Human alpha 1-microglobulin levels in neurological disorders.

The concentration of alpha 1-microglobulin (alpha 1-m) in sera and cerebrospinal fluids (CSF) was measured in 121 patients with various neurological disorders. Using single radial immunodiffusion, its serum level was determined. No significant difference was found between the patients (29.1 +/- 4.3 mg/l; mean +/- 1 SD) and normal control group (23.7 +/- 4.6 mg/l). The level of CSF alpha 1-m was determined by the radioimmunoassay of solid antibody system. Its CSF level in the control group was 34.8 +/- 16.0 micrograms/l, while it was significantly increased in the patients with viral meningitis (p less than 0.01) and cerebral infarct (p less than 0.05). The level was also elevated in some cases of brain tumor, bacterial meningitis, cerebral hemorrhage, cervical spondylosis, and acute lymphocytic leukemia. There was a positive correlation between alpha 1-m and albumin levels in CSF. The analysis by CSF/serum albumin ratio and alpha 1-m ratio suggested that the increase of alpha 1-m in CSF could be explained mainly by an increase in permeability of the serum alpha 1-m through damaged blood brain barrier under these pathological conditions. Its local production within the central nervous system, however, could not be ruled out in these disorders.