Pregnancy-specific beta 1 glycoprotein (SP1) in the cerebrospinal fluid.

Pregnancy-specific beta 1 glycoprotein (SP1) was assayed by Particle Counting Assay in the cerebrospinal fluid (CSF) from 26 non-neurological patients, from 190 patients with various neurological disorders and from 84 patients with malignant hemopathies. With a sensitivity limit of 0.5 microgram/l, SP1 was undetectable in normal CSF. High levels were observed in CSF from one pregnant woman with herpetic encephalitis and from another woman with post-puerperal thrombophlebitis as a result of high serum concentrations and leakage of the blood-brain barrier. SP1 was detected at low levels in the CSF from 1 patient out of 5 with Creutzfeldt-Jakob disease and from a patient with Behçet's disease. Seven patients out of 84 with malignant hemopathies presented cerebral involvement; 3 of them had detectable SP1. However, SP1 was also detected in the CSF of 2 patients in apparently complete remission. The determination of SP1 in CSF appears to be of limited value in the diagnosis of neurological disorders and in the early detection of a cerebral localization of malignant hemopathies.