Blood-CSF barrier permeability and central nervous system immunoglobulin G in schizophrenia.

The ratio of albumin in cerebrospinal fluid (CSF) to serum may serve as an index of the integrity of the blood-CSF barrier, with increases in this ratio indicating increased permeability. The ratio of immunoglobulin G (IgG) in CSF to serum (divided by the albumin ratio to correct for variance in blood-CSF permeability) represents an index of the endogenous production of IgG in the central nervous system (CNS), with increases reflecting a possible infectious and/or autoimmune process stimulating central IgG synthesis. We analyzed simultaneously collected CSF and serum samples from 46 schizophrenic subjects, 8 of whom were studied both on and off neuroleptic treatment, and samples from 20 normal controls. The data indicated increases in CSF/serum albumin ratios or CSF/serum IgG indices in 22% and 20%, respectively, of the schizophrenic patients. Only 3 patients showed elevations in both indices. Comparison of values on and off neuroleptics indicated no significant effect of neuroleptics on these indices.