Interferon crosses blood-cerebrospinal fluid barrier in monkeys.

Interferon was detected in the cerebrospinal fluid (CSF) of monkeys injected iv or im with 30 million units of human leukocyte interferon. The im injection maintained a long-lasting plateau at about 1/30th of the corresponding level of interferon in the serum. Interferon injected into the serum. Interferon injected into the cerebrospinal canal was cleared from CSF at a similar rate as it disappeared from blood after iv administration of a high dose. A relatively stable serum level was maintained for 12-24 hr after the injection of interferon into the CSF space.