PURPOSE OF THE STUDY.
The goal of this study was to compare household peanut consumption (HPC) with the level of peanut in the home and to determine if ambient peanut in the home was biologically active.
Forty-five families were recruited from pediatric allergy clinics. Three peanut-allergic and 3 nonallergic children were recruited for basophil activation tests.
A semiquantitative assessment of total HPC over 1 week, 1 month, and 6 months was obtained by using information gathered from a questionnaire. Moderate to high HPC consumption was defined as ≥10 g/wk. To quantify ambient household peanut levels, dust samples from all household members’ beds, the infant’s crib, and the infant’s play area were obtained by vacuuming. Wipe samples were obtained from the infant’s and parents’ eating areas, taps, dishwasher and refrigerator handles, and the infant’s crib rail. Peanut protein in the samples was measured by using enzyme-linked immunosorbent assay and converted to micrograms of peanut protein per gram of dust.
Peanut consumption by each parent and their cumulative consumption correlated with levels of environmental peanut protein in the parental beds (mother: rs = 0.698, P < .001; father: rs = 0.672, P < .001). Only 6 infants were eating peanut, but their consumption correlated with levels in the play area and crib, and all levels of peanut protein were high (≥10 μg/g of dust). HPC was most highly correlated with ambient peanut protein levels in the infants’ cribs and play areas (rs > 0.700, P < .001 in all cases and over all durations of HPC measurements). Paternal consumption correlated with levels in the crib to a greater extent than did maternal peanut consumption. Peanut protein was found in the cribs of infants who did not eat peanut. Levels were high when parental consumption was moderate to high even if the child did not eat peanut.
HPC correlated with peanut protein levels from wipe samples from all sites. Basophil activation tests were conducted by using extracted dust samples of low or high peanut protein content. Samples containing <0.375 ng/mL did not upregulate CD63 expression (a marker of basophil activation) in samples from peanut-allergic children. However, at higher peanut protein concentrations in extracted dust samples, there was a dose-dependent increase in CD63 expression.
Peanut protein levels in homes correlate with HPC. Peanut protein in household dust is biologically active and is a possible route of sensitization.
Should families with infants ban peanut from the home? I don’t know, and I wouldn’t yet venture a guess. Previous research by this group found that HPC was a risk factor for the development of peanut allergy. Conversely, with all the HPC in this study, only 6 infants had peanut allergy. Maybe there is a “window” of ambient peanut protein concentration that increases risk of peanut allergy and a different “window” that increases the likelihood of tolerance. As the authors very importantly note, the levels of household peanut protein found in this study might be enough to induce sensitization but are not likely to be high enough to trigger clinical reactions in sensitized individuals.
- Copyright © 2014 by the American Academy of Pediatrics