THE RELATION of the thymus to immunologic competence has received much attention recently. It has been shown to play an integral part in the development of the immunological system of the mouse, rat, hamster, and chicken.1,2,3 The role of the thymus in the adult animal has not been clearly defined and although thymectomy in some adults leads to a decrease in circulating lymphocytes, this is not followed by any significant impairment of immune function.1
Several investigators have postulated that the activity of an immunosuppressive drug might be potentiated by thymectomy. Starzl4 treated thymectomized, splenectomized, kidney allograft patients with azathioprine, but reported no obvious increase in survival of the grafts. This was confirmed by animal studies. Recently, however, he has urged reevaluating the value of thymectomy in preventing late rejection of kidney allografts.5 Calne6 reported no prolongation of kidney allografts in the adult thymectomized, azathioprine-treated dog.