THE EFFECT OF THYMECTOMY ON AUTOREACTIVE T-LYMPHOCYTE AND B-LYMPHOCYTE IN MYASTHENIA-GRAVIS

Eleven patients with myasthenia gravis were followed for three years a fter thymectomy. Acetylcholine receptor-specific T-cell stimulation wa s found in 8/11 patients before operation as compared to 2/11 three ye ars after thymectomy. Changes of T-cell antireceptor-reactivity were c ommonly paralleled by changes in disease severity. The numbers of cell s secreting IL-2 upon stimulation with human acetylcholine receptor co rrelated with those secreting IFN-gamma. T-cell reactivity against a m onoclonal acetylcholine receptor antibody did not decrease after thyme ctomy. Such reactivity could reflect a beneficial immune response coun teracting anti-receptor reactivity. The frequency of autoantibody-secr eting cells remained unchanged, while the serum concentration of acety lcholine receptor antibodies started to decrease one year after thymec tomy. All examined thymus-cell suspensions contained autoreactive T- a nd B-lymphocytes. There was a preferential enrichment of autoreactive lymphocytes in the thymus in a few patients with recent onset of disea se.