Significance of Mycobacterium tuberculosis antigen expression in cerebrospinal fluid monocytes in diagnosing tuberculous meningitis.

ABSTRACT

Background: The aim of this study was to investigate the signifi cance of positive expression of Mycobacterium tuberculosis, (MTB) antigen in the cerebrospinal fl uid (CSF) monocytes in diagnosing tuberculous meningitis (TBM). Materials and Methods: A total of 50 inpatients of TBM, 30 viral meningitis and 20 healthy controls were studied at the 1st, 2nd, and 4th week during their treatment course. Immunohistochemical assay were used to detect early secreted antigenic target 6 (ESAT-6) positive cells, and positive cases were also observed. Results: The percentage of positive cases and positive cells of ESAT-6 in CSF monocytes were all higher in the 1st and 2nd week than in the 4th week in TBM patients (P < 0.01); and percentage of positive cases and positive cells of MTB antigen in CSF monocytes were higher in TBM patients than in viral meningitis and health control in the 1st and 2nd week (P < 0.01). The sensitivity was 90% and the specifi city was 92% in the early stage (within 2 weeks) of TBM. Conclusion: The positive expression of ESAT-6 in CSF monocytes is helpful for the early diagnosis of TBM.