Detection of mycobacterial antigen in cerebrospinal fluid in patients with chronic meningitis by inhibition enzyme linked immunosorbent assay.

In a retrospective study, cerebrospinal fluid (CSF) specimens from 50 patients of chronic meningitis were investigated for tuberculous etiology by inhibition enzyme-linked immunosorbent assay (ELISA). CSF specimens from 10 patients of tuberculous meningitis in whom Mycobacterium tuberculosis was isolated, formed the positive control group of this study. The assay yielded positive results in CSF specimens for mycobacterial antigens in 8 of the 50 patients of chronic meningitis. No false positive results were recorded in 50 patients of non-meningitic (negative control group) neurological diseases. Inhibition ELISA procedure described here is reproducible and had 100 per cent specificity for tuberculous etiology. This assay could be applied as a diagnostic tool for tuberculous etiology, particularly in patients of chronic meningitis in whom repeated CSF cultures for any microbial agents are negative.