However, in a case series of nivolumab-induced thyroiditis, PD-L1 and PD-L2 were found in normal thyroid glands, which suggests that administration of PD-1 inhibitors can disrupt the interaction between PD-1 on T cells and PDL-1/2 on thyrocytes, leading to T-cell activation against thyroid antigens [24,25]. This evidence concerns the gene PDCD1 and thyroiditis.