[Changes in clinical and immunological status after post-thymectomized irradiation for invasive thymoma with myasthenia gravis].

We report a detailed analysis of the clinical courses and the immunological examinations in seven patients with myasthenia gravis (MG) and invasive thymoma (Ossermann's type I: 3 cases, IIa: 1 case and IIb: 3 cases), who underwent a transsternal extended thymectomy and postoperative radiation therapy. Two patients with Ossermann's type IIb showed the deterioration of MG after the irradiation. Immunological examinations by an analysis of the subsets of peripheral blood lymphocytes demonstrated a significant decrease of the proportion in CD4 + CD45RA+ T (naive) cells and a significant increase in CD4 + CD45RA-(memory) T cells. Further, the percentage of activated (HLADR+) CD4T cell subsets were increased. The present study suggests that post-thymectomized irradiation may change the balance of the proportion in CD4+ T cell subsets, thereby resulting in the deterioration of MG.