Apoptosis of Peripheral Blood Lymphocytes in the Members of the Techa River Cohort Chronically Exposed to Radiation

: The purpose of the present research was to estimate the intensity of the apoptotic death of lymphocytes during the period of carcinogenic effect realization in the residents of the Techa riverside villages. The investigation included analyses of the frequency of lymphocytes at the early and late stages of apoptosis and necrosis of peripheral blood lymphocytes using the method of FITC Annexin V, lymphocyte counts at the stage of DNA fragmentation using the TUNEL method, and the number of CD95(+)-lymphocytes. In the capacity of additional tests, loading tests involving in vitro irradiation at the dose of 1 Gy of a suspension of lymphocytes and incubations for 5 and 24 hours were used. Activation of the initial apoptotic and necrotic death of peripheral blood lymphocytes was revealed in the persons chronically exposed to low-intensity radiation within the range from 0.01 to 4.23 Gy. Exposed patients demonstrated a decrease in the number of CD95(+)-cells as compared to unexposed patients. The results of the cell death studies in the persons residing in the Techa riverside villages testify indirectly to the genomic instability of the peripheral blood lymphocytes.