Immune responsiveness to squaric acid dibutylester in human subjects.
Baron-ED; Swick-AR; Ryan-CA; Gerberick-GF; Tinkle-SS; Nedorost-ST; Cooper-KD; Stevens-SR
Working Partnerships: Applying Research to Practice, NORA Symposium 2003, June 23-24, 2003, Arlington, Virginia. Washington, DC: National Institute for Occupational Safety and Health, 2003 Jun; :26
Understanding dose-response characteristics is essential in the prevention of allergic contact dermatitis. Squaric acid dibutyl ester (SADBE) is a known contact sensitizer, but dose-response data have not been reported. This study is aimed at determining the relationship between sensitization dose and contact hypersensitivity (CHS) response to SADBE in human volunteers and investigating the correlation of clinical response with T-cell proliferation in vitro. Thirty-six healthy volunteers were sensitized to either .025,.05,.1 or .5% SADBE on the buttock, followed two weeks later by elicitation on the arm using 5 graded doses from 0 to 1%. An additional control group of 10 subjects underwent elicitation without prior sensitization. 180 cc of blood was obtained immediately prior to sensitization and elicitation. In some subjects, blood was also obtained 4-10 months after elicitation. Results show that there is a direct relationship between sensitization dose and immune response. The SADBE dose capable of sensitizing 50% of the population was .05%. Although the T-cell proliferation assay was not sensitive enough to detect changes two weeks after sensitization, but prior to elicitation, post-elicitation analyses revealed that sufficient numbers of circulating reactive T cells are present to allow detection by in vitro methods. These results suggest that either time (4-10 months) or re-exposure is necessary for this expansion of reactive T-cell numbers.
Dose-response; Allergic-dermatitis; Allergies; Allergic-reactions; Hypersensitivity; Immune-system; Immune-reaction
Research Tools and Approaches: Exposure Assessment Methods
Working Partnerships: Applying Research to Practice, NORA Symposium 2003, June 23-24, 2003, Arlington, Virginia