Evaluation of adenosine deaminase activity in the Mycobacterium tuberculosis culture supernatants

Background. Adenosine deaminase (ADA) catalyzes hydrolytic and irreversible deamination of deoxyadenosine into deoxyinosine and of adenosine into inos ine, and is related to lymphocytic proliferation and differentiation. The m easurement of ADA activity in body fluids is a useful tool in the evaluatio n of mycobacterial infections, Elevated ADA activity has been found in pleu ral effusions of patients with pleural tuberculosis relative to those from patients with nontuberculous pleural diseases, and is mainly associated wit h cellular host factors such as monocyte-macrophages or lymphocytes, In con trast, there is little information about ADA activity measurement in mycoba cteria culture supernatants. Methods. We evaluated ADA activity as described by Giusti in the culture su pernatants of eight Mycobacterium tuberculosis isolates. Results. Mycobacteria culture supernatants did not display any ADA activity . Conclusions. This result supports the notion that Mycobacterium tuberculosi s is not the source of ADA activity. However, increased ADA activity in bio logical fluids from tuberculosis patients might be due to the interaction o f the mycobacterium with host factors. (C) 1999 IMSS. Published by Elsevier Science Inc.