Achim C L, Morey M K, Wiley C A
University of California, San Diego, School of Medicine, Department of Pathology, La Jolla 92093-0612.
AIDS. 1991 May;5(5):535-41. doi: 10.1097/00002030-199105000-00009.
HIV establishes a chronic infection in the central nervous system (CNS) of AIDS patients. The immunopathogenesis of this chronic encephalitis is unknown. Because of the importance of major histocompatibility (MHC) class I and class II antigens in modulating the immune response, we examined the tissue expression of MHC molecules in relation to CNS damage and expression of viral antigens. By immunocytochemical staining we found that beta 2-microglobulin (beta 2M) expression is elevated in all cases with signs of viral encephalitis. beta 2M was expressed at high levels on endothelial cells, macrophages and possible oligodendroglia within regions of histopathology. In histologically normal regions elevated expression of beta 2M was noted only on endothelial cells. MHC class II expression was elevated only in the HIV encephalitis cases, and was restricted to macrophages/microglia and occasional endothelial cells. When compared with other viral encephalitides these findings suggest that the intra-CNS immune response to HIV is appropriate for viral presentation; however, the absence of responsive systemic T cells may lead to chronic viral infection.
人类免疫缺陷病毒（HIV）在艾滋病患者的中枢神经系统（CNS）中建立慢性感染。这种慢性脑炎的免疫发病机制尚不清楚。由于主要组织相容性（MHC）I类和II类抗原在调节免疫反应中的重要性，我们研究了MHC分子的组织表达与中枢神经系统损伤及病毒抗原表达的关系。通过免疫细胞化学染色，我们发现，在所有出现病毒性脑炎迹象的病例中，β2-微球蛋白（β2M）的表达均升高。在组织病理学区域内，β2M在内皮细胞、巨噬细胞以及可能的少突胶质细胞上高水平表达。在组织学正常的区域，仅在内皮细胞上观察到β2M的表达升高。MHC II类分子的表达仅在HIV脑炎病例中升高，且仅限于巨噬细胞/小胶质细胞以及偶尔的内皮细胞。与其他病毒性脑炎相比，这些发现表明中枢神经系统内对HIV的免疫反应适合病毒呈递；然而，缺乏反应性的全身T细胞可能导致慢性病毒感染。
