Immunodiagnosis of tuberculous meningitis: detection of antibody reactivity to antigens of Mycobacterium tuberculosis and Cysticercus cellulosae in cerebrospinal fluid tuberculous meningitis patients by ELISA.

Enzyme-linked immunosorbent assay (ELISA) was standardized and evaluated for detection of antibody response in cerebrospinal fluid (CSF) to antigens of Mycobacterium tuberculosis and Cysticercus cellulosae. Sonicated extracts of heat killed M. tuberculosis H37Rv and C. cellulosae were prepared and used in ELISA to detect respective antibody response in CSFs for a definitive diagnosis as to tuberculous meningitis (TBM)/neurocysticercosis (NCC). ELISA was performed in a total of 201 CSF samples, which include Group I: chronic infections of the central nervous system (CNS) with possible diagnosis of TBM, tuberculoma, or NCC (n = 70), and Group II: control group of patients with infectious neurological (n = 19), non-infectious neurological (n = 82), and non-infectious non-neurological conditions, i.e., spinal anaesthesia CSFs (n = 30). Specificity in this study was 99.9% and no true cross-reactivity between antimycobacterial antibodies and C. cellulosae antigens and vice-versa was observed. However, in 17.14% of CSFs (12/70), both antimycobacterial and anticysticercal antibodies were detected, 50% of these cases were diagnosed as TBM. But none of the proven NCC cases showed presence of antimycobacterial antibodies. Results of this study would indicate that it would be beneficial if both antibody and antigen responses are detected in CSFs to infectious aetiologies such as M. tuberculosis, C. cellulosae, and C. neoformans in order to enhance the diagnostic accuracy and proper management, as these diseases are highly endemic in underdeveloped and developing countries.