Cellular immune responses to ESAT-6 discriminate between patients with pulmonary disease due to Mycobacterium avium complex and those with pulmonary disease due to Mycobacterium tuberculosis.
ESAT-6 (for 6-kDa early secreted antigenic target) is a secreted antigen found almost exclusively in organisms of the Mycobacterium tuberculosis complex. We compared in vitro gamma interferon (IFN-gamma) responses by peripheral blood mononuclear cells to this antigen in patients with pulmonary disease due to either Mycobacterium avium complex (MAC) or Mycobacterium tuberculosis with those in healthy, skin test-negative, control subjects. Significant IFN-gamma responses to ESAT-6 were detected in 16 (59%) of 27 M. tuberculosis pulmonary disease patients, 0 (0%) of 8 MAC disease patients, and 0 (0%) of 8 controls. Significant IFN-gamma responses to M. tuberculosis purified protein derivative were detected in 23 (85%) of 27 M. tuberculosis disease patients, 2 (25%) of 8 MAC disease patients, and 5 (63%) of 8 healthy controls. M. avium sensitin was recognized in 24 (89%) of 27 M. tuberculosis disease patients, 4 (50%) of 8 MAC disease patients, and 1 (13%) of 8 controls. IFN-gamma responses to ESAT-6 are specific for disease due to M. tuberculosis and are not observed in patients with MAC disease or in healthy controls.
Department of Medicine, Infectious Disease Section, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03756, USA. dlein@hitchcock.org
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Lein
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von Reyn
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Ravn
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Horsburgh
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Alexander
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Andersen
D000328:Adult; D000368:Aged; D000942:Antigens, Bacterial / Q000276:immunology*; D001426:Bacterial Proteins; D005260:Female; D006801:Humans; D007111:Immunity, Cellular; D007371:Interferon-gamma / Q000097:blood; D007963:Leukocytes, Mononuclear / Q000737:chemistry; D008297:Male; D008875:Middle Aged; D015269:Mycobacterium avium Complex; D015270:Mycobacterium avium-intracellulare Infection / Q000276:immunology*; D009169:Mycobacterium tuberculosis; D012882:Skin Tests; D014374:Tuberculin Test; D014397:Tuberculosis, Pulmonary / Q000382:microbiology*
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C093276:ESAT-6 protein, Mycobacterium tuberculosis; D007371:Interferon-gamma