Deep Sequencing of T-Cell Receptors for Monitoring Peripheral CD8+ T Cells in Chinese Advanced Non-Small-Cell Lung Cancer Patients Treated With the Anti-PD-L1 Antibody.

Jin Sheng,Jiawei Shou,Pengfei Xu,Yunyun Deng,Yong Fang,Hong Pan,Huadi Wang,Xiaoyun Zhou,Hongsen Li,Tao Sun,Hongming Pan,Weidong Han,Yingying Yu,Xiao Liu

doi:10.3389/fmolb.2021.679130

Abstract

Background: Atezolizumab, a high-affinity engineered human anti–PD-L1 antibody, has produced a clinical benefit for patients with advanced non–small-cell lung cancer (NSCLC). However, associated with T-cell regulation, the immunomodulatory effect of PD-L1 blockade and its biomarker in peripheral immunity remains elusive. Methods: In a prospective cohort with 12 Chinese advanced NSCLC patients who received atezolizumab 1,200 mg every 3 weeks as a second-line treatment, blood samples were obtained before and 6 weeks after atezolizumab initiation, and when disease progression was confirmed. Patients were classified into a response or progression group according to response evaluation criteria in solid tumors (RECIST) 1.1. Fresh peripheral blood mononuclear cells (PBMCs) from patients were stained with antihuman CD3, CD8, and PD-1 antibodies for flow cytometry analysis. T-cell receptor (TCR)-β chains of CD8+ T cells were analyzed by next-generation sequencing (NGS) at the deep level. Diversity, clonality, and similarity of TCR have been calculated before and after treatment in both groups. Results: Clonal expansion with high PD-1 expression was detected in all patients’ peripheral CD8+ T cells before the treatment of atezolizumab. Unlike the progression group, the diversity of TCR repertoire and singletons in the TCRβ pool increased over time with atezolizumab administration, and the TCR repertoire dynamically changes in the response group. The percentage of CD8+ PD-1high terminal exhausted T cells declined in the response group after the PD-L1 blockade. Two patterns of TCR changes among patients who received PD-L1–targeted immunotherapy were observed. Conclusions: Deep sequencing of the T-cell receptors confirmed the existence of CD8+ PD-1high T cells with an exhaustion phenotype in Chinese NSCLC patients. Our study demonstrated that efficient anti–PD-L1 therapy could reshape the TCR repertoire for antitumor patients. Furthermore, singleton frequency may help us select patients who are sensitive to anti–PD-L1 immunotherapy.

Highlights

Non–small cell lung cancer (NSCLC) that accounts for almost 85 percent of total lung cancer patients is still the leading cause of cancer-related mortality, especially in those with advanced disease (Sui et al, 2018; Seigel et al, 2017)
Over the past few years, the introduction of the epidermal growth factor receptor (EGFR), tyrosine kinase inhibitors (TKIs), and anaplastic lymphoma kinase (ALK)-based target therapy dramatically improved the therapeutic efficacy for lung cancer patients with specific gene mutations (Califano et al, 2017; Hida et al, 2017; Peters et al, 2017; Kiura et al, 2018; Novello et al, 2018)
Patients received a median of seven cycles of progressive disease (PD)-L1 blockade immunotherapy, while half of them progressed after six cycles of treatment (Figure 1A)

Summary

Introduction

Non–small cell lung cancer (NSCLC) that accounts for almost 85 percent of total lung cancer patients is still the leading cause of cancer-related mortality, especially in those with advanced disease (Sui et al, 2018; Seigel et al, 2017). Immune checkpoint blockade (ICB) immunotherapy had changed the landscape for treating advanced NSCLC, with a more durable response than targeted therapy and chemotherapy. T cells respond highly specific to particular antigens as a consequence so that the gene encoding their adaptive immune receptors is generated somatically through a process that creates unique sequences when they encounter the cognate antigen. The generation process of adaptive immune receptor genes results in a tremendously diverse repertoire of distinct T-cell receptors (TCR) to bind the particular antigens (Robins et al, 2010; Warren et al, 2013; Zarnitsyna et al, 2013; Kaplinsky and Arnaout, 2016; Briney et al, 2019). Atezolizumab, a high-affinity engineered human anti–PD-L1 antibody, has produced a clinical benefit for patients with advanced non–small-cell lung cancer (NSCLC). Associated with T-cell regulation, the immunomodulatory effect of PD-L1 blockade and its biomarker in peripheral immunity remains elusive

Methods

Results

Discussion

Conclusion