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Published on: November 23, 2010
Intracellular ESAT-6: A new biomarker for Mycobacterium tuberculosis infection
Nikolaos Poulakis1, Angelos D Gritzapis2, Maria Ploussi2,3
1Department of Pulmonary Medicine, Locus Medicus S.A., Athens, Greece.
Background:
Early secreted antigenic target 6 (ESAT-6) is a virulent factor of Mycobacterium tuberculosis (MTB). The identification of intracellular (i/c) ESAT-6 in host cells would be a direct marker of MTB infection. We developed a method to detect i/cESAT-6 by flow cytometry. The aim of this study is to investigate the expression of i/cESAT-6 in the host cells of individuals with MTB infection.
Methods:
The expression of i/cESAT-6 was examined in the blood of 58 active TB patients, in 10 naïve to TB infection controls, in 17 patients who completed anti-TB treatment, and in 56 close contacts with an index TB case. Additionally, it was examined in the sputum of 12 active TB patients.
Results:
The i/cESAT-6 was positively detected in the blood of 52 out of 58 (90%) active TB patients. All naïve to TB infection controls were negative. Three out of 17 (18%) patients at the end of anti-TB treatment were positive. Twenty-six out of 56 (46%) close contacts tested positive. The i/cESAT-6 was detected in all culture positive TB sputum specimens.
Conclusions:
The i/cESAT-6 is a promising biomarker of MTB infection that could be used in the evaluation of active TB patients and in the diagnosis of latent TB infection. Further studies are needed to validate its potential diagnostic role. © 2014 International Clinical Cytometry Society.
Insights
Intracellular Early secreted antigenic target 6 (ESAT-6) is a promising biomarker for Mycobacterium tuberculosis (MTB) infection. Detection in host cells can aid in evaluating active TB and diagnosing latent TB infection.
Area of Science:
- Immunology
- Microbiology
- Infectious Diseases
Background:
- Early secreted antigenic target 6 (ESAT-6) is a key virulence factor of Mycobacterium tuberculosis (MTB).
- Intracellular detection of ESAT-6 (i/cESAT-6) in host cells offers a direct marker for MTB infection.
- A novel flow cytometry method was developed to detect i/cESAT-6.
Purpose of the Study:
- To investigate the expression of i/cESAT-6 in host cells of individuals with MTB infection.
- To assess the diagnostic potential of i/cESAT-6 as a biomarker for tuberculosis.
Main Methods:
- Examined i/cESAT-6 expression in blood samples from 58 active TB patients, 10 TB-naïve controls, 17 patients who completed treatment, and 56 close contacts.
- Analyzed i/cESAT-6 in sputum from 12 active TB patients.
- Utilized flow cytometry for detection.
Main Results:
- i/cESAT-6 was detected in 90% of active TB patients' blood.
- 26% of close contacts and 18% of patients who completed treatment showed positive results.
- All culture-positive TB sputum specimens were positive for i/cESAT-6.
Conclusions:
- i/cESAT-6 shows promise as a biomarker for MTB infection.
- It may aid in evaluating active TB and diagnosing latent TB infection.
- Further research is required to validate its diagnostic utility.
