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: Unknown
[{'content': 'Which of the following is a major cell infiltrate in rheumatoid arthritis? \nSelect and explain. \nA. CD4+helper cell, B. Macrophage, C. Lymphocyte, D. Dendritics cells', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ref. Robbins Pathology. 9th edition. Page. 1209\nRheumatoid Arthritis\nCD4+ T helper (TH) cells may initiate the autoimmune response in RA by reacting with an arthritogenic agent, perhaps microbial or a self-antigen \n\nIFN-γ from TH1 cells activates macrophages and resident synovial cells.\nIL-17 from TH17 cells recruits neutrophils and monocytes.\nTNF and IL-1 from macrophages stimulates resident synovial cells to secrete proteases that destroy hyaline cartilage.\nRANKL expressed on activated T cells stimulates bone resorption.\n\nMicroscopy:\nThe characteristic histologic features include\n\nSynovial cell hyperplasia and proliferation\nDense inflammatory infiltrates (frequently forming lymphoid follicles) of cd4+ helper t cells, b cells, plasma cells, dendritic cells, and macrophages\nIncreased vascularity due to angiogenesis\nFibrinopurulent exudate on the synovial and joint surfaces;\nOsteoclastic activity in under- lying bone', 'role': 'assistant'}]