[Relationship between the activity of serum adenosine deaminase including its isozymes and lymphocyte subpopulation in patients with pulmonary tuberculosis].

Adenosine deaminase (ADA) is one of the enzymes in the purine metabolism and divided into two isozymes, ADA-1 and ADA-2. It is known that the activity of this enzyme is elevated in the sera of patients with pulmonary tuberculosis, sarcoidosis and other diseases, however there are few reports about the change of the activity of this enzyme under treatment. It is often said that this enzyme may have its origin in T lymphocyte, but it remains to be proved. That goes for each of two isozymes, too. In this study, we investigated the activity of serum total ADA, ADA-1 and ADA-2 in patients with pulmonary tuberculosis on admission and after three months' treatment. We also studied the correlation of lymphocyte subpopulation with these enzymes. The activity of total ADA, ADA-1 and ADA-2 was significantly higher in the sera of patients with pulmonary tuberculosis than in those of healthy persons. ADA-2 activity correlated significantly and negatively with the number of CD3+ lymphocytes and CD4+ lymphocytes. The change rate of ADA-2 activity during three months' treatment correlated significantly and negatively with the change rate of CD4/8. These results may suggest that there is a close correlation between the activity of ADA-2 and lymphocyte subpopulation in the sera of patients with pulmonary tuberculosis. ADA-1 activity did not correlate with lymphocyte subpopulation significantly, but it decreased significantly after three months' treatment. The activity of ADA-1 also may have certain relations with the disease process of pulmonary tuberculosis.