Rapid diagnosis of tuberculous meningitis by a dot-immunobinding assay

In this study, a dot-immunobinding assay (Dot-Iba) was standardized to meas ure circulating antimycobacterial antibodies in the cerebrospinal fluid (CS F) specimens for the rapid laboratory diagnosis of tuberculous meningitis ( TBM). Specific CSF-IgG antibody to Mycobacterium tuberculosis from a cultur e proven patient with TBM was isolated and coupled with activated Cynogen b romide-Sepharose 4B. Using an immunoabsorbent affinity chromatography, 14 k Da antigen present in the culture filtrates of ill. tuberculosis was isolat ed and this antigen was used in the Dot-Iba, to quantitate specific antimyc obacterial antibodies in CSF specimens. The Dot-Iba gave positive results i n all the 5 culture proven patients with TBM and gave no false positive res ults in CSFs from patients with partially treated pyogenic meningitis. Dot- Iba developed in our laboratory is a simple, rapid and specific method and more importantly suited for the routine application in laboratories with li mited resources.