The association of ROS levels in blood cells with age, past radiation exposure, and IL6R gene polymorphisms (CCR3P.211)

<jats:title>Abstract</jats:title> <jats:p>Reactive oxygen species (ROS) play an important role in cell-mediated immune responses, although overproduction and excessive accumulation of ROS may also enhance risks of inflammation-related diseases. To address these concerns, we have developed an assay system to determine ROS (H2O2 and O2.-) levels in blood cells to investigate the effects age and of radiation exposure on ROS levels in the blood cells obtained from 2,789 Japanese atomic-bomb survivors, as well as associations between intracellular ROS levels and immune-/inflammation-related gene polymorphisms. The results showed that H2O2 levels in monocyte and granulocyte fractions increased with age (P&amp;lt;0.001) but not with radiation dose. No effects of age or radiation dose on H2O2 levels were observed for T-cell subsets. On the other hand, O2.- levels in both lymphocyte and granulocyte fractions increased with age and radiation dose (P&amp;lt;0.05). In addition, O2.- levels in T cells, especially in CD8+ T cells, increased with age and radiation dose (P&amp;lt;0.05). Analysis of the association between intracellular ROS levels and gene polymorphisms revealed a significant difference in O2.- levels in T cells by IL6R genotypes. These results suggest that ROS levels in selected types of immune cells are affected by aging, radiation, and genetic factor. Thus, the intracellular ROS levels may serve as a biomarker for age of the cells as well as for estimating the risk of inflammation-related disease development.</jats:p>