Abstract
Purine metabolism is important in lymphocyte differentiation and proliferation. These enzyme activities in lymphoid malignancy were investigated extensively. The purpose of this report is to compare measurements of purine enzyme activities and subtypes of acute leukemias of children. Adenosine deaminase (ADA), purine nucleoside phosphorylase (PNP), adenine phosphoribosyltransferase (APRT) and hypoxanthine-guanine phosphoribosyltransferase (HGPRT) activities were measured in mononuclear cells of patients with acute leukemia and lymphoma. ADA, APRT and HGPRT activities were measured by radioisotope method and PNP activity was measured by Kalcker's method. T-ALL have significantly higher ADA activity, lower PNP activity and relatively lower APRT, HGPRT activity, so T-ALL have highest ADA/PNP ratio and lower APRT/HGPRT ratio. Null-ALL have high ADA activity, relatively low PNP activity and APRT, HGPRT similar to normal mononuclear cells. Therefore, in the null-ALL, ADA/PNP ratio was high and APRT/HGPRT ratio was similar to normal mononuclear cells. AML showed similar results to null-ALL. NHL have lower PNP activity and relatively low ADA activity, so NHL have relatively low ADA/PNP ratio. These findings suggest that ADA/PNP ratio may be useful for T-cell lineage biochemical marker.
