Beta-trace protein in cerebrospinal fluid: a blood-CSF barrier-related evaluation in neurological diseases

Beta-trace protein concentrations in cerebrospinal fluid (CSF) and serum from 113 patients with various neurological diseases and 65 controls were determined with a sensitive and specific immunonephelometric assay. In adult control patients, beta-trace concentrations were 14.6+/-4.6 mg/L in CSF and 0.46+/-0.13 mg/L in serum, that is, 32-fold higher in CSF. beta-trace levels in CSF correlated with age as well as with the albumin CSF/serum ratio (Q(Alb)), which is considered a measure for blood-CSF barrier function. The relationship between CSF beta-trace levels and elevated Q(Alb) values was studied in various neurological diseases with CSF protein increase. In spinal canal stenosis, CSF beta-trace (mean=29.5+/-10.5 mg/L) correlated positively with increasing Q(Alb) values. In bacterial meningitis, CSF beta-trace (mean=8.7+/-3.9 mg/L) remained invariant to changes of Q(Alb) values. In Guillain-Barré syndrome, CSF beta-trace (mean=14.4+/-6.8 mg/L) was below the Q(Alb)-dependent reference range. In multiple sclerosis and viral meningoencephalitis, beta-trace levels were within the reference range. Beta-trace concentration in CSF can be used in conjunction with Q(AlB) to distinguish between different neurological pathologies associated with CSF protein increase.