Effects of inhalative exposure to dioxins in wood preservatives on cell-mediated immunity in day-care center teachers.
The study investigated the effects of chronic inhalative low-level exposure to dioxins in day-care centers containing wood treated with preservatives on (1) the number of peripheral CD4 and CD8 cells and the CD4:CD8 ratio in peripheral blood and (2) the delayed-type hypersensitivity reaction of the skin (Multitest Méreux). The study population consisted of 221 exposed and 189 unexposed employees of day-care centers in or near Hamburg. A status of decreased skin test reagibility was operationalized as hypoergy I (score < 5 mm), hypoergy II (< or = 1 positive reaction), and anergy (no positive reaction). Taking the fading during postexposure time into account, a surrogate for the dioxin burden based on the concentration of dioxins in indoor air (measured using the 2,3,7,8-TCDD TEF followed by the Federal Republic of Germany) was modeled. No effect was found regarding the number of CD4 cells, CD8 cells, and CD4:CD8 ratio. However, some evidence for an increasing dose-response relationship between inhalative exposure to dioxins and the risk of hypoergy and anergy was found, both in the total study population and among subjects with a short postexposure time (< or = 6 months). Subjects with a short postexposure time and a dioxin burden > 0.6 pg/m3 had a significantly higher risk of hypoergy than unexposed subjects (hypoergy I: OR = 9.51, 95% CI = 1.96-42.02; hypoergy II: OR = 2.92, 95% CI = 1.14-7.5). It is concluded that a suppressive effect of inhalative exposure to dioxins in wood preservatives on human cell-mediated immunity cannot be ruled out.
Wolf
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Institute of Medical Sociology, University Hospital Eppendorf, Hamburg, Germany.
Karmaus
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W
D000293:Adolescent; D000328:Adult; D000368:Aged; D016902:Air Pollution, Indoor / Q000009:adverse effects*; D016516:CD4-CD8 Ratio / Q000187:drug effects; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects; D002656:Child Day Care Centers; D003430:Cross-Sectional Studies; D004147:Dioxins / Q000009:adverse effects*; D005260:Female; D005858:Germany; D006801:Humans; D006968:Hypersensitivity, Delayed / Q000276:immunology; D007111:Immunity, Cellular / Q000187:drug effects*; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D012882:Skin Tests; D013601:T-Lymphocytes / Q000187:drug effects* / Q000276:immunology; D013663:Teaching; D014934:Wood
D004147:Dioxins