2',3'-Cyclic nucleotide 3'-phosphodiesterase activity in the cerebrospinal fluid of patients with demyelinating diseases.

We aimed to study the level of CNPase activity in the cerebrospinal fluid of patients with demyelinating diseases and other neurological diseases, particularly multiple sclerosis, with reference to CSF myelin basic protein content. CNPase activity was measured paper chromatographically using radioactive 2',3'-cAMP as a substrate. Myelin basic protein content was measured with a radioimmunoassay. The mean level of CNPase activity was significantly higher for multiple sclerosis than for nonneurological controls. Dividing the disease phases of multiple sclerosis into the three periods, the CNPase activity was found to be significantly elevated in the worsening period and reduced in the improving period and the inactive period. The level of CNPase activity in the cerebrospinal fluid of multiple sclerosis coincided with the clinical activity of the disease. The level of CNPase activity correlated well (r = 0.84) with the level of myelin basic protein content in cerebrospinal fluid. The ratio for CNPase activity and myelin basic protein content in cerebrospinal fluid was almost the same as that in human central nerve myelin. We concluded that CNPase activity in the cerebrospinal fluid from neurological patients is an indicator of destruction of myelin in the central nervous system, and the measurement of CNPase activity in the cerebrospinal fluid of multiple sclerosis could be useful in the clinical management.