Circulating CD4+CD8+ cells in myasthenia gravis: supplementary immunological parameter for long-term prognosis.

Twenty patients with myasthenia gravis (MG) were studied prospectively for up to 5 years after thymectomy, in order to clarify the relationships between disease severity, anti-acetylcholine receptor antibody (anti-AChR) titres, proportions of circulating CD4+CD8+ cells (CD4+CD8+ cell level) and major lymphocyte subsets. The CD4+CD8+ cell levels were closely related to the clinical change within 1 year after surgery in 8 patients who showed a preoperative elevation in the cell levels. This group of patients consisted of six thymomatous and two non-thymomatous patients; the latter were both negative for anti-AChR. The anti-AChR titres generally changed in parallel with the clinical state in 9 of the 16 patients who were followed up for more than a year after thymectomy, and the CD4+CD8+ cell levels were useful in predicting the clinical course in 6 of the above 9 patients and 3 other patients, including antibody-negative cases. The present study suggests that the CD4+CD8+ cell levels may serve as an indicator for long-term prognosis of MG.