PDCD1 and thyroiditis: In patients with thyroiditis who were treated with anti-PD-1 inhibitors, diminished numbers of immature NK cells (natural killer cells) (CD56brCD16-) as well as of immunosuppressive monocytes with low expression of HLA-DR (human leukocyte antigen–DR isotype) (CD14+HLA-DRlo/neg) were documented [19].