Chronic myeloid leukemia: correlation between purine metabolism enzyme activities and membrane immunophenotype

Abstract

Peripheral blood or bone marrow of 24 patients with chronic myeloid leukemia (CML) were characterized for their surface membrane marker profiles using flow cytometry and fluorescence microscopy. Purine metabolism enzyme activities were compared with membrane immunophenotype and cytochemical stains. CML subtypes were correlated with the expression of surface membrane antigens detected by the monoclonal antibodies. On the basis of immunophenotyping we found the following characteristic marker profiles: In stable phase of CML (CML-SP)-CD15, CD11b, CDw65, CD13, in accelerated phase of CML (CML-AP)-CD15, CDw65, CD11b, CD13 and CD33, in myeloid blastic phase of CML(CML-BP-M)-CD13, CD33, HLA-DR, CD11b, CD15, CDw65, in myeloid and lymphoid (mixed) blastic phase of CML (CML-BP-M+L)-CD13, CD33, CD34, HLA-DR, CD11b, CD10 and in chronic myelomonocytic leukemia (CMML)-CD14, CDw65, CD11b, CD33 and HLA-DR. Analysis of purine metabolism enzyme activities showed that there was a correlation between the values of adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) and various types of CML. ADA levels in CML-SP, CML-AP and CMML were comparable with those in normal cells. In CML-BP-M, which represents proliferation of less mature myeloid cells (similar to less mature AML subtypes), ADA activity increased and PNP activity decreased. ADA activity was significantly different between control group and CML-BP-M (p < 0.01), between CML-SP and CML-BP-M (p < 0.05). The values of PNP activity were the highest in stable phase of CML (125 pkat. 10(-6) cells) and the lowest (23 pkat.10(-6) cells) in CML-BP-M+L. PNP activity in the other groups corresponded to control values. High ADA/PNP ratio was found in CML-BP-M and CML-BP-M+L (0.7 and 2.0, respectively) in comparison to CML-SP (0.2). It follows from our results that ADA/PNP ratio enables to discriminate between stable and blast phases of CML (p < 0.01). The level of the cytochemical enzymes (CHAE, MPO, SBB, ANAE and 5' NT) varied and reflected the degree of cell differentiation and maturation. CHAE and MPO were characteristic enzymes for CML, ANBE for CMML and 5' NT for CML-BP-lymphoid.