Monitoring of the frequency of lymphocytes with mutations at T-cell receptor locus in Chernobyl cleanup workers

Monitoring of the frequency of lymphocytes with mutations at T-cell receptor (TCR) locus in Chernobyl cleanup workers was performed 9-25 years after radiation exposure. Study group consists of 355 persons, most of them were irradiated at low doses (up to 200 mGy). Elevated frequencies of the TCR-mutant cells were found in part (12.5 %) of the persons. The percentage of such persons did not significantly change within period of the examination. Individual analysis of possible changes of the mutant cell frequency was conducted in 66 persons after repeated measurements. It was found that the frequency of the TCR-mutant cells remained constant in 70 % of persons and increased or decreased in 30 %. It is possible to assume that these effects are caused by occurrence of radiation-induced genome instability in the part of irradiated persons. The genome instability can persist for a long time after influence (up to 25 years in our research). The effect doesn't depend on dose of the radiation exposure.