Cultured epidermal autografts for treatment of stable vitiligo: Quantitative analysis of color matching with surrounding normally pigmented skin

Abstract Cultured epidermal autografts (CEA) are surgical therapeutic alternatives for patients with stable vitiligo resistant to conventional medical treatments. In the present study, we assessed color matching before and at 12 months after CEA treatment. Eleven patients with 16 vitiligo lesions were included in this prospective study. The recipient sites were prepared by CO2 laser superficial ablation and subjected to CEA application. We clinically evaluated and categorized the color matching of the repigmented skin as well as the percentage of repigmentation. We also obtained three color values (L*a*b*) for the vitiligo lesions and surrounding normally pigmented skin. We then calculated the color differences between the two regions and compared them before and at 12 months after treatment. The mean percentage of repigmentation was 63.3% at 12 months. Six of the 16 lesions were categorized as “same as” and had color difference values of ≤5 at 12 months after treatment. Clinical evaluation of the color matching coincided well with the calculated color difference values. CEA application after CO2 laser superficial ablation was useful for treating vitiligo assessed by the percentage of repigmentation and color matching. Quantification of color differences may be a useful parameter for evaluating color matching in vitiligo.

Eleven patients with 16 vitiligo lesions 2 that were stable for at least 6 months and unresponsive to conventional therapies were enrolled in this prospective study (Table 1). CEA were produced by Green's culture technique at Japan Tissue Engineering. 3 The epidermis of the affected area was removed by superficial ablation with a CO 2 laser AcuPluse™ (Lumenis). Cultured autografts were then applied and occluded with silicon products.
The treated area appeared red, and steroid ointment was applied topically. Patients were asked to expose the area to sunlight at home for 5 min daily with gradual progression to a maximum of 30 min daily after 3 months postoperatively. 3 The patients were followed up at 1 week, and at 1, 3, 6, and 12 months.
Percentage of repigmentation was determined by planimetry using the VECTRA H1 ® (Canfield Scientific) at 12 months after treatment. 4 The repigmented skin was clinically evaluated and the color was categorized as "somewhat lighter than", "same as", or "somewhat darker than" the surrounding skin. 1,5 Three color values (L*a*b*) were obtained for the vitiligo lesions and surrounding normally pigmented skin using a digital camera (EOS Kiss X6i; Canon) after calibrating the images with a color reference marker, Casmatch™ (http:// www.Bearmedic-en.com), and Adobe Photoshop 2021 (Adobe Systems). [6][7][8] We selected three directions centering on vitiligo, such as the cranial, the temporal, and the caudal, and measured the color values once in the peripheral part in each direction. We also measured the values once in the vitiligo region in the same direction. The respective color values were then averaged, and the color difference (ΔE*ab) between the lesions and the surrounding skin was calculated Note. Clinical evaluation:"lighter", "somewhat lighter than"; same, "same as".
according to the formula. 6 We then compared them before and at 12 months after treatment at the same anatomical points.

| RE SULTS
The results are summarized in Table 2 Locations such as the cheek, forehead, glabella, and lip tended to show more marked improvement in the color difference.
There was two-case presentation who had a uniform pigmentation and a patchy pattern (Figure 1). Areas of patchy pigmentation had a lower color difference number after averaging compared with the clinical evaluation.

| DISCUSS ION
We quantitatively assessed color differences of the treated skin with the surrounding skin to evaluate color matching. A spectrophotometer, 9,10 colorimeter, 9 or digital camera 7,8 can be used to objectively assess color and color differences. In the digital images obtained by a camera, there is non-uniformity related to the local conditions, such as the distance from object to illumination. 7 Therefore, we used a photographic studio with the camera body and ring flash set at a fixed distance from the subject. We also adjusted the images using Casmatch™ and Photoshop™. 8 We averaged each of the three color values because the lesion color was often uneven. Finally, and most importantly, we did not evaluate the color values themselves, but The present study has some limitations of the small sample size and non-standardized analysis.

ACK N OWLED G M ENT
The authors thank Dr Kenichiro Hata, President of Japan Tissue Engineering for clinical advice.