Quantification of the local inflammatory cytokines of erythema-nodosum like skin lesions in Beh\00E7et's disease using laser capture microdissection

Abstract

Introduction: Behçet’s disease (BD) is a chronic multisystemic inflammatory disease characterized by oral ulcer, genital ulcer, ocular lesions and skin involvements. Cutaneous manifestations are common in BD, and previous studies reported that erythema nodosum (EN)-like lesions in BD are histologically different from classical EN. Immunologically, both Th1 and Th17 mediated cytokines are important in skin lesions of BD, but specific cytokine profiles at panniculus in EN-like lesions have not been studied. Laser capture microdissection (LCM) is a recently developed technique which enables delicate analysis of specific cell populations within tissue samples. In this study, we tried to identify the dominant cytokine milieu at the inflammatory foci of EN-like skin lesion in BD using LCM.Methods: A total of 12 BD patients fulfilling the International Study Group for BD criteria were enrolled, and 18 skin samples including non-lesional skin tissues were taken. Inflammatory foci within panniculus were excised using LCM, and the levels of mRNA expression of cytokines were measured by quantitative RT-PCR.Results: Inflammatory foci of EN-like lesion of BD showed increased mRNA expression of IFN-γ, IL-17A and IL-10 compared with non-lesional skin. The overall mRNA levels of IFN-γ and IL-17 in the EN-like skin lesions from patients who were taking systemic medication were significantly lower than those from patients who were not treated. When the EN-like lesions were further divided into acute and resolving lesions, there was significantly increased expression of IFN-γ and IL-17A in the acute EN-like lesions.Conclusion: Microdissection of the inflammatory foci within EN-like BD skin lesions showed Th1- and Th17-biased cytokine milieu. IFN-γ and IL-17A were significantly elevated in active EN-like skin lesions. Cytokine levels of IL-10 and IL-4 were also slightly elevated, although it did not reach statistical significance.