according to a study of children with and without AD and FA.
The researchers included 62 children aged 4-17 years, who were divided into three groups: atopic dermatitis and food allergy (AD FA+, n = 21), atopic dermatitis and no food allergy (AD FA−, n = 19), and nonatopic controls (NA, n = 22).
“In this prospective clinical study with laboratory personnel blinded to minimize bias, we demonstrate that children with AD FA+ represent a unique endotype that can be distinguished from AD FA− or NA,” wrote Donald Y. M. Leung, MD, of National Jewish Health, Denver, and his coauthors. Their work was published online in Science Translational Medicine.
According to three different scoring systems, the two AD groups were measured to have similar skin disease severity. Dr. Leung and colleagues then used skin tape stripping to measure the first layer of skin tissue for transepidermal water loss (TEWL) and stratum corneum (SC) composition, along with other variables that would indicate a difference between AD FA+ and the other groups.
Upon analysis, children in the AD FA+ group were found to have “a constellation of SC attributes,” including increased TEWL and lower levels of filaggrin gene breakdown products (urocanic acid and pyroglutamic acid) at nonlesional layers. In addition, there was an increase of Staphylococcus aureus on the nonlesional skin of AD FA+, compared with NA.
The coauthors shared the study’s limitations, which included transcriptome analysis being successful for only a fraction of the patients and the lack of skin biopsies, which would be useful to confirm “the potential role of changes in the deeper layers of skin.” However, they also noted that using minimally invasive STS led to more patients providing samples, and thus less bias in collection. “Although future studies are needed to validate our findings,” Dr. Leung and his associates wrote, “our current data support the concept that primary and secondary prevention of AD and FA in this subset of AD should focus on improving skin barrier function.”
The study was funded by the National Institute of Health/The National Institute of Allergy and Infectious Diseases’ Atopic Dermatitis Research Network, with partial support from the Edelstein Family Chair for Pediatric Allergy at NIH and a NIH/National Center for Advancing Translational Sciences Colorado Clinical and Translational Science Awards grant. Three of the authors declared being inventors of a patent that covers methods of identifying AD with FA as a unique endotype. No other conflicts of interest were reported.
SOURCE: Leung DYM et al. Sci Transl Med. 2019 Feb 20. doi: 10.1126/scitranslmed.aav2685.