title: Comparison of purine degradative enzymes and terminal deoxynucleotidyl transferase in T cell leukaemias and in normal thymic and post-thymic T cells.
abstract: Adenosine deaminase (ADA), ecto 5' nucleotidase (5'NT), purine nucleoside phosphorylase (PNP) and terminal deoxynucleotidyl transferase (TdT) were measured in the cells of patients with acute or chronic T cell leukaemia and compared with normal putative prothymocytes (large, blast-like cortical thymocytes), cortical and medullary thymocytes and peripheral blood T lymphocytes. Distinct patterns of enzyme activities were found in the individual types of T cell leukaemia. Mean ADA, TdT and 5'NT activities in thymic acute lymphoblastic leukaemia (Thy-ALL) were 41.9 u/10(8) cells, 31.1 u/10(8) cells and 4.7 u/10(6) cells respectively; in chronic T cell leukaemia they were 7.1 u/10(8) cells, 0.6 u/10(8) cells and 18.1 u/10(6) cells respectively. Mean PNP activity was similar between these two groups of leukaemia (68.6 u/10(6)cells in Thy-ALL and 77.9 u/10(6) cells in chronic T cell leukaemia). The activities of these four enzymes in OKT4+ chronic T cell leukaemia did not differ significantly from those in the OKT8+ chronic T cell leukaemia cases. The activities of TdT, ADA, PNP and 5'NT in Thy-ALL closely resembled those in normal immature thymocytes, and in the chronic T cell leukaemias showed a similar pattern of enzyme activities to that of mature T lymphocytes. These findings are consistent with surface phenotypic studies of T cell malignancies which suggest that different T cell leukaemias represent malignant proliferation of T cell clones arrested at different stages of T cell differentiation. They also demonstrate the value of biochemical markers in defining the different subtypes of acute and chronic leukaemia.
mesh_terms: D015720:5'-Nucleotidase; D000243:Adenosine Deaminase / Q000378:metabolism; D000328:Adult; D001402:B-Lymphocytes / Q000201:enzymology; D004253:DNA Nucleotidylexotransferase / Q000378:metabolism*; D004254:DNA Nucleotidyltransferases / Q000378:metabolism*; D006801:Humans; D007223:Infant; D007938:Leukemia / Q000201:enzymology*; D007945:Leukemia, Lymphoid / Q000201:enzymology; D008214:Lymphocytes / Q000201:enzymology*; D009708:Nucleotidases / Q000378:metabolism; D011683:Purine-Nucleoside Phosphorylase / Q000378:metabolism; D012751:Sezary Syndrome / Q000201:enzymology; D013601:T-Lymphocytes / Q000201:enzymology*; D013950:Thymus Gland / Q000201:enzymology
chemical_list: D011683:Purine-Nucleoside Phosphorylase; D004254:DNA Nucleotidyltransferases; D004253:DNA Nucleotidylexotransferase; D009708:Nucleotidases; D015720:5'-Nucleotidase; D000243:Adenosine Deaminase