Early Hematopoietic Effects of Chronic Radiation Exposure in Humans

Abstract

The major goal of this study was to identify and quantitatively describe the association between the characteristics of chronic (low-dose rate) exposure to (low LET) ionizing radiation and cellularity of peripheral blood cell lines. About 3,200 hemograms (i.e., spectra of blood counts) obtained over the years of maximal exposure to ionizing radiation (1950)(1951)(1952)(1953)(1954)(1955)(1956)) for inhabitants of the Techa River were used in analyses. The mean cumulative red bone marrow dose (with standard errors), calculated using Techa River Dosimetry System-2000, was 333.6 ± 4.6 mGy (SD = 259.9 mGy, max = 1151 mGy) to the year 1956. The statistical approach included both empirical methods for estimating frequencies of cytopenic states of the investigated blood cell lines (e.g. neutrophile, platelets, erythrocyte, etc.), and regression methods, including generalized linear models and logistic regressions which allowed taking into account confounding factors (e.g., attained age, age at maximal exposure, presence of concomitant diseases, and demographic characteristics). The results of the analyses demonstrated hematopoiesis inhibition manifested by a decrease in peripheral blood cellularity and an increase in the frequency of cytopenia in all blood cell lines (leukocytes, including lymphocytes, monocytes, neutrophiles, as well as platelets and erythrocytes). The intensity of hematopoiesis inhibition in the period of maximal exposures is determined by the combined influence of the dose rate and cumulative dose. The contribution of specific confounding factors was quantified and shown to be much less important than dose characteristics. The best predictor among dose characteristics was identified for each blood cell line. A 2-fold increase in dose rate is assumed to be a characteristic of radiosensitivity and a quantitative characteristic of the effect.

Chronic exposure to low concentrations of strontium 90 affects bone physiology but not the hematopoietic system in mice

“…These changes were mainly expressed as a decrease in T and B lymphocyte numbers (Chernyshov et al, 1997;Yarilin et al, 1993), in a modified ratio of CD4 + /CD8 + lymphocytes (Chumak et al, 2001), and impaired production of IgG or IgM (Titov et al, 1995). In addition, Techa riverside residents showed hematological changes such as granulocytopenia and modifications in immune populations with decreased antigen expression (Akleyev et al, 2010a(Akleyev et al, , 2010b. However, in all of these studies, it is difficult to ascribe observed effects to a specific pathway of exposure.…”

DoReMi workshop on multidisciplinary approaches to evaluating cancer risks associated with low-dose internal contamination

“…Alexander Akleyev (URCRM, Russia) presented recent results on haematopoietic effects of chronic radiation exposure obtained from the Techa river cohort. These data have allowed the analysis of the dynamics of blood and red bone marrow cell counts as a function of dose, and to evaluate the pertinence of these biological modifications with respect to the risk of leukaemia occurrence (Akleyev et al, 2010a(Akleyev et al, , 2010bAkushevich et al, 2011). These results constitute a very good illustration of the integration between epidemiology and biology, and highlight the usefulness of biological information in the estimation of the radiation-induced risk of cancer in a population.…”

Effect of 90Sr internal emitter on gene expression in mouse blood

“…Xbp1, X-box binding protein 1, also predicted to be inhibited in this study, is a known regulator of MHC (major histocompatibility complex) class II molecule expression in B-cells [ 42 ]. This may have an effect on the development of B-cells in vivo , which is also known to occur in response to long-term 90 Sr exposure in humans [ 43 ].…”