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

Abstract

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 and annual internal radiation doses from 137Cs in children – residents of radiologically contaminated territories in the late period after the Chornobyl Nuclear Power Plant (ChNPP) accident. Materials and methods. There were 175 children included in the study comprising residents of radiologically contaminated territories (n = 79) aged from 4 to 18 years. Annual internal radiation doses in children from 137Cs ranged from 0.004 to 0.067 mSv. Certain blood parameters were assessed in a comparative mode in children having got the radiation doses up to 0.01 mSv and higher. The comparison group (n = 96) included children living in settlements not attributed to the radiologically contaminated ones. Incidence and type of somatic diseases and its impact on quantitative and qualitative changes in blood parameters (i.e. lymphocyte, neutrophilic granulocyte, monocyte, and platelet count) were studied. The cell size, state of nucleus, membranes and cytoplasm, signs of proliferative and degenerative 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 in the comparison group (16.6 % vs. 7.3 %). There were, however, no correlation between these changes and radiation doses. Number of activated blood monocytes with cytoplasmic basophilia and residues of nucleoli in nuclei was higher in individuals with internal radiation doses > 0.01 mSv. A direct correlation between the qualitative parameters of monocytes and internal radiation doses was established (rs = 0.60; р < 0.001), as well as a direct correlation of different strength between qualitative parameters of blood cells, indicating their unidirectional pattern depending on the somatic morbid conditions. Regardless of annual internal radiation dose, there was an increase in the number of degenerative and aberrant cells vs. the comparison group (р < 0.05), which could be due to the role of non-radiation factors. Conclusions. Results of the assessment of quantitative and qualitative parameters of peripheral blood cells reflected the state of morbid conditions in children and are of a diagnostic value. The identified dose-dependent changes in monocyte lineage of hematopoiesis may be the markers of impact of long-term radionuclide incorporation with food in children living in environmentally unfavorable conditions after the ChNPP accident. Key words: annual internal radiation dose from 137Cs, children, peripheral blood, lymphocytes, neutrophilic granulocytes, monocytes, platelets, qualitative signs.