Tu127 - Diminished V-set Domain-containing T-cell Activation inhibitor-1 (VTCN1) Positive Immune Cell Subpopulations in Generalized Active Vitiligo

Abstract Text:

Background: Vitiligo, a prevalent skin-disfiguring autoimmune disease, has prompted the exploration of immunomodulation as a crucial strategy for intervention. VTCN1 (V-set domain containing T cell activation inhibitor 1), a member of the B7 superfamily molecules, plays a pivotal role in negatively regulating T cell activation. Given its significance, it becomes imperative to investigate the immunophenotypic profile of VTCN1 in both the Blood and Skin of generalized active vitiligo patients.

Methods: We recruited 25 generalized active vitiligo patients and 30 healthy controls to assess VTCN1 expression in blood for the immunophenotypic analysis. Additionally, 13 generalized active vitiligo patients, and 10 healthy controls were included to examine VTCN1 expression on different T cells from the skin. Furthermore, we monitored VTCN1 expression on THP1 cells and evaluated the impact of IFN-γ, TNF-α, and IL-10 treatment using western blot analysis.

Results: Our findings indicated a noteworthy decrease in the percentage of VTCN1-positive CD4, CD8, and regulatory T cells (p=0.030, p=0.004, and p=0.012) in vitiligo patients. Intriguingly, we observed a significant increase in activated T cells among vitiligo patients and a substantial reduction in CD8+ CD69+ VTCN1+ positive cells (p=0.001 and p=0.016). Moreover, VTCN1+ dendritic cells were significantly diminished in vitiligo patients (p=0.030).

Conclusions: This study unveiled a significant reduction in VTCN1-positive CD4, CD8, regulatory T cells, and dendritic cells in vitiligo patients, indicating a breakdown in tolerance. This breakdown may trigger autoreactive T cells, fostering an exacerbated response against healthy melanocytes, ultimately contributing to melanocyte destruction and advancing the progression of vitiligo.