PDCD1 and Autoimmunity: Tregs in BALB/c-Pdcd1−/− Lag3aida/aida mice had substantial suppressive function, contradicting that myocarditis in this model is mainly orchestrated by the failure of regulatory cells. As Lag3 deficiency did not induce autoimmunity in non-autoimmune-prone mouse models, the synergistic actions of LAG-3 and PD-1 are crucial in mediating the autoimmunity [68].