Background: Using the ELISPOT assay, a promising immunological tool for detecting Mycobacterium tuberculosis (MTB) antigen-specific response, we monitored the clinical course of patients with tuberculosis (TB).
Methods: Blood samples were obtained from 35 patients with TB and healthy controls, numbering 52 age-matched control subjects and 43 university students. Nine of those with TB were examined twice before and after anti-tuberculosis treatment. The frequency of IFN-gamma secreting cells was determined using the ELISPOT assay in peripheral mononuclear cells (PBMC) stimulated with purified protein derivative (PPD), early secretory antigenic target 6 (ESAT-6), and culture filtrate protein 10 (CFP-10).
Results: The frequency of PPD secreting cells correlated significantly with tuberculin skin test (TST) magnitude in BCG-vaccinated individuals. Significant responses to either ESAT-6 or CFP-10 were found in 94% of those with TB. The frequency of IFN-gamma secreting cells decreased when negative sputum tests were confirmed by successful tuberculosis treatment.
Conclusions: The ELISPOT assay detecting MTB-specific immune response is promising both in diagnosing MTB and monitoring responsiveness to tuberculosis therapy.