Increased frequency of circulating invariant natural killer T cells in malignant pleural mesothelioma patients

Tumor Immune Microenvironment and Genetic Alterations in Mesothelioma

Malignant pleural mesothelioma (MPM) is a rare and fatal disease of the pleural lining. Up to 80% of the MPM cases are linked to asbestos exposure. Even though its use has been banned in the industrialized countries, the cases continue to increase. MPM is a lethal cancer, with very little survival improvements in the last years, mirroring very limited therapeutic advances. Platinum-based chemotherapy in combination with pemetrexed and surgery are the standard of care, but prognosis is still unacceptably poor with median overall survival of approximately 12 months. The genomic landscape of MPM has been widely characterized showing a low mutational burden and the impairment of tumor suppressor genes. Among them, BAP1 and BLM are present as a germline inactivation in a small subset of patients and increases predisposition to tumorigenesis. Other studies have demonstrated a high frequency of mutations in DNA repair genes. Many therapy approaches targeting these alterations have emerged and are under evaluation in the clinic. High-throughput technologies have allowed the detection of more complex molecular events, like chromotripsis and revealed different transcriptional programs for each histological subtype. Transcriptional analysis has also paved the way to the study of tumor-infiltrating cells, thus shedding lights on the crosstalk between tumor cells and the microenvironment. The tumor microenvironment of MPM is indeed crucial for the pathogenesis and outcome of this disease; it is characterized by an inflammatory response to asbestos exposure, involving a variety of chemokines and suppressive immune cells such as M2-like macrophages and regulatory T cells. Another important feature of MPM is the dysregulation of microRNA expression, being frequently linked to cancer development and drug resistance. This review will give a detailed overview of all the above mentioned features of MPM in order to improve the understanding of this disease and the development of new therapeutic strategies.

CD4CD8 Double Positive T cell responses during Mycobacterium tuberculosis infection in cynomolgus macaques

BACKGROUND

Tuberculosis (TB) kills millions of people every year. CD4 and CD8 T cells are critical in the immune response against TB. T cells expressing both CD4 and CD8 (CD4CD8 T cells) are functionally active and have not been examined in the context of TB.

METHODS

We examine peripheral blood mononuclear cells (PBMC) and bronchoalveolar lavage cells (BAL) and lung granulomas from 28 cynomolgus macaques during Mycobacterium tuberculosis (Mtb) infection.

RESULTS

CD4CD8 T cells increase in frequency during early Mtb infection in PBMC and BAL from pre-infection. Peripheral, airway, and lung granuloma CD4CD8 T cells have distinct patterns and greater cytokine production than CD4 or CD8 T cells.

CONCLUSION

Our data suggest that CD4CD8 T cells transient the blood and airways early during infection to reach the granulomas where they are involved directly in the host response to Mtb.

Advances in the diagnosis, treatment and prognosis of malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a rare cancer originated from pleural mesothelial cells. MPM has been associated with long-term exposure to asbestos. The prognosis of MPM is poor due to the difficulty of making diagnosis in the early stage, the rapid progression, the high invasiveness and the lack of effective treatment. Although the incidence of MPM is low in China to date, it has a tendency to increase in the coming years. The variety of clinical features may cause the delay of diagnosis and high rate of misdiagnosis. The diagnosis of MPM is based on biopsy of the pleura and immunohistochemistry. As China has become the largest country in the consumption of asbestos, it would give rise to a new surge of MPM in the future. The current treatment of MPM is multimodality therapy including surgery, radiotherapy, chemotherapy and immunotherapy. Two surgical procedures are commonly applied: extrapleural pneumonectomy (EPP) and pleurectomy/decortication (P/D). Three dimensional conformal radiotherapy is used to denote a spectrum of radiation planning and delivery techniques that rely on the 3D imaging to define the tumor. Cisplatin combined with pemetrexed (PEM) is the first-line chemotherapy for MPM. The principal targets in immunotherapy include T cells (Treg), CTLA-4 and PD-1. The diagnosis, treatment and prognosis still remain a major challenge for clinical research and will do so for years to come.

Cell origins and significance of IL-17 in malignant pleural effusion

PURPOSE

T cells are dominant in the immune regulation of malignant pleural effusion (MPE). However, it is unclear about the role of IL-17+ T cells, particularly for IL-17+CD8+ Tc17 cells in antitumor immunity. This retrospective study is aimed at evaluating the prognostic significance of IL-17+ T cells in patients with MPE.

METHODS

The frequency of IL-17+CD4+ Th17 and IL-17+CD8+ Tc17 cells in peripheral blood (PB), pleural fluids (PF), and tumor tissues in 24 patients undergoing thoracoscopy was determined by flow cytometry, immunohistochemistry, and ELISA. The association among the different measures was analyzed by Spearman's correlation tests.

RESULTS

The percentages of PF Th17 and Tc17 cells were significantly higher than those in the PB of MPE patients and healthy controls (p < 0.01). Analysis of Th17 and Tc17 cells in the tumor tissues indicated that the percentages of Th17 and Tc17 cells in the invading tumor edge were significantly higher than those in the non-tumor tissues and intra-tumor regions (p < 0.05). More importantly, the percentages of IL-17+ T cells were associated with prolonged survival of patients with MPE.

CONCLUSIONS

Both Th17 and Tc17 cells were involved in the tumor immunity against MPE. Increased frequency of Tc17 cells may serve as a biomarker for the prognosis of patients with MPE.