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.

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.

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.

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.