Communication between hair follicles and lymphatic endothelial cells revealed prominent ligand-receptor pairs in normal skin, such as DSG1 and its receptor DSC3, COL6A1 (Collagen Type VI Alpha 1 Chain) and its receptors ITGA2 (Integrin Subunit Alpha 2) and ITGB1 (Integrin Subunit Beta 1), while in psoriasis, they were APP and its receptor CD74, LAMC1 and its receptor CD44, and COL4A2 and its receptor CD44. Here, APP is linked to psoriasis.