High-dimensional profiling of circulating dendritic cells and monocytes in atopic dermatitis patients by mass cytometry

Abstract Atopic dermatitis (AD) is a chronic inflammatory skin disorder, with a multifactorial pathophysiology, including barrier dysfunction, dysbiosis and immune dysregulation. Although AD has been characterized by a T helper type 2 cell response, the role of the myeloid populations in the pathogenesis of AD still remains unclear. Here, we used mass cytometry, a high-dimensional analysis tool, primarily focusing on these cell populations to identify differences in the immune phenotypes of circulating dendritic cells and monocytes in AD. Peripheral blood mononuclear cells (PBMCs) from 48 Korean AD patients and 48 age-, sex-matched healthy controls were profiled. We report significant differences in the frequency and phenotypic markers of dendritic cells and monocytes. The frequency of CD141 +CLEC9A +cDC1 was significantly decreased in AD, and its frequency negatively correlated with disease severity and serum IgE levels. This suggests that cDC1 may have preferentially migrated to the lesional skin to control the inflammation, especially in severe AD. CLEC9A expression was significantly reduced, while FceRIa expression was significantly increased in cDC1. The expression of FceRIa was also elevated in cDC2, pDC, and Axl +DC. In cDC2, HLA-DR expression was decreased, and CD163 expression was increased. These results indicate changes in the immunophenotypes of circulating dendritic cells in AD compared with healthy controls. Although further investigation is needed, our results suggest a potential role of dendritic cells in modulating AD pathophysiology.