Malignant mesothelioma effusions are infiltrated by CD3+ T cells highly expressing PD-L1 and the PD-L1+ tumor cells within these effusions are susceptible to ADCC by the anti-PD-L1 antibody avelumab

Swati Khanna, Anish Thomas, Daniel Abate-Daga, Jingli Zhang, Betsy Morrow, Seth M. Steinberg, Augusto Orlandi, Patrizia Ferroni, Jeffrey Schlom, Fiorella Guadagni, Raffit Hassan

Research output: Contribution to journalArticlepeer-review

Abstract

Introduction: The functional aspects of programmed death 1 (PD-1) and PD ligand 1 (PD-L1) immune checkpoints in malignant mesothelioma have not been studied. Methods: Tumor samples from 65 patients with mesothelioma were evaluated for PD-L1 expression by immunohistochemistry, and its prognostic significance was examined. Malignant effusions from patients with pleural and peritoneal mesothelioma were evaluated for PD-1-positive and PD-L1-positive infiltrating lymphocytes and their role in inducing PD-L1 expression in tumor cells. Antibodydependent cellular cytotoxicity (ADCC) of avelumab, a fully humanized immunoglobulin G1 anti PD-L1 antibody against primary mesothelioma cell lines, was evaluated in presence of autologous and allogeneic natural killer cells. Results: Of 65 pleural and peritoneal mesothelioma tumors examined, 41 (63%) were PD-L1-positive, which was associated with slightly inferior overall survival compared to patients with PD-L1-negative tumors (median 23.0 versus 33.3 months, p = 0.35). The frequency of PD-L1 expression was similar in patients with pleural and peritoneal mesothelioma, with 62% and 64% of samples testing positive, respectively. In nine mesothelioma effusion samples evaluated, the fraction of cells expressing PD-L1 ranged from 12% to 83%. In seven patients with paired malignant effusion and peripheral blood mononuclear cell (PBMC) samples, PD-L1 expression was significantly higher on CD3-positive T cells present in malignant effusions as compared with PBMCs (p = 0.016). In addition, the numbers of CD14-positive PD-1-positive cells were increased in malignant effusions compared with PBMCs (p = 0.031). The lymphocytes present in malignant effusions recognized autologous tumor cells and induced interferon-γ-mediated PD-L1 expression on the tumor cell surface. Of the three primary mesothelioma cell lines tested, two were susceptible to avelumab-mediated ADCC in the presence of autologous natural killer cells. Conclusions: Most pleural as well as peritoneal mesotheliomas express PD-L1. Malignant effusions in this disease are characterized by the presence of tumor cells and CD3-positive T cells that highly express PD-L1. In addition, mesothelioma tumor cells are susceptible to ADCC by the anti-PD-L1 antibody avelumab.

Original languageEnglish
Pages (from-to)1993-2005
Number of pages13
JournalJournal of Thoracic Oncology
Volume11
Issue number11
DOIs
Publication statusPublished - Nov 13 2016

Keywords

  • 031ADCC
  • Avelumab
  • Mesothelioma
  • PD-1-PD-L1

ASJC Scopus subject areas

  • Oncology
  • Pulmonary and Respiratory Medicine

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