The immunologic evaluation of the Yucheng children.

The immunologic effects of in utero exposure to polychlorinated biphenyls (PCBs)/polychlorinated dibenzofurans (PCDFs) were evaluated in the Yucheng children in this study. The study subjects consisted of 105 Yucheng children and 101 control children. The Yucheng children were born, between July 1978 and June 1987, to women who had exposed to high dose of PCBs/PCDFs through consumption of contaminated rice bran oil in 1978-1979. These children had been reported to have higher frequencies of bronchitis than their controls in the first six months of life, and higher frequencies of respiratory tract and ear infection in a 6-year follow-up. The low resistance of the Yucheng children to infection suggested that their immune function was suppressed by the PCBs/PCDFs they had exposed to in utero. In the summer and fall of 1995, a thorough physical examination and blood draw were performed on the study children. The Yucheng children were reported by their parents to have higher frequencies of influenza attacks than the control children during the six months prior to the examination. The frequencies of other symptoms were similar between the two groups. The serum levels of various immunoglobulins were similar between the two groups. Fifty-one serum samples, 29 of Yucheng and 22 of control children, were available for cell-mediated immunologic analysis. The percentages of various T cell markers, CD3, CD4, and CD8, and B cell and NK cell markers were not different between the Yucheng and the control children. No dose-response relationship was found between 27 Yucheng children's serum PCB/PCDF levels and any of their immunologic markers. WE concluded that 16 years after the Yucheng incident, Yucheng children exposed to high dose of PCBs/PCDFs in utero did not show, with the serum immunologic marker analyses, suppressed immunity when compared to their controls. To explain the consistent higher frequencies of upper respiratory tract infection in the Yucheng children, immune functional tests such as delayed hypersensitive skin reaction, in vitro lymphocyte proliferation, and antibody synthesis following immunization may be necessary.