These authors performed T cell receptor (TCR) sequencing and identified 3 major histocompatibility complex I restricted TCRs specific for a cardiac specific protein (α-myosin) that was not detected in the thymus, suggesting that escape from central tolerance was responsible for the development of spontaneous CD8+ myocarditis in the Pdc1−/−/Ctla4+/− mice. Here, CTLA4 is linked to myocarditis.