Adenosine deaminase (ADA) in leukemia: Clinical value of plasma ADA activity and characterization of leukemic cell ADA

Abstract

Adenosine deaminase (ADA) activity was measured in plasma, erythrocytes, and mononuclear cells from 18 patients with acute and chronic leukemia. High levels of ADA activities were found in plasma, erythrocytes, and mononuclear cells from patients with acute leukemia, especially acute lymphoblastic leukemia, and blastic crisis of chronic myeloid leukemia. Serial determination of plasma ADA activities was done in 9 patients with acute leukemia. All patients untreated or in relapse had an elevation of plasma ADA activity, which decreased to normal or subnormal levels during complete remission. On starch gel electrophoresis, plasma ADA in leukemic patients separated into two bands. The major band showed a mobility identical to that of normal red cells and mononuclear cells, and the minor band corresponded to that of normal plasma ADA. Enzymatic and immunological studies were performed on ADA from leukemic cells of acute myeloid and lymphoblastic leukemia. There were no differences in Michaelis constant for adenosine, thermostability, electrophoretic mobility, immunological reactivity, and specific activity between ADA of leukemic cells and normal mononuclear cells. These results strongly suggest that the increased ADA activity in leukemic cells is caused by an increased synthesis of a structurally normal enzyme and that increased plasma ADA activity in leukemic patients reflects an increment of leukemic cells in bone marrow. Therefore, serial determination of plasma ADA activities seems to provide a good indicator of the total mass of leukemic cells in bone marrow.

Characterization of purine nucleoside phosphorylase in leukemia

“…Several studies on PNP in leukemic cells showed that the abnormal PNP activity in ALL might correspond to immaturity of leukemic cells but that abnormal PNP activity in CLL differed from the change of normal lymphoid cell maturation or differentiation [ 16,211. Thus the abnormality of PNP activity in this study and that of ADA activity in our previous study [7] might be due to the changes in the mechanism regulating enzyme synthesis in the purine metabolism in leukemic clones.…”

“…We characterized leukemic cell ADA and found that leukemic cells synthesize an increased amount of structurally normal ADA [7]. Several observations of abnormal PNP activity have been made in leukemic patients [8,9], but few studies have been done on the mechanism of these abnormalities.…”

Genetic analysis of adenosine deaminase expression in adult T‐cell leukemia

“…In hematologic malignancy, studies of ADA in leukemic cells have shown that ADA activity is greatly elevated in ALL, particularly in T-cell ALL and adult Tcell leukemia (ATL) [ 11. We have reported that there is no difference in enzymatic properties between ADA of leukemic cells and that of normal mononuclear cells and that the increased ADA activity in leukemic clones is most likely due to increases of the ADA protein [2].…”

Larenks Kanseri̇nde Serum Adenozi̇n Ve Si̇ti̇di̇n Deami̇naz Akti̇vi̇teleri̇ni̇n Değerlendi̇ri̇lmesi̇

“…Lösemik hücrelerde ve plazmalarda yapılan çalışmalarda, KLL'de ADA aktivitesinin normal veya düşük, ALL'de ise oldukça yüksek olduğu ve seri olarak ölçülen plazma ADA aktivitelerinin klinik gidişi yansıtabileceği öne sürülmüştür (8,9). Solid tümörlere ilişkin yayınlar ise sınırlı sayıdadır ve sonuçlar birbirinden farklı olduğu için bir karara varmak güçtür (10-14).…”