TNNI3 and familial dilated cardiomyopathy: Okazaki et al. found that mice lacking PD-L1 could develop autoimmune dilated cardiomyopathy (DCM) and produce high-titer autoantibodies against cardiac troponin-I (cTnI), and the administration of cTnI monoclonal antibody in wild-type mice could cause cardiac dilation and cardiac dysfunction.