Specificity and correlation with disease activity of cerebrospinal fluid osteopontin levels in patients with multiple sclerosis

Background: Despite recent advances in therapy that have improved the overall disease course in multiple sclerosis (MS), the prognosis at the outset remains unpredictable. Objectives: To investigate whether cerebrospinal fluid (CSF) osteopontin levels correlate with disability or active disease in MS and to determine whether elevated CSF osteopontin levels are only seen in MS. Design: Cerebrospinal fluid osteopontin was assayed using enzyme-linked immunosorbent assay in duplicate by an observer blinded to the clinical status of the sample. Cerebrospinal fluid samples were not obtained from any patient who had received high-dose corticosteroid therapy in the month before analysis. Setting: Medical research institute. Patients: Thirty patients (18 women and 12 men; age range, 24-71 years) with clinically definite MS and 36 patients (22 women and 14 men; age range, 20-71 years) with other neurological diseases (ONDs) or nonneurological illnesses were included in the study. Main Outcome Measures: Disease activity for patients with MS was based on observations in the year preceding the study, including the number of relapses, the change in disability according to the Expanded Disability Status Scale, and increased T2-weighted or gadolinium-enhancing lesions on brain magnetic resonance imaging. Results: Higher CSF osteopontin levels were seen in patients with MS having active disease and in patients with ONDs that are actively deteriorating or inflammatory. However, CSF osteopontin levels in patients with MS did not correlate with disability status. Conclusions: Cerebrospinal fluid osteopontin levels do not correlate with disability in MS but tend to be higher in patients with active disease. Elevated CSF osteopontin levels are not a specific marker for MS, as they are found in patients with ONDs and nonneurological illnesses. In ONDs, the highest CSF osteopontin levels are seen in patients with rapidly progressive neurological dysfunction or widespread inflammation of the central nervous system.