Dihydropteridine reductase activity and neopterin levels in leukemias and lymphomas: is there any correlation between these two parameters?

Urinary neopterin levels, blood dihydropteridine reductase activity as well as other frequently used clinical parameters were evaluated in 110 patient s suffering from various types of lymphomas and leukemias. Among them neopt erin was detected as the most sensitive marker representing the severity of malignancy (p<0.00001). All patients with active diseases had significantl y raised urinary neopterin levels compared to those in remission and health y controls. Of 69 patients with active disease 66 (96%) were above the uppe r limit seen in healthy subjects. In addition, the highest neopterin excret ion was found in patients with active chronic myeloid leukemia (1469+/-479 mu mol/mol creatinine n=16). In contrast, only 1 of 41 patients in stable r esponsive disease and remission (2.4%) had increased urinary neopterin leve ls above the upper limit. Dihydropteridine reductase (DHPR) activities were also detected in all pati ents and control groups. In active disease slightly reduced (DHPR) activiti es were evident (3.42 +/- 0.37 for controls, 2.92 +/- 0.39 in active diseas e and 3.28 +/- 0.42 nmol red cytochrome C/min/5 mm diameter disc in remissi on patients). However in patients under medication this was strengthened, T his data also suggest that DHPR activity can be effected by chemotherapy. The results of the present study support the fact that urinary neopterin le vels may be an useful and reliable early prognostic marker for neoplasia wh en used together with other prognostic indicators. Our data also suggest th at reductions in DHPR activities may also be an underlying cause for the ne urological disorders that are commonly seen in patients with haematological malignancies.