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Bladder cancer (BC) is one of the most prevalent cancers around the world and, if not treated well, has high morbidity and mortality. Many studies have indicated that there may be various roles for the aryl hydrocarbon receptor (AHR) in the immune system. The aim of this study was to determine the frequency of Foxp3(+) regulatory T (Treg) and T helper 17 cells (Th17) in BC tissue in comparison with controls and determine the relationship between AHR, Foxp3(+) Treg and Th17 cells in BC. A total of 40 patients with BC were enrolled in this study. The control group was selected from non‐tumoural parts of bladder tissues from the patients who have undergone cystoscopy. The percentage of regulatory T cells (Foxp3(+)/CD4(+)) and Th17 (IL‐17(+)/CD4(+)), as well as AHR(+) cells in BC tissues and controls, were determined by immunohistochemistry. The results of this study showed that the number of Foxp3(+) Treg and Th17 is significantly higher in bladder tumour tissues in comparison with non‐tumoural tissues. Also, the percentage of AHR(+) lymphocytes and AHR(+) cells was increased significantly in bladder tumour tissues rather than non‐tumoural tissues. This study also found a relation between AHR and Foxp3(+)/CD4(+) T lymphocytes ratio cells in BC. The percentage of Foxp3(+) Tregs and AHR(+) cells were significantly correlated with the grade and stage of BC. An increase in the percentage of Foxp3(+) Treg and Th17 cells may play an important role in tumour immunity; and determining the relationship between AHR and differentiation of Th17/Foxp3(+)Treg in BC can lead to a potential cancer therapeutic possibility.

Programmed death‐ligand 1 (PD‐L1) blockade has revolutionized the prognosis of several cancers, but shows a weak effect on pancreatic cancer (PC) due to poor effective immune infiltration. Chemokine C‐C motif ligand 21 (CCL21), a chemokine promoting T cell immunity by recruiting and colocalizing dendritic cells (DCs) and T cells, serves as a potential antitumor agent in many cancers. However, its antitumor response and mechanism combined with PD‐L1 blockade in PC remain unclear. In our study, we found CCL21 played an important role in leukocyte chemotaxis, inflammatory response, and positive regulation of PI3K‐AKT signaling in PC using Metascape and gene set enrichment analysis. The CCL21 level was verified to be positively correlated with infiltration of CD8+ T cells by the CIBERSORT algorithm, but no significant difference in survival was observed in either The Cancer Genome Atlas or the International Cancer Genome Consortium cohort when stratified by CCL21 expression. Additionally, we found the growth rate of allograft tumors was reduced and T cell infiltration was increased, but tumor PD‐L1 abundance elevated simultaneously in the CCL21‐overexpressed tumors. Then, CCL21 was further verified to increase tumor PD‐L1 level through the AKT‐glycogen synthase kinase‐3β axis in human PC cells, which partly impaired the antitumor T cell immunity. Finally, the combination of CCL21 and PD‐L1 blockade showed superior synergistic tumor suppression in vitro and in vivo. Together, our findings suggested that CCL21 in combination with PD‐L1 blockade might be an efficient and promising option for the treatment of PC., Chemokine C‐C motif ligand 21 (CCL21) in the tumor microenvironment can promote T cell infiltration and enhance their antitumor immune response. However, CCL21 also stabilizes and upregulates programmed death‐ligand 1 (PD‐L1) expression on pancreatic cancer cells through the AKT‐glycogen synthase kinase‐3β signaling pathway at the same time, which could partly impair the local immune response. Thus, PD‐L1 blockade was used in combination with CCL21, which showed a powerful synergism and promising therapeutic efficacy.

Tumour-infiltrating lymphocytes (TILs) are known to mediate potent anti-tumour activity. As T-cell-based therapies start to reach clinical practice, it becomes increasingly important to understand what characterizes a successful anti-tumour T-cell response and to exploit this knowledge for patient stratification. Next-generation sequencing of T-cell receptors (TCRs) promises to provide insights into the complexity of the tumour T-cell infiltrate that go beyond the phenotypic level. A recent study by Chen et al made use of this novel technology to demonstrate that the TIL repertoire of oesophageal squamous cell carcinoma patients is distinct from that of non-tumour sites and is characterized by significant intratumoural heterogeneity. This study illustrates the great potential of the method and addresses several technical and biological hurdles that need to be considered. Careful sampling, normalization, and error correction will be required to optimally use TCR sequencing to answer biological questions and define predictive biomarkers, e.g. for cancer immunotherapy. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

The mechanisms underlying immune tolerance during pregnancy are poorly understood. We recently proposed a crucial role of T regulatory cells (Treg) in avoiding immunological rejection of the fetus, since we observed diminished number and function of Treg in abortion-prone mice. We further confirmed the protective role of Treg during pregnancy by transferring pregnancy-induced Treg into abortion-prone mice, which prevented rejection. Here, we analyzed the mechanisms involved in Treg-mediated protection. We transferred mice undergoing abortion with Treg from mice having normal pregnancies, including normal pregnant and abortion-prone mice as controls. We evaluated decidual lymphocytes for their cytokine profile. The mRNA levels for several tolerance-associated cytokines were also analyzed. As expected, Treg therapy prevented abortion, while expanding the peripheral and thymic Treg population. Locally, augmented foxp3 levels could be observed. Surprisingly, after therapy the decidual levels of the Th1 cytokines IFN-γ and TNF-α were not diminished. The transfer of Treg dramatically up-regulated the expression of LIF, TGF-β and HO-1 at the fetal-maternal interface. Our data suggest that Treg-treatment can not prevent T cell infiltration or high Th1 levels but is able to create a privileged tolerant microenvironment at the fetal-maternal interface, further shedding light onto the molecular mechanisms involved in pregnancy tolerance.