Human skin T_reg cells

Regulatory T cells (T_reg cells) are present in tissues throughout the body, where they serve important roles in maintaining immunological homeostasis; however, few studies have examined human tissue-resident T_reg cells. In the Journal of Clinical Investigation, Rosenblum et al. characterize a population of T_reg cells in human skin that accumulate progressively with age. Skin T_reg cells have a distinct effector-memory phenotype suggestive of previous antigen recognition. These T_reg cells are poorly migratory and thus seem to be a true skin-resident population 'preferentially' associated with hair follicles. Sequencing of T cell antigen receptors demonstrates that this population has a repertoire distinct from that of their conventional effector T cell counterparts. Finally, skin T_reg cells isolated from psoriatic lesions are more proliferative and express the inflammatory cytokine IL-17. Human skin therefore has a resident T_reg cell population that may be functionally defective under conditions of inflammation.

J. Clin. Invest. 124, 1027–1036 (2014)