The lymphocyte activity of adenosine deaminase and enzymes of AMP metabolism in mammary carcinogenesis: the effect of thymostimulin.

Studies were undertaken on the activity of adenosine deaminase (ADA) and metabolic enzymes of AMP in the spleen and thymus cells of rats with DMBA-induced carcinogenesis of the mammary glands and on the effect of thymostimulin (TS) on this activity. In addition, we investigated the activity of ADA in the peripheral blood lymphocytes of the patients with premalignant diseases and cancer of the mammary glands (Stages I-IV) as well as the possibility of its enhancement by TS. The disturbances of these enzyme activities characterized by a decrease in ADA activity and an increase in activity of the AMP metabolism enzymes, predisposed for adenosine accumulation in lymphoid cells. Injection of TS normalized the ADA activity and decreased the activity of the AMP metabolic enzymes. Analogous results were obtained in the studies of ADA activity in the human materials. With the human tumor growth the in vitro effect of TS on the lymphocyte ADA activity decreased. We may suggest that measurement of the ADA activity in the lymphocytes may serve as a reliable tool to control the state of immune system and the effectiveness of immunotherapy with the thymic humoral factors.