Significance of mycobacterial immune complexes (IgG) in the diagnosis of tuberculous meningitis.
METHODS
Tuberculous meningitis (TBM) has high mortality, especially in children. Early accurate diagnosis and adequate treatment would reduce this mortality. Diagnosis of TBM remains an enigma because of low cerebrospinal fluid (CSF) culture positivity for Mycobacterium tuberculosis and weak clinical correlation with conventional immunoassays.


OBJECTIVE
To evaluate significance of mycobacterial immune complexes (IgG) and anti-mycobacterial antibodies in the diagnosis of TBM.


METHODS
CSF from TBM patients and various types of other neurological (both infectious and non-infectious) and non-neurological cases was studied for the presence of IgG and anti-mycobacterial antibodies using antigen capture (by anti-BCG) and multilayered ELISA (using M. tuberculosis soluble extract), respectively.


RESULTS
IgG in CSF could be detected in 33 of 55 (60%) and anti-mycobacterial antibodies in 30 of 55 (55%) TBM cases. Presence of IgG, anti-mycobacterial antibodies or both could be detected in 45 of 55 (82%) of the TBM cases. Excepting three of the pyogenic meningitis CSF, none of the infectious (49), non-infectious neurological cases (30) and non-neurological controls (32) showed the presence of IgG or anti-mycobacterial antibodies.


CONCLUSIONS
Detection of IgG along with anti-mycobacterial antibodies aids in diagnosis of a large proportion of TBM cases.
Patil
S A
SA
Department of Microbiology, National Institute of Mental Health and Neurosciences, Bangalore, India.
Gourie-Devi
M
M
Anand
A R
AR
Vijaya
A N
AN
Pratima
N
N
Neelam
K
K
Chandramuki
A
A
D000907:Antibodies, Bacterial / Q000134:cerebrospinal fluid*; D000936:Antigen-Antibody Complex / Q000134:cerebrospinal fluid*; D003937:Diagnosis, Differential; D006801:Humans; D007074:Immunoglobulin G / Q000134:cerebrospinal fluid*; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D009422:Nervous System Diseases / Q000175:diagnosis; D014390:Tuberculosis, Meningeal / Q000175:diagnosis* / Q000276:immunology
D000907:Antibodies, Bacterial; D000936:Antigen-Antibody Complex; D007074:Immunoglobulin G