Tumors are sustained by complex networks of interactions between malignant cells, stromal cells and tumor-infiltrating immune cells. These networks differ from patient to patient in terms of nature, ...composition and organization as well as with regard to the precise localization of tumor-infiltrating cells. Of note, the heterogeneity of the immunological component of the tumor microenvironment, as opposed to its mere abundance, has been shown to influence disease outcome. However, a key question remains: where does the activation of tumor-specific T cells take place? The recently described, tumor-associated lymph node-like entities termed "tertiary lymphoid structures" exhibit a structural organization that is reminiscent of secondary lymphoid organs, and thus may imprint the local immune contexture. Here, we discuss how cancer-associated tertiary lymphoid structures impact on the tumor micro-architecture, immune microenvironment, and ultimately, patient survival.
Highlights • Tertiary lymphoid structures (TLS) are common at sites of chronic inflammation. • TLS shape local adaptive immune responses in inflamed and tumoral tissues. • TLS represent prognostic ...biomarkers and therapeutic targets in cancer.
De novo formation of tertiary lymphoid structures (TLS) has been described in lung cancers. Intratumoral TLS seem to be functional and are associated with a long-term survival for lung cancer ...patients, suggesting that they represent an activation site for tumor-specific T cells. Here, we characterized T-cell recruitment to TLS in human lung cancer to identify the adhesion molecules and chemoattractants orchestrating this migration. We found that most TLS T cells were CD62L+ and mainly of CD4+ memory phenotype, but naive T cells were highly enriched in these structures as compared with the rest of the tumor. A specific gene expression signature associated with T cell presence was identified in TLS, which included chemokines (CCL19, CCL21, CXCL13, CCL17, CCL22, and IL16), adhesion molecules (ICAM-2, ICAM-3, VCAM-1, and MAdCAM-1) and integrins (alphaL, alpha4, and alphaD). The presence of the corresponding receptors on TLS T cells was confirmed. Intratumoral PNAd+ high endothelial venules also were exclusively associated with TLS and colocalized with CD62L+ lymphocytes. Together, these data bring new insights into the T-cell recruitment to intratumoral TLS and suggest that blood T cell enter into TLS via high endothelial venules, which represent a new gateway for T cells to the tumor. Findings identify the molecules that mediate migration of tumor-specific T cells into TLS where T cell priming occurs, suggesting new strategies to enhance the efficacy of cancer immunotherapies.
It is now well established that immune responses can take place outside of primary and secondary lymphoid organs. We previously described the presence of tertiary lymphoid structures (TLS) in ...patients with non-small cell lung cancer (NSCLC) characterized by clusters of mature dendritic cells (DCs) and T cells surrounded by B-cell follicles. We demonstrated that the density of these mature DCs was associated with favorable clinical outcome.
To study the role of follicular B cells in TLS and the potential link with a local humoral immune response in patients with NSCLC.
The cellular composition of TLS was investigated by immunohistochemistry. Characterization of B-cell subsets was performed by flow cytometry. A retrospective study was conducted in two independent cohorts of patients. Antibody specificity was analyzed by ELISA.
Consistent with TLS organization, all stages of B-cell differentiation were detectable in most tumors. Germinal center somatic hypermutation and class switch recombination machineries were activated, associated with the generation of plasma cells. Approximately half of the patients showed antibody reactivity against up to 7 out of the 33 tumor antigens tested. A high density of follicular B cells correlated with long-term survival, both in patients with early-stage NSCLC and with advanced-stage NSCLC treated with chemotherapy. The combination of follicular B cell and mature DC densities allowed the identification of patients with the best clinical outcome.
B-cell density represents a new prognostic biomarker for NSCLC patient survival, and makes the link between TLS and a protective B cell-mediated immunity.
Tumor-infiltrating T cells, particularly CD45RO(+)CD8(+) memory T cells, confer a positive prognostic value in human cancers. However, the mechanisms that promote a protective T-cell response in the ...tumor microenvironment remain unclear. In chronic inflammatory settings such as the tumor microenvironment, lymphoid neogenesis can occur to create local lymph node-like structures known as tertiary lymphoid structures (TLS). These structures can exacerbate a local immune response, such that TLS formation in tumors may help promote an efficacious immune contexture. However, the role of TLS in tumors has yet to be investigated carefully. In lung tumors, mature dendritic cells (DC) present in tumor-associated TLS can provide a specific marker of these structures. In this study, we evaluated the influence of TLS on the characteristics of the immune infiltrate in cohorts of prospective and retrospective human primary lung tumors (n = 458). We found that a high density of mature DC correlated closely to a strong infiltration of T cells that are predominantly of the effector-memory phenotype. Moreover, mature DC density correlated with expression of genes related to T-cell activation, T-helper 1 (Th1) phenotype, and cytotoxic orientation. Lastly, a high density of TLS-associated DC correlated with long-term survival, which also allowed a distinction of patients with high CD8(+) T-cell infiltration but a high risk of death. Taken together, our results show how tumors infiltrated by TLS-associated mature DC generate a specific immune contexture characterized by a strong Th1 and cytotoxic orientation that confers the lowest risk of death. Furthermore, our findings highlight the pivotal function of TLS in shaping the immune character of the tumor microenvironment, in promoting a protective immune response mediated by T cells against cancer.
Hypothesizing that nutritional status, systemic inflammation and tumoral immune microenvironment play a role as determinants of lung cancer evolution, the purpose of this study was to assess their ...respective impact on long-term survival in resected non-small cell lung cancers (NSCLC).
Clinical, pathological and laboratory data of 303 patients surgically treated for NSCLC were retrospectively analyzed. C-reactive protein (CRP) and prealbumin levels were recorded, and tumoral infiltration by CD8+ lymphocytes and mature dendritic cells was assessed. We observed that factors related to nutritional status, systemic inflammation and tumoral immune microenvironment were correlated; significant correlations were also found between these factors and other relevant clinical-pathological parameters. With respect to outcome, at univariate analysis we found statistically significant associations between survival and the following variables: Karnofsky index, American Society of Anesthesiologists (ASA) class, CRP levels, prealbumin concentrations, extent of resection, pathologic stage, pT and pN parameters, presence of vascular emboli, and tumoral infiltration by either CD8+ lymphocytes or mature dendritic cells and, among adenocarcinoma type, tumor grade (all p<0.05). In multivariate analysis, prealbumin levels (Relative Risk (RR): 0.34 0.16-0.73, p = 0.0056), CD8+ cell count in tumor tissue (RR = 0.37 0.16-0.83, p = 0.0162), and disease stage (RR 1.73 1.03-2.89; 2.991.07-8.37, p = 0.0374- stage I vs II vs III-IV) were independent prognostic markers. When taken together, parameters related to systemic inflammation, nutrition and tumoral immune microenvironment allowed robust prognostic discrimination; indeed patients with undetectable CRP, high (>285 mg/L) prealbumin levels and high (>96/mm2) CD8+ cell count had a 5-year survival rate of 80% 60.9-91.1 as compared to 18% 7.9-35.6 in patients with an opposite pattern of values. When stages I-II were considered alone, the prognostic significance of these factors was even more pronounced.
Our data show that nutrition, systemic inflammation and tumoral immune contexture are prognostic determinants that, taken together, may predict outcome.
Group 3 innate lymphoid cells (ILC3s) regulate immunity and inflammation, yet their role in cancer remains elusive. Here, we identify that colorectal cancer (CRC) manifests with altered ILC3s that ...are characterized by reduced frequencies, increased plasticity, and an imbalance with T cells. We evaluated the consequences of these changes in mice and determined that a dialog between ILC3s and T cells via major histocompatibility complex class II (MHCII) is necessary to support colonization with microbiota that subsequently induce type-1 immunity in the intestine and tumor microenvironment. As a result, mice lacking ILC3-specific MHCII develop invasive CRC and resistance to anti-PD-1 immunotherapy. Finally, humans with dysregulated intestinal ILC3s harbor microbiota that fail to induce type-1 immunity and immunotherapy responsiveness when transferred to mice. Collectively, these data define a protective role for ILC3s in cancer and indicate that their inherent disruption in CRC drives dysfunctional adaptive immunity, tumor progression, and immunotherapy resistance.
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•Profiling of human and mouse CRC reveals a substantial dysregulation of ILC3s•ILC3 and T cell interactions support microbiota that drives type-1 immunity•ILC3 impairment drives CRC progression and immunotherapy resistance in mice•Humans with altered ILC3s harbor microbiota that causes immunotherapy resistance
ILC3s are altered in the tumor microenvironment of humans with colorectal cancer, resembling those found in the inflamed intestine. In mice, ILC3s regulate adaptive immunity, shape the microbiota composition, and protect from tumor progression as well as colorectal cancer immunotherapy resistance.
Tertiary lymphoid structures (TLS) are de novo lymphoid formations that are induced within tissues during inflammatory episodes. TLS have been reported at various anatomic sites and in many different ...contexts like cancer, infections, autoimmunity, graft rejection, and idiopathic diseases. These inducible, ectopic, and transient lymphoid structures exhibit the prototypical architecture found within secondary lymphoid organs (SLO) and have been recently appreciated as a major driver of the local adaptive immune reaction. As TLS emerge within tissues, the isolation in situ and the molecular characterization of these structures are challenging to operate. Laser capture microdissection (LCM) is a powerful tool to isolate selective structural components and cells from frozen or paraffin-embedded tissues. We and other groups previously applied LCM to decipher the molecular network within TLS and uncover their intrinsic connection with the local microenvironment. In this chapter, we describe a detailed LCM method for selecting and isolating TLS in situ to perform comprehensive downstream molecular analyses.
The presence of tertiary lymphoid structures (TLS) in the tumor microenvironment is associated with better clinical outcome in many cancers. In non-small cell lung cancer (NSCLC), we have previously ...showed that a high density of B cells within TLS (TLS-B cells) is positively correlated with tumor antigen-specific antibody responses and increased intratumor CD4
T cell clonality. Here, we investigated the relationship between the presence of TLS-B cells and CD4
T cell profile in NSCLC patients. The expression of immune-related genes and proteins on B cells and CD4
T cells was analyzed according to their relationship to TLS-B density in a prospective cohort of 56 NSCLC patients. We observed that tumor-infiltrating T cells showed marked differences according to TLS-B cell presence, with higher percentages of naïve, central-memory, and activated CD4
T cells and lower percentages of both immune checkpoint (ICP)-expressing CD4
T cells and regulatory T cells (Tregs) in the TLS-B
tumors. A retrospective study of 538 untreated NSCLC patients showed that high TLS-B cell density was even able to counterbalance the deleterious impact of high Treg density on patient survival, and that TLS-B
Treg
patients had the best clinical outcomes. Overall, the correlation between the density of TLS-B
tumors with early differentiated, activated and non-regulatory CD4
T cell cells suggest that B cells may play a central role in determining protective T cell responses in NSCLC patients.
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