IFNG and alopecia areata: Not surprisingly, a majority of studies exploring the serum expression of Th1 cytokines have demonstrated an increase in the Th1 hallmark cytokine IFNγ [9,22,24,25,26,27,40,50,51,52,53,54,55,84], and IFNγ-induced collapse of hair follicle immune privilege has been described as a key element in the pathogenesis of alopecia areata [85].