[Assessment of bronchopulmonary immunity status for Mayak PA workers at the late period after prolonged exposure]

Samples of induced sputum from 187 individuals were used to estimate the bronchopulmonary immunity status after a prolonged radiation exposure (120 individuals who are the Mayak main plant workers were exposed to combined internal a-radiation due to incorporated plutonium (239Pu) and external y-radiation during their career). The control group included 67 Ozersk residents of a corresponding age and gender, without any occupational exposure, who were examined at the same period. The immune system is the most important component in homeostasis. In occupational workers, the status of the systemic and bronchopulmonary immunity after 30-55 years of career was estimated by the level of regulatory proteins in the samples of blood and the induced sputum supernatant stored at low temperatures in freezers of the Radiobiological human tissue Repository, SUBI (interleukins IL-1beta, IFN-gamma, IL-12+p70, IL-15, IL-17A and growth factors EGF, TGF-beta1, FGF and PDGF-AA), as well as by the content of effector and regulatory lymphocytes in blood. After the examination period, each registrant was provided with dosimetry data: 239Pu body burden was from 0.03 kBq to 11.89 kBq, the absorbed dose to the lung from incorporated radionuclide - from 0.01 Gy to 1.38 Gy, and accumulated doses of external y-radiation during the occupational career - from 0.02 Gy to 7.91 Gy. In the case of the prolonged combined radiation, the tensioned mode of immunity cell link functioning and the increase of activated lymphocyte forms were detected. Comparison of correlation coefficients between the content oflymphocytes, the level ofinterleukins and growth factors and the dose load allowed us to find relation of these ratios to the type of exposure, Pu body burden, the absorbed 239Pu dose to the lung and the accumulated external dose. The reduced concentration of the main growth factors in the group of Mayak workers is the evidence for the declined control function of proteins and immunodeficiency. The analysis of the regulatory proteins content in blood and sputum following occupational exposure allowed us to find specific features of the protein expression in support of the local and systemic immune homeostasis.