Kaminski HJ et al.
Abstract
The role of immunosenescence, particularly the natural process of thymic involution during aging, is increasingly acknowledged as a factor contributing to the development of autoimmune diseases and cancer. Recently, a concern has been raised about deleterious consequences of the surgical removal of thymic tissue, including for patients who undergo thymectomy for myasthenia gravis (MG) or resection of a thymoma. This review adopts a multidisciplinary approach to scrutinize the evidence concerning the long-term risks of cancer and autoimmunity post-thymectomy. We conclude that for patients with acetylcholine receptor antibody-positive MG and those diagnosed with thymoma, the removal of the thymus offers prominent benefits that well outweigh the potential risks. However, incidental removal of thymic tissue during other thoracic surgeries should be minimized whenever feasible.
The thymus is a primary lymphoid organ that serves as the site of T-cell maturation to assure a robust response toward foreign antigens, while maintaining a tolerance toward self. During life, structural changes affect the thymus, such as natural thymic involution related to aging or alterations induced by stress or pathologic conditions. Historically, the prevailing belief was that the thymus holds minimal significance in adulthood because of its involution. However, a growing body of evidence challenges this perspective. There are reports that indicate that sustaining thymopoiesis well into adulthood can have significant benefits while its deterioration may elevate the risk of neoplasia and autoimmune disorders. Consequently concerns have been raised that surgical removal of the thymus in a variety of clinical scenarios may lead to deleterious consequences.
On the other hand, studies have documented unequivocal benefits of thymus removal in specific cases, such as patients with certain autoimmune forms of myasthenia gravis (MG) and individuals diagnosed with thymic neoplasia who require surgery. Nevertheless, the potential negative impact of surgical thymus removal on immune function, potentially leading to increased rates of cancer and autoimmunity, deserves further scrutiny. Here, we briefly review the function of the thymus, assess what is known about adverse effects of thymic resection on immune function, and address the current limitations of our knowledge in guiding clinical decisions concerning thymectomy.