Myasthenia Gravis: Serum Globulin Bound in Vivo to Skeletal Muscle Striations

GLOBULINS which bind in vitro to cross striations of skeletal muscle, as demonstrated by immunofluorescent techniques, were first reported in the serums of patients with myasthenia gravis by Strauss and associates.¹ These globulins have been reported to bind to striations of skeletal muscle from experimental animals, normal humans, and myasthenic patients, including patients from whom serum was obtained.^2-5 The presence of the striation binding globulin has been reported in the serum of 18% to 68% of patients with myasthenia gravis,^1,4-10 and the binding activity of the globulin tends to be higher in myasthenic patients with more severe conditions^4-7,9-11 and with thymoma.^11-13

Serum globulin bound to cross striations was found in excised muscle in two of five myasthenic patients examined by Gordon and associates¹⁴ and in two of four patients examined by Beutner and associates.¹⁵ The serums of all of these patients