Biomedical subjects
Publications and source records attributed to A Evoli.
Patients treated with interferon alfa can develop autoantibodies and autoimmune diseases. We describe two patients who developed myasthenia gravis with abnormal levels of serum anti-acetylcholine receptor antibodies during interferon alfa-2b treatment for malignancies. One of these patients had myopathic findings on EMG and focal deficiency of cytochrome c oxidase on muscle biopsy.
We studied 111 myasthenic patients with thymoma followed over the last 20 years. Most patients were affected with severe myasthenia gravis (MG) and had been treated with immunosuppressive drugs. At the end of the follow-up, we observed good therapeutic results in 74% of patients, but a complete remission in only 10% of cases. The survival rate in thymoma patients was significantly lower than in nonthymoma cases. Clinical parameters, MG response to treatment and survival rate did not differ in patients with invasive and noninvasive thymic neoplasms. Patients with invasive thymoma showed slightly higher surgical mortality and a 10% incidence of tumor relapse.
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The effects of high-dose intravenous immunoglobulin (i.v.Ig) in 12 MG patients were studied. All patients had severe symptoms. In two cases anti-acetylcholine receptor antibodies (anti-AChR abs) were not detectable. I.v.Ig was administered to 9 patients already on long-term immunosuppressive therapy and to 3 patients at the beginning of azathioprine treatment. 10 patients (83%) improved; the duration of improvement was longer in immunosuppressed patients. Anti-AChR abs generally decreased after infusion but we did not find a constant correlation between reduction in ab titers and clinical improvement. Side effects included one case of severe hemolysis. In our experience i.v.Ig therapy is effective in MG. The chief indication for its use appears to be the treatment of deterioration of the disease in patients already on immunosuppressive therapy.
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We studied the long-term outcome of prednisone therapy in 104 patients with myasthenia gravis (MG). At the end of the follow-up period, good therapeutic results were recorded in 85 patients (81.7%), poor results in 13 (12.5%) and no significant change of MG status in 6 (5.8%). We found a correlation between the duration of treatment and the incidence of steroid side effects. The presence of thymoma and severe forms of MG were associated with relapsing disease requiring prolonged corticosteroid regimens. The age at the start of therapy did not influence significantly the response to treatment.
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The prognosis of myasthenia gravis (MG) was assessed retrospectively using life-table analysis in 844 patients followed up for a mean period of 5 years in 3 major Italian centers. The chance of achieving at least a 1-year remission after treatment withdrawal (complete remission) was assessed as a specific end-point in the whole population and in selected subgroups with reference to the principal prognostic variables. The cumulative probability of complete remission was 1% by 1 year, 8% by 3 years, 13% by 5 years, and 21% by 10 years. The only variables correlated to the chance of complete remission were younger age at onset of MG, lower severity of symptoms at onset and nadir, and shorter disease duration at diagnosis. In addition, thymectomy and early surgery seemed to influence the chance of remission. Other factors (including the presence of thymoma) did not significantly influence the outcome of the disease.
A case of Lambert-Eaton myasthenic syndrome (LEMS) revealed by prolonged apnea following the administration of pancuronium during surgery for squamous cell carcinoma of the lung is reported. The postoperative respiratory failure allowed the correct interpretation of a poor clinical picture:slight weakness of the lower limbs and no other signs of neuromuscular disease. In the authors' opinion prolonged apnea always requires accurate neurophysiological investigation in order to detect latent neuromuscular transmission defects which are frequently underevaluated.
We studied 59 children with myasthenia gravis (MG). Disease onset was pre-pubertal in 26 patients and post-pubertal in 33. The male to female ratio was 0.62 in the early- and 0.17 in the late-onset groups. The frequency of ocular MG was higher in patients with prepubertal onset. Patients with generalized MG generally showed a good response to thymectomy and corticosteroid therapy proved effective with no major side-effects. In our experience early-onset MG has the same course as in adult life. We recommend thymectomy for generalized disease in childhood, except in very young children on account of possible long-term effects on immunological development. Immunosuppressive therapy should be considered in severely affected patients who do not respond adequately to other therapies.
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Autoantibodies that interfere with neurotransmitter release by affecting the function of voltage-operated calcium channels (VOCCs) have been found in patients with Lambert-Eaton myasthenic syndrome (LES). To find out the nature of the antigen to which these autoantibodies bind, tests were done with omega-conotoxin, which blocks some types of VOCCs. LES antibodies were able to immunoprecipitate VOCCs prepared from the human neuronal cell line IMR32 which were pre-labelled with the specific VOCC ligand omega-conotoxin. LES autoantibodies are also able to specifically down-regulate the expression of VOCCs in IMR32 cells. A new radioimmunoassay for the quantitative detection of LES antibodies was developed and found to be of value in distinguishing LES patients from patients with myasthenia gravis and some other neurological disorders.
The clinical and immunological characteristics of myasthenia gravis (MG) patients without detectable anti-Acetylcholine Receptor (anti-AChR) antibody were studied. Sixty anti-AChR negative MG patients were compared with 287 anti-AChR positive cases. Significant differences were found with respect to the sex incidence, the disease severity and the thymic pathology, while the age at the onset of the disease, the presence of other auto-antibodies and the efficacy of medical treatments were similar in the two groups of patients. Anti-AChR-negative MG could have pathogenetic mechanisms different from the antibody-positive disease.
We made a retrospective assessment of the long-term outcome in 247 consecutive patients with myasthenia gravis (MG) who underwent thymectomy in the period January 1971-December 1985. In 84 cases a thymoma was found at surgery, while 163 patients had a non-neoplastic thymus. The duration of symptoms before surgery, the age at onset of the disease and the presence of germinal centres in the thymus did not appear to influence the prognosis. Patients with a non-neoplastic thymus showed a better response to thymectomy. Thymoma was associated with more severe disease and with a higher mortality; moreover, more thymoma patients required corticosteroid treatment in order to achieve good therapeutic results. In our opinion, thymectomy is indicated in the treatment of generalized MG, while ocular myasthenia seems not to be improved by the removal of the thymus.
Forty-eight patients with purely ocular myasthenia were studied. Tensilon test was positive in 46 patients (95%); decremental response from limb muscles was present in 24 patients (50%); anti-AChR antibodies were detected in 20 patients of 44 (45.5%). Twenty-two patients underwent thymectomy, 18 were given corticosteroids, 42 received AChE drugs. At the end of the observation period, 8% of the patients were in remission, 67% were improved, 25% were unchanged. In our experience, the diagnosis of ocular myasthenia relies mainly on clinical data; AChE drugs are not very effective in extrinsic ocular muscles; indications for thymectomy should be restricted to thymoma cases and, perhaps, to patients in the early stages of the disease, within the first year of onset; corticosteroids are effective in most cases, but relapses after withdrawal are not uncommon.
Two cases of familial myasthenia gravis are reported. One patient is a typical case of autoimmune myasthenia with positive anti acetylcholine receptor antibodies, while in the second patient the impairment of neuromuscular transmission is likely to be due to antibodies directed against determinants other than the acetylcholine receptors.
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We studied 7 mothers with myasthenia gravis (MG) and their infants. We confirmed that the development of neonatal MG was not related to the serum titer of maternal anti-acetylcholine receptor antibody (anti-AChR ab). To investigate the possibility that specific immunization of the newborn infant had occurred, serial serum determinations of total and 'specific' anti-AChR IgG and IgM were performed. We found that: the decay in total IgG was within the normal range in all the babies; there was a shorter half-life of 'specific' IgG, compared to total IgG, in 3 of the cases, 2 of which did have neonatal MG; no difference was found between the decay of anti-AChR ab in the babies who had neonatal MG and those who did not; there was no anti-AChR IgM-associated activity. Our data suggest that neonatal MG is due to maternal anti-AChR abs and that affected infants do not produce specific antibodies.