Subpopulations of monocytes and natural killer cells of human peripheral blood in the long-term period of chronic irradiation

Introduction. An increased risk of malignancy and cardiovascular diseases is revealed in exposed individuals from different cohorts. Monocyte and natural killer (NK) cells modulate inflammation and carcinogenesis. Objective. To evaluate absolute and relative cell counts in monocyte and natural killer cell subpopulations in the peripheral blood of individuals exposed to chronic irradiation. Materials and methods. Thirty-five persons from the Techa River cohort were examined, divided into three subgroups depending on the radiation absorbed dose calculated to the red bone marrow (RBM) (70–249 mGy; 250–699 mGy; 700–1429 mGy, respectively). The mean age of patients was 74.9 years; the mean value of the radiation absorbed dose to RBM was 542.0±65.3 mGy, while that of the radiation absorbed dose to thymus and peripheral lymphoid organs was 99.7±14.4 mGy. The comparison group consisted of 10 persons without a history of anthropogenic irradiation of similar gender and ethnicity, mean age — 71.8 years. Results. In the second dose subgroup, the proportion of CD14 – CD16 + monocytes was statistically significantly higher (8.47%) than in the comparison group (5.52%, p =0.014), and the absolute CD14 – CD16 + monocytes count (0.040×10 9 /l) was also higher than in the third subgroup (0.018×10 9 /l, p =0.044) without correlations with radiation and non-radiation factors. No statistically significant differences of other studied parameters between the groups were revealed. Conclusion. In persons from the second subgroup the relative number of CD14 – CD16 + monocytes was statistically significantly higher than in the comparison group; the absolute CD14 – CD16 + monocytes count was also higher than in the third subgroup without correlations with factors of a radiation and non-radiation nature. The findings are preliminary.