PURINE NUCLEOSIDE PHOSPHORYLASE IN CHRONIC LYMPHOCYTIC-LEUKEMIA (CLL)

  • 1 January 1978
    • journal article
    • research article
    • Vol. 52  (5) , 886-895
Abstract
Purine nucleoside phosphorylase (PNP), the enzyme schematically next to adenosine deaminase in the purine salvage pathway, was demonstrated cytochemically in peripheral blood lymphocytes of healthy subjects and 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 [sheep erythrocyte] rosette-forming cells and is inversely proportional to the number of Ig[immunoglobulin]-bearing cells. In 6 of 7 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 7th CLL patient: 66% were strongly reactive for PNP, an important number formed E rosettes and a minor percentage were Ig bearing. PNP can be useful as a nonmembrane marker in the differentiation of the B [bone marrow derived] and T [thymus-derived] cell origin in CLL and deserves to be studied in other lymphoproliferative disorders.