Search

Myeloid-derived suppressor cells (MDSC) promote immunosuppression and are a target in the field of immuno-oncology. Accumulation of MDSCs is associated with poor prognosis and resistance to immunotherapy for several cancers. Here, we describe an accumulation of a subset of circulating monocytic MDSCs (M-MDSC) overexpressing TIE2, the receptor for angiopoietin-2 (ANGPT2), in patients with non–small cell lung cancer (NSCLC). Greater numbers of circulating TIE2+ M-MDSCs were detected in patients with NSCLC compared with healthy subjects, and this accumulation correlated with ANGPT2 concentration in blood. The presence of an ANGPT2-rich environment was associated with impairment of preexisting T-cell responses against tumor-associated antigens (TAA) in patients with NSCLC. We demonstrated that ANGPT2 sensitizes TIE2+ M-MDSCs such that these cells suppress TAA-specific T cells. In patients with NSCLC, upregulation of the ANGPT2/TIE2+ M-MDSC signature in blood was associated with a poor prognosis. Our results identify the ANGPT2/TIE2+ M-MDSC axis as a participant in tumor immune evasion that should be taken into account in future cancer immunotherapy.

Biochemical recurrence (BCR) occurs in up to 40% of prostate cancer patients after prostatectomy. In our study, we performed an immune monitoring study in 20 prostate cancer patients with BCR previously treated with metronomic cyclophosphamide (mCTX). We observed a decrease of regulatory T cells (Tregs) from 2 months and this was more pronounced after 6 months of mCTX treatment. This drop of Tregs was associated with increased level of activated HLADR+ CD45R0+ T cells in peripheral blood. Furthermore, a reactivation of Th1 polarized anti-PSA T-cell response was detected in BCR patients treated with mCTX. However, dendritic cell subsets counts and activation were not influenced by the treatment. In the clinical setting, we found that PSA level control was observed in 82% (9/11) of patients with a significant diminution of Tregs after mCTX compared to 33% (3/9) in patients without Tregs decrease. In addition, 30% (6/20) of patients previously treated with mCTX remained free for androgen deprivation therapy. In conclusion, Tregs diminution and immune activation associated with PSA level control occurred after mCTX in prostate cancer patients with BCR.

Exosomes are involved in modulating the immune system and mediating communication between cells. The aim of this study was to investigate the involvement of exosomes in psoriasis. Exosomes from patients with psoriasis were analysed by nanoparticle tracking analysis and protein expression was analysed by western blotting. The concentration of HSP70 was determined by an enzyme-linked immunosorbent assay, and concentrations of interleukin (IL)-1β, IL-2, IL-6, IL-10, IL-17A and tumour necrosis factor alpha (TNF-α) were determined by flow cytometry. Based on the severity of psoriasis, evaluated by body surface area (≤ 10% vs. > 10%), 2 groups of patients were compared (49 with mild psoriasis and 71 with moderate-to-severe psoriasis). The number (2.52×1011 ± 2.29×1010 vs. 1.79×1011 ± 1.93×1010, p = 0.19) and size (94.44 ± 22.00 nm vs. 96.87 ± 28.30 nm, p = 0.72) of exosomes and the concentration of HSP70 in the exosomes were not significantly different in the 2 groups of patients. IL-17A exosome levels were significantly higher in patients with moderate-to-severe psoriasis compared with those with mild psoriasis (p = 0.02). There were no significant differences in levels of TNF-α, IL-1, IL-2, IL-6 and IL-10. This study shows, for the first time, the presence of circulating exosomes in patients with psoriasis. These data confirm the involvement of circulating exosomes in psoriasis, in particular in moderate-to-severe psoriasis, through IL-17A-producing exosomes.

Inflammatory response in patients with COPD secondary to organic dust exposure (OD-COPD) is poorly understood. We therefore aimed to characterize inflammatory and immune profile from peripheral blood mononuclear cells (PBMC) in a group of patients with mild-to-moderate COPD secondary to organic dust exposure (OD-COPD), tobacco smoking (T-COPD), or both. We compared T, B and NK cells distribution and inflammatory (TNF-α, Il-1β, IL-6), type 1 (IFN-γ), type 2 (IL-4, IL-13) and type 3 (IL-17) immunity related cytokines at baseline, and after stimulation with LPS, flagellin and CD3/CD28 beads in all COPD groups. OD-COPD displayed significantly lower NK cells and CD8+ T cells compared with controls. After flagellin stimulation, T-COPD had significantly lower IL-13 levels than OD-COPD and controls (p 0.05) whereas IFN-γ tended to be lower in OD-COPD. All COPD groups displayed higher IL-1β and IL-17 than controls after CD3/CD28 stimulation. Inflammatory responses in OD-COPD were different from T-COPD. OD-COPD displayed higher levels of type 2 immunity related cytokines.

CD4 T cells play a key role in anticancer immunity. In this study, we investigate the clinical relevance of circulating CD4 T helper type 1 (Th1) response against telomerase (anti-TERT Th1 response) in patients with melanoma. The spontaneous anti-TERT Th1 response was detected in 54.5% (85/156) of patients with melanoma before treatment. The prevalence of this systemic response was inversely related to Breslow thickness >1 mm and American Joint Committee on Cancer stage ≥II (P = 0.001 and 0.032, respectively). In contrast to patients treated with targeted therapies, the anti-TERT Th1 immunity was associated with an objective response after immune checkpoint inhibitors treatment. Hence, 86% (18/21) of responder patients exhibited pre-existing anti-TERT Th1 versus 35% (6/19) in nonresponders (P = 0.001). This response was also associated with increased progression-free survival and overall survival in patients with melanoma treated with immune checkpoint inhibitors (P = 0.0008 and 0.012, respectively). Collectively, the presence of circulating anti-TERT Th1 response is inversely related to melanoma evolution and appears to be a predictive factor of response to immunotherapy. Our results highlight the interest in telomerase-specific CD4 Th1 response as a promising blood-based biomarker of immune checkpoint inhibitors therapy in melanoma.

mTOR pathway inhibitors such as rapalogs represent a promising tool to induce functional memory CD8 T cells. In our study, we investigated the combination of temsirolimus with anticancer vaccines. Using various designs of cancer vaccines (short and long peptides or the B subunit of Shiga toxin as an antigen delivery vector) and tumor models (melanoma, lung and colon cancer), we showed that the administration of temsirolimus efficiently decreased tumor growth and enhanced tumor-specific CD8 T-cell responses induced by vaccination. Furthermore, tumor-specific CD8 T cells induced by the bi-therapy (vaccine + temsirolimus) exhibit phenotypic characteristics of central memory (CD127+ CD62L+ ) CD8 T cells compared to vaccination alone. We demonstrated that regulatory CD4 T cells (Tregs ) expansion in vivo limits the efficacy of the bi-therapy by altering the antitumor CD8 T-cell responses. Finally, the use of a small molecule CCR4 antagonist to prevent Tregs induction considerably improved the efficacy of the bi-therapy by enhancing CD8 T cells-mediated antitumor immunity. Taken together, our study highlights the potential interest of combining cancer vaccines with drugs that promote memory CD8 T cells and inhibit Tregs .

3044 Background: Increasing evidence highlights the crucial roles played by CD4+ Th1 cells in cancer immunity and immunotherapy (Spitzer et al., Cell 2017, Borst et al., Nat rev Immunol 2018). Here, we investigate the relevance of circulating CD4 Th1 response against shared tumor-associated antigens (TAA) in cancer patients treated by anti-PD-1 immunotherapy. Methods: A total of 46 advanced cancer patients (pts) including 32 pts with non-small cell lung cancer (NSCLC), 14 pts with melanoma, were enrolled (ITHER trial NCT02840058). Patients were treated with anti-PD-1 therapy as standard of care (26 pts with nivolumab and 20 pts with pembrolizumab). Peripheral blood mononuclear cells were collected before and after treatment at 1 and 3 months. The presence of circulating TAA-specific Th1 response was measured by IFNy ELISPOT assay using a mixture of 15mer peptides derived from telomerase (TERT) (Laheurte et al., Oncoimmunology 2016 and Br J C 2019). Results: At the baseline, the anti-TERT Th1 response was observed in 37% of pts. After anti-PD-1 therapy, de novo induction and/or amplification of pre-existing anti-TERT Th1 response was found in 26 % of pts (12/46). Whereas, a decrease of this response was documented in 15% of pts (7/46).The presence of anti-TERT Th1 response in peripheral blood during anti-PD-1 treatment was associated with a prolonged progression free-survival (PFS) as compared to the immune non responder pts (14.4 vs 2.6 months respectively, p = 0.006, HR 0.39 [0.2;0.76]). Similar observation was made for the overall survival (OS) (22.3 vs 12.3 months respectively, p = 0.04 HR 0.45 [0.21;0.96]). Notably, de novo reinvigoration of peripheral anti-TERT Th1 response after anti-PD-1 therapy was associated with a better clinical outcome as compared to the group of pts with decreased immune response after treatment (Median OS not reached vs 5.8 months). In contrast, no association with anti-PD-1 response was observed neither with circulating anti-NY-ESO-1 or with anti-viral Th1 response, concurrently measured in these patients. Conclusions: The reinvigoration of circulating CD4 Th1 against telomerase in patients treated by anti-PD-1 is associated with a better clinical outcome. These results underline the potential interest of monitoring circulating antitumor CD4 Th1 response for immune checkpoint inhibitors management.

Despite the critical roles played by IFN-γ+ CD4 Th1 response in tumor immunity, the translation of their potential in clinic remains challenging. Here, we evaluate the clinical significance of circulating anti-tumor CD4 Th1 response in non-small cell lung cancer (NSCLC) patients. 170 naïve-treatment patients were enrolled in this immune monitoring study. The antitumor adaptive Th1 response was assessed by IFN-γ ELISPOT assay in blood lymphocytes using a mixture of eight highly promiscuous and Th1-polarized HLA class II-restricted epitopes from telomerase (TERT). The presence of anti-TERT Th1 response was detected in 59/170 patients (35%). We found an opposite link between anti-TERT Th1 and hyper exhausted T cells co-expressing PD-1+ and TIM-3+ in NSCLC patients. In contrast to hyper exhausted CD8 T cells, the presence of anti-TERT Th1 response was associated with a low rate of hyper exhausted CD4 T cells. We showed that NSCLC stage dissemination is associated with a decrease of anti-TERT Th1 response but an increase of circulating hyper exhausted PD-1+/TIM-3+ CD4 T cells. Notably, anti-telomerase Th1 response and hyper exhausted CD4 T-cells displayed opposite prognosis value in NSCLC. While high level of anti-TERT Th1 cells play a protective role, hyper-exhausted PD-1+TIM-3+ CD4 T cells negatively affect patients’ survival. By using these two circulating immune factors, we stratified patients in distinct prognostic group. Patients with anti-TERT Th1high/CD4 PD-1 TIM-3low immune profile had better overall survival than anti-TERT Th1low/CD4 PD-1 TIM-3high group (median OS : not reached versus 4 months respectively p Citation Format: Caroline Laheurte, Magalie Dosset, Dewi Vernerey, Elodie Lauret Marie Joseph, Laura Boullerot, Vincent Kaulec, Marion Jacquin, Laurie Cuche, Guillaume Eberst, Pascale Jacoulet, Virginie Westeel, Olivier Adotevi. Adaptive CD4 Th1 response against telomerase in blood counteracts T-cell exhaustion in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 575.