A Follow-up for Myasthenia Gravis after Low Dose Whole Body Irradiation

Lee, Kyu Yong; Lee, Young Joo; Kim, Hee Tae; Kim, Seung Hyun; Kim, Ju Han; Kim, Myung Ho

Abstract

BACKGROUND: Whole body irradiation (WBI) for myasthenia gravis is known to produce prolonged immunosuppres-sion with rare side effects. This study evaluated the duration of immunosuppression effects of WBI for long-term fol-low-up and decision time of 'booster' WBI treatments by analyzing clinical symptoms and laboratory findings.
METHODS
We studied 11 patients with intractable myasthenia gravis. All patients had been treated with WBI and were followed for at least 5 years except for 2 patients died. Clinical status and immunological parameters were assessed at baseline and every year after the initial dose of irradiation. During the follow-up period, patients with declining clinical or immunological parameters were given 'booster' WBI treatments.
RESULTS
WBI was associated with objective clini-cal improvements in seven patients: 3 patients had none or mild symptoms without any medications, 3 patients had 'booster' WBI treatments at 34 months(25-40 months) due to clinical or immunological declines, 1 patient had a stable clinical course with anticholinesterase medication. WBI was associated with clinical decline or no change in four patients: 2 patients died and 2 patients did not experience a change in clinical status. WBI produced a long-lasting lym-phopenia for more than 2 years with decreased absolute lymphocytes counts. There was no statistical differences in clinical and immunological parameters between the 'booster' WBI groups and non-'booster' WBI groups in good responders. 'Booster' WBI patients had no significant side effects.
CONCLUSIONS
WBI has an effective therapeutic modality in intractable long-term myasthenia gravis. In this study, the duration of immnunosuppression effects of WBI was found to last 2 years. It is suggested that patients with declining clinical or immunological parameters be given 'booster' WBI treatments.