MOLECULAR-FORMS OF ADENOSINE-DEAMINASE DO NOT AID THE DIAGNOSIS OF TUBERCULOSIS

To investigate the diagnostic utility of adenosine deaminase as a test for tuberculosis, molecular forms of the enzyme indicative of cell-me diated immunity were studied in tuberculous pleural effusion, peritoni tis and meningitis. Twenty-six pleural, 21 peritoneal, and 24 cerebros pinal tuberculous and non-tuberculous fluids were examined for adenosi ne deaminase and the large and small forms of the enzyme were differen tiated on immunoblots. Adenosine deaminase levels ranged from zero to 81 units/L, zero to 31 units/L and zero to 31 units/L in the pleural, peritoneal and cerebrospinal fluids, respectively. The large form of a denosine deaminase (280 kDa) was detected in one of 14 proved tubercul ous cases, a peritoneal fluid. The small form of the enzyme (35-39 kDa ) was seen in both tuberculous and non-tuberculous conditions in 6 ple ural, 7 peritoneal and 8 cerebrospinal fluids. Molecular forms of aden osine deaminase did not, appear to help in the diagnosis of tuberculos is in this patient population and may not be suited for analysis in fl uids with low enzyme activity.