ASSESSMENT OF QUALITATIVE CHANGES IN PERIPHERAL BLOOD CELLS IN CHILDREN - RESIDENTS OF RADIOLOGICALLY CONTAMINATED TERRITORIES IN THE LATE PERIOD AFTER THE ChNPP ACCIDENT.

Objective: to establish the relationship between quantitative and qualitative parameters of peripheral blood cells(lymphocytes, neutrophilic granulocytes, monocytes, platelets) depending on the type of somatic diseases andannual internal radiation doses from 137Cs in children - residents of radiologically contaminated territories in thelate period after the Chornobyl Nuclear Power Plant (ChNPP) accident.

Materials and methods: There were 175 children included in the study comprising residents of radiologically con-taminated territories (n = 79) aged from 4 to 18 years. Annual internal radiation doses in children from 137Cs rangedfrom 0.004 to 0.067 mSv. Certain blood parameters were assessed in a comparative mode in children having got theradiation doses up to 0.01 mSv and higher. The comparison group (n = 96) included children living in settlementsnot attributed to the radiologically contaminated ones. Incidence and type of somatic diseases and its impact onquantitative and qualitative changes in blood parameters (i.e. lymphocyte, neutrophilic granulocyte, monocyte, andplatelet count) were studied. The cell size, state of nucleus, membranes and cytoplasm, signs of proliferative anddegenerative processes were taken into account.

Results: Incidence and type of somatic diseases in children did not depend on the annual internal radiation dose.Number of cases of monocytosis was significantly higher among the children exposed to ionizing radiation than inthe comparison group (16.6 % vs. 7.3 %). There were, however, no correlation between these changes and radiationdoses. Number of activated blood monocytes with cytoplasmic basophilia and residues of nucleoli in nuclei washigher in individuals with internal radiation doses > 0.01 mSv. A direct correlation between the qualitative param-eters of monocytes and internal radiation doses was established (rs = 0.60; р < 0.001), as well as a direct correlationof different strength between qualitative parameters of blood cells, indicating their unidirectional pattern depend-ing on the somatic morbid conditions. Regardless of annual internal radiation dose, there was an increase in thenumber of degenerative and aberrant cells vs. the comparison group (р < 0.05), which could be due to the role ofnon-radiation factors.

Conclusions: Results of the assessment of quantitative and qualitative parameters of peripheral blood cells reflect-ed the state of morbid conditions in children and are of a diagnostic value. The identified dose-dependent changesin monocyte lineage of hematopoiesis may be the markers of impact of long-term radionuclide incorporation withfood in children living in environmentally unfavorable conditions after the ChNPP accident.