title: Purine pathway enzymes in the circulating malignant cells of patients with cutaneous T-cell lymphoma.
abstract: The activities of three purine pathway enzymes--adenosine deaminase (ADA), 5'-nucleotidase (5'N) and purine nucleoside phosphorylase (PNP)--were examined in the circulating malignant cells (Sezary cells) of eight patients with cutaneous T-cell lymphoma (CTCL). Cell lines derived from two other patients with CTCL were also studied. These were compared with enzyme activities in peripheral blood T-lymphocytes from 11 normal donors and six samples of human thymocytes. ADA activities were similar in the Sezary cells and peripheral blood T-cells (medians 7 U and 15 U, P = 0.14), and both of these groups demonstrated significantly lower activity than did the thymocytes (median 100 U, P = 0.002). 5'N activity in the Sezary cells was also similar to that of the T-lymphocytes (median 0.022 U and 0.030 U, P greater than 0.05) and both of these groups had significantly greater activity than did the thymocytes (median 0.002 U, P = 0.001). Median PNP activity in the Sezary cell population was also comparable to that measured in normal T-cells. These findings suggest there is a characteristic purine pathway enzyme pattern in Sezary cells that is similar to that seen in normal T-lymphocytes. This pattern is clearly distinguishable from that of thymocytes and from that previously described in lymphoblasts from patients with T-cell acute lymphoblastic leukaemia. These results support the concept that Sezary cells are well-differentiated with respect to the T-cell axis. Quantitation of purine pathway enzymes may be useful in defining subsets of T-cell malignancy.
mesh_terms: D000243:Adenosine Deaminase / Q000097:blood*; D006801:Humans; D008223:Lymphoma / Q000201:enzymology* / Q000473:pathology; D009700:Nucleoside Deaminases / Q000097:blood*; D009708:Nucleotidases / Q000097:blood*; D010430:Pentosyltransferases / Q000097:blood*; D011683:Purine-Nucleoside Phosphorylase / Q000097:blood*; D012878:Skin Neoplasms / Q000201:enzymology* / Q000473:pathology; D013601:T-Lymphocytes / Q000201:enzymology
chemical_list: D010430:Pentosyltransferases; D011683:Purine-Nucleoside Phosphorylase; D009708:Nucleotidases; C029296:purine 5'-nucleotidase; D009700:Nucleoside Deaminases; D000243:Adenosine Deaminase