The etiology of polyarteritis nodosa (PAN) and localized PAN, including cutaneous arteritis (CA), remains unknown; however, initial endothelial damage has been implicated. The intima of the vasculitis lesions is predominantly infiltrated by innate-like bystander-activated CD8 T cells, in addition to the macrophages. Macrophages are among the major inflammatory cells involved in innate immunity and are classified into M1 and M2 subtypes. M1-type macrophages kill pathogens and cause inflammation, while M2-type macrophages promote the repair of tissues. Macrophage subtypes infiltrating in PAN and localized PAN vasculitis lesions have not yet been investigated. Innate immune response to a triggering factor on the endothelial cell surface may initiate CA pathogenesis. Thus, many M1-type macrophages may infiltrate in the intima during early CA. We assessed this hypothesis by immunohistochemical observation of macrophage phenotypes and polarization. Twenty-seven skin biopsy specimens from patients with CA were retrieved. Based on histology, we classified CA into four phases. The phenotypes of infiltrating macrophages in CA were evaluated by immunohistochemistry using antibodies against Iba-1, a pan-macrophage marker, and CD163, an M2-type macrophage marker. Our results showed that the ratio of CD163-positive M2-type macrophages to Iba1-positive macrophages was lower in the intima in the early stage of CA than in the later stage. In the media to adventitia, there was no significant difference in the ratios between these stages. These findings indicate that innate immunity is involved in the intima in the early stage of CA, suggesting that a trigger for CA might exist in endothelial cells.

结节性多动脉炎 (PAN) 和局部 PAN，包括皮肤动脉炎 (CA) 的病因仍然未知；然而，最初的内皮损伤已被牵连。除了巨噬细胞外，血管炎病变的内膜主要被先天样旁观者激活的 CD8 T 细胞浸润。巨噬细胞是参与先天免疫的主要炎症细胞之一，分为 M1 和 M2 亚型。M1型巨噬细胞杀死病原体并引起炎症，而M2型巨噬细胞促进组织修复。尚未研究浸润 PAN 和局部 PAN 血管炎病变的巨噬细胞亚型。对内皮细胞表面触发因子的先天免疫反应可能启动 CA 发病机制。因此，在早期 CA 期间，许多 M1 型巨噬细胞可能会渗入内膜。我们通过巨噬细胞表型和极化的免疫组织化学观察评估了这一假设。检索了来自 CA 患者的 27 个皮肤活检标本。基于组织学，我们将 CA 分为四个阶段。使用针对 Iba-1（一种泛巨噬细胞标记物）和 CD163（一种 M2 型巨噬细胞标记物）的抗体，通过免疫组织化学评估 CA 中浸润性巨噬细胞的表型。我们的结果表明，CA早期内膜CD163阳性M2型巨噬细胞与Iba1阳性巨噬细胞的比例低于CA后期。在介质到外膜中，这些阶段之间的比率没有显着差异。这些发现表明先天免疫参与了 CA 早期的内膜，表明 CA 的触发因素可能存在于内皮细胞中。