Beta-2-microglobulin and ferritin in cerebrospinal fluid for evaluation of patients with meningitis of different etiologies

To determine whether or not the beta-2-microglobulin (β2-m) and/or ferritin levels in cerebrospinal fluid (CSF) can be used as markers for the differential diagnosis of meningitis and determination of the response to treatment, 122 subjects with etiologically well-characterized diagnoses were classified into three groups: bacterial meningitis (n=5; mean age±SD, 1.0±1.0 year), viral meningitis (n=39; 5.9±3.8 years), and a non-meningitis group (n=78; 5.2±4.9 years). The levels of β2-m and ferritin in CSF were determined by means of a latex photometric immunoassay. The statistical significance of the data was analyzed with the Mann–Whitney U-test. A receiver operating characteristic curve was used to evaluate the diagnostic accuracy of each prediction marker. This study indicated that (1) the levels of β2-m and ferritin in CSF were related with age in the non-meningitis group: subjects of up to 5 months of age exhibited higher concentrations of these proteins than ones of above 6 months of age (β2-m, 1.89±1.13 vs. 0.84±0.65 mg/l, P<0.01; ferritin, 2.97±2.04 vs. 1.81±1.34 μg/l, P=0.09); (2) the β2-m level was significantly higher in the CSF of patients with viral meningitis than in ones without meningitis (2.41±1.23 vs. 0.84±0.65 mg/l, P<0.01): the best cut-off value was 1.2 mg/l (3) the ferritin level was significantly higher in the CSF of patients with bacterial meningitis than in ones with viral meningitis (43.24±39.49 vs. 6.81±7.41 μg/l, P<0.01): the best cut-off value was 7.5 μg/l; and (4) sequential measurement of the CSF ferritin level was of value for determination of the response to antibiotic treatment for bacterial meningitis. These results only apply to patients of greater than 6 months of age. β2-m and ferritin in the CSF can be used as an ancillary tool for diagnostic guidance in the acute phase of meningitis and determination of the response to treatment for bacterial meningitis.