Evaluation of programmed death ligand 1 (PD-L1) expression and CD8+ T-cell immune response in primary pterygium

PURPOSE: This study aimed to investigate the differences in the immunoreactivity of programmed death ligand (PD-L1) and CD8 in pterygium tissues and normal conjunctival tissues. METHODS: Forty-two patients diagnosed with primary pterygium were included in the study. Control samples were obtained from the superior bulbar conjunctiva of the same patients during autograft pterygium surgery. Both normal conjunctival tissue and pterygium samples were immunohistochemically stained for PD-L1 and CD8. Immunoreactivity levels between the two groups were compared using a paired t -test. RESULTS: PD-L1 immunoreactivity was significantly higher in pterygium tissue than in normal conjunctiva ( P < 0.001). CD8 immunoreactivity was also significantly elevated in pterygium samples compared to controls ( P < 0.001). CONCLUSION: The increased expression of PD-L1, a known immune checkpoint regulator, in pterygium tissue highlights the role of immunological mechanisms in pterygium pathogenesis. Immunotherapy, which is widely used in tumor treatment, may hold promise as a therapeutic option for pterygium.