Recently, we were intrigued by a recent study by Fong and colleagues,1 in which they found that Lactobacillus gallinarum could reduce regulatory T-cell (Treg) infiltration and enhance CD8+ T-cell effector function, thus improving anti-PD1 efficacy in patients with colorectal cancer, which was confirmed in mouse models. Interestingly, Lactobacillus was observed to be related to smoke exposure, with decreased Lactobacillus in smoke-exposed mice.2 However, the relationships between cigarette smoking, human gut microbiota and infiltration of colorectal cancer immune cells have not been determined in humans. Therefore, by leveraging large population studies, we sought to evaluate the relationship between smoking, Lactobacillus and colorectal cancer immune cell infiltration using Mendelian randomisation methods (online supplemental materials).### Supplementary data [gutjnl-2023-331865supp001.pdf] In this study, we first evaluated the association between smoking and Lactobacillus abundance. Although we did not observe a significant association between some smoking phenotypes (eg, Agesmk, CigDay, SmkInit and SmkIndex) and Lactobacillus , compared with former smoking, genetically predicted current smoking was borderline significantly associated with a depleted Lactobacillus ( β (inverse-variance weighted (IVW))=−0.485, P =3.2×10−2; table 1), consistent with previous findings.2 Furthermore, as …

中文翻译：

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结直肠癌中与吸烟相关的乳酸菌和免疫细胞浸润：基于人群的研究的证据

最近，我们对 Fong 及其同事最近的一项研究很感兴趣，1 他们发现鸡乳杆菌可以减少调节性 T 细胞 (Treg) 浸润并增强 CD8+ T 细胞效应功能，从而提高 PD1 患者的抗 PD1 疗效。结直肠癌，这一点在小鼠模型中得到证实。有趣的是，据观察，乳酸菌与烟雾暴露有关，暴露于烟雾的小鼠中乳酸菌含量减少。2 然而，吸烟、人类肠道微生物群和结直肠癌免疫细胞浸润之间的关系尚未在人类中确定。因此，通过利用大量人群研究，我们试图使用孟德尔随机化方法（在线补充材料）评估吸烟、乳酸菌和结直肠癌免疫细胞浸润之间的关系。###补充数据[gutjnl-2023-331865supp001.pdf]研究中，我们首先评估了吸烟与乳酸菌丰度之间的关联。尽管我们没有观察到一些吸烟表型（例如，Agesmk、CigDay、SmkInit 和 SmkIndex）与乳酸菌之间存在显着关联，但与以前吸烟相比，基因预测当前吸烟与乳酸菌消耗（β（逆方差加权）呈显着相关性。 (IVW))=−0.485，P =3.2×10−2；表 1)，与之前的研究结果一致。2此外，...