Usefulness of ELISA using antigen A60 in serodiagnosis of neurotuberculosis

Anti-mycobacterial antibody to A60 antigen were quantified in the sera and cerebrospinal fluid (csf) samples of one hundred patients of neurotuberculosis and twenty non-tubercular controls by immunoenzymatic (ELISA) assay. Sixty three patients (63%) had "significant" antibody titres in serum and/or CSF samples. In contrast, none of the samples from the control group showed this level of antibody concentration. The evaluation of this assay in tuberculoma (group A, 79 cases) vis-a-vis tubercular meningitis or TBM (group B, 21 patients) revealed significant antibody levels in the former 46 (58.2%) in comparison to 17 (77.3%) in the latter group. A positive relationship was observed in the titres of anti-mycobacterial antibodies in serum and in CSF both in cases of tuberculoma and TBM. This study indicates the utility of A60 antigen ELISA assay in categorising these patients into tubercular aetiology specially in the absence of bacteriological isolation from CSF which still remains the gold standard diagnostic criterion.