Recent immunologic studies, combined with an increasing awareness of some of the more unusual features of classical myasthenia gravis, have led writers to question whether this disease might not be a further example of the expanding group of hyperimmune diseases. The evidence for this concept, first advanced by Simpson (1), has been recently reviewed by Harvey and Johns (2), and by Osserman (3).
The above hypothesis is enhanced by the frequent occurrence of myasthenia, or myasthenic syndromes, with known auto-immune diseases, or with entities that have, or may have, immunologic implications. The association of myasthenia with tumors of the thymus,