This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
[{'content': 'Autoimmunity is caused \nSelect and explain. \nA. The pressure of forbidden clones, B. Expression of cryptic antigens, C. Negative selection of T-cells in the thymus, D. Inappropriate expression of the MHC proteins', 'role': 'user'}, {'content': "Answer: C \nExplanation: Autoimmunity is the system of immune responses of an organism against its own healthy cells and tissues. Any disease that results from such an aberrant immune response is termed an autoimmune disease. Prominent examples include celiac disease, diabetes mellitus type 1, sarcoidosis, systemic lupus erythematosus (SLE), Sjogren's syndrome, eosinophilic granulomatosis with polyangiitis, Hashimoto's thyroiditis, Graves' disease, idiopathic thrombocytopenic purpura, Addison's disease, rheumatoid ahritis (RA), ankylosing spondylitis, polymyositis (PM), and dermatomyositis (DM). Autoimmune diseases are very often treated with steroids.", 'role': 'assistant'}]