Augmented expression of programmed death-1 in both neoplastic and non-neoplastic CD4+ T-cells in adult T-cell leukemia/lymphoma

Adult T-cell leukemia/lymphoma (ATL) is a CD4(+)CD25(+) T-cell malignancy infected with human T-cell leukemia virus type-I (HTLV-I). HTLV-I infection causes the T-cell dysfunction, which contributes to the immunodeficient state of the patients. Programmed death-1 (PD-1) can negatively regulate T-cell response, when its ligand, PD-L1 or PD-L2 mainly expressed on antigen presenting cells, binds to this B7 family receptor. We investigated whether PD-1 is expressed on CD4(+) neoplastic (and/or non-neoplastic) cells or CD8(+) cytotoxic cells in peripheral blood mononuclear cells from 11 patients with ATL. By flow cytometry, we found that the levels of PD-1 expression on both CD4(+)CD25(+) and CD4(+)CD25(-) T-cell populations were increased in ATL patients compared to normal healthy volunteers, while PD-1 levels on CD8(+) T-cells were comparable between the patients and normal subjects. In stimulation with anti-CD3 antibody, the proliferation of PD-1-expressing T-cells from ATL patients was weak when compared to that of PD-1-nonexpressing normal T-cells. In addition to PD-1, PD-L1 was coexpressed on ATL cells in some patients, and PD-L1 expression was enhanced by stimulation with anti-CD3 antibody. Finally, the production of cytokines such as TNF-alpha by ATL cells was restored by blockade of PD-1/PD-L1 interaction. These findings suggest that CD4(+) T-cells are the main PD-1-expressing cells rather than CD8(+) T-cells in ATL patients, and both neoplastic and normal CD4(+) cells are exhausted as a result of PD-1 expression, and additionally PD-L1 expression on the neoplastic cell.     

免疫球蛋白超家族受体在肿瘤免疫治疗中的研究进展

近年来免疫检查点阻断在癌症治疗中的应用引起广泛关注。靶向PD-1、PD-L1或CTLA-4的药物在临床试验中仅有部分患者受益。确定新的免疫检查点,探索其作用机制将进一步发展肿瘤免疫疗法。TIGIT、CD226、CD112R和CD96是免疫细胞表达的一组免疫球蛋白超家族受体,与肿瘤细胞表达的Nectin/Necl家族配体（CD155、CD112）相互结合,在肿瘤免疫反应中发挥巨大作用,是新一代的免疫检查点。本文将对CD155、CD112、TIGIT、CD226、CD112R及CD96的分子结构与在肿瘤免疫反应中的作用进行阐述,探讨在癌症免疫治疗中的潜在应用。      

Anti-PD-1 checkpoint blockade improves the efficacy of a melphalan-based therapy in experimental melanoma

IntroductionThe induction of adaptive cellular immunity in patients with in-transit melanoma metastasis treated with hyperthermic isolated limb perfusion (ILP) with melphalan has been shown to contribute to the effectiveness of the therapy. Activated CD8⁺ T cells appear to be of particular importance for the efficacy of melphalan-based ILP therapy, as observed in both patients and animal models. In this study, we explored the possible synergistic effects of combining melphalan-based therapy with the checkpoint inhibitor anti-PD-1 on tumours in a mouse melanoma model.MethodsA murine vaccination model that utilized melphalan-exposed melanoma cells was used to mimic certain immunological features of melphalan-based ILP. The effects of the vaccine on tumour growth and PD-1 expression on CD8⁺ tumour-infiltrating T cells were analyzed. The melphalan-based vaccine was then combined with an anti-PD-1 antibody and tumour growth was assessed.ResultsTreatment with melphalan-based therapy significantly induced the expression of PD-1 on CD8⁺ tumour-infiltrating lymphocytes. Combination therapy using melphalan-based therapy followed by treatment with PD-1 antibodies significantly reduced early-stage tumour growth relative to monotherapies and no treatment.ConclusionsThis study thus suggests that the addition of PD-1 blockade to melphalan-based therapies, such as ILP, may be therapeutically beneficial.     

Effects of interferon-α-transduced tumor cell vaccines and blockade of programmed cell death-1 on the growth of established tumors

Interferon-alpha (IFN-α) has strong antitumor effects, and IFN-α gene therapy has been used clinically against some cancers. In this study, we evaluated the efficacy of the combination of IFN-α-transduced tumor cell vaccines and programmed cell death 1 (PD-1) blockade, and investigated the mechanisms of the antitumor effects of the combined therapy. A poorly immunogenic murine colorectal cancer cell line, MC38, was transduced to overexpress IFN-α. In a therapeutic model, parental tumor-bearing mice were inoculated with MC38-IFNα cells and an anti-PD-1 antagonistic antibody. Analyses of immunohistochemistry and tumor-specific lysis were performed. The outgrowth of the established tumors was significantly reduced in mice treated with the combination of IFN-α and anti-PD-1. Immunohistochemical analyses of the therapeutic model showed marked infiltration of CD4(+) cells and CD8(+) cells in the established MC38 tumors of mice treated with both IFN-α and anti-PD-1. Significant tumor-specific cytolysis was detected when splenocytes of mice that were treated with both IFN-α and anti-PD-1 were used as effector cells. These results suggest that blockade of the PD-1 PD-ligand enhanced the Th1-type antitumor immune responses induced by IFN-α. The combination of IFN-α gene-transduced tumor cell vaccines and PD-1 blockade may be a possible candidate for a cancer vaccine for clinical trials.     

125I粒子植入联合抗PD-1治疗对小鼠Lewis肺癌的抑制作用研究

目的:研究125I粒子植入对免疫微环境的影响,以及125I粒子植入联合抗程序性死亡受体-1(programmed cell death receptor-1,PD-1)治疗的抗肿瘤疗效.方法:在小鼠右后肢皮下注射Lewis肺癌(LLC)细胞构建肿瘤模型,利用流式细胞术分析125I粒子植入后PD-1、程序性死亡配体1(p...     

Expansion of effector T cells associated with decreased PD-1 expression in patients with indolent B cell lymphomas and chronic lymphocytic leukemia

In patients with chronic lymphocytic leukemia (CLL), numbers of CD8 + CD45RA +/- CD27- effector T cells are expanded. We investigated whether this expansion is also present in other B cell malignancies and the possible mechanism underlying these changes. Whereas an increase in total CD4+and CD8+ T cell numbers was found only in CLL, numbers of CD4+ and CD8+ effector T cells were significantly increased in both CLL and indolent lymphoma, but not aggressive lymphoma and myeloma. Interestingly, PD-1 expression was decreased on effector T cells and inversely correlated with effector T cell numbers, suggesting a functional role for PD-1 in regulating T cell homeostasis. In vitro experiments revealed impaired up-regulation of PD-1 upon T cell activation in the presence of malignant but also healthy B cells. Our data suggest that in CLL and indolent lymphoma, the malignant B cells affect PD-1 expression on effector T cells, resulting in an expansion of these subsets.     

Safety of resuming anti-PD-1 in patients with immune-related adverse events (irAEs) during combined anti-CTLA-4 and anti-PD1 in metastatic melanoma

BackgroundCombined cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed death 1 (PD-1) blockade induces high rates of immune-related adverse events (irAEs). The safety of resuming anti-PD-1 in patients who discontinue combination therapy due to irAEs is not known.Patients and methodsWe assessed patients who experienced clinically significant irAEs from combined CTLA-4 and PD-1 blockade leading to treatment discontinuation at four academic centers. We assessed the safety of resuming anti-PD-1 in terms of recurrent and distinct irAEs.ResultsEighty patients discontinued combination therapy due to irAEs, including colitis (41%), hepatitis (36%), and pneumonitis (4%). Of these, 96% received corticosteroids and 21% received additional immunosuppression (e.g. infliximab). All were rechallenged with anti-PD-1, and 14 (18%) had recurrent irAEs at a median of 14 days after therapy resumption (six grade 1–2, seven grade 3–4, and one grade 5 Steven–Johnson Syndrome). Colitis was less likely to recur than other irAEs (6% versus 28%, P = 0.01). Clinically significant but distinct toxicities occurred in an additional 17 (21%) patients (11 grade 1–2 and 6 grade 3–4). Duration of steroid taper, severity of initial irAEs and use of additional immunosuppressants did not predict for toxicity on rechallenge, although patients remaining on steroid therapy at anti-PD-1 resumption had higher rates of toxicities (55% versus 31%, P = 0.03).ConclusionsPatients who discontinued CTLA-4/PD-1 blockade for severe irAEs had relatively high rates of recurrent or distinct toxicities with anti-PD-1 resumption. However, many patients, particularly with combination-induced colitis, tolerated anti-PD-1 rechallenge well, and this approach can be considered in selected patients.     

Immune inhibitory molecules LAG-3 and PD-1 synergistically regulate T-cell function to promote tumoral immune escape

Inhibitory receptors on immune cells are pivotal regulators of immune escape in cancer. Among these inhibitory receptors, CTLA-4 (targeted clinically by ipilimumab) serves as a dominant off-switch while other receptors such as PD-1 and LAG-3 seem to serve more subtle rheostat functions. However, the extent of synergy and cooperative interactions between inhibitory pathways in cancer remain largely unexplored. Here, we reveal extensive coexpression of PD-1 and LAG-3 on tumor-infiltrating CD4(+) and CD8(+) T cells in three distinct transplantable tumors. Dual anti-LAG-3/anti-PD-1 antibody treatment cured most mice of established tumors that were largely resistant to single antibody treatment. Despite minimal immunopathologic sequelae in PD-1 and LAG-3 single knockout mice, dual knockout mice abrogated self-tolerance with resultant autoimmune infiltrates in multiple organs, leading to eventual lethality. However, Lag3(-/-)Pdcd1(-/-) mice showed markedly increased survival from and clearance of multiple transplantable tumors. Together, these results define a strong synergy between the PD-1 and LAG-3 inhibitory pathways in tolerance to both self and tumor antigens. In addition, they argue strongly that dual blockade of these molecules represents a promising combinatorial strategy for cancer.     

Immunotherapies targeting neoantigens are effective in PD-1 blockade-resistant tumors

Only a small fraction of tumor-infiltrating lymphocytes can specifically recognize and attack cancer cells in PD-1/PD-L1 blockade therapy. Here, we investigate approaches to expand the neoantigen-specific CD8⁺ T cells to overcome the difficulties in treating PD-1/PD-L1 blockade-resistant tumors. Mutation-associated neoepitopes of murine nonsmall cell lung cancer ASB-XIV were estimated by whole-exome and RNA sequencing and predicted by MHC-I binding affinity (FPKM >1) in silico. Using ASB-XIV-specific CD8⁺ T cells, we screened a panel of 257 neoepitope peptides derived from ASB-XIV missense and indel mutations. Mutated Phf3 peptide (mPhf3) was successfully identified as an immunogenic neoepitope. Prophylactic mPhf3-DC vaccination inhibited ASB-XIV tumor growth through CD8⁺ T cell-mediated antitumor immunity. Combining the mPhf3-DC vaccine and anti-PD-1 treatment elicited robust antitumor activity through the induction of mPhf3-specific CD8⁺ T cells in the tumor microenvironment. Furthermore, the adoptive transfer of mPhf3-specific CD8⁺ T cells eradicated ASB-XIV tumors. Likewise, the combination of mutated Cdt1 peptide (mCdt1)-DC vaccine and anti-PD-1 treatment or adoptive transfer of mCdt1-specific CD8⁺ T cells also led to significant regression of PD-1 blockade-resistant murine gastric YTN16 tumors. In conclusion, a novel immunogenic neoepitope of ASB-XIV was identified for immunotherapy targeting neoantigens. Identification of immunogenic neoantigens can extend the therapeutic strategies by increasing the frequency of neoantigen-specific T cells, even for PD-1/PD-L1 blockade-resistant tumors.     

外周T细胞淋巴瘤患者中PD-1的表达对CD45RA+、CD45RO+T细胞的影响

目的:探讨外周T细胞淋巴瘤(PTCL)患者淋巴瘤组织中PD-1的表达与外周血中初始和记忆T细胞水平的关系.方法:20例PTCL患者采用免疫组化法检测淋巴瘤组织中PD-1的表达,采用流式细胞术检测CHOP方案化疗前后外周血中CD4+CD45RA+、CD4+CD45RO+、CD8+CD45RA+和CD8+CD45RO+T细胞的比例,分析PD-1的表达与T细胞亚群的关系.结果:PD-1、PD-L1蛋白在PTCL患者中表达升高,PD-1阳性患者疗效较差.PD-1阳性患者中CD4+T细胞、CD8+T细胞明显低于PD-1阴性患者;PD-1阴性组患者CD4+CD45RO+、CD8+CD45RA+、 CD8+CD45RO+T细胞明显高于PD-1阳性患者,差异有统计学意义.结论:PTCL患者中存在PD-1/PD-L1蛋白的表达异常,PD-1阳性患者存在更明显的T细胞免疫功能缺陷.     

外周血PD-1及相关免疫指标在鼻咽癌患者放化疗过程中的变化及其意义

目的：检测鼻咽癌患者接受放化疗过程中T细胞表面PD-1表达、T细胞亚群等免疫指标的水平,探讨不同治疗时间段内患者的免疫功能。方法：收集2015年4月至2015年9月在福建省肿瘤医院经病理确诊的30例鼻咽癌患者的血液标本,通过流式细胞术动态监测患者在不同治疗时段（治疗前、新辅助化疗后、放疗结束）的免疫指标水平,包括T细胞上PD-1及T细胞亚群、NK细胞、B细胞等。结果：与治疗前相比,新辅助化疗后外周血CD3+细胞、CD4+T细胞、CD8+CD28+T细胞及CD4+/CD8+比值显著升高,而CD19（+ 即B细胞）及CD3-CD16+CD56（+ 即NK细胞）细胞水平显著下降（均P<0.05）。放化疗结束后,外周血CD4+细胞、CD8+CD28+T细胞、CD4+/CD8+比值下调至较治疗前更低的水平（均P<0.05）,而NK细胞的比例则表现为上调（P<0.05）。与治疗前相比,放疗后T细胞PD-1的表达水平显著升高（P<0.05）。结论：鼻咽癌患者外周血T细胞亚群比例在新辅助化疗后上调,而放疗结束时明显下降,提示放疗结束时患者的免疫功能受到显著抑制;T细胞PD-1的表达水平在放疗结束时显著上调,意味着放化疗结束时可能正是使用PD-1抑制剂的良机,抗PD-1维持治疗有望产生更高效持久的抗肿瘤效应。     

Prognostic value of programmed death-1, programmed death-ligand 1, programmed death-ligand 2 expression,and CD8(+) T cell density in primary tumors and metastatic lymph nodes from patients with stage T1-4N+M0 gastric adenocarcinoma

Background: Anti-programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) immunotherapy has been proved to be effective on gastric cancer in ongoing clinical trials. However, the value of PD-L1 in predicting responses of patients with gastric cancer to anti-PD-1/PD-L1 immunotherapy is controversial. Some studies suggested that intra- and inter-tumoral heterogeneity of PD-L1 expression might explain the controversy. This study aimed to analyze the expression of PD-L1, PD-L2, and PD-1 as well as CD8(+) T-cell density in primary tumors and lymph nodes from patients with stage T1-4N+M0 gastric adenocarcinoma to explore the heterogeneity of PD-1 signaling pathway molecules. Methods: In primary tumors and metastatic as well as non-metastatic lymph nodes from patients with stage T1-4N+M0 gastric adenocarcinoma, we detected PD-L1 and PD-L2 expression with immunohistochemistry. CD8(+) T-cell density in primary tumors and PD-1 expression on CD8(+) T cells were detected with immunofluorescence. Uni-variate analysis was used to determine the prognostic values of them. Cox proportional hazard regression model was used to identify independent risk factors that affect patients' overall survival and disease-free survival. Results: Among 119 eligible patients who had undergone surgical resection, the positive rate of PD-L1 was higher in metastatic lymph nodes than in primary tumors (45.4％ vs. 38.7％,P= 0.005); the positive rate of PD-1 on CD8(+) T cells was significantly higher in primary tumors and metastatic lymph nodes than in tumor-free lymph nodes (both P < 0.001). The intensity of PD-1 expression on CD8(+) T cells in primary tumors and in metastatic lymph nodes were stronger than that in tumor-free lymph nodes from the same patient. Beside, the positive rate of PD-L2 did not show any differences between primary tumors and metastatic lymph nodes. In multivariate analysis, PD-L1 expression, PD-L2 expression, a low density of CD8(+) T cells in primary tumors, and PD-1 expression on CD8(+) T cells in primary tumors were associated with poor prognosis.Conclusion: The expression of PD-L1 is heterogeneous in primary tumors and in metastatic lymph nodes from patients with stage T1-4N+M0 gastric adenocarcinoma, which might explain the inconsistent results in assessing the prognostic value of PD-L1 expression in previous studies.     

Greater extent of blood-tumor TCR repertoire overlap is associated with favorable clinical responses to PD-1 blockade

With the widespread use of programmed death receptor-1 (PD-1) blockade therapy, sensitive and specific predictive biomarkers that guide patient selection are urgently needed. T-cell receptor (TCR) repertoire, which reflects antitumor T-cell responses based on antigen specificity, is expected as a novel biomarker for PD-1 blockade therapy. In the present study, the TCR repertoire of eight patients with gastrointestinal cancer treated with anti-PD-1 antibody (nivolumab) was analyzed. To analyze the tumor-associated T-cell clones in the blood and their mobilization into the tumor, we focused on T-cell clones that presented in both blood and tumor (blood-tumor overlapping clones). Responders to PD-1 blockade tended to exhibit a higher number of overlapping clones in the tumor and a higher total frequency in the blood. Moreover, a higher total frequency of overlapping clones in blood CD8⁺ T cells before treatment was associated with a favorable clinical response. Collectively, these results suggest the possibility of blood-tumor TCR repertoire overlap to predict clinical response to PD-1 blockade and guide patient selection before the treatment.     

CD8(+) T cells specific for tumor antigens can be rendered dysfunctional by the tumor microenvironment through upregulation of the inhibitory receptors BTLA and PD-1

Cytotoxic T cells that are present in tumors and capable of recognizing tumor epitopes are nevertheless generally impotent in eliciting tumor rejection. Thus, identifying the immune escape mechanisms responsible for inducing tumor-specific CD8(+) T-cell dysfunction may reveal effective strategies for immune therapy. The inhibitory receptors PD-1 and Tim-3 are known to negatively regulate CD8(+) T-cell responses directed against the well-characterized tumor antigen NY-ESO-1. Here, we report that the upregulation of the inhibitory molecule BTLA also plays a critical role in restricting NY-ESO-1-specific CD8(+) T-cell expansion and function in melanoma. BTLA-expressing PD-1(+)Tim-3(-) CD8(+) T cells represented the largest subset of NY-ESO-1-specific CD8(+) T cells in patients with melanoma. These cells were partially dysfunctional, producing less IFN-γ than BTLA(-) T cells but more IFN-γ, TNF, and interleukin-2 than the highly dysfunctional subset expressing all three receptors. Expression of BTLA did not increase with higher T-cell dysfunction or upon cognate antigen stimulation, as it does with PD-1, suggesting that BTLA upregulation occurs independently of functional exhaustion driven by high antigen load. Added with PD-1 and Tim-3 blockades, BTLA blockade enhanced the expansion, proliferation, and cytokine production of NY-ESO-1-specific CD8(+) T cells. Collectively, our findings indicate that targeting BTLA along with the PD-1 and Tim-3 pathways is critical to reverse an important mechanism of immune escape in patients with advanced melanoma.     

Concurrent High PD-L1 Expression and CD8+ Immune Cell Infiltration Predict PD-1 Blockade Efficacy in Advanced EGFR-Mutant NSCLC Patients

ObjectivesThe effectiveness of PD-1 blockade therapy in advanced epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) is limited. We investigated whether patient characteristics, PD-L1 expression, and immune cell (IC) status in the tumor microenvironment (TME) were associated with PD-1 blockade therapy outcomes.Materials and methodsWe retrospectively reviewed patients with advanced EGFR-mutant NSCLC treated with PD-1 blockade (nivolumab or pembrolizumab) between January 2016 and March 2018. The PD-L1 expression tumor proportion score (TPS) and types and distribution of ICs (CD8, PD-1, CD204, tumoral, and stromal) in the TME were analyzed.ResultsAmong 57 EGFR-mutant NSCLC patients treated with PD-1 blockade, 39 patients had sufficient tissues for analyzing the TME. The overall response rate (ORR) of PD-1 blockade was 12.3%. Only tumoral CD8 positive (CD8⁺) IC status was significantly associated with the response (median tumoral CD8⁺ICs: 299/mm² vs. 115/mm², P < .01). Among the 6 patients with concurrent high PD-L1 expression (TPS: ≥ 50%)/high tumoral CD8⁺ ICs (≥ 205/mm²), 5 (83.3%) showed a response and a significantly longer progression-free survival (PFS) (PFS: 9.4M vs. 1.8M, P < .01). In contrast, none of the 7 patients with high PD-L1 expression/low tumoral CD8⁺ICs (<205/mm²) showed a response.ConclusionConcurrent high PD-L1 expression and high tumoral CD8⁺ ICs could predict the response and longer PFS of PD-1 blockade therapy in EGFR-mutant patients.     

Chronic lymphocytic leukaemia cells become both activated and immunosuppressive following interaction with CD3 and CD28 stimulated PBMC

Chronic lymphocytic leukaemia (CLL) is associated with immunosuppression. The activation of CLL cells induced by interaction with other cell types, particularly activated T-cells, within the tumour micro-environment is thought to be important for CLL progression. However it is unclear whether activated CLL cells (CLL^Act) have immunosuppressive capacity. We report that co-culture of CLL cells with normal PBMC in the context of CD3/CD28 T-cell activation generates CLL^Act with increased CD38 expression that are capable of suppressing the proliferative responses of both CD4+ and CD8+ T-cells. The suppression required cell contact but did not involve induction of T-cell apoptosis.     

Bcl-2 and bax expression and chlorambucil-induced apoptosis in the T-cells and leukaemic B-cells of untreated B-cell chronic lymphocytic leukaemia patients

Chlorambucil and other cytotoxic drugs kill cells, non-selectively, by inducing apoptosis. In this study, we measured the apoptotic response to chlorambucil in T- and B-cells from untreated B-CLL patients and T-cells, from normal control subjects. We found increased chemosensitivity in the T-cells of B-CLL patients compared to the controls (P=0.0002). The chlorambucil ID(50) values for T-cells from B-CLL patients showed a direct correlation with Bcl-2 expression (P=0.002) and an inverse correlation with CD3 cell count (P<0.0001), suggesting a trend of increasing chemosensitivity and decreasing Bcl-2 expression with an elevated T-cell count. There was no differential expression of Bcl-2 or Bax between the CD4(+) and CD8(+) cells of B-CLL patients, isolated by immunomagnetic separation. We found correlations in the leukaemic B-cells between chlorambucil ID(50) values and both Bcl-2 expression (P=0.006), and Bcl-2/Bax ratios (P=0.002), suggesting a role for the Bcl-2/Bax ratio in predicting the response of untreated CLL patients to cytotoxic treatment. Chlorambucil produced almost identical changes in Bcl-2 and Bax expression in normal T-cells and leukaemic B-cells triggered to die by apoptosis, which together with the correlation between Bcl-2 and chemosensitivity confirms a pivotal role for Bcl-2 in regulating a distal step in the apoptotic pathway following cytotoxic cellular damage.     

CD4+ and CD8+ T cells in sentinel nodes exhibit distinct pattern of PD-1, CD69, and HLA-DR expression compared to tumor tissue in oral squamous cell carcinoma

Anticancer immunotherapies have revolutionized cancer management, yet the effect of systemic anti-programmed cell death protein 1 (PD-1) treatment is predominantly studied in tumor-infiltrating lymphocytes (TILs). Its impact on PD-1 expressing cells in tumor-draining lymph nodes (TDLNs) is not well understood and yet to be explored. Thus, further research aiming for better understanding of the PD-1 pathway not only in tumor tissue but also in TDLNs is warranted. In this study, we investigated the expression of PD-1, CD69, and HLA-DR on CD4⁺ and CD8⁺ T cells by flow cytometry analysis of peripheral blood mononuclear cells (PBMCs), TDLNs, and tumor samples from patients with oral squamous cell carcinoma (OSCC). Our data showed that both helper and cytotoxic T lymphocytes in OSCC tissue were highly activated and expressed high level of PD-1 (over 70% positivity). Lymphocytes in TDLNs and peripheral blood expressed significantly lower levels of PD-1 and other activation markers compared to TILs. Moreover, we demonstrated that a significant fraction of PD-1 negative TILs expressed high levels of human leukocyte antigen – DR isotype and CD69. In contrast, PD-1 negative cells in TDLNs and PBMCs scarcely expressed the aforementioned activation markers. Furthermore, we proved that patients with a high percentage of CD3⁺ PD-1⁺ cells in tumor-draining lymph nodes had significantly lower disease-free and overall survival rates (log-rank test P = .0272 and P = .0276, respectively). Taken together, we proved that flow cytometry of lymph nodes in OSCC is feasible and may be used to investigate whether PD-1 levels in TDLNs correspond with survival and potentially with response to anti-PD-1 therapy. Such knowledge may ultimately help guide anti-PD-1 treatment.     

Tumor regression after combination of radiation and PD-1 antibody nivolumab treatment in a patient with metastatic mediastinal leiomyosarcoma: a case report

The PD-1/PD-L1 axis is characterized as an important checkpoint of immune activation, particularly through negatively regulating T cell function. Although accumulated evidence has demonstrated the patients with some types of tumor benefit from blockade of PD-1/PD-L1 signaling pathway, the possible synergistic effect of combination of radiotherapy and anti-PD-1/PD-L1 antibody still need to be explored. Here, we report a case of patient who was diagnosed with metastatic mediastinal leiomyosarcoma and treated by combination of local radiotherapy and anti-PD-1 antibody nivolumab. Remarkable tumor regression was observed at both the irradiated focus and distant metastatic sites 2 months later after combined treatment. The patient has tumor mutational burden (8.7 somatic mutations/Mb) and positive PD-L1 expression. The increased circulating lymphocytes suggest induced activation of immune response after combination treatment. Free disease progression has reached one and a half years as far.