Peanut protein in household dust is related to household peanut consumption and is biologically active

Background: Peanut allergy is an important public health concern. To understand the pathogenesis of peanut allergy, we need to determine the route by which children become sensitized. A dose-response between household peanut consumption (HPC; used as an indirect marker of environmental peanut exposure) and the development of peanut allergy has been observed; however, environmental peanut exposure was not directly quantified. Objective: We sought to explore the relationship between reported HPC and peanut protein levels in an infant's home environment and to determine the biological activity of environmental peanut. Methods: Peanut protein was quantified in wipe and dust samples collected from 45 homes with infants by using a polyclonal peanut ELISA. Environmental peanut protein levels were compared with peanut consumption assessed by using a validated peanut food frequency questionnaire and other clinical and household factors. Biological activity of peanut protein in dust was assessed with a basophil activation assay. Results: There was a positive correlation between peanut protein levels in the infant's bed, crib rail, and play area and reported HPC over 1 and 6 months. On multivariate regression analysis, HPC was the most important variable associated with peanut protein levels in the infant's bed sheet and play area. Dust samples containing high peanut protein levels induced dose-dependent activation of basophils in children with peanut allergy. Conclusions: We have shown that an infant's environmental exposure to peanut is most likely to be due to HPC. Peanut protein in dust is biologically active and should be assessed as a route of possible early peanut sensitization in infants.