Halawi Ali, Kurban Mazen, Abbas Ossama
Dermatology Department, American University of Beirut Medical Center, Lebanon.
Sarcoidosis Vasc Diffuse Lung Dis. 2018;35(1):55-61. doi: 10.36141/svdld.v35i1.5793. Epub 2018 Apr 28.
While absent from normal skin, plasmacytoid dendritic cells (pDCs) infiltrate the skin in several infectious, inflammatory, and neoplastic entities. In addition to providing anti-viral resistance, pDCs link the innate and adaptive immune responses. Sarcoidosis is an idiopathic multi-system granulomatous disease characterized by epitheliod granulomas. Its underlying immunopathogenesis involves hyperactivity of cell-mediated immune system with involvement of CD4+ T-helper cells of the Th1 subtype. Recently, pDCs have been shown to contribute to other cutaneous granulomatous disorders such as granuloma annulare (GA). Here, we intend to investigate pDC occurrence and activity in cutaneous sarcoidosis. Twenty cutaneous sarcoidosis cases and a comparable group of 20 cases of GA were retrieved from our database and were immunohistochemically tested for pDC occurrence and activity using anti-BDCA-2 and anti-MxA antibodies, respectively. Fifteen cases of cutaneous lupus erythrematosus (LE) were used as a comparison group. A semi-quantitative scoring system was used. pDCs were present in all cutaneous sarcoidosis in peri-vascular and/or peri-adnexal location admixed with lymphocytes. pDC numbers in sarcoidosis were comparable to those in GA, while pDCs were significantly more abundant in LE. MxA expression was mostly patchy in cutaneous sarcoidosis and GA cases, while LE cases showed diffuse and strong MxA expression. In conclusion, we have shown that pDCs are recruited into the skin lesions of sarcoidosis and GA. Despite the diminished type I IFN production demonstrated in our study, the consistent presence of pDCs in all cutaneous sarcoidosis cases speaks in favor of some role of these cells in the pathogenesis of granulomatous disorders. .
浆细胞样树突状细胞（pDCs）在正常皮肤中不存在，但在多种感染性、炎症性和肿瘤性疾病中会浸润皮肤。除了提供抗病毒抵抗力外，pDCs还连接先天性和适应性免疫反应。结节病是一种特发性多系统肉芽肿性疾病，其特征为上皮样肉芽肿。其潜在的免疫发病机制涉及细胞介导的免疫系统亢进，Th1亚型的CD4 +辅助性T细胞参与其中。最近，pDCs已被证明与其他皮肤肉芽肿性疾病有关，如环状肉芽肿（GA）。在此，我们旨在研究皮肤结节病中pDCs的出现情况和活性。从我们的数据库中检索出20例皮肤结节病病例和一组与之相当的20例GA病例，并分别使用抗BDCA-2和抗MxA抗体对pDCs的出现情况和活性进行免疫组织化学检测。15例皮肤红斑狼疮（LE）病例用作对照组。使用半定量评分系统。pDCs存在于所有皮肤结节病的血管周围和/或附件周围位置，与淋巴细胞混合。结节病中的pDC数量与GA中的相当，而LE中的pDCs明显更多。MxA表达在皮肤结节病和GA病例中大多呈斑片状，而LE病例则表现为弥漫性和强MxA表达。总之，我们已经表明pDCs被募集到结节病和GA的皮肤病变中。尽管我们的研究显示I型干扰素产生减少，但所有皮肤结节病病例中pDCs的持续存在表明这些细胞在肉芽肿性疾病的发病机制中发挥了某种作用。
