Reciprocal interaction of cutaneous T-cell lymphoma cells, the reactive infiltrate, and the lesional microbiome

蕈样肉芽肿（MF）是皮肤T细胞淋巴瘤（CTCL）的最常见形式，其特征在于恶性T细胞在慢性炎症环境中的增殖。虽然MF通常表现为惰性病程，但一部分患者表现为侵袭性病程，伴有早期肿瘤发展、全身受累和高疾病特异性死亡率。目前，还不知道是什么区分惰性和侵略性MF形式。鉴于疾病的遗传同质性，讨论了外在因素，例如，皮肤微生物组的组成。事实上，我们最近已经表明，皮肤微生物组的变化与上皮癌的促进有关。值得注意的是，细菌经常定植在MF病变处，并且由于受损的皮肤屏障，发生生态失调。晚期患者常死于败血症，而不是恶性肿瘤直接累及器官。另一方面，临床观察表明，细菌，特别是金黄色葡萄球菌（S。金黄色葡萄球菌），在MF进展中发挥直接作用，例如通过促进肿瘤促进微环境。我们以前的研究表明，细菌超抗原（SA）介导的CTCL细胞与反应性炎症浸润的相互作用发挥作用。此外，我们观察到S.金黄色葡萄球菌与SA反应性T细胞受体（TCR）Vβ家族的丰度相关，这一发现表明反应性浸润受到SA刺激，而不管抗原特异性如何。初步单细胞转录组学研究的结果与反应性和恶性T细胞的这种促肿瘤相互作用一致。不幸的是，小的患者群体-在罕见疾病中很典型-对微生物组数据的统计分析是一个挑战。因此，传统的计算方法和模型必须伴随着先进的专业技术，以得出可靠的结论。我们的工作假设表明，由于CTCL对肿瘤微环境的影响，特别是反应性T细胞浸润，因此病变微生物组的组成和动力学与CTCL的病程之间存在相互作用。因此，我们将仔细研究恶性细胞、反应性浸润和微生物组的相互作用。具体而言，我们将确定MF病变的综合单细胞转录组学和TCR库分析的相关性，这些MF病变包括恶性CTCL克隆、反应性T细胞浸润和额外的基质细胞，以及病变微生物组。我们将在一个更大的系列生物库福尔马林固定石蜡包埋临床注释，连续CTCL组织样本中验证我们的观察结果。在选定的情况下，我们将使用空间分辨转录组学。预期的结果将允许发现侵袭性疾病的预后标志物，并制定适当的治疗策略。

Mycosis fungoides (MF), the most common form of cutaneous T-cell lymphoma (CTCL), is characterized by the proliferation of malignant T cells in a chronic inflammatory environment. Although MF often shows an indolent disease course, a subset of patients exhibits an aggressive course with early tumor development, systemic involvement, and high disease-specific mortality. Currently, it is not known what distinguishes indolent from aggressive MF forms. Given the genetic homogeneity of the disease, extrinsic factors are discussed, e.g., the composition of the cutaneous microbiome. Indeed, we have recently shown that a shift in the cutaneous microbiome is associated with the promotion of epithelial cancers. Notably, bacteria frequently colonize MF lesions and, because of the compromised skin barrier, dysbiosis occurs. Patients with advanced disease frequently die of sepsis rather than of direct organ involvement by the malignancy. On the other hand, clinical observations suggest that bacteria, particularly Staphylococcus aureus (S. aureus), play a direct role in MF progression, e.g. by contributing to a tumor-promoting microenvironment. Our previous studies indicated that bacterial superantigen (SA)-mediated interactions of CTCL cells with the reactive inflammatory infiltrate play a role. Furthermore, we observed that the presence of S. aureus is correlated with the abundance of SA-reactive T-cell receptor (TCR) Vβ families, a finding suggesting that the reactive infiltrate is stimulated by SA, regardless of antigen specificity. The results of preliminary single-cell transcriptomic studies are in line with such tumor-promoting interactions of reactive and malignant T cells. Unfortunately, small patient cohorts – typical in rare diseases – are a challenge for statistical analysis of microbiome data. Thus, the conventional computational methods and models must be accompanied by advanced specialized techniques in order to draw reliable conclusions. Our working hypothesis suggests that there is a reciprocal interaction between the composition and the dynamics of the lesional microbiome and the course of CTCL because of its effect on the tumor microenvironment, particularly the reactive T-cell infiltrate. Thus, we will scrutinize the reciprocal action of malignant cells, the reactive infiltrate, and the microbiome. Specifically, we will determine the correlation of comprehensive single-cell transcriptomic and TCR repertoire analyses of MF lesions composing the malignant CTCL clone, the reactive T-cell infiltrate, and additional stromal cells, with the lesional microbiome. We will validate our observations in a larger series of biobanked formalin-fixed paraffin-embedded clinically annotated, sequential CTCL tissue samples. In selected cases we will use spatially resolved transcriptomics. The expected results will allow discovery of prognostic markers for aggressive disease and developing adequate therapeutic strategies.