Cellular immunity in myasthenia gravis after thymectomy and corticosteroid therapy

Clinical and immunological changes in patients with myasthenia gravis (MG) who had extended thymectomy (Tx) and/or corticosteroid therapy were examined to elucidate the mechanisms of improvement following the treatments. The changes found were: 1) After Tx and steroid therapy, in patients with MG who showed clinical improvement, the CD4/CD8 ratio and B lymphocyte subpopulations were markedly decreased. 2) Linear correlations between two T-cell subsets were evident in CD3 against CD4 and CD4/CD8 against CD4 after both Tx and steroid therapy. 3) T lymphocytes-CD8 decreased immediately after Tx and returned to pre-treatment levels within three weeks. 4) Cellular sensitization against a nicotine acetylcholine receptor (AChR)-like protein isolated from fetal calf thymus decreased after steroid therapy. These results indicate that clinical improvement in MG after the treatments was accompanied by a decrease in helper/inducer T lymphocytes, B lymphocytes and specific lymphocyte sensitization against nicotinic AChR.