Di-(2-ethylhexyl) phthalate possesses an adjuvant effect in a subcutaneous injection model with BALB/c mice.

The prevalence of allergic airway diseases is rapidly increasing in Western Europe and North America and the introduction of anthropogenic chemicals may explain a part of this increase. Recently, our group found that degradation products from several commonly used phthalate plasticizers possess adjuvant activity in an animal model. Mono-2-ethylhexyl phthalate, which is the degradation product of di-(2-ethylhexyl) phthalate (DEHP), was among these substances. These findings prompted the study of the adjuvant activity of the parent compound itself. Thus, DEHP was studied in a model using ovalbumin (OA) as the model antigen. OA was injected subcutaneously in the neck region of BALB/cJ mice with or without DEHP. The levels of OA-specific IgE, IgG1 and IgG2a antibodies in sera were measured by ELISA. Adjuvant effect, defined as a statistically significant increase in antibody level, was observed with IgG1 at a concentration of 2000 microg DEHP/ml after both one and two boosters.

Possible mechanisms for the respiratory tract effects of noncarcinogenic indoor-climate pollutants and bases for their risk assessment.

This review outlines the effects of pollutants on the lungs. Mechanisms and effects relevant to the assessment of indoor-air risk are especially dealt with. Important mediators have also been considered. Concentration-effect relationships exist for toxic reactions, sensitization reactions, and neurogenic effects. If Harber's Law is used for extrapolations from higher concentrations to the lower indoor-air levels, the indoor-air risk estimate may exceed the real risk. Additivity seems to apply to toxic and neurogenic effects of low doses. Only already sensitized subjects and possible subjects with a profound alpha 1-antitrypsin deficiency appear to be extremely sensitive, and a safety factor of 10 seems adequate for the protection of other groups. Thus combining occupational exposure limits (OEL), Harber's Law, and the safety factor suggests that no direct lung effects should be expected from a substance if the exposure level does not exceed 1/40.OEL.