Single-cell profiling of blood and cerebrospinal fluid in tuberculous meningitis

Tuberculous meningitis (TBM) is the most severe form of tuberculosis, with a fatality rate of 20-50% in treated individuals. Although corticosteroid therapy can increase survival in HIV-negative people with TBM, better antimicrobial and host-directed therapies are required to improve outcome. There is, therefore, a need to better understand local immunopathologic pathways. Despite its power in identifying disease-specific cellular profiles, single-cell RNA-sequencing (scRNA-seq) has been underutilized in cerebral samples in brain infection. We employed scRNA-seq to analyze fresh pretreatment cerebrospinal fluid (CSF) from four TBM patients, along with paired peripheral blood mononuclear cells (PBMCs). While 29 cell subtypes were present in both tissues, their relative abundance varied significantly. In particular, CSF was enriched with highly inflammatory microglia-like macrophages, GZMK+-expressing CD8+ T cells, and CD56bright NK cells. The latter two subsets exhibited features associated with dysfunctional cytotoxicity. Across multiple cell types, inflammatory signaling pathways were increased and oxidative phosphorylation was decreased in CSF compared to PBMCs. This study highlights the value of scRNA-seq for exploring CSF immunopathogenesis in TBM patients and offers a resource for future studies investigating the pathophysiology of TBM and other brain infections, including potentially targetable cell populations linked with immune-mediated pathology. To analyze the cell composition and transcriptional landscape of PBMCs and CSF in TBM, we performed scRNA-seq on fresh paired pretreatment samples from four Tuberculosis meningitis patients.

结核性脑膜炎（Tuberculous meningitis, TBM）是结核病最严重的临床类型，接受治疗的患者病死率仍达20%~50%。尽管糖皮质激素治疗可提高HIV阴性TBM患者的生存率，但仍需开发更有效的抗菌疗法与宿主导向疗法以改善患者预后。因此，亟需深入解析其局部免疫病理通路。单细胞RNA测序（single-cell RNA-sequencing, scRNA-seq）虽可有效识别疾病特异性细胞谱，但在脑感染的脑组织样本中应用仍相对不足。本研究利用scRNA-seq分析了4例TBM患者治疗前采集的新鲜脑脊液（cerebrospinal fluid, CSF）样本，以及配对的外周血单个核细胞（peripheral blood mononuclear cells, PBMCs）。尽管两种组织中共存在29种细胞亚型，但其相对丰度存在显著差异。其中，脑脊液中富集了高度炎症活化的小胶质细胞样巨噬细胞、表达GZMK+的CD8+ T细胞以及CD56bright自然杀伤细胞（NK细胞）；后两类细胞亚群呈现出细胞毒性功能失调的特征。相较于配对的PBMCs，脑脊液中多种细胞类型的炎症信号通路显著上调，而氧化磷酸化通路则受到抑制。本研究证实了scRNA-seq在解析TBM患者脑脊液免疫发病机制中的应用价值，可为未来探究TBM及其他脑感染的病理生理机制提供宝贵资源，包括潜在的与免疫介导病理损伤相关的可靶向细胞群。为解析TBM患者PBMC与CSF的细胞组成及转录图谱，本研究对4例TBM患者治疗前采集的新鲜配对样本开展了scRNA-seq检测。