Immunological studies on the cerebrospinal fluid in neurological sarcoidosis.

The rate of intrathecal IgG synthesis and the degree of permeability of the blood-brain barrier in 5 patients with sarcoidosis involving the central nervous system are described. Intrathecal IgG synthesis was unusual but increased leakiness of the blood-brain barrier was common in these patients; a finding which may help differentiate such cases from patients with multiple sclerosis.