CD163/CD63+ Monocyte-Derived DC Profiled in Tissue by Multi-Antigen Analysis (MAA) Discriminate Chronic Eczema and Psoriasis

Psoriasis (Pso) is a chronic inflammatory skin disease with a genetic predisposition and an assumed autoimmune pathomechanism. Autoantigens, dendritic cells (DCs), and the TNF/IL23/Il17 axis are seemingly the main drivers of this process. However, the difference to other DC-driven immune processes, like in eczematic skin, is insufficiently understood. Multi-antigen analysis (MAA) allows the staining of tissue with 100 antigens and more and provides a deeper insight into pathological processes, using advanced imaging analysis and quantification of topographical allocated processes. Here we used this technology to assess and compare the skin immune infiltrations in Pso, chronic eczema, and healthy controls. Tissue samples from both skin diseases (<i>n</i> = 30) were stained for 63 antigens, including 45 immune markers, and cells were analysed and quantified in both epidermis and dermis. The presence of different types of monocyte-derived DC in the epidermis was the most notable distinction between both skin diseases. While in Pso a monocyte-derived DC (CD14+CD1a+CD11c+) predominated, possibly a Langerhans cell (LC)-like DC, eczema displayed a marker combination of a seemingly more differentiated monocyte-derived DC (CD14+CD63+CD163+), potentially a DC3 cell type.