This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hypersensitivity, Subject name: Pathology
[{'content': 'Type I hypersensitivity reaction is mediated by: \nSelect and explain. \nA. IgG, B. IgM, C. IgD, D. IgE', 'role': 'user'}, {'content': 'Answer: D \nExplanation: In immediate hypersensitivity (type I hypersensitivity)- the injury is caused by TH2 cells, IgE antibodies, and mast cells and other leukocytes. Mast cells release mediators that act on vessels and smooth muscle and pro-inflammatory cytokines that recruit inflammatory cells.', 'role': 'assistant'}]