Clinical relevance of terminal transferase and adenosine deaminase in leukemia

Lymphoblastic Lymphoma in Adults: A Study on 30 Patients Treated with Two Different Programs According to Bone Marrow Findings

Thirty adult patients with lymphoblastic lymphoma were treated with two different programs according to bone marrow findings. Bone marrow positive patients were given an ALL-like program: vincristine, daunorubicin, cyclophosphamide and prednisone for induction of remission, CNS prophylaxis, continuous maintenance for three years and monthly reinductions. Bone marrow negative patients were given a conventional lymphoma program with CHOP-Bleo and limited RT on bulky mediastinum without CNS prophylaxis. The CR rate of the whole group was 54 % (62 % for ALL-treated versus 47 % for lymphoma-treated patients; not significantly different), with a median survival for remitters of 28.5 mos. Relapse-free survival of the whole group was 65 % at 12 and 25 % at 24 mos. Stage IV ALL-treated patients had a median survival of 16.5 versus 10 mos for stage IV lymphoma-treated ones (p = 0.05); the three-years survival was 24 and 10 %, respectively. No patients undergoing CNS prophylaxis (ALL-therapy) had neurological complications or late meningeal relapse. The better prognosis of ALL-treated patients, in spite of bone marrow positivity, argues in favor of an ALL-like therapy in all adult lymphoblastic lymphomas, in terms of CR rate, overall survival, and absence of CNS relapse. This therapy must be adopted irrespective of bone marrow findings, and regardless of how localized the lymphoma appears to be.

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.

Terminal deoxynucleotidyl transferase activity in childhood leukemia

The activity of terminal deoxynucleotidyl transferase (Tdt) was measured in mononuclear cells of 70 children with acute leukemia, in whom raised levels of Tdt were noted at diagnosis, relapse, or during remission. Serial measurements of Tdt activity were related to the percentage of blasts in the bone marrow and the clinical course of children both during therapy and after its completion. The Tdt values did not predict relapse in children with acute lymphoblastic leukemia nor did the quantitative determination correlate with the percentage of blasts in the bone marrow.

Biochemical enzyme analysis in acute leukaemia

This report summarises the current knowledge regarding the clinical utility of biochemical enzyme markers for both diagnostic and therapeutic purposes in acute leukaemia. The enzymes studied most extensively in this field are terminal deoxynucleotidyl transferase, adenosine deaminase, 5'-nucleotidase, purine nucleoside phosphorylase, and acid phosphatase, esterase, hexosaminidase isoenzymes. For each enzyme, the quantitative and qualitative characteristics in various immunologically defined subclasses of acute leukaemia are described. The quantitative evaluation of enzyme activities represents an adjunctive classification technique which should be incorporated into the multivariate analysis, the "multiple marker analysis." By qualitative characterisation pronounced heterogeneity of leukaemia subsets is uncovered. The application of 2'-deoxycoformycin, a specific inhibitor of adenosine deaminase, and the potential usefulness of two other enzymes as targets for treatment with selective agents is discussed. The concept that gene products expressed at certain developmental stages of normal cells can similarly be detected in leukaemic cells (which therefore seem to be "frozen" or "arrested" at this particular maturation/differentiation stage) is supported by the results obtained in enzyme studies. Besides their practical clinical importance for classification and treatment of acute leukaemias, biochemical enzyme markers constitute a valuable research tool to disclose biological properties of leukaemic cells.

Meningeal Leukemia following Lymphoid Blast Crisis in Chronic Myeloid Leukemia: Therapeutic Implications

Five of 40 patients with chronic myeloid leukemia (CML) had lymphoid blast crisis and 4 of them achieved complete remission of metamorphosis with vincristine and prednisone. While in hematologic remission, two of these subjects developed meningeal leukemia. Clinical and biologic data indicated that the course of the disease after lymphoid blast crisis was very similar to that of acute lymphoblastic leukemia (ALL). It is suggested that patients with CML who develop lymphoid blast crisis should be treated with an intensive therapeutic protocol including early prevention of meningeal leukemia.