[Serum anti-arrestin antibody and disease activity of multiple sclerosis--a case report of 4-year-old child].

We report a 4-year-old girl with multiple sclerosis (MS) and increased serum anti-arrestin antibody. She was admitted to our hospital because of sustained fever, headache and anorexia. Serial magnetic resonance imaging (MRI) revealed diffuse high intensity of cerebral white matter and basal ganglia on T2-weighted imaging. We treated her with high-dose intravenous methylprednisolone under a diagnosis of ADEM. She recovered without any neurological sequelae in three months and the MRI lesion almost disappeared. However, she developed optic neuritis and two episodes of neurologic involvement associated with multiple white matter lesions in the next two years. She was then diagnosed as having clinically definite MS. Anti-arrestin antibody is reportedly present specifically in adult patients with MS and uveitis. We performed an immunoblot assay using bovine retina, and our case revealed the presence of anti-arrestin antibody. Serial examinations showed that the serum anti-arrestin antibody titer correlated well with the disease activity. These results indicate that anti-arrestin antibody may be a good parameter of the disease activity of MS even in childhood.