Highly significant, positive correlations between the D-score of TCR-β2 and infiltrating αβ2 T (P < 0.0001), CD4-CD8α+ (P < 0.0001) and CD4+CD8α+ (P = 0.0003) cells were found in data obtained from vitiligo-expressing Smyth chickens. Here, CD4 is linked to vitiligo.