Orphanidou et al. [11] compared ADA activity and lysozyme levels in BAL fluid of smear-negative pulmonary TB patients and non-TB lung disease patients and found that there was no significant difference in lysozyme level of BAL fluids between the two groups, but ADA level in BAL fluids of pulmonary TB patients was significantly higher than that of non-TB lung disease patients (P < 0.001). This evidence concerns the gene ADA and tuberculosis.