Assessment of programmed cell death 1 and its programmed cell death ligand 1 levels in vitiligo
Hanan R. Nada, Ahmed Mourad, Laila A. Rashed, Ghada M. El-Hanafy, Nermeen M.A. Abdallah, Mohamed M. AbdelhadyBackground
Programmed cell death 1 (PD-1) is a cell surface protein that serves as an immune checkpoint in conjunction with its two ligands, PD-L1 and PD-L2. Recently, there has been a lot of interest in the role of the PD-1/PD-L1 pathway in immunoregulation.
Objective
To assess both PD-1 and PD-L1 levels in vitiligo patients’ marginal and nonlesional biopsies compared with normal controls and to correlate them with disease parameters.
Patients and methods
A total of 30 vitiliginous patients and 30 age and sex-matched controls were included. Full history and clinical examination were done and ELISA measured tissue levels of PD-1 and PD-L1 from lesional and nonlesional biopsies.
Results
Levels of tissue PD-1 in marginal biopsies (mean 7.89±2.48 ng/mg) were significantly higher than in nonlesional biopsies (mean 3.65±1.11 ng/mg;
Conclusion
Our results suggest that the PD-1/PD-L1 checkpoint seems to be implicated in the loss of peripheral tolerance in human vitiligo, with PD-1 being highly expressed, yet insufficiently stimulated due to lack of local PD-L1 expression. Since PD1 plays an important role, its agonists may have therapeutic implications in vitiligo and other autoimmune diseases but need wider-scale studies before clinical implementation.