CD274 and laryngotracheoesophageal cleft: In the present study, the programmed cell death protein 1 (PD-1) and its ligand (PD-L1), the human leukocyte antigens (HLA-DR and HLA-I), CD3, CD8, CD4, characterizing T cells, as well as myeloid markers such as CD33, CD163, and CD68 were evaluated by immunohistochemistry (IHC) on surgical samples collected from 68 operable never-smokers LC patients with high and low CRP plasma levels.