AHR and vitiligo: We therefore examined the major cytokines of T helper and regulatory T cells in 16 vitiligo patients and 16 age- and sex-matched controls carrying various AHR −129 genotypes (n = 10 for CC, n = 4 for CT and n = 2 for TT in vitiligo patients; n = 11 for CC, n = 4 for CT and n = 1 for TT in controls; Hardy–Weinberg equilibrium test: χ2 = 0.515, P = 0.473).