CD4 and Crohn disease: As representative examples of TCR-independent reactivation of T cells, CD49a+CD8+ TRM cells in the skin tissue of patients with vitiligo, CD161+CD103+CD4+ TRM cells in the intestinal tissue of patients with Crohn’s disease, and KIR+NKG2A+NKG2D+CD8+ TVM cells in patients with alopecia areata can exert cytotoxic functions, including the secretion of Prf1 and Gzms, and the production of IFN-γ [199, 209, 228].