This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': 'Thymectomy causes - \nSelect and explain. \nA. Failure of rejection of transplanted organs, B. Myastheina gravis, C. Autoimmune disorders, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: • In adult life, thymectomy has no demonstrable effect on antibody response or upon homograft survival.\n• However, it has been shown that thymectomy in adult mice, combined with total body irradiation, can result in homograft tolerance of a high degree.\n• This finding suggests that the thymus gland may resume its perceptor function in adult life under circumstances in which there is temporary suppression of the lymphopoietic system.', 'role': 'assistant'}]