CYTOGENETIC INDICATORS OF ACUTE RADIATION SICKNESS (THE CHORNOBYL EXPERIENCE)

The objective of the study was to improve the biological dosimetry approach among patients with acute radiation sickness of various degrees based on the analysis of radiation-induced chromosome aberrations in peripheral blood lymphocytes of the victims. Materials and methods. The study was based on primary cytogenetic data obtained in May 1986 within examination of the 30 clean-up workers («liquidators») having got stage I–III acute radiation sickness. Dose verification was performed using the cytogenetic dosimetry based on a culture of peripheral blood lymphocytes with metaphase analysis of chromosome aberrations. Results. A new method of evaluating the results of patients’ cytogenetic examination at the beginning of specific therapy has been developed. Procedure was performed using a model of multiple linear regression (complex of cytogenetic parameters) and provided a satisfactory diagnostic level (featuring a compliance with initially defined clinical and laboratory diagnoses). Overall frequency of the aberrant cells and radiation markers increased in higher disease stages. There was a trend of the frequency growth of chromatid-type aberrations with increasing of radiation burden. Adequacy of the proposed method based on the regression analysis of cytogenetic results was confirmed through the preservation of group differences in estimates of disease stage in subjects with verified diagnosis. Conclusion. Cytogenetic dosimetry in the scope of examination of persons exposed to ionizing radiation is an obligatory component of radiation sickness stage verification. The recommended method of cytogenetic data evaluation before and at the beginning of detoxification therapy provides a satisfactory level of diagnostics. Key words: acute radiation sickness, Chornobyl NPP accident, cytogenetic dosimetry, blood lymphocytes, chromosome aberrations, multiple linear regression model.