Choi DI, Park JH, Choi JY, et al. - Since keratinocytes are expected to play an important role in the early phase of type 2 inflammation including atopic dermatitis (AD) pathogenesis, researchers ascertained if keratinocytes-derived reactive oxygen species (ROS) could be produced by the allergens or non-allergens, and the keratinocytes-derived ROS could modulate a set of biomarkers for type 2 inflammation of the skin. Normal human epidermal keratinocytes were treated with either a house dust mite (HDM) allergen or a 48/80 compound (C48/80) non-allergen. Then, reverse transcriptase-polymerase chain reaction and western immunoblot experiments tested biomarkers for type 2 inflammation of the skin, including those for neurogenic inflammation. According to findings, HDM or C48/80 has been found to increase the level of expression of the tested biomarkers, including type 2 T helper-driving pathway (KLK5, PAR2, and NFκB), epithelial-cell-derived cytokines (thymic stromal lymphopoietin, interleukin [IL]-25, IL-33), and neurogenic inflammation (NGF, CGRP). The outcomes show that ROS derived from keratinocytes, regardless of their origin from allergens or non-allergens, has the potential to cause AD skin type 2 inflammation.