The association of adenosine deaminase activity with T-lymphocytes and subsets in pulmonary tuberculosis and bronchogenic carcinoma.

Simultaneous determination of blood/lung ADA activity and T-lymphocyte subsets was conducted in 12 patients with active pulmonary tuberculosis, 12 patients with bronchogenic carcinoma and 11 healthy volunteers. Differences were significant only in the tuberculosis patients, namely, increased mean enzyme values in both the peripheral blood (36.68 +/- 10.90 U/L) and in the BALF (4.25 +/- 2.19 U/L), and correlation of ADA activity between the blood and the diseased lung only; the difference in elevated enzymatic activity between the tuberculosis group and the cancer group was of no statistical significance. We conclude that simultaneous ADA analysis of the blood and the BALF may be of diagnostic value in cases suspected of having tuberculosis as yet undiagnosed by other means. Based on the lowest value of enzymatic activity in the blood of patients with tuberculosis (28 U/L), the test has a sensitivity of 75 per cent and a specificity of 100 per cent; whereas the lowest value in the BALF of tuberculosis patients (2.9 U/L), the test has a sensitivity of 77 per cent and a specificity of 82 per cent. Findings that there was a blood-lung correlation of elevated ADA activity and a correlation of enzymatic elevation with increased numbers of T-cells bearing IL-2 receptor in cases of pulmonary tuberculosis only provide evidence in support of T-lymphocytes actively participating in the ongoing immune process.