A Quantitative Deficiency in Peripheral Blood Vγ9Vδ2 Cells Is a Negative Prognostic Biomarker in Ovarian Cancer Patients

Aurélie Thedrez,Jean Levêque,Pascale Daniel,Florian Cabillic,Benoit Dessarthe,Véronique Catros,Isabelle Jaffre,Vincent Lavoué,Sébastien Henno

doi:10.1371/journal.pone.0063322

Abstract

Vγ9Vδ2 cells are cytotoxic T cells that are able to recognize epithelial ovarian carcinoma (EOC) cells. Therefore, Vγ9Vδ2 cell-based adoptive transfer is an attractive therapy for EOC. However, the inefficient ex vivo expansion after specific stimulation of Vγ9Vδ2 cells from some patients and the relationships between Vγ9Vδ2 cells and clinical course of EOC are issues that remain to be clarified. Herein, peripheral blood mononuclear cells (PBMCs) from 60 EOC patients were stimulated with bromohydrin pyrophosphate (BrHPP) or zoledronate, which are specific agonists of Vγ9Vδ2 cells. The compounds differed in their efficacies to induce ex vivo Vγ9Vδ2 PBMC expansion, but 16/60 samples remained inefficiently expanded with both stimuli. Interestingly, the Vγ9Vδ2 cells in these low-responding PBMCs displayed before expansion (ex vivo PBMCs) an altered production of the pro-inflammatory cytokines IFN-γ and TNF-α, a decreased naive fraction and a reduced frequency. No evidence of an involvement of CD4+CD25+Foxp3+ regulatory cells was observed. Importantly, our data also demonstrate that a Vγ9Vδ2 cell frequency of 0.35% or less in EOC PBMCs could be used to predict low responses to both BrHPP and zoledronate. Moreover, our data highlight that such a deficiency is not correlated with advanced EOC stages but is associated with more refractory states to platinum-based chemotherapy and is an independent predictor of shorter disease-free survival after treatment. These results are the first to suggest a potential contribution of Vγ9Vδ2 cells to the anti-tumor effects of chemotherapeutic agents and they strengthen interest in strategies that might increase Vγ9Vδ2 cells in cancer patients.

Highlights

Human Vc9Vd2 cells are a predominant subset of peripheral blood cd T cells that express a unique TCR with Vc9-Vd2 regions
We compared the expansions of peripheral blood mononuclear cells (PBMCs) from 60 epithelial ovarian carcinoma (EOC) patients (EOC PBMCs) and from 13 healthy female donors after a specific Vc9Vd2 cell stimulation with a single dose of either bromohydrin pyrophosphate (BrHPP) or zoledronate (Zol), which were relevant to clinical trial protocols, and a culture for two weeks in presence of IL-2 (Fig. 1)
The median frequency of Vc9Vd2 cells in expanded PBMCs (Fig. 1A) and the median number of expanded Vc9Vd2 cells (Fig. 1B) were significantly lower in EOC patients than in donors at 14 days post-stimulation with either BrHPP or Zol. These data confirm that the responses of Vc9Vd2 PBMCs to both stimulation protocols are significantly reduced in EOC patients

Summary

Introduction

Human Vc9Vd2 cells are a predominant subset of peripheral blood cd T cells that express a unique TCR with Vc9-Vd2 regions. Several currently available clinical-grade compounds are able to strongly activate Vc9Vd2 cells and, with IL-2, can induce the selective outgrowth of these cells in vitro and in vivo These compounds are either synthetic phosphoantigens, such as bromohydrin pyrophosphate (BrHPP, PhosphostimTM), or pharmacological inhibitors of the mevalonate pathway, such as the aminobisphosphonates (i.e., zoledronate, ZometaTM). Such compounds have been recently assessed in passive or active immunotherapeutic trials in patients with hematological malignancies or solid tumors [5,6,7,8,9,10,11,12,13,14]. These treatments have been generally well tolerated and have induced encouraging objective responses in some patients [12,15,16]

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