Studies in Myasthenia Gravis

Abstract

Thirty-four adult patients with myasthenia gravis, of whom 21 were thymectomized, and 29 normal controls were studied for "H" agglutinin response to triple typhoid vaccine. Myasthenic patients respond normally to primary stimulation. Secondary response is diminished. This is most apparent in reduced persistence of antibody titers at 6 months. Thymectomy was associated with a more marked inhibition of immune responsiveness. While it is uncertain whether thymectomy or increased severity of disease plays the greater role, thymectomy is the more suspect. Type of thymus pathology did not correlate with agglutinin response. Immunofluorescent muscle auto-antibodies were demonstrated in 9 of 21 thymectomized myasthenics and in 3 of 13 non-thymectomized patients. There is a definite relationship between presence of such antibodies, clinical severity of disease and type of thymic pathology, especially thymoma. Twenty-one myasthenics, including 16 thymectomized patients, gave normal delayed intracutaneous tests to tuberculin, tricophytin, monilia extracts and 1-chloro-2, -4-dinitro-benzene. Thymectomy or thymic pathology did not affect established delayed hypersensitivity or the capacity to become sensitized to new antigen.