Intralymphocytic Adenosine Deaminase (ADA) and Purine Nucleoside Phosphorylase (PNPase) Activity in Chronic Lymphocytic Leukemia (CLL) : Effect of Thymostimulin

Abstract Purine nucleoside phosphorylase (PNP), the enzyme schematically next to adenosine deaminase in the purine salvage pathway, has been demonstrated cytochemically in peripheral blood lymphocytes of healthy subjects and chronic lymphocytic leukemia (CLL) patients. The enzyme activity is confined to the cytosol. In healthy subjects the majority of lymphocytes are strongly reactive for PNP, whereas the rest are devoid of cytochemically demonstrable activity. The percentage of PNP- positive cells largely corresponds to the number of E rosette-forming cells and is inversely proportional to the number of Ig-bearing cells. In six of seven CLL patients studied only a minor percentage of the lymphocytes showed strong PNP activity, whereas the large majority (88%- -98%) possessed trace activity. Such patients have a high number of Ig- bearing cells and a low number of E rosette-forming cells. A different pattern of markers was found in the lymphocytes of the seventh CLL patient: 66% were strongly reactive for PNP, an important number formed E rosettes, and a minor percentage were Ig bearing. These data indicate that PNP can be useful as a “nonmembrane” marker in the differentiation of the B and T cell origin in CLL and deserves to be studied in other lymphoproliferative disorders.

Download Full-text

Purine nucleoside phosphorylase in chronic lymphocytic leukemia (CLL)

Blood ◽

10.1182/blood.v52.5.886.bloodjournal525886 ◽

1978 ◽

Vol 52 (5) ◽

pp. 886-895

Author(s):

M Borgers ◽

H Verhaegen ◽

M De Brabander ◽

J De Cree ◽

W De Cock ◽

...

Keyword(s):

Chronic Lymphocytic Leukemia ◽

Healthy Subjects ◽

Purine Nucleoside Phosphorylase ◽

Peripheral Blood Lymphocytes ◽

Lymphocytic Leukemia ◽

Purine Nucleoside ◽

Salvage Pathway ◽

Purine Salvage ◽

Nucleoside Phosphorylase ◽

A Minor

Purine nucleoside phosphorylase (PNP), the enzyme schematically next to adenosine deaminase in the purine salvage pathway, has been demonstrated cytochemically in peripheral blood lymphocytes of healthy subjects and chronic lymphocytic leukemia (CLL) patients. The enzyme activity is confined to the cytosol. In healthy subjects the majority of lymphocytes are strongly reactive for PNP, whereas the rest are devoid of cytochemically demonstrable activity. The percentage of PNP- positive cells largely corresponds to the number of E rosette-forming cells and is inversely proportional to the number of Ig-bearing cells. In six of seven CLL patients studied only a minor percentage of the lymphocytes showed strong PNP activity, whereas the large majority (88%- -98%) possessed trace activity. Such patients have a high number of Ig- bearing cells and a low number of E rosette-forming cells. A different pattern of markers was found in the lymphocytes of the seventh CLL patient: 66% were strongly reactive for PNP, an important number formed E rosettes, and a minor percentage were Ig bearing. These data indicate that PNP can be useful as a “nonmembrane” marker in the differentiation of the B and T cell origin in CLL and deserves to be studied in other lymphoproliferative disorders.

Download Full-text

Purine nucleoside phosphorylase (PNP) and adenosine deaminase (ADA) activities examined cytochemically in unfixed lymphocytes of patients with lymphoproliferative disorders

Blood ◽

10.1182/blood.v58.5.897.897 ◽

1981 ◽

Vol 58 (5) ◽

pp. 897-903 ◽

Cited By ~ 6

Author(s):

K Maeda ◽

K Ito ◽

N Yamaguchi

Keyword(s):

Enzyme Activity ◽

Adenosine Deaminase ◽

Purine Nucleoside Phosphorylase ◽

Human Lymphocytes ◽

Lymphoproliferative Disorders ◽

Lymphocytic Leukemia ◽

Lymphoid Cells ◽

Purine Nucleoside ◽

Nucleoside Phosphorylase ◽

Cell Fractions

Abstract New techniques have been devised for the cytochemical demonstration of purine nucleoside phosphorylase (PNP) and adenosine deaminase (ADA) activities in unfixed human lymphocytes. A suspension of living lymphocytes is mixed with agarose sol containing the reagents for the detection of PNP or ADA activity on a glass slide. The mixture solidifies, is incubated, and then dried for lightmicroscopic observation. Reactive cells are recognized by the diffusely deposited granules of formazan, the end-product of the cytochemical reaction, and are divided into three groups of the cell with the low, middle, and high enzyme activity by the number of the granule. In healthy adults, the mean percentages of PNP- and ADA-positive cells were more than 90% in unfractionated lymphocytes, T-cell fractions, and complement- receptor cell fractions and cells with middle PNP and ADA activities were predominant. The PNP and ADA staining was observed in lymphoid cells of patients with lymphoproliferative disorders. A decrease in the percentage of PNP-positive cells concomitant with a relative increase of cells with the low enzyme activity was observed in the lymphocytes of nine patients with chronic lymphocytic leukemia (CLL). Similar findings were obtained in the ADA staining of the lymphocytes of five patients with B-cell CLL.

Download Full-text

Purine nucleoside phosphorylase (PNP) and adenosine deaminase (ADA) activities examined cytochemically in unfixed lymphocytes of patients with lymphoproliferative disorders

Blood ◽

10.1182/blood.v58.5.897.bloodjournal585897 ◽

1981 ◽

Vol 58 (5) ◽

pp. 897-903

Author(s):

K Maeda ◽

K Ito ◽

N Yamaguchi

Keyword(s):

Enzyme Activity ◽

Adenosine Deaminase ◽

Purine Nucleoside Phosphorylase ◽

Human Lymphocytes ◽

Lymphoproliferative Disorders ◽

Lymphocytic Leukemia ◽

Lymphoid Cells ◽

Purine Nucleoside ◽

Nucleoside Phosphorylase ◽

Cell Fractions

New techniques have been devised for the cytochemical demonstration of purine nucleoside phosphorylase (PNP) and adenosine deaminase (ADA) activities in unfixed human lymphocytes. A suspension of living lymphocytes is mixed with agarose sol containing the reagents for the detection of PNP or ADA activity on a glass slide. The mixture solidifies, is incubated, and then dried for lightmicroscopic observation. Reactive cells are recognized by the diffusely deposited granules of formazan, the end-product of the cytochemical reaction, and are divided into three groups of the cell with the low, middle, and high enzyme activity by the number of the granule. In healthy adults, the mean percentages of PNP- and ADA-positive cells were more than 90% in unfractionated lymphocytes, T-cell fractions, and complement- receptor cell fractions and cells with middle PNP and ADA activities were predominant. The PNP and ADA staining was observed in lymphoid cells of patients with lymphoproliferative disorders. A decrease in the percentage of PNP-positive cells concomitant with a relative increase of cells with the low enzyme activity was observed in the lymphocytes of nine patients with chronic lymphocytic leukemia (CLL). Similar findings were obtained in the ADA staining of the lymphocytes of five patients with B-cell CLL.

Download Full-text

Forodesine, an inhibitor of purine nucleoside phosphorylase, induces apoptosis in chronic lymphocytic leukemia cells

Blood ◽

10.1182/blood-2006-03-007468 ◽

2006 ◽

Vol 108 (7) ◽

pp. 2392-2398 ◽

Cited By ~ 52

Author(s):

Kumudha Balakrishnan ◽

Ramadevi Nimmanapalli ◽

Farhad Ravandi ◽

Michael J. Keating ◽

Varsha Gandhi

Keyword(s):

Clinical Trial ◽

Chronic Lymphocytic Leukemia ◽

Purine Nucleoside Phosphorylase ◽

Phase 1 ◽

Lymphocytic Leukemia ◽

Purine Nucleoside ◽

Parp Cleavage ◽

High Accumulation ◽

Nucleoside Phosphorylase

Abstract Purine nucleoside phosphorylase (PNP) deficiency in humans results in T lymphocytopenia. Forodesine, a potent inhibitor of PNP, was designed based on the transition-state structure stabilized by the enzyme. Previous studies established that forodesine in the presence of deoxyguanosine (dGuo) inhibits the proliferation of T lymphocytes. A phase 1 clinical trial of forodesine in T-cell malignancies demonstrated significant antileukemic activity with an increase in intracellular dGuo triphosphate (dGTP). High accumulation of dGTP in T cells may be dependent on the levels of deoxynucleoside kinases. Because B-cell chronic lymphocytic leukemia (B-CLL) cells have high activity of deoxycytidine kinase (dCK), we hypothesized that these lymphocytes would respond to forodesine. This postulate was tested in primary lymphocytes during in vitro investigations. Lymphocytes from 12 patients with CLL were incubated with forodesine and dGuo. These CLL cells showed a wide variation in the accumulation of intracellular dGTP without any effect on other deoxynucleotides. This was associated with DNA damage-induced p53 stabilization, phosphorylation of p53 at Ser15, and activation of p21. The dGTP accumulation was related to induction of apoptosis measured by caspase activation, changes in mitochondrial membrane potential, and PARP cleavage. Based on these data, a phase 2 clinical trial of forodesine has been initiated for CLL patients.

Download Full-text