It is generally known that the nucleus : cytoplasmic ratio is a very useful marker for the evaluation of the cell activity and identification. In contrary, the nucleolus : nucleus ratio was less studied. The present study was undertaken to provide more information on that ratio during the differentiation and maturation of human lymphocytes. The ratio of nucleolar bodies to the nuclear body indicated that the size of the nuclear space occupied by nucleolar bodies in B chronic lymphocytic

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... (CLL) during the cell differentiation and maturation (terminal differentiation) decreased in both untreated and treated patients with the anti-leukemic therapy. However, the nuclear space occupied by nucleolar bodies was apparently characteristic for each differentiation and maturation step. A similar trend was apparent in non-leukemic T lymphocytes of blood donors using in vitro de-differentiated lymphocytes as progenitors. During the cell differentiation and maturation, the size reduction of nucleolar bodies of both patients suffering from CLL and blood donors was apparently larger than that of the nucleus. As it was expected, the decreased size of nucleolar bodies was accompanied by the decreasing nucleolar transcription activity expressed by the reduced number of fibrillar centers.