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': 'A 45-year old patient presented with fever, night sweats and weight loss. On X-ray, a mass was seen in the apical lobe. On histopathology, caseous necrosis was present. What is the name of the underlying process? \nSelect and explain. \nA. Enzymatic degeneration, B. Acute decrease in blood supply, C. Decreased supply of growth factor, D. Hypersensitivity reaction with modified macrophages, lymphocytes and giant cells', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Clinical features like fever; night sweats and weight loss and X-ray finding of a mass in apical lobe with\xa0histopathological findings of caseous necrosis are highly suggestive of tuberculosis. The underlying\xa0process is type IV hypersensitivity, which is characterized by the presence of modified macrophages, lymphocytes & giant cells.\nSchematic illustration of the events that give rise to the formation of granulomas in cell-mediated (type IV)\xa0hypersensitivity reactions.\nTuberculosis\n\nAntigenic property :\nGroup specificity is due to polysaccharide\xa0while type specificity is due to a protein antigen.\nAntibodies are not useful for diagnosis and immunity.\n\nPathogenicity:\n\nMacrophages are the primary cells infected\xa0by M. tuberculosis.\nM. tuberculosis replicated within the macrophages (phagosome) by blocking fusion of\xa0phagosome and Lysosome.\nIt is due to the escape of killing by macrophages\xa0and induction of type IV hypersensitivity.\nFactors contributing to pathogenesis: Cord factor, Lipoarabinomannan, Complement system, M.\xa0tuberculosis heat shock proteins.\nRisk of acquiring infection is determined mainly by exogenous factors\xa0while the risk of developing\xa0disease depends largely on endogenous factors\nMost potent risk factor- HIV coinfection\nClinical Features', 'role': 'assistant'}]