PDCD1LG2 and dilated cardiomyopathy: On the other hand, C57BL/6J mice are resistant to myocarditis [11], and PD-1−/−, PD-L1−/−, or PD-L2−/− mice on the C57BL/6J background do not develop spontaneous myocarditis and dilated cardiomyopathy [12].