Scollard D M, McCormick G, Allen J L
Department of Research Pathology, G. W. L. Hansen's Disease Center at Louisiana State University, Baton Rouge, LA, USA.
Am J Pathol. 1999 May;154(5):1611-20. doi: 10.1016/S0002-9440(10)65414-4.
Infection of peripheral nerve by Mycobacterium leprae, the histopathological hallmark of leprosy, is a major factor in this disease, but the route and mechanisms by which bacilli localize to peripheral nerve are unknown. Experimentally infected armadillos have recently been recognized as a model of lepromatous neuritis; the major site of early accumulation of M. leprae is epineurial. To determine the epineurial cells involved, 1-cm segments of 44 nerves from armadillos were screened for acid-fast bacilli and thin sections were examined ultrastructurally. Of 596 blocks containing nerve, 36% contained acid-fast bacilli. Overall, M. leprae were found in endothelial cells in 40% of epineurial blood vessels and 75% of lymphatics, and in 25% of vessels intraneurally. Comparison of epineurial and endoneurial findings suggested that colonization of epineurial vessels preceded endoneurial infection. Such colonization of epineurial nutrient vessels may greatly increase the risk of endoneurial M. leprae bacteremia, and also enhance the risk of ischemia following even mild increases in inflammation or mechanical stress. These findings also raise the possibility that early, specific mechanisms in the localization of M. leprae to peripheral nerve may involve adhesion events between M. leprae (or M. leprae-parasitized macrophages) and the endothelial cells of the vasa nervorum.
麻风分枝杆菌感染周围神经是麻风病的组织病理学标志，也是导致这种疾病的主要因素，但杆菌定位于周围神经的途径和机制尚不清楚。实验感染的犰狳最近被认为是瘤型神经炎的模型；麻风分枝杆菌早期聚集的主要部位是神经外膜。为了确定涉及的神经外膜细胞，对来自犰狳的44条神经的1厘米节段进行抗酸杆菌筛查，并对薄切片进行超微结构检查。在596个含有神经的组织块中，36%含有抗酸杆菌。总体而言，在40%的神经外膜血管和75%的淋巴管的内皮细胞中发现了麻风分枝杆菌，在神经内的25%的血管中也发现了麻风分枝杆菌。神经外膜和神经内膜结果的比较表明，神经外膜血管的定植先于神经内膜感染。神经外膜营养血管的这种定植可能会大大增加神经内膜麻风分枝杆菌菌血症的风险，并且即使在炎症或机械应激轻度增加后也会增加缺血的风险。这些发现还提出了一种可能性，即麻风分枝杆菌定位于周围神经的早期特定机制可能涉及麻风分枝杆菌（或麻风分枝杆菌寄生的巨噬细胞）与神经血管内皮细胞之间的黏附事件。
