Chronic relapsing experimental allergic encephalomyelitis. Immunological and blood--cerebrospinal fluid barrier-dependent changes in the cerebrospinal fluid.

Cerebrospinal fluid (CSF) and plasma were taken from strain 13 guinea pigs in various stages of chronic relapsing experimental allergic encephalomyelitis using techniques which allowed repeated sampling from the same animal. Samples were assayed for albumin and IgG and the corresponding CSF/plasma quotients evaluated graphically using a method which could discriminate between blood-CSF barrier dysfunction and local IgG synthesis in the central nervous system (CNS). During the disease a 2-3-fold increase in plasma IgG concentration developed and an increase in blood-CSF permeability was noted. Isoelectric focusing revealed an oligoclonal IgG pattern identical in both plasma and CSF. The results provided no evidence for a local production of IgG in the CNS like that which is known to occur in multiple sclerosis.