Diffuse gliomas are aggressive brain tumors that respond poorly to immunotherapy including immune checkpoint inhibition. This resistance may arise from an immunocompromised microenvironment and deficient immune recognition of tumor cells because of low mutational burden. The most prominent genetic alterations in diffuse glioma are mutations in the isocitrate dehydrogenase (IDH) genes that generate the immunosuppressive oncometabolite d-2-hydroxyglutarate. Our objective was to explore the association between IDH mutation and presence of cells expressing the immune checkpoint proteins galectin-9 and/or T cell immunoglobulin and mucin-domain containing-3 (TIM-3). Astrocytic gliomas of World Health Organization (WHO) grades III or IV (36 IDH-mutant and 36 IDH-wild-type) from 72 patients were included in this study. A novel multiplex chromogenic immunohistochemistry panel was applied using antibodies against galectin-9, TIM-3, and the oligodendrocyte transcription factor 2 (OLIG2). Validation studies were performed using data from The Cancer Genome Atlas (TCGA) project. IDH mutation was associated with decreased levels of TIM-3⁺ cells (p < 0.05). No significant association was found between galectin-9 and IDH status (p = 0.10). Most TIM-3⁺ and galectin-9⁺ cells resembled microglia/macrophages, and very few TIM-3⁺ and/or galectin-9⁺ cells co-expressed OLIG2. The percentage of TIM-3⁺ T cells was generally low, however, IDH-mutant tumors contained significantly fewer TIM-3⁺ T cells (p < 0.01) and had a lower interaction rate between TIM-3⁺ T cells and galectin-9⁺ microglia/macrophages (p < 0.05). TCGA data confirmed lower TIM-3 mRNA expression in IDH-mutant compared to IDH-wild-type astrocytic gliomas (p = 0.013). Our results show that IDH mutation is associated with diminished levels of TIM-3⁺ cells and fewer interactions between TIM-3⁺ T cells and galectin-9⁺ microglia/macrophages, suggesting reduced activity of the galectin-9/TIM-3 immune checkpoint pathway in IDH-mutant astrocytic gliomas.

中文翻译：

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WHO III 级和 IV 级星形胶质细胞瘤中 TIM-3 阳性细胞的存在与异柠檬酸脱氢酶突变状态相关

弥漫性神经胶质瘤是侵袭性脑肿瘤，对免疫治疗（包括免疫检查点抑制）反应不佳。这种抗性可能源于免疫功能低下的微环境和由于低突变负担而对肿瘤细胞的免疫识别缺陷。弥漫性神经胶质瘤最显着的遗传改变是异柠檬酸脱氢酶 (IDH) 基因的突变，这些基因产生免疫抑制性癌代谢物d-2-羟基戊二酸。我们的目标是探索 IDH 突变与表达免疫检查点蛋白 galectin-9 和/或 T 细胞免疫球蛋白和含有粘蛋白结构域 3 (TIM-3) 的细胞之间的关联。本研究纳入了来自 72 名患者的世界卫生组织 (WHO) III 级或 IV 级星形胶质细胞瘤（36 例 IDH 突变型和 36 例 IDH 野生型）。使用针对 galectin-9、TIM-3 和少突胶质细胞转录因子 2 (OLIG2) 的抗体应用了一种新型的多重显色免疫组织化学组。使用来自癌症基因组图谱 (TCGA) 项目的数据进行验证研究。IDH 突变与 TIM-3 ⁺细胞水平降低有关 ( p  < 0.05)。半乳糖凝集素9与IDH状态之间没有发现显着关联（p  = 0.10)。大多数 TIM-3 ⁺和 galectin-9 ⁺细胞类似于小胶质细胞/巨噬细胞，而很少有 TIM-3 ⁺和/或 galectin-9 ⁺细胞共表达 OLIG2。^{TIM-3 +} T 细胞的百分比普遍较低，但 IDH 突变肿瘤中 TIM-3 ⁺ T 细胞的含量显着减少（p < 0.01），并且 TIM-3 ⁺ T 细胞与半乳凝素 9 的相互作用率较低⁺小胶质细胞/巨噬细胞 ( p  < 0.05)。TCGA 数据证实IDH 突变体中TIM-3 mRNA 表达低于 IDH 野生型星形细胞胶质瘤（p = 0.013)。我们的研究结果表明，IDH 突变与 TIM-3 + 细胞水平降低以及^{TIM-3 + T}细胞与 galectin-9 ⁺小胶质细胞/巨噬细胞之间的相互作用减少有关，这表明 galectin-9/TIM-3 免疫检查点的活性降低IDH突变型星形细胞胶质瘤的通路。