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The role of immune checkpoint inhibitors in metastatic lung cancer has been established in recent years and the pretherapeutic profiles of the tumor microenvironment in responders have been increasingly reported. The role of salvage surgery and the immune profiles of the posttherapeutic specimens in patients achieving an objective response have rarely been studied. We report a case of metastatic lung cancer treated by anti‐programmed death‐1 Ab followed by surgical resection. The immune status of the tumor was assessed, showing germinal center formation, memory B cell infiltration, and a high frequency of interferon gamma ‐secreting T cells. [ABSTRACT FROM AUTHOR]

Background: Due to the strong tumoricidal activities of activated natural killer T (NKT) cells, invariant NKT cell-based immunotherapy has shown promising clinical efficacy. However, suppressive factors, such as regulatory T cells (Tregs), may be obstacles in the use of NKT cell-based cancer immunotherapy for advanced cancer patients. Here, we investigated the suppressive effects of Tregs on NKT cells and the underlying mechanisms with the aim to improve the antitumor activities of NKT cells. Methods: Peripheral blood samples were obtained from healthy donors, patients with benign tumors, and patients with head and neck squamous cell carcinoma (HNSCC). NKT cells, induced with α-galactosylceramide (α-GalCer), and monocyte-derived dendritic cells (DCs) were co-cultured with naïve CD4+ T cell-derived Tregs to investigate the mechanism of the Treg suppressive effect on NKT cell cytotoxic function. The functions and phenotypes of NKT cells were evaluated with flow cytometry and cytometric bead array. Results: Treg suppression on NKT cell function required cell-to-cell contact and was mediated via impaired DC maturation. NKT cells cultured under Treg-enriched conditions showed a decrease in CD4− NKT cell frequency, which exert strong tumoricidal responsiveness upon α-GalCer stimulation. The same results were observed in HNSCC patients with significantly increased effector Tregs. Conclusion: Tregs exert suppressive effects on NKT cell tumoricidal function by inducing more CD4− NKT cell anergy and less CD4+ NKT cell anergy. Both Treg depletion and NKT cell recovery from the anergy state may be important for improving the clinical efficacy of NKT cell-based immunotherapy in patients with advanced cancers. [ABSTRACT FROM AUTHOR]

Background: Tumor immunity has been suggested to play a key role in clinical and biological behavior of neuroblastomas. Given that CD1-restricted invariant natural killer T (iNKT) cells enhance both innate and acquired tumor immunity, we investigated the expression of the iNKT-cell-specific T-cell receptor Vα24-Jα18 in neuroblastoma tissues and its correlation with clinical and biological characteristics.Methods: Using real- time quantitative PCR, we quantified the expression of Vα24-Jα18 in untreated tumor samples from 107 neuroblastoma cases followed in our institution and analyzed the correlation between the presence of infiltrated iNKT cells and clinical characteristics or patients' outcome.Results: Vα24-Jα18 receptor was detected in 62 untreated cases (57.9%). The expression was significantly higher in stages 1, 2, 3, or 4S (P = 0.0099), in tumors with low or intermediate risk (P = 0.0050), with high TrkA expression (P = 0.0229), with favorable histology (P = 0.0026), with aneuploidy (P = 0.0348), and in younger patients (P = 0.0036). The overall survival rate was significantly higher in patients with iNKT-cell infiltration (log-rank; P = 0.0089).Conclusions: Since tumor-infiltrating iNKT cells were predominantly observed in neuroblastomas undergoing spontaneous differentiation and/or regression, we suggest that iNKT cells might play a key role in these processes. [ABSTRACT FROM AUTHOR]

Background: Invariant natural killer T (iNKT) cells play an important role in tumor immunity, enhancing both innate and acquired immunity. We have previously shown the enhancement of antibody-dependent cellular cytotoxicity against neuroblastoma by activated iNKT cells. As a first step towards clinical application, we studied the frequency and proliferative response of circulating iNKT cells in children with and without cancer.Methods: Blood samples were collected from 10 patients with pediatric malignant solid tumors and 11 patients with non-neoplastic diseases (control). The frequency of circulating iNKT cells was quantified by flow cytometry. Whole peripheral blood mononuclear cells were then stimulated with α-galactosylceramide (α-GalCer) for 7 days, and the expansion rate of the iNKT-cell fraction was assessed.Results: The frequency of iNKT cells in the patients of the cancer and control group did not differ to a statistically significant extent. The iNKT-cell population increased after α-GalCer stimulation in all cases. The iNKT cells of patients who had undergone intensive chemotherapy also had the potential to expand in vitro.Conclusions: Unlike adult cancer patients, the numbers of circulating iNKT cells were not decreased in pediatric cancer patients. α-GalCer stimulation induced a proliferative response in all of the patients. [ABSTRACT FROM AUTHOR]

Myeloid-derived suppressor cells (MDSC) are a heterogeneous population of immature and progenitor myeloid cells with an immunosuppressive role in various types of cancer, including head and neck squamous cell carcinoma (HNSCC). However, the effect on the host immune system, especially on invariant NKT (iNKT) cells with potent anti-tumor activity, remains unclear. In this study, we investigated the effects of circulating MDSC subsets on the peripheral lymphocytes of patients with head and neck tumors. A significant accumulation of CD15+ granulocytic MDSC (G-MDSC) and CD14+ monocytic MDSC (M-MDSC) was demonstrated in HNSCC patients. The percentage of G-MDSC showed an inverse correlation with the percentage of T cells in the peripheral blood. The increased G-MDSC was significantly associated with advanced clinical stage and poor prognosis of HNSCC patients. The proliferation and viability of T cells were suppressed by CD15+ cells, and the suppression was reversed by adding the hydrogen peroxide scavenger catalase. However, iNKT cell activation upon α-galactosylceramide (αGalCer) stimulation was not affected by the presence or absence of CD15+ G-MDSC. These results indicate that increased G-MDSC negatively affects peripheral T cell immunity, but not iNKT cells, in HNSCC patients, and that T cells are more sensitive to hydrogen peroxide produced by G-MDSC than iNKT cells. Cancer immunotherapy designed to enhance the antitumor activity of iNKT cells by stimulation with αGalCer may remain effective in the presence of G-MDSC. [ABSTRACT FROM AUTHOR]