Multiple sclerosis is a chronic inflammatory, demyelinating disease, although it has been suggested that in the progressive late phase, inflammatory lesion activity declines. We recently showed in the Netherlands Brain Bank multiple sclerosis-autopsy cohort considerable ongoing inflammatory lesion activity also at the end stage of the disease, based on microglia/macrophage activity. We have now studied the role of T cells in this ongoing inflammatory lesion activity in chronic multiple sclerosis autopsy cases. We quantified T cells and perivascular T-cell cuffing at a standardized location in the medulla oblongata in 146 multiple sclerosis, 20 neurodegenerative control and 20 non-neurological control brain donors. In addition, we quantified CD3⁺, CD4⁺, and CD8⁺ T cells in 140 subcortical white matter lesions. The location of CD8⁺ T cells in either the perivascular space or the brain parenchyma was determined using CD8/laminin staining and confocal imaging. Finally, we analysed CD8⁺ T cells, isolated from fresh autopsy tissues from subcortical multiple sclerosis white matter lesions (n = 8), multiple sclerosis normal-appearing white matter (n = 7), and control white matter (n = 10), by flow cytometry. In normal-appearing white matter, the number of T cells was increased compared to control white matter. In active and mixed active/inactive lesions, the number of T cells was further augmented compared to normal-appearing white matter. Active and mixed active/inactive lesions were enriched for both CD4⁺ and CD8⁺ T cells, the latter being more abundant in all lesion types. Perivascular clustering of T cells in the medulla oblongata was only found in cases with a progressive disease course and correlated with a higher percentage of mixed active/inactive lesions and a higher lesion load compared to cases without perivascular clusters in the medulla oblongata. In all white matter samples, CD8⁺ T cells were located mostly in the perivascular space, whereas in mixed active/inactive lesions, 16.3% of the CD8⁺ T cells were encountered in the brain parenchyma. CD8⁺ T cells from mixed active/inactive lesions showed a tissue-resident memory phenotype with expression of CD69, CD103, CD44, CD49a, and PD-1 and absence of S1P1. They upregulated markers for homing (CXCR6), reactivation (Ki-67), and cytotoxicity (GPR56), yet lacked the cytolytic enzyme granzyme B. These data show that in chronic progressive multiple sclerosis cases, inflammatory lesion activity and demyelinated lesion load is associated with an increased number of T cells clustering in the perivascular space. Inflammatory active multiple sclerosis lesions are populated by CD8⁺ tissue-resident memory T cells, which show signs of reactivation and infiltration of the brain parenchyma.

中文翻译：

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组织驻留性记忆T细胞在多发性硬化症白质病变中侵入脑实质。

多发性硬化症是一种慢性炎性，脱髓鞘性疾病，尽管有人提出在进行性晚期阶段，炎性病变活性会下降。我们最近在荷兰脑库显示，基于小胶质细胞/巨噬细胞活性，多发性硬化-尸检队列在疾病的末期也有相当大的进行性炎性病变活动。现在，我们已经研究了T细胞在慢性多发性硬化症尸检病例中这种持续的炎性病变活动中的作用。我们在146个多发性硬化症，20个神经退行性对照和20个非神经性对照脑供体中的延髓延髓的标准化位置量化了T细胞和血管周围T细胞的套扎。此外，我们量化了CD3 ⁺，CD4 ⁺和CD8 ⁺140个皮质下白质病变中的T细胞。使用CD8 / laminin染色和共聚焦成像确定CD8 ⁺ T细胞在血管周围空间或脑实质中的位置。最后，我们分析了CD8 ⁺ T细胞，这些细胞是从皮层下多发性硬化症白质病变（n =  8），多发性硬化正常出现的白质（n =  7）和对照白质（n = 10），通过流式细胞仪。在正常出现的白质中，与对照白质相比，T细胞的数量增加了。在活动性和混合性活动/非活动性病变中，与正常出现的白质相比，T细胞的数量进一步增加。活动性和混合性活动/非活动性病变均富含CD4 ⁺和CD8 ⁺ T细胞，后者在所有病变类型中均更为丰富。与没有延髓的周围血管簇的病例相比，仅在进行性疾病病程的病例中发现了延髓的T细胞的血管周围簇，并且与活动/不活动的混合病灶和更高的病灶负荷相关。在所有白质样品中，CD8 ⁺T细胞主要位于血管周围空间，而在混合的活动/非活动性病变中，脑实质中遇到了16.3％的CD8 ⁺ T细胞。来自混合的活动/非活动性病变的CD8 ⁺ T细胞表现出具有CD69，CD103，CD44，CD49a和PD-1表达且不存在S1P1的组织驻留记忆表型。他们上调了归巢（CXCR6），再激活（Ki-67）和细胞毒性（GPR56）的标志物，但缺乏溶细胞酶颗粒酶B。这些数据表明，在慢性进行性多发性硬化症病例中，炎性病变活动和脱髓鞘病变负荷相关在血管周围空间聚集的T细胞数量增加。炎性活动性多发性硬化症病变由CD8 ^+组成 组织驻留记忆T细胞，显示出脑实质的重新激活和浸润迹象。