On the other hand, making use of islet‐specific BDC‐2.5 TCR transgenic CD4+ autoimmune T cells, Kupfer et al., demonstrated that these pathogenic T cells can also destroy islet allografts that are MHC class II mismatched.[51] This again suggests that the destruction of islet allografts is a complicated process that involves both allo‐rejection and recurrence of autoimmunity. This evidence concerns the gene CD4 and Autoimmunity.