Reactivity of Myasthenia Gravis Serum γ-Globulin with Skeletal Muscle and Thymus Demonstrated by Immunofluoirescence.

Summary Sera from patients with myasthenia gravis (36 out of a total of 90) showed reactivity with epithelial cells in the thymus by means of the immunofluorescence technique. This antibody was cross reactive with skeletal muscle. All 9 sera of patients whose myasthenia was associated with a thymoma showed strong reactivity in serum dilutions of up to 1:60. Antigenic change in epithelial cells is postulated as a possible mechanism initiating an auto-immune response in the thymus. Photographs prepared by Dr. van der Geld in association with Dr. Strauss. The authors gratefully acknowledge the assistance of Dr. Arthur J. L. Strauss, Dr. Howard C. Goodman and Dr. Maurice Landy in facilitating confirmation and publication of these findings. Dr. van der Geld, in his confirmatory studies, also employed fluorescein rabbit anti-human γ-globulin prepared by Dr. Strauss(16). We should like to thank Thea d'Ailly-Harkema, A. L. van Rossum and H. Borstel for technical assistance. We wish to thank Dr. Raffaele Lattes Laboratory of Surgical Pathology, Columbia Univ. College of Physicians and Surgeons, for viewing the hematoxylin-eosin and fluorescent slides and confirming our opinion that the reactivity in the thymus is with epithelial cells.