Biochemical markers in leukaemia and lymphoma

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.

Studies of terminal deoxynucleotidyl transferase in normal and neoplastic human cells

Optimized biochemical assays and cytoimmunofluorescence tests were used to detect terminal deoxynucleotidyl transferase, TdT, in malignant cells of 36 leukemias and 75 lymphomas from patients not receiving chemotherapy. TdT was virtually absent from normal lymph nodes and from leukocytes of chronic lymphocytic leukemia, CLL, taken as controls. Its quantitative distribution in the neoplasms matched the current knowledge. Appreciable amounts of TdT were found in all the 10 lymphomas of lymphoblastic type, LL, and in the white blood cells of: 16 out of 19 acute lymphoblastic leukemia, AAL, perhaps with modulation in the various phenotypes; 2 out of 3 acute undifferentiated leukemias, AUL; and 3 out of 7 blastic crises in chronic myelogenous leukemia, b.c. CML. Biochemical and cytoimmunological analyses yielded concordant responses and even roughly comparable estimates in the same patients. TdT immunofluorescence was clearly nuclear in most cells and was cytoplasmic occasionally. Definite correlations between concentrations of enzymatic activity and percentage of immunofluorescent cells could not e established. Further detailed work will be required to identify putative subgroups in TdT-positive blast populations.

Terminal transferase expression in relapsed acute myeloid leukaemia

In three cases of acute myeloid leukaemia marked increases in expression of the nuclear enzyme, terminal deoxynucleotidyl transferase (TdT), were observed during disease relapse. The first case was heterogeneous at diagnosis, consisting of subpopulations of large TdT- myeloblasts and small TDT+ blasts; however, at relapse there was complete replacement by TdT+ lymphoblasts. The other cases at diagnosis were both typical acute myeloid leukaemia, TdT-; at relapse, one showed a mixture of TdT- myeloblasts and TdT+ lymphoblasts, while in the other, TdT was demonstrated on a subpopulation of myeloblasts. No chromosomal abnormalities were found. It is suggested that in the first two cases these phenomena may have been due to leukaemic involvement of a pluripotential stem cell, or that sub-clones with different properties may have coexisted. In the third case at relapse, TdT was expressed aberrantly by malignant myeloid cells.

Enzyme and membrane markers in leukaemia: recent developments

Terminal deoxynucleotidyl transferase (TdT) assay has proved a valuable test for distinguishing lymphoblastic from myeloblastic leukaemias, particularly in adults whose blast cells are often negative for the c-ALL antigen. The immunofluorescence assay, particularly when used in combination with antisera to surface membrane antigens, has proved a sensitive technique for detecting small numbers of lymphoblasts in extramedullary sites, for example, testis or cerebrospinal fluid, or of residual Thy-ALL blasts in the marrow, which might otherwise be difficult to recognise. Differences in concentration of several enzymes concerned in purine metabolism have been detected between the blast cells in the various acute leukaemias. Adenosine deaminase (ADA) concentrations tend to be higher in Thy-ALL than in other forms of leukaemia, but the wide overlap reduces the diagnostic value of this assay. Thy-ALL blasts, however, appear to be selectively and exquisitely susceptible to inhibition of ADA by the drug deoxycoformycin, which has now been used sucessfully in a number of other wise resistant patients with Thy-ALL to obtain a complete remission. The recently introduced technique for the production of monoclonal antibodies has substantially widened the reagents available for analysing the membrane characteristics of bone marrow stem cells and of cell lineages derived from them. These have revealed previously unsuspected heterogeneity among different cases of acute lymphoblastic leukaemia, for example, among Thy-ALL blasts from different patients, and they have also delineated minor populations of immature thymocytes from which these leukaemic cells are derived. The potential use of these antibodies to prevent graft-versus-host disease by selective removal of T-lymphocytes from donor bone marrow before allogeneic bone marrow transplantation, or to prevent recurrence of Thy-ALL and other lymphoblastic leukaemias or lymphomas by selective removal of leukaemic or lymphoma malignant cells before autologous transplantation, is reviewed.

Low- and high-risk non-T and non-B and T-cell acute lymphoid leukemia (ALL) in childhood: different duration of remission and survival

In a prospective, nonrandomized trial clinical (initial WBC and chest film) and immunological (surface immunoglobulin and rosetting with pretreated sheep red blood cells) criteria were used to stratify 69 children with previously untreated acute lymphoid leukemia (ALL). Forty of 61 evaluable patients had low-risk ALL (initial WBC less than or equal to 20,000/mm3, no mediastinal mass) and were treated less intensively. Twenty-one of 61 patients had high-risk ALL (initial WBC greater than 20,000/mm3 and/or mediastinal mass) and were treated more intensively. Of the high-risk patients 15 had non-T non-B and 6 T ALL. Sixty of 61 patients went into complete remission. After a median observation period of 27 months, 32 of 40 low-risk, 7 of 14 high-risk non-T non-B, and none of 6 high-risk T ALL patients were in continuous first remission. Thirty-six of 40 low-risk, 9 of 15 high-risk non-T non-B, and none of 6 T ALL patients were alive. Despite more intensive treatment, the duration of remission and the survival were significantly shorter in the high-risk than in the low-risk patients. Among the high-risk ALL, non-T non-B ALL did better than T ALL.

Characterization of lymphoid cells in the blood of healthy adults: sequential immunological, cytochemical and cytokinetic studies

With a new method, sequential immunological, cytochemical and cytokinetic studies were done on lymphoid cells in the peripheral blood of 12 healthy adults. Every single lymphoid cell could therefore be characterized by the following markers: surface immunoglobulins (sIg); rosetting with sheep red blood cells (E); unspecific acid alpha-naphthyl acetate esterase (ANAE); and 3HdT incorporation. Significantly more E+sIg-ANAE-cells (51% and 22% of all lymphoid cells, respectively). Of all ANAE+ cells 90% were E+, but 64% of all ANAE- cells were also E+. In all individuals a subpopulation of E+sIg+ cells was found. The esterase pattern of these cells was similar to that of E-sIg+ cells. The overall labeling index of the lymphoid cells examined was less than or equal to 0.2%.

Malignant lymphoma of pre-T-cell type terminating in acute myelocytic leukemia. A case report with enzymic and immunologic marker studies

We report a case of a T-zone malignant lymphoma of a cervical lymph node developing in a 25-year-old man. Only 14% of the marrow was originally involved, but within two months massive, leukemic dissemination ensued. The blast cells were unable to bind sheep erythrocytes (E) but expressed human thymus leukemia antigen (HTLA) and common ALL-stem-cell (cALL) antigen and had high terminal deoxynucleotidyl transferase (TdT) and acid phosphatase activity. These findings suggest a malignant lymphoproliferative disorder of pre-T-cell type. Complete remission was achieved with intensive chemotherapy. Two months later, acute myelomonocytic leukemia was diagnosed; at this time, over 90% of the blast cells were peroxidase, sudan black, and chloracetate-esterase positive. Consistent with loss of high TdT activity and HTLA and cALL antigens, 86% of the blasts now expressed Ia-like antigens. Cytogenetic studies demonstrated hyperdiploidy. Reports of granulocytic leukemia in lymphoma are reviewed in the context of the above findings and the hypothesis that a leukemogenic factor affects a multipotential stem cell.