Objective: To investigate the level of specific cellular immunity in patients with active pulmonary tuberculosis and its potential relationship with severity of the disease.
Methods: Thirty active pulmonary tuberculosis patients with positive tubercle bacilli in sputum were enrolled for the study. Immune responses including lymphocytes proliferation enhanced by enhance intracellular survival (EIS) antigen and cytokine production including interferon-gamma (IFN-gamma) and interleukin-10 (IL-10), were assayed. Cell proliferation was determined by methyl thiazolyl tetrazolium (MTT), while cytokine production was quantified by enzyme linked immunoadsorbent assay (ELISA). The results were compared to those of 20 healthy individuals and 16 persons recovered from tuberculosis.
Results: Cell proliferation response and IFN-gamma production were significantly higher in patients convalescent from tuberculosis compared to patients with active pulmonary tuberculosis, EIS antigen was found to elicit a dominant Th2 cytokine response.
Conclusion: Impaired Th1 immune response to EIS is observed in patients with active pulmonary tuberculosis. Induction of imbalance of Th1/Th2 immune response may be the main action of EIS, which may be a factor of pathogenesis of tuberculosis.