1270 Non-invasive imaging reveals keratinocyte-melanocyte changes in treatment-resistant vitiligo skin

Vitiligo is an autoimmune skin disease characterized by the progressive destruction of melanocytes by autoreactive T cells, resulting in persistent white patches. We previously combined multiphoton microscopy (MPM) and single cell RNA sequencing (scRNA-seq) in stable vitiligo lesions to identify a subset of metabolically shifted keratinocytes, which we now call ‘stable vitiligo keratinocytes’ (SVKs), that accumulate in stable vitiligo skin. SVKs produce high levels of chemokines known to induce vitiligo (CXCL9, CXCL10) and low levels of Wnt signals known to recruit melanocytes. SVKs were associated with stable vitiligo disease persistence, as they were not observed in acute vitiligo. We also noted that SVKs were less numerous in skin from patients that responded to punch grafting treatment as compared to patients that failed to respond. To further investigate the role of SVKs in treatment resistance, we followed 15 stable vitiligo patients treated with punch grafting over time using two live imaging methods – MPM and reflectance confocal microscopy (RCM), which has a wider field of view that allows us to better visualize migrating melanocytes. We observed that SVKs persisted up to 6 weeks in treatment responders but were less abundant after 10 weeks. In treatment resistant patients, SVKs persisted past 10 weeks. Using RCM, we showed that melanocytes could be visualized in skin surrounding punch grafts as early as 3 weeks and were observed in treatment responders after 10 weeks. In contrast, no melanocytes were visualized in lesions that did not respond to treatment. In summary, our work indicates that SVKs are more abundant and melanocytes less abundant in lesions that fail to respond to punch grafting therapy, suggesting that the presence of SVKs may be a biomarker for lesions that would fail to respond to therapy.