Enlargement of the thymus frequently occurs in myasthenie patients, and thymectomy has been followed by clinical improvement, particularly for certain classes of patients. However, there is no demonstrated causal relationship between thymic enlargement and production of faulty neuromuscular transmission. Results of immunological research conducted over the past few years indicate that very early in life the thymus is responsible for the establishment of certain immunological defenses of the body. If, as proposed in 1960,1 myasthenia gravis is an autoimmune disease, perhaps there is at least some basis for connecting the thymic enlargement seen in myasthenia with certain immunological disturbances which occur in this disease. It is possible that thymectomy might break a chain of influences which leads to the production of autoimmune responses manifest in myasthenia gravis.
An investigation observing the influence of thymectomy on certain immunological derangements which occur in myasthenia gravis is published in the July Archives
THYMECTOMY IN MYASTHENIA GRAVIS. JAMA. 1966;197(1):51-52. doi:10.1001/jama.1966.03110010103030