Radioimmunoassay of Myelin Basic Protein in Spinal Fluid: An Index of Active Demyelination

With a sensitive radioimmunoassay that can measure as little as 2 ng of basic protein in cerebrospinal fluid we studied 303 patients with a variety of neurologic diseases. Patients with active demyelinating diseases had high levels (17 to 100 ng per milliliter) of basic protein. Moreover, patients with multiple sclerosis in acute exacerbation had these high levels, those with slowly progressive multiple sclerosis had lower levels (6 to 16 ng per milliliter), and those in remission had less than 4 ng per milliliter, comparable to the control population. Thus, the assay appears to be a useful index of active demyelination. (N Engl J Med 295:1455-1457, 1976). Early studies on the cerebrospinal fluid of patients with multiple sclerosis showed the presence of elevated protein or IgG or both.¹However, patients with nondemyelinative neurologic disease also had increased levels of cerebrospinal-fluid protein and IgG, and in no case did the values fluctuate with the activity of the disease. At present, there is no specific test for active demyelination. Such a test not only would help in the diagnosis of multiple sclerosis but also would be extremely useful for monitoring the course of the disease and the effects of treatment for active demyelination. In 1969, electron microscopy revealed the.