[Chromosomal study of polycythemia during different stages of the disease].

A cytogenetic analysis of blood and bone marrow cells of 15 polycythemia vera patients was carried out at different stages of disease during the G-banding technique. Chromosome aberrations of single character were noted before treatment only in one case, i.e. with the patient at stage II of disease. Cell clones with marker chromosomes were revealed in 6 of 9 patients examined in the course of treatment at stages II and III. The cytogenetic analysis was applied to the terminal stage of polycythemia (blast crisis) in one case, when 3 aberrant clones with multiple quantitative and structural chromosome rearrangements were discovered in blood cell cultures with and without PHA. No preferential involvement of definite chromosomes in aberrations was noticed in all the cases examined, no deletion of the 20q --chromosome being discovered. The role of the treatment in the induction of chromosome aberrations is discussed in addition to its dependence on the stage of disease. It is possible that all the clones of pathological character may appear during the long-termed course of polycythemia in patients treated at more serious stages of the disease.