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Activity of ribonuclease H in cells of chronic B‐lymphocytic leukaemia: correlation with clinical stage
Author(s) -
Papaphilis A. D.,
Kamper E. F.,
Kattamis C.,
Pangalis G. A.
Publication year - 1988
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1988.tb02486.x
Subject(s) - peripheral blood mononuclear cell , ribonuclease , enzyme , clone (java method) , enzyme assay , immunology , biology , microbiology and biotechnology , medicine , biochemistry , rna , gene , in vitro
Peripheral blood mononuclear cells (PBMNC) from 23 healthy subjects and 39 patients with B‐cell chronic leukaemia (B‐CLL) were assayed for ribonuclease H activity using as substrate the filter‐immobilized synthetic homopolymer hybrid 3 H‐poly(rA):poly(dT). In 69% of the leukaemia patients examined enzyme activities were above those estimated in cells from the healthy controls. The mean enzyme levels for the normal and the leukaemic samples group were (per cent substrate hydrolysis): 8.1 ± 8.9 and 58.7 ± 40.8, respectively, their difference being statistically highly significant ( P < 0.0001). This result does not represent homogeneity within the cells but is due to a subclass of cells within the leukaemic clone containing the enzyme, thus contributing through pool size fluctuation to the wide variations of enzyme activity observed among the patients. These cells containing high activity could not be identified with either the prolymphocytes or the large lymphocytes. The activity of ribonuclease H in the examined CLL patients correlated with disease stage (Binet) ( P = 0.011) and appeared to serve as a sensitive indicator of disease progression when compared with a number of other known prognostic parameters.