A new humanized mouse model for alopecia areata.

Although alopecia areata (AA) is not life threatening, it may lead to severe psychological disturbances, reducing the quality of life in all ages. Thus, a new animal model is needed for shedding more light onto the pathogenesis of this cell-mediated, organ-specific autoimmune disease to identify more effective therapeutic strategies. Recently, we succeeded in developing a new humanized mouse model of AA, which includes transplantation of healthy human scalp skin obtained from normal volunteers on to severe-combined immunodeficient mice. This is followed by intradermal injection of either autologous or allogeneic peripheral blood mononuclear cells, which had been cultured with high dose of IL-2 and enriched for natural killer group 2D-positive (NKG2D+) and CD56+ cells. This protocol leads to rapid and predictable development of focal hair loss, with all the characteristic clinical, histological, and immunohistochemical features of AA. This humanized mouse AA model underscores the functional importance of NKG2D+ and CD56+ cells in AA pathogenesis and promises to be instrumental for identifying novel AA treatment strategies.