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: Pathology
[{'content': 'In graft rejection, type of HLA involved is? \nSelect and explain. \nA. MHC Class II, B. MHC class I, C. MHC Class III, D. MHC Class IV', 'role': 'user'}, {'content': 'Answer: B \nExplanation: In transplantation immunology, the major impact in graft loss comes from the effects of HLA-B\xa0and HLA-DR antigens\nThe histocompatibility antigens (human leukocyte antigens - HLA) are cell surface antigens that\xa0induce a response leading to rejection of allografts\nThe principal physiologic function of the cell surface histocompatibility molecules is the bound\xa0peptide fragments foreign proteins for presentation to antigen-specific T cells.\nThe histocompatibility antigens are encoded by a closely linked multiallelic cluster of genes:\xa0Mix histocompatibility complex (MHC) or Human leukocyte antigens complex (HLA complex)\nHLA complex of genes is located on the short arm of chromosome 6.\nIt consists of three separate clusters of genes:\n\nHLA Complex (MHC complex)', 'role': 'assistant'}]