Expression of immune checkpoints in active nonsegmental vitiligo: a pilot study

Vitiligo is a depigmentary skin disfigurement resulting from destruction of melanocytes caused by a possible malfunctioning immunity. This destruction could be linked to an aberrant T-cell-mediated immune response. Cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) and programmed death-1 (PD-1) are immune checkpoints capable of downregulating T-cell immune functions.

To evaluate the pattern of expression of PD-1 and CTLA-4 in active vitiligo skin.

Thirty nonsegmental vitiligo (NSV) patients had been included in this pilot study. Marginal, lesional, and nonlesional skin biopsies were obtained. PD-1 and CTLA-4 immunohistochemistry expression in the mononuclear inflammatory infiltrates were evaluated using digital images.

The marginal and lesional inflammatory infiltrates were significantly abundant when compared to nonlesional ones. The marginal infiltrates were significantly abundant when compared to the lesional ones. PD-1 and CTLA-4 were significantly expressed in the marginal and lesional infiltrates when compared to nonlesional skin. Moreover, the marginal expression of PD-1 was significantly higher than the lesional expression. However, no similar significant difference in CTLA-4 expression was found between the marginal and lesional infiltrates. Significant positive correlations were found between the expressions of PD-1 and CTLA-4 in marginal and lesional infiltrates.

Programmed death-1 and CTLA-4 are expressed within the inflammatory infiltrate of active NSV. Further studies are required to confirm their significance in the development or limitation of the disease.