CD4 and Autoimmunity: There are two plausible outcomes: If the partially activated CD4+ T cell is self-reactive against mTECs, then it will be differentiated into a subset of CD4+ regulatory T cells; however, if the partially activated CD4+ T cell has no self-reactivity against mTECs, then it will be transformed into a subset of CD4+ helper T cells, which might be involved in regulating anticancer immunity or autoimmunity (discussed in Section 2.6).