Similar to CTLA-4 blockade, knockout or blockade of PD-1 or polymorphisms in PD-1/PD-L1 genes in mice leads to autoimmune-like conditions such as cardiomyopathy (82), progressive arthritis, lupus-like glomerulonephritis (83), diabetes (46), Graves’ disease (84), and multiple sclerosis (85). The gene discussed is PDCD1; the disease is diabetes mellitus.