Immune responses to the Mycobacterium tuberculosis-specific antigen ESAT-6 signal subclinical infection among contacts of tuberculosis patients.

Diagnosis of latent Mycobacterium tuberculosis infection is considered essential for tuberculosis control but is hampered by the lack of specific reagents. We report that strong recognition of tuberculosis complex-specific antigen ESAT-6 by healthy household contacts of tuberculosis patients correlates with the subsequent development of active tuberculosis during a 2-year follow-up period.