Variations in serum alkaline DNase activity: a new means to assess early detection of relapse in patients treated for acute nonlymphoblastic leukemia

Our previously published clinical results on various malignancies indicated that the variations in serum alkaline DNase activity (SADA) could be a sensitive test for therapeutic monitoring of human malignancies. In the present study, the clinical efficacy of SADA detecting relapse in 32 acute nonlymphoblastic leukemia (ANLL) patients in remission was tested. The observation period ranged from 3 to 17 months. A simple and rapid biochemical technique based on spectrophotometric measurements was used to assay SADA. Of the 32 patients, 17 remained in remission and had less than a 15% variation in SADA levels. They had no clinical symptoms of recurrence at any time. In the remaining 15 patients, after a period of stability, a progressive decrease in SADA, with variations of more than 15%, was observed without any treatment. At that time, no abnormalities of clinical parameters were detected in these patients. A recurrence of disease as evidenced by routine examinations was found relatively late after the first decrease in SADA in all 15 patients (range 1.5 to 5.5 months). These results suggest that periodic measurements of SADA during the posttherapeutic course can be used as a means to assess early detection of an eventual recurrence.