“…In addition, Th17 cells, Th9 cells, type 2 innate lymphoid (ILC2s), and mast cells are suggested to participate in pathological cutaneous foci as IL-9 producers (Lozano-Ojalvo et al, 2019;Nowak et al, 2009;Rauber et al, 2017;Schlapbach et al, 2014). Given that IL-9 regulates the metabolic reprogramming of human keratinocytes (Marathe et al, 2021) and IL-9R is highly expressed in keratinocytes in atopic dermatitis (Hong et al, 2015), IL-9 may play a certain role in unresolved skin inflammation. However, the interplay between keratinocytes and other cells in inflammatory skin lesions is complex.…”