Response of thymectomy: clinical and pathological characteristics among seronegative and seropositive myasthenia gravis patients

Guillermo, García Ramos; Téllez-Zenteno, J F; Weder‐Cisneros, N.; Mimenza, Alberto José; Estañol, Bruno; Troche, José María Remes; Cantú-Brito, Carlos

doi:10.1034/j.1600-0404.2003.00209.x

Cited by 44 publications

(26 citation statements)

References 22 publications

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“…The present study is the first published study examining long‐term prognosis of AChR and MuSK antibody negative MG. A recently published short‐term study showed no difference in the outcome of AChR antibody negative and positive MG, but the patients were followed up for 3 years only (Guillermo et al. , 2004).…”

Section: Discussionmentioning

confidence: 99%

Seronegative myasthenia gravis: disease severity and prognosis

Romi

Aarli

Gilhus

2005

Euro J of Neurology

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Around 10-20% of myasthenia gravis (MG) patients do not have acetylcholine receptor (AChR) antibodies (seronegative), of whom some have antibodies to a membrane-linked muscle specific kinase (MuSK). To examine MG severity and long-term prognosis in seronegative MG compared with seropositive MG, and to look specifically at anti-AChR antibody negative and anti-MuSK antibody negative patients. Seventeen consecutive seronegative non-thymomatous MG patients and 34 age and sex matched contemporary seropositive non-thymomatous MG controls were included in a retrospective follow-up study for a total period of 40 years. Clinical criteria were assessed each year, and muscle antibodies were assayed. There was no difference in MG severity between seronegative and seropositive MG. However, when thymectomized patients were excluded from the study at the year of thymectomy, seropositive MG patients had more severe course than seronegative (P < 0.001). One seropositive patient died from MG related respiratory insufficiency. The need for thymectomy in seronegative MG was lower than in seropositive MG. None of the seronegative patients had MuSK antibodies. This study shows that the presence of AChR antibodies in MG patients correlates with a more severe MG. With proper treatment, especially early thymectomy for seropositive MG, the outcome and long-term prognosis is good in patients with and without AChR antibodies.

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Section: Discussionmentioning

confidence: 99%

Seronegative myasthenia gravis: disease severity and prognosis

Romi

Aarli

Gilhus

2005

Euro J of Neurology

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“…Some patients are false negative as they have low affinity AChR antibodies not detected by standard assays [34], whilst others have MuSK and possible other still undetected antibodies. A retrospective cohort study displayed a similar post‐operative course in AChR antibody‐negative and AChR antibody‐positive patients with a follow‐up of at least 3 years [35]. Remission or improvement after TE occurred in 57% of AChR antibody‐negative patients and in 51% of AChR antibody‐positive patients.…”

Section: Myasthenia Gravis (Mg)mentioning

confidence: 97%

Guidelines for treatment of autoimmune neuromuscular transmission disorders

Skeie

Apostolski

Evoli

et al. 2010

Euro J of Neurology

402

258

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Background: Important progress has been made in our understanding of the autoimmune neuromuscular transmission (NMT) disorders; myasthenia gravis (MG), Lambert–Eaton myasthenic syndrome (LEMS) and neuromyotonia (Isaacs’ syndrome). Methods: To prepare consensus guidelines for the treatment of the autoimmune NMT disorders, references retrieved from MEDLINE, EMBASE and the Cochrane Library were considered and statements prepared and agreed on by disease experts. Conclusions: Anticholinesterase drugs should be given first in the management of MG, but with some caution in patients with MuSK antibodies (good practice point). Plasma exchange is recommended in severe cases to induce remission and in preparation for surgery (recommendation level B). IvIg and plasma exchange are effective for the treatment of MG exacerbations (recommendation level A). For patients with non‐thymomatous MG, thymectomy is recommended as an option to increase the probability of remission or improvement (recommendation level B). Once thymoma is diagnosed, thymectomy is indicated irrespective of MG severity (recommendation level A). Oral corticosteroids are first choice drugs when immunosuppressive drugs are necessary (good practice point). When long‐term immunosuppression is necessary, azathioprine is recommended to allow tapering the steroids to the lowest possible dose whilst maintaining azathioprine (recommendation level A). 3,4‐Diaminopyridine is recommended as symptomatic treatment and IvIG has a positive short‐term effect in LEMS (good practice point). Neuromyotonia patients should be treated with an antiepileptic drug that reduces peripheral nerve hyperexcitability (good practice point). For paraneoplastic LEMS and neuromyotonia optimal treatment of the underlying tumour is essential (good practice point). Immunosuppressive treatment of LEMS and neuromyotonia should be similar to MG (good practice point).

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“…The immune response exposes additional antigens widening the autoimmune process (epitope spreading). 9 Proposed mechanisms for favorable response after thymectomy include elimination of the source of continued antigenic stimulation (considering the expression of the alpha subunit of AChR in the thymus as a source of auto-antigen), removal of a reservoir of B cells that secrete AChR antibodies, correction of a disturbance of immune regulation in MG. 10 Besides anti-AChR synthesizing B cells the thymus is also suggested to harbor clonally restricted T cells specific for AChR epitopes that regulate the immune response and induce antibody production in MG. 11−13 The benefit from thymectomy is usually unlikely in seronegative patients and/or late-onset MG. 2,14 Thymomas are well known to be associated with various autoimmune disorders. The pathological basis for the autoimmune process remains obscure.…”

Section: Discussionmentioning

confidence: 99%

Post-thymectomy, Seronegative Myasthenia Gravis

Tan

Kansu

Akarsu

2008

Neuro-Ophthalmology

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Patients with thymoma associated myasthenia gravis (MG) usually present with severe disease unresponsive to usual treatment and almost all have antibodies against acetylcholine receptors (AChR). We like to present a case of post-thymectomy, seronegative MG. A 55-year-old man was referred with horizontal diplopia and abduction deficit in the right eye two years after he had thymectomy for a thymoma. Single-fiber electromyography was diagnostic for MG and AChR titer was undetectable. Ocular signs did not response to pyridostigmine, prednisolone and immunoglobulin treatments and the patient also suffered from proximal weakness and pain in the extremities. Cyclosporine-A was started and the initial response was favorable with a decrease in general weakness.

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Response of thymectomy: clinical and pathological characteristics among seronegative and seropositive myasthenia gravis patients

Abstract: The response to thymectomy was similar between the two groups. It has been suggested that seronegative patients have a better prognosis, but our results show no differences.

Cited by 44 publications

References 22 publications

Seronegative myasthenia gravis: disease severity and prognosis

Seronegative myasthenia gravis: disease severity and prognosis

Guidelines for treatment of autoimmune neuromuscular transmission disorders

Post-thymectomy, Seronegative Myasthenia Gravis

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