disorder in which the nicotinic acetylcholine receptor (AChR) is the major autoantigen. In an attempt to develop an antigen-specific therapy for MG, we administered a nonmyasthenogenic recombinant fragment of AChR orally to rats. This fragment, corresponding to the extracellular domain of the human AChR alpha-subunit (Halpha1-205), protected rats from subsequently induced experimental autoimmune myasthenia gravis (EAMG) and suppressed ongoing EAMG when treatment was initiated during either the acute or chronic phases of disease. Prevention and suppression of EAMG were accompanied by a significant decrease in AChR-specific humoral and cellular responses. The underlying mechanism for the Halpha1-205-induced oral tolerance seems to be active suppression, mediated by a shift from a T-helper 1 (Th1) to a Th2/Th3 response. This shift was assessed by changes in the cytokine profile, a deviation of anti-AChR IgG isotypes from IgG2 to IgG1, and a suppressed AChR-specific delayed-type hypersensitivity response. Our results in experimental myasthenia suggest that oral administration of AChR-specific recombinant fragments may be considered for antigen-specific immunotherapy of myasthenia gravis.

Administration, Oral↗

A limited epidemiological study of seropositive myasthenia gravis in Tayside.

Myasthenia gravis is an acquired disorder of the neuromuscular junction characterised by fatiguable weakness of the limbs, bulbar and facial muscles and may be complicated by respiratory muscle weakness and failure. One often confirms the diagnosis by a simple serological test looking for the presence of the nicotinic acetylcholine receptor antibody. However, seronegative myasthenia constitutes about 20% of cases and in the case of ocular myasthenia, only 50% will have the antibody. Therefore, the diagnosis can be less than straightforward especially if the patient presents with vague symptoms such as fatigue or presents to specialities other than neurology or ophthalmology. The fact that the diagnosis may prove to be challenging, compounded by the fact that the condition is relatively rare and that the antibody to the acetylcholine receptor is not always present, epidemiological data is often less than precise and indeed difficult to acquire. We felt it was necessary to try to establish the epidemiological data on seropositive myasthenia gravis in Tayside, (this has never been carried out) bearing in mind the above pitfalls, and see how the incidence compares with similar and previous studies.

Adult↗

Gender prevalence in childhood multiple sclerosis and myasthenia gravis.

Multiple sclerosis and myasthenia gravis are the most common autoimmune diseases affecting the nervous system, with generally a female predominance in adults. To determine the gender distribution in childhood, we reviewed 28 patients with definite multiple sclerosis and 44 patients with myasthenia gravis with onset before 16 years. In myasthenia gravis, a significant female preponderance was observed only with onset after 10 years of age; earlier disease showed no gender difference. Multiple sclerosis tended to affect boys more than girls before age 10 years and both sexes equally after this age. Gender prevalence in childhood multiple sclerosis and myasthenia gravis is different than in adult series; these results may provide insight into pathogenesis or clinical approach.

Adolescent↗

Tests for juvenile myasthenia gravis: comparative diagnostic yield and prediction of outcome.

The clinical picture, family history, laboratory data, treatment modalities, and outcome in 27 juvenile myasthenics seen over a 25-year period are presented. Onset was after 10 years of age in the majority of patients. Half presented with ocular signs, the other half with generalized-onset myasthenia. Half of those with ocular-onset myasthenia progressed to generalized myasthenia. The female-to-male ratio was 3.5:1. Myasthenia gravis was reported in the mother of one patient. Ptosis was the most common presenting sign. It was unilateral at onset in 33% of patients and remained unilateral in 11%. Pharmacologic tests (neostigmine methylsulfate and edrophonium chloride) were positive in 92% of patients. Serology was positive in 63%, whereas repetitive nerve stimulation was positive in 33% when distal nerves were stimulated and in 66% when proximal and distal nerves were stimulated. Seropositivity tended to increase with generalization of the myasthenic process. No statistically significant difference in seropositivity was noted between males and females. Anti-striated muscle antibodies were detected in two patients, neither of whom had thymoma. The yield of repetitive stimulation increased with generalization of the myasthenic process and when proximal nerves were stimulated. No statistically significant difference was noted in the decremental response between seropositive and seronegative patients. The majority of ocular myasthenics were treated with pyridostigmine bromide monotherapy. With generalization of the myasthenic process, other modes of medical and surgical therapies were needed. All patients given corticosteroids ultimately underwent thymectomy. The mean age at presentation and the duration of symptoms at presentation were longer in thymectomized patients than in those without thymectomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Recurrence of thymoma and myasthenia gravis after 19 years. A case report.

Myasthenia gravis developed in a 51-year-old woman in 1956; she was found to have a thymoma. Complete remission of the myasthenia gravis occurred within 18 months of thymomectomy. In 1975, myasthenia gravis recurred in association with recurrence of the thymoma. Remission of the myasthenic state once more followed the thymomectomy. The asymptomatic period of 18 years is, to our knowledge, the longest reported interval for recurrence of a thymoma-associated myasthenia gravis; 15 years is the longest reported interval for recurrence of a thymoma.

Female↗

Penicillamine-associated myasthenia gravis.

Electroneuromyographic studies have been reported as abnormal in only 9 of 23 cases of penicillamine-associated myasthenia gravis (MG). We report a patient with rheumatoid arthritis who developed clinical and electrodiagnostic evidence of myasthenia 7 months after beginning penicillamine therapy. Six months after discontinuing penicillamine, it was possible to discontinue anticholinesterase medications. With clinical improvement, electrodiagnostic studies (including single-fiber electrmyography) improved, serum antibody titers to human muscle acetylcholine receptor fell, and lymphocytes became more responsive to the nonspecific mitogen phytohemagglutinin. Evidence suggests that penicillamine-associated myasthenia is a distinct syndrome rather than the chance occurrence of two diseases. This syndrome is clinically and electrophysiologically distinguishable from idiopathic myasthenia only by the high remission rate after penicillamine is discontinued.

Arthritis, Rheumatoid↗

Ice pack test for myasthenia gravis.

A common symptom of myasthenia gravis is eyelid ptosis. Often, the edrophonium test is negative, particularly in ocular myasthenia gravis. Myasthenic weakness is often improved by cold. We applied ice packs to the eye in 10 myasthenic patients and 7 disease controls. Eight of 10 patients with myasthenia gravis improved, whereas none of the controls improved. The ice pack test is useful in the diagnosis of myasthenia gravis.

Adolescent↗

Memory dysfunction in myasthenia gravis: evidence for central cholinergic effects.

Two studies are presented that investigate the possible central cholinergic effects of myasthenia gravis as measured by cognitive dysfunction. In the first study, performance on a battery of cognitive tasks by 12 subjects with myasthenia gravis is compared with that of ten healthy control subjects and ten medical control subjects with chronic disease of a nonneurologic nature. The tests used were the Boston Naming Test, Rey Auditory Verbal Learning Test (AVLT), and the Logical Memory and Design Reproduction portions of the Wechsler Memory Scale (WMS). Results indicate that the myasthenic group was significantly impaired relative to both the medical and healthy control groups for performance on the Boston Naming Test, WMS Logical Memory, and WMS Design Reproduction. Both the myasthenic and the medical control groups were impaired relative to the healthy controls on the AVLT. In the second study, a myasthenic patient had plasmapheresis for treatment of her myasthenia on two separate occasions. Her memory was examined prior to as well as following each series of plasma exchanges with a variation of the Peterson-Peterson consonant trigram task. Results showed that this patient had significantly fewer interference effects and less rapid forgetting following plasmapheresis. The results of these two studies support the hypothesis that myasthenia gravis has central cholinergic effects manifested by cognitive dysfunction.

Adult↗

Indications for thymectomy in myasthenia gravis.

Fifty-six board-certified neurologists with interest and expertise in myasthenia completed a survey of indications for thymectomy in myasthenia gravis. Thymectomy was advocated for virtually all patients with thymoma, for a variable subset of patients with generalized myasthenia without thymoma, and occasionally for selected patients with disabling ocular myasthenia.

Humans↗

Minimally invasive gastric bypass in a morbidly obese patient with myasthenia gravis.

Associated or rare diseases, such as myasthenia gravis, introduce a challenge to the perioperative management of severely obese patients undergoing bariatric surgery. We report the surgical management and unique anesthetic approach to a 55-year-old morbidly obese woman with a complex past medical history that included myasthenia gravis, who underwent laparoscopic gastric bypass. Her myasthenia was controlled on pyridostigmine and her greatest concern was the potential need for postoperative mechanical ventilation. While the laparoscopic surgical approach was ideal to reduce pain and the adverse effects on ventilatory mechanics associated with open upper abdominal surgery, a combined inhalational and intravenous anesthetic without muscle relaxants resulted in satisfactory surgical conditions, and allowed for immediate postoperative extubation followed by an uneventful postoperative course. Continued perioperative anticholinesterase administration may have facilitated this successful outcome. We conclude that a diagnosis of myasthenia gravis does not mandate postoperative mechanical ventilation following laparoscopic gastric bypass.

Anesthesia, Inhalation↗

Neonatal myasthenia gravis and the role of agalactosyl IgG.

Neonatal autoimmune diseases are thought to be due to the transfer of maternal autoantibodies. However, there is a puzzling lack of correlation between maternal autoantibody titres and disease in the neonate. So far, no factor reliably predictive of neonatal disease has been found. Agalactosyl IgG is a variable feature of normal IgG. Preliminary studies indicated that the percentage of agalactosyl IgG is lower in the serum of normal neonates, than in the serum of the mother at delivery. Since raised % agalactosyl IgG is often associated with autoimmune disease we sought to determine whether this relationship holds true in a neonatal autoimmune disease. We measured the % agalactosyl IgG in paired maternal-cord sera from patients with myasthenia gravis, some of whom had offspring with neonatal myasthenia gravis. We found that the percentage of agalactosyl IgG was significantly higher in affected than in unaffected neonates. Moreover % agalactosyl IgG was higher in sera of affected neonates than in serum from their mothers, while unaffected infants of mothers with myasthenia had %Gal(0) lower than their mothers, mimicking the normal situation. This suggests that in affected neonates a high proportion of the IgG is synthesised by the baby itself rather than derived from the mother. This agrees with previous evidence based on the presence of idiotypes not found in the mother which implied that the neonates with neonatal myasthenia gravis produce their own autoantibodies.

Age Factors↗

Coexistence of myasthenia gravis and pemphigus foliaceus.

Myasthenia gravis and pemphigus are both considered to have an autoimmune basis. Although immunological and clinical studies have been performed on large numbers of patients with myasthenia gravis, the coexistence of myasthenia gravis and pemphigus foliaceus has rarely been described. We recently have the opportunity to study a 33-year-old female patient having both of these autoimmune diseases confirmed by various diagnostic methods. This rare coexistence of myasthenia gravis and pemphigus foliaceus has not been previously documented in Korea.

Adult↗

Dominantly inherited familial myasthenia gravis as a separate genetic entity without involvement of defined candidate gene loci.

Myasthenia gravis (MG) is a sporadic autoimmune disorder affecting neuromuscular transmission. Very rarely autoimmune myasthenia gravis may be inherited within a family. We present here the genetic analysis of a Hungarian family where nine members from two generations are affected by myasthenia gravis. Genetic characterisation of this unique Hungarian family using linkage analysis and mutation screening excludes the involvement of defined candidate gene loci. These findings point to familial MG as a separate genetic entity. Identification of the underlying genetic defect in this family may greatly enhance our understanding of the pathogenesis of myasthenia gravis.

Adolescent↗

Myasthenia gravis mimicking stroke in elderly patients.

Myasthenia gravis is the most common disease of neuromuscular transmission; however, it may be difficult to diagnose in the elderly patient with comorbid illnesses and vague symptoms. We report two cases of myasthenia gravis in elderly women, in whom the initial diagnosis of ischemic stroke by neurologists was inaccurate; radiographic evidence of stroke was considered confirmatory. In light of the high prevalence of silent cerebrovascular disease in elderly patients, incidental neuroimaging findings may mislead clinicians. Current aggressive therapies, including thrombolysis, can cause significant morbidity in patients whose condition is misdiagnosed as stroke. Although myasthenia gravis most commonly occurs in younger people, 13 to 20% of all patients with this disease are in the seventh decade of life or beyond. When faced with new-onset weakness in an elderly patient, particularly of cranial musculature, clinicians should consider myasthenia gravis as a diagnostic possibility.

Aged↗

[A case of nephrotic syndrome associated with myasthenia gravis and malignant thymoma].

A 26-year-old woman who presented facial and lower leg edema associated with massive proteinuria was admitted to our hospital in February 1992. Nine months before this admission, she exhibited myasthenia gravis and malignant thymoma, and underwent total thymectomy. On admission, there was no symptom of myasthenia gravis. She was diagnosed as having nephrotic syndrome and the first renal biopsy was performed. The histological findings showed membranous nephropathy. Immunofluorescent microscopy revealed that IgG and C3 were stained in a granular pattern in the periphery, and subepithelial deposits were observed in the basement membrane of the glomerulus by electron microscopy. With the administration of prednisolone, proteinuria disappeared and the nephrotic syndrome remitted. She was admitted again in January 1993 due to proteinuria and lower leg edema following cystitis. The findings of the second renal biopsy were unremarkable. She was administered cyclosporin A to improve the nephrotic syndrome and to reduce the side effects of prednisolone. The proteinuria disappeared again and this effect was dependent on the dose of cyclosporin A. Since the first administration, no symptoms of myasthenia gravis or malignant thymoma have been observed. The relationships among myasthenia gravis, malignant thymoma and nephrotic syndrome were examined. Although the first renal biopsy findings showed membranous nephropathy, from the therapeutic responses of both prednisolone and cyclosporin A, the main course of proteinuria in this case may have been due to minimal change nephrotic syndrome. We consider this case of nephrotic syndrome to be important considering its etiology and the relationship between the histological findings and its clinical course.

Adult↗

[The level of DNA antibodies in patients with different forms of myasthenia].

A total of 95 patients with different forms of myasthenia were examined for the blood serum presence of DNA autoantibodies using an enzyme-immunoassay system. Patients with generalized form of myasthenia display an increased blood serum level of DNA autoantibodies, whereas in local form of myasthenia there comes to be a negative test for DNA autoantibodies. The latter are detected in all cases presenting with myasthenia concurrent with other autoimmune disorders and tumour of the thymus gland, their content correlating with severity of the course, getting decreased during the course of treatment (thymectomy, PPh).

Adolescent↗

[Myasthenia gravis: diagnosis and treatment].

INTRODUCTION: Myasthenia gravis is an autoimmune disorder characterized by fluctuating muscle weakness and fatigue of different muscle groups. Myasthenia gravis may affect persons of all ages, but especially women aged 20 to 40 years. DEVELOPMENT AND CONCLUSIONS: The ocular, facial and bulbar muscles are most often involved in this disease. The muscle weakness of patients with myasthenia gravis becomes worse with intercurrent episodes of infection, fever and physical or emotional exhaustion. Respiratory infection (bacterial or viral) is the most frequent trigger factor. The presence of antibodies to acetylcholine receptors in a patient with the clinical features of myasthenia gravis, confirms the diagnosis. Treatment is controversial. Each patient therefore has to be treated individually, as no single treatment is suitable for all patients. Treatment may include anticholinesterase drugs, corticosteroids, plasmapheresis, immunoglobulin, immunosuppressive drugs and thymectomy.

Adult↗

Coexistence of epilepsy, myasthenia gravis and psoriasis vulgaris.

We report the case of a 36-year-old Chinese man with a history of complex partial seizure of temporal lobe origin since the age of 12 years, superimposed by myasthenia gravis since the age of 27 years and psoriasis vulgaris since the age of 29 years. With an eight-year follow-up, the above three diseases remained without complete remission. Anticonvulsant therapy (phenytoin and trimethadione) caused drug-induced myasthenia gravis, which should gradually disappear after discontinuing the drugs. However, the myasthenic symptoms and serum acetylcholine receptor antibody persisted following the discontinuation of phenytoin in our patient. Myasthenia gravis and psoriasis are both autoimmune diseases and correlate with specific human histocompatibility antigens. This suggests a close connection between these two diseases. The coexistence of epilepsy, myasthenia gravis and psoriasis vulgaris has not been previously reported, and to the best of our knowledge, our patient is the first reported case. The relationship among these three diseases requires further investigation.

Adult↗