X chromosome aberrations in peripheral blood T lymphocytes of women with chronic radiation exposure in long-term follow-up: a pilot study

BACKGROUND: Chronic radiation exposure due to residence in areas contaminated with radionuclides remains a pressing concern globally, as it increases the risk of leukemia, solid malignancies, and other diseases. According to current understanding, many human pathologies are underpinned by somatic mosaic mutagenesis, particularly involving sex chromosomes. The X chromosome plays a critical role in immune function and autoimmune pathogenesis, and X chromosome aneuploidy is linked to development of various somatic disorders. Prior cytogenetic studies of radiation-exposed populations in the Southern Urals revealed increased X chromosome involvement in micronuclei formation, warranting further investigation into X chromosome aberrations.

AIM: To assess intra- and interchromosomal aberrations involving the X chromosome in peripheral blood T lymphocytes in women with chronic radiation exposure during long-term follow-up.

METHODS: This pilot study included five women exposed to chronic radiation in the Southern Urals (mean age: 74.0 ± 0.8 years; mean cumulative red bone marrow dose: 1.35 ± 0.30 Gy). A comparison group consisted of five women (mean age: 66.3 ± 1.2 years; mean red bone marrow dose: 0.010 ± 0.006 Gy; range: 0–0.03 Gy) who lived under similar socioeconomic conditions and had received less than 70 mGy of total red bone marrow exposure during follow-up. X chromosome aberrations were analyzed using multicolor banding (mBAND). Aberration frequency was calculated per genome equivalent, adjusted for donor age. The frequency of cells with X chromosome aneuploidy was also assessed.

RESULTS: The frequency of X chromosome aberrations was higher in irradiated women compared to the comparison group (0.100 ± 0.036 vs 0.019 ± 0.011; U = 3, p = 0.0476). In irradiated women, a greater variety of aberration types was noted, including a ring chromosome, an isochromosome, and a chromosome presumably formed as a result of chromothripsis. The mean frequencies of X chromosome aneuploidy in irradiated women did not differ significantly from those in the comparison group (p = 0.4); however, interindividual variation may exist.

CONCLUSION: The findings may indicate a more intense mutational process in individuals chronically exposed to radiation. The study of X chromosome aberrations in peripheral blood T lymphocytes of women chronically exposed to radiation in the Southern Urals is promising and should be continued.