Intralesional injection of vitamin D in verruca vulgaris increases cathelicidin (LL37) expression; therapeutic and immunohistochemical study.

INTRODUCTION: Despite the promising results of intralesional vitamin D in verruca treatment; its precise mechanism of action is not fully understood. AIM OF THE WORK: To investigate immunohistochemical expression of cathelicidin (LL 37) before and after injection of vitamin D in verruca vulgaris and to clarify its possible role in pathogenesis of verruca. PATIENTS AND METHODS: This study included 20 patients with multiple verrucae vulgaris. Vitamin D was intralesionally injected every 2 weeks for a maximum of 4 sessions or clearance of verrucae. Skin biopsies were taken from the patients before and at the end of the study and compared to skin samples from ten apparently healthy, age and sex matched individuals for histopathological and immunohistochemical assessment of LL37 expression. RESULTS: Eight (40%) verrucae showed complete response, seven (35%) showed partial response and five (25%) showed no response. Decreased epidermal thickness and reduced density of inflammatory cells in dermis were observed after injection. Significant increase in LL37 intensity of expression was observed after intralesional injection of vitamin D3 ( = .003) and in verrucae showing complete clinical response ( = .022). CONCLUSIONS: Intralesional injection of vitamin D is effective and safe treatment for verruca vulgaris and causes increase in LL37 expression.