Determination of somatic mutant frequencies at glycophorin A and T-cell receptor loci for biodosimetry of prolonged irradiation

Abstract

Purpose: To determine the variant frequencies (VF) at glycophorin A (GPA) and T-cell receptor (TCR) loci in persons exposed to prolonged ionizing radiation at different doses and to assess the significance of the GPA and TCR assays for biodosimetry of prolonged irradiation. Materials and methods: The VF values were determined by means of flow cytometry in 120 persons exposed between 1968-1996. Most exposures were in Chernobyl clean-up workers in 1986-1987. Results: A significant correlation was shown between the N GPA variant cell frequency and dose (r 0.61, p 0.0001). The slope of the linear regression was 6.3 x 10-6 N mutant cells/Gy. Dose-dependent increase in the TCR VF was found in the group with recent exposures (slope 2.1 10-4 variant cells/Gy, r 0.75, p 0.0002). In the Chernobyl clean up workers who received doses less than 0.25 Gy the TCR VF unlike the GPA VF was significantly higher than in the control non-irradiated individuals (p 0.01 and p 0.05 respectively). Conclusions: The GPA assay has limited potential to be used as a biodosimeter of prolonged irradiation, at least in dose interval up to 2.0 Gy. The TCR assay is likely to have greater potential in estimation of recent radiation exposure than the GPA assay.