β-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-Barre 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.