“…Studies on community residents of Quail Run Mobile Home Park (Missouri residents, USA), environmentally exposed to contaminated industrial sludge, showed a significantly decreased percentage of lymphocytes expressing CD3þ, CD4þ, and CD2þ, but the mean numbers of each of the T-cell subsets was comparable between the groups (Hoffman et al 1986;Knutsen et al 1987). Subsequent studies (Evans et al 1988;Webb et al 1989) showed significant increases associated with higher concentrations of TCDD for IgG, %CD3þ, %CD8þ, number of T-cells, percentages of CD2þ, and CD4þ/Leu-8 position.…”