PD-1 deficiency causes dilated cardiomyopathy mediated by antibodies deposition on cardiac cells in mice with a Th2 bias response (Nishimura et al., 2001; Okazaki et al., 2003), which are more prompt to develop a humoral response (Busch et al., 2016). Here, PDCD1 is linked to dilated cardiomyopathy.