CTLA4 and Autoimmunity: Specifically, it was observed that Treg cells with a high-affinity TCR were characterized by increased expression of IL-10, TIGIT, GITR, and CTLA-4, while those with low affinity showed increased transcripts for Areg and Ebi3. These data suggested that the degree of TCR affinity for self-antigen may influence the mechanisms by which autoimmunity is controlled (22).