Epidermal T cells: Their functional role and disease relevance for dermatologists

[摘要] T cells found within the epidermis in inflammatory dermatoses are generally accepted as making a major contribution to epidermal damage, On the other hand, those T cells residing in the murine epidermis are supposed to play an important role in protecting the epidermis from potentially dangerous immune reactions, Overwhelming evidence has accumulated that dendritic epidermal T cells (DETC) expressing monomorphic TCR gamma delta are responsible for the protection of epidermal structures against skin tumor, bacterial infection, and autoimmune attack, In animals congenitally lacking these gamma delta(+) DETC, the epidermis is populated with bone marrow-derived TCR alpha beta(+), CD8(+) DETC, Although it remains unclear whether this subset of DETC could home to the epidermis to substitute for the physiologic function of gamma delta(+) DETC or whether they would be pathologically relevant to epidermal injury, it should be noted that this subset represents the major fraction of T cells present in normal human epidermis and the most abundant in the lesional epidermis of fixed drug eruption (FDE), Because they are shown to kill target cells including keratinocytes upon stimulation and utilize a very limited range of TCR V alpha and V beta gene families, localized epidermal injury in FDE lesions would be mediated by activation of these epidermal T cells with autoaggressive potential, Epidermal T cells are thus likely to form several T-cell populations with different immunologic functions that are triggered by different modes of stimulation. Immune homeostasis in the epidermis would rely on a delicate balance between at least two types of epidermal T cells: autoaggressive T cells and protective T cells.

[发布日期] 1997-09-01

[关键词] dendritic epidermal T cells;gamma delta T cells;graft versus host disease;fixed drug eruption