Enzyme markers in acute myeloid leukaemia

The levels of TdT, AdA, 5'-N, 20 alpha-SDH and TK1 were analyzed in different FAB subgroups of AML. AdA, 5'-N, 20 alpha-SDH and TK1 showed large variations both within and between the different subgroups. It therefore seems unlikely that measurements of these enzymes will be able to aid morphological subclassification of AML. Neither could analysis of these enzymes give prognostic information. TdT was detectable in 46% of AML but the levels were only 1/10-1/100 of those found in ALL. The enzyme was detected in leukaemic granulocytopoietic cells while leukaemic cells of monocytic origin were negative in all but 1 case. In addition, increased TdT activity was positively correlated to the length of survival.