Intrahepatic CD69⁺Vδ1 T cells re-circulate in the blood of patients with metastatic colorectal cancer and limit tumor progression

Abstract

BackgroundMore than 50% of all patients with colorectal cancer (CRC) develop liver metastases (CLM), a clinical condition characterized by poor prognosis and lack of reliable prognostic markers. Vδ1 cells are a subset of tissue-resident gamma delta (γδ) T lymphocytes endowed with a broad array of antitumor functions and showing a natural high tropism for the liver. However, little is known about their impact in the clinical outcomes of CLM.MethodsWe isolated human γδ T cells from peripheral blood (PB) and peritumoral (PT) tissue of 93 patients undergone surgical procedures to remove CLM. The phenotype of freshly purified γδ T cells was assessed by multiparametric flow cytometry, the transcriptional profiles by single cell RNA-sequencing, the functional annotations by Gene Ontology enrichment analyses and the clonotype by γδ T cell receptor (TCR)-sequencing.ResultsThe microenvironment of CLM is characterized by a heterogeneous immune infiltrate comprising different subsets of γδ tumor-infiltrating lymphocytes (TILs) able to egress the liver and re-circulate in PB. Vδ1 T cells represent the largest population of γδ TILs within the PT compartment of CLM that is greatly enriched in Vδ1 T effector (TEF) cells expressing constitutive high levels of CD69. These Vδ1 CD69+ TILs express a distinct phenotype and transcriptional signature, show high antitumor potential and correlate with better patient clinical outcomes in terms of lower numbers of liver metastatic lesions and longer overall survival (OS). Moreover, intrahepatic CD69+ Vδ1 TILs can egress CLM tissue to re-circulate in PB, where they retain a phenotype, transcriptional signature and TCR clonal repertoires resembling their liver origin. Importantly, even the increased frequencies of the CD69+ terminally differentiated (TEMRA) Vδ1 cells in PB of patients with CLM significantly correlate with longer OS. The positive prognostic score of high frequencies of CD69+ TEMRA Vδ1 cells in PB is independent from the neoadjuvant chemotherapy and immunotherapy regimens administered to patients with CLM prior surgery.ConclusionsThe enrichment of tissue-resident CD69+ Vδ1 TEMRA cells re-circulating at high frequencies in PB of patients with CLM limits tumor progression and represents a new important clinical tool to either predict the natural history of CLM or develop alternative therapeutic protocols of cellular therapies.

A close look at current γδ T-cell immunotherapy

“…The relationship between gd T cells and cancer prognosis is influenced by factors such as the pathological type of cancer (31), the gd T-cell subset (32), the time of sample harvesting (33), and the functioning state of the gd T cells (34). Clinical prognosis studies typically involve the analysis of either peripheral gd T cells or tumor-infiltrating gd T cells, and common methods include flow cytometry (35), immunohistochemistry (31,36), and gene expression measurement (34,37). Early studies often measured peripheral gd T cells without distinguishing subsets (38), whereas later studies began to analyze subsets separately (35).…”

“…As most studies on solid tumors have focused on tumor-infiltrating cells, the majority of correlations between prognosis and gd T cells have been found in tumor-infiltrating cells. Effector Vd1 gd T cells have been found to be beneficial in skin cancers (32,48), colon cancer (34), and lung cancer (35), based on protein-level analysis. Similarly, using the more commonly used gene expression analysis, tumor-infiltrating gd T cells were found to be favorable in ovarian cancer (49), head and neck cancer (50), and bladder cancer (37).…”

Gamma delta T-cell-based immune checkpoint therapy: attractive candidate for antitumor treatment

“…High levels of γδT cells were positively correlated with clinical stage, overall survival (OS) time, and CD8+/CD4+ T-cell infiltration [ 45 ]. In metastatic colorectal cancer, γδT cells still show the ability to limit tumor progression [ 5 ]. By analyzing 25 kinds of cancers (other than brain cancers), it was found that a tumor-related γδT-cell gene signature was the factor most correlated with the OS rate of patients [ 46 ].…”

“…In recent years, many studies have shown that cytotoxic γδT cells have a strong killing ability toward autologous, allogeneic or xenogeneic tumor cells, and their concentration is often closely related to the clinical prognosis of patients [ 1 – 5 ]. In contrast to αβT cells, γδT cells can recognize antigens in a way that is not restricted by major histocompatibility complex (MHC) molecules [ 6 ], and they mediate the killing of target cells in various ways, participate in immunomodulation, and have a broader tumor cell killing spectrum [ 7 , 8 ].…”

NKG2A Immune Checkpoint in Vδ2 T Cells: Emerging Application in Cancer Immunotherapy

“…Vδ3 T cells are enriched in the liver and in patients with some chronic viral infections and leukemias. They bind to glycolipid antigens presented by the MHC class I-like molecule CD1d and annexin A2 [15][16][17][18]. Other human γδ T cell subsets, such as Vδ4, Vδ5, Vδ6, Vδ7, and Vδ8 T cells, have been mainly found in patients with pathological conditions [19,20].…”