Frequent natural killer cell abnormality in children in an area highly contaminated by the Chernobyl accident

Since January 1991, we have been performing thyroid surveys and hematologic and immunologic screening on children in Chechersk, Belarus, a city situated in one of the areas most seriously contaminated with high levels of radionuclides after the Chernobyl accident. Ten children selected from 713 children because of goiter did not show a decrease in humoral immunity or in the number and function of T cells. By contrast, natural killer (NK) cell activity against K562 cells was depressed in 4 of these 10 children. The clinical and laboratory findings indicated that previously reported diseases with NK cell dysfunction could be excluded. A comparative analysis of NK cell activity in children from areas with and without high ¹³⁷Cs levels revealed a high frequency of abnormal NK cell activity only in children from the area contaminated by radioactive fallout. In addition, there was no correlation between NK cell activity and NK cell number as percentage in the children from the area with high ¹³⁷Cs levels. Neither activity nor number of NK cells was correlated with the body content of ¹³⁷Cs. Thus, the frequent abnormality of NK cell function may not have been due to actual internal exposure to the long-lived radionuclide.