CD6 and psoriasis: Immune histological staining of T cells in the epidermis (E) of skin tissue sections derived from psoriasis patients revealed that CD3+ T cells highly express CD6 if they were located in close proximity to the border between epidermis and dermis (Figure 2F, arrow; Figure S2C) while T cells located in the “middle” of the epidermis seemed to downregulate CD6 expression (Figure 2F; Figure S2C).