The PD-1/PD-L1 checkpoint is implicated in autoimmune diseases and a high incidence of vitiligo like lesions is reported as an adverse
effect of PD-1/PD-L1 blockade, raising the possibility of a role for PD-1/PD-L1 checkpoint in vitiligo pathogenesis. We found that PD-1 in marginal biopsies was significantly higher than both in nonlesional biopsies and in controls, while PD-L1 in marginal biopsies was significantly lower than both in nonlesional biopsies and in controls. PD-1 in nonlesional biopsies was significantly higher than in controls and PD-L1 in nonlesional biopsies was significantly lower than in controls. A significant positive correlation was found between marginal and nonlesional PD-1 levels. 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 on infiltrating T cells yet sufficiently stimulated due to lack of local PD-L1 expression. PD-1 agonists may be of therapeutic value, but need wider scale studies before clinical implementation.
Additional Authors
Prof. Dr. Hanan Rabea Nada Professor of Dermatology Faculty of Medicine- Cairo University
A.Prof. Dr. Ghada Mohamad El Hanafi Assistant Professor of Dermatology Faculty of Medicine- Cairo University
A.Prof. Dr. Mohamed Abd El-Hady Assistant Professor of Dermatology Faculty of Medicine - Cairo University
Prof. Dr. Laila Ahmed Rashed Professor of Medical Biochemistry and Molecular Biology Faculty of Medicine - Cairo University
