This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
[{'content': 'A pediatric patient with progressively developing degenerative neurologic disease/disorder has an elevated CSF antibody titer to measles virus. You should suspect which of the following? \nSelect and explain. \nA. Acute Lyme disease, B. Fifth disease, C. Possible hepatitis B infection, D. Possible subacute sclerosing panencephalitis (SSPE)', 'role': 'user'}, {'content': 'Answer: D \nExplanation: SSPE is thought to be caused by a measles-related virus present in the central nervous system. Most SSPE patients show elevated measles virus antibodies in serum and CSF. In patients with MS, lower CSF antibody titers have been observed, suggesting a possible etiologic role for measles virus in MS.', 'role': 'assistant'}]