Regularities of somatic mutagenesis in the Chernobyl clean-up workers in long dates after irradiation

Frequency of somatic cells with gene mutations at glycophorin A (GPA) and T-cell receptor (TCR) loci was determined in the Chernobyl clean-up workers exposed to radiation with doses up to 0.25 Gy and control persons. The effectiveness of damaged cell apoptotic elimination in these persons was studied and compared with TCR-mutant cell frequency. The following regularities of somatic mutagenesis were determined 9-17 years after low dose irradiation: elevation of average frequency of TCR-mutant lymphocytes as compared with that in control group and maintenance of GPA (NO)-variant erythrocyte frequency at the control level; the absence of monotonic dependence between TCR-mutant cell frequency and the irradiation dose; preservation of stable effect (increased frequency of TCR-mutant lymphocytes) during 9-17 years after exposure; manifestation of the effect only in part of irradiated persons. The investigation of damaged cell apoptotic death testify about importance of this process as the mechanism for maintenance of genetic stability at the level of cell population. However, in most cases, elevation of TCR-mutant cell frequency in examined clean-up workers was not associated with decreasing efficiency of apoptotic elimination of damaged cells.