Heterochromatin condensation in central and peripheral nuclear regions of maturing lymphocytes in the peripheral blood of patients suffering from B chronic lymphocytic leukemia - a cytochemical study.

The present study was undertaken to provide complementary information on heterochromatin condensation in central and peripheral nuclear regions during maturation of human leukemic lymphocytes using simple image processing and DNA image densitometry at the single cell level. Such approach indicated that the heterochromatin condensation in perinucleolar and extranucleolar "gene rich" central nucleolar regions preceded that in the "gene poor" nuclear periphery at the nuclear membrane. Thus, the maturation of lymphocytes was accompanied by a marked increase of the heterochromatin condensation at the nuclear membrane that reflected the maturity of these cells. In addition, in contrary to the nuclear size, no substantial differences of the heterochromatin condensation in central and peripheral nuclear regions were noted between untreated and treated patients with cytostatic therapy at the time of taking samples for the present study. On the other hand, the larger heterochromatin condensation in central nuclear regions occasionally persisted in small mature lymphocytes of all studied patients. Such phenomenon might represent the return to the cell cycle or a further type of maturation asynchrony that in leukemic cells is not exceptional.