CD4 and Alopecia universalis: However, when patients with alopecia universalis (n = 8) were excluded from the analysis, a strong significant correlation between disease extent and AhR expression emerged for all T cell subsets examined: CD4+ T cells (r = 0.458; p = 0.014), Th1 cells (r = 0.453; p = 0.016), Th17 cells (r = 0.518; p = 0.005), and CD8+ T cells (r = 0.543; p = 0.003).