Study of cathelicidin (LL-37) immunoexpression in the skin of vitiligo patients

Vitiligo is a pigmentary disorder acquired and caused by the loss or destruction of melanocytes from the epidermis. There is strong proof that vitiligo is mainly an autoimmune disease. Cathelicidin (LL37), an antimicrobial polypeptide, is an important part of the innate immune system and has a role in different skin autoimmune diseases. The present work aimed to study the immunoexpression of cathelicidin in the vitiligo patients' skin to elucidate its possible role in vitiligo pathogenesis. Twenty vitiligo patients and 20 controls of matched sex and age were included. A 3 mm punch biopsy was taken from the non-lesional and lesional skin of each patient and controlled subjects. Each was stained with hematoxylin and eosin (H&E) and subjected to cathelicidin immunostaining detection. A significant difference was detected between the two studied groups regarding cathelicidin immunohistochemical expression (Pvalue < 0.001). The lesional immunohistochemical expression of cathelicidin showed a mean of 2.85 ± 0.67. The non-lesional immunohistochemical expression of cathelicidin showed a mean of 2.05 ± 0.51 with a statistically significant higher mean value in the patients' group than the controls (P < 0.001) which recommends that cathelicidin may play a role in the vitiligo pathogenesis. The immunohistochemical scores of the lesional and non-lesional cathelicidin levels were significantly related to the VIDA score (p < 0.001 and = 0.016, respectively) which suggests a role of cathelicidin in vitiligo activity. A significant elevation was indicated in the non-lesional cathelicidin expression, indicating that cathelicidin may be able to predict the appearance of future lesions in non-lesional skin, this requires further longitudinal studies to be confirmed.