Significance of immune response to Mycobacterium tuberculosis culture filtrate protein antigens in cerebrospinal fluid of tuberculous meningitis patients: A search for diagnostic marker.

Mycobacterium tuberculosis (H37Ra) culture filtrate proteins (CFP) are explored as a diagnostic marker for tuberculous meningitis (TBM). Cerebrospinal fluid (CSF) samples from patients were categorized as confirmed (n = 47), suspected (n = 20), and non-TBM (n = 25) cases. Immune response by Western blot revealed TBM CSF samples are having heterogeneous response to CFP. CFP ELISA was 92% sensitive and 38.30% specific. ODs of confirmed TBM and non-TBM cases were significantly different (P < 0.0001) and also the suspected TBM and non-TBM cases (P = 0.0001). No significant difference noticed in TBM and suspected TBM (P = 0.90). Thus, CFP can be a better biomarker for the diagnosis of TBM.