September 19, 1986

Lack of Health Effects of Long-term Exposure to 2,3,7,8-Tetrachlorodibenzo-p-Dioxin-Reply

Author Affiliations

Center for Environmental Health Centers for Disease Control Atlanta

JAMA. 1986;256(11):1447. doi:10.1001/jama.1986.03380110052023

In Reply.—  Skin test results collected by two of the four skin test readers for both exposed and unexposed participants were excluded because the data were judged to be invalid by numerous criteria, exactly as if a laboratory had one run for a particular test out of its quality control limits. This is different from what Allison and Lewis suggest— that the skin test data were biased.The skin test results are the main reason for suggesting that TCDD exposure may be associated with depressed cell-mediated immunity. We could not, however, ignore a number of additional findings from the in vitro immune tests. These findings included statistically significant differences in mean lymphoproliferative response to pokeweed mitogen (increased in exposed group), the mean number of non-T cells (increased in exposed group), and the mean cytotoxic T-lymphocyte activity (decreased activity in exposed group determined by using log10-transformed values) (A. P. Knutsen, MD,