脓肿分枝杆菌性角膜炎的病理学研究

目的 探讨脓肿分枝杆菌性角膜炎(MAK)的细胞病理学、组织病理学、免疫组织化学及超微结构改变.方法 回顾性系列病例分析.刮取6例角膜异物剔除术后急性期MAK的病灶组织,其中4例作涂片Ziehl-Neelsen抗酸染色,3例作透射电镜(TEM)检查.另取2例角膜移植术中获得的慢性期MAK的角膜组织作病理学检查包括苏木精-伊红(HE)染色、抗酸染色、免疫组织化学染色及TEM检查.结果 4例角膜刮片组织涂片抗酸染色后均见单个或聚集成束状、团块状红色分枝杆菌;还可见大量中性白细胞及坏死的角膜上皮和基质组织,炎性细胞内外散在大量抗酸染色阳性分枝杆菌.2例角膜移植术者病变角膜HE染色可见角膜上皮局限性增生,基质变性、坏死、溃疡形成,病灶中可见中性白细胞和淋巴细胞浸润,并可见新生血管形成与纤维瘢痕组织增生;Ziehl-Neelsen抗酸染色未见明显阳性分枝杆菌;免疫组织化学检查均未见CD4+、CD8+细胞.3例角膜刮片组织电镜下可见形态多样的脓肿分枝杆菌,并可被单核巨噬细胞或中性白细胞吞噬,菌体中可见小空泡、异染颗粒等多种包含物;2例角膜移植术中获得的角膜板层组织电镜下见脓肿分枝杆菌形态多为细长杆状,细胞壁缺失(L型杆菌),内含物结构不清甚至消失,可见数个至几十个高电子密度的小颗粒散在于菌体内外.结论 脓肿分枝杆菌引起的角膜炎早期呈急性化脓性炎症反应改变,晚期呈非特异性慢性炎症反应改变,分枝杆菌多转变为L型,导致炎症反应长期迁延不愈.

Pathological study of mycobacterium abscessus keratitis

Objective To characterize the cytopathology, histopathology, immunohistochemistry and ultrastructural organization features of Mycobacterium abscessus keratitis. Methods This retrospective case report included six cases with the lesions tissues scraped from acute phase of mycobacterium abscessus keratitis after corneal foreign body removal Among the 6 scrapings, 4 were tested for Ziehl-Neelsen acid-fast staining and 3 were examined by transmission electron microscopy (TEM). The corneal tissues of 2 cases in chronic phase of the disease were collected during keratoplasty and were examined by pathological examination including hematoxylin-eosin (HE) staining, acid-fast staining, immunohistostaining and TEM.Results A single or fascicular red bacilli were observed after acid-fast staining in the four cases of corneal scrapings. The smear samples contained a large number of neutrophils and necrotic corneal epithelium and stroma tissue accompanying with a large number of mycobacteria that were positive for acid-fast staining scattered in and out of inflammatory cells. The corneal buttons obtained at keratoplasty in the 2 patientsdemonstrated corneal epithelial hyperplasia, stroma degeneration, necrosis and elcosis, neutrophil and lymphocyte infiltration, neovascularization and fibrous hyperplasia, but no positive mycobacteria by ZiehlNeelsen acid-fast staining. There were no CD4+ or CD8+ cells from immunohistochemistry examination.TEM of the corneal scrapings of the 3 cases showed phagocytosis of mycobacterium abscessus in mononuclear macrophage or neutrophils, inclusion compounds of small vacuoles and metachromatic granules in the thalline. TEM of corneal buttons of 2 cases showed slender rod-shaped mycobacteria with several to dozens of finely ground particles with high electron-dense, but no cell wall (L-form) or inclusion compounds.Conclusions Mycobacterium abscessus keratitis presents acute purulent inflammatory changes in early stage and advances to chronic and non-specificity inflammation changes in late stage. L-formed mycobacterium abscessus make the disease protraction.