Immunosuppressive properties of human PD-1 + , PDL-1 + and CD80 + dendritic cells from lymph nodes aspirates of lung cancer patients

CCL22 Induces the Polarization of Immature Dendritic Cells into Tolerogenic Dendritic Cells in Radiation-Induced Lung Injury through the CCR4-Dectin2-PLC-γ2-NFATC2-Nr4a2-PD-L1 Signaling Pathway

Recruitment of immune cells to the injury site plays a pivotal role in the pathology of radiation-associated diseases. In this study, we investigated the impact of the chemokine CCL22 released from alveolar type II epithelial (AT2) cells after irradiation on the recruitment and functional changes of dendritic cells (DCs) in the development of radiation-induced lung injury (RILI). By examining changes in CCL22 protein levels in lung tissue of C57BL/6N mice with RILI, we discovered that ionizing radiation increased CCL22 expression in irradiated alveolar AT2 cells, as did MLE-12 cells after irradiation. A transwell migration assay revealed that CCL22 promoted the migration of CCR4-positive DCs to the injury site, which explained the migration of pulmonary CCR4-positive DCs in RILI mice in vivo. Coculture experiments demonstrated that, consistent with the response of regulatory T cells in the lung tissue of RILI mice, exogenous CCL22-induced DCs promoted regulatory T cell proliferation. Mechanistically, we demonstrated that Dectin2 and Nr4a2 are key targets in the CCL22 signaling pathway, which was confirmed in pulmonary DCs of RILI mice. As a result, CCL22 upregulated the expression of PD-L1, IL-6, and IL-10 in DCs. Consequently, we identified a mechanism in which CCL22 induced DC tolerance through the CCR4-Dectin2-PLC-γ2-NFATC2-Nr4a2-PD-L1 pathway. Collectively, these findings demonstrated that ionizing radiation stimulates the expression of CCL22 in AT2 cells to recruit DCs to the injury site and further polarizes them into a tolerant subgroup of CCL22 DCs to regulate lung immunity, ultimately providing potential therapeutic targets for DC-mediated RILI.

Imbalance of B-Cell Subpopulations in the Microenvironment of Sarcoidosis or Lung Cancer

Although the role of T lymphocytes in sarcoidosis (SA) and lung cancer (LC) is quite well reported, the occurrence of B cells in disease microenvironments may suggest their potential role as natural modifiers of the immune response. The aim of this study was to investigate the B-cell profile and lymphocyte-related hematological parameters between patients with SA, LC and healthy controls (HCs). The cells were assessed by flow cytometry and a hematological analyzer in peripheral blood (PB) and material from lymph nodes (LNs) obtained by the EBUS/TBNA method. We showed that in SA patients, there were higher percentages of naïve B and CD21low B cells and a lower percentage of class-switched memory B cells than LC patients in LNs. We observed a higher median proportion of non-switched memory and transitional B cells in the PB of SA patients than in LC patients. We noticed the lowest median proportion of class-switched memory B cells in the PB from SA patients. LC patients had a higher percentage of RE-LYMP and AS-LYMP than SA patients. Our study presented a different profile of B-cell subpopulations in SA and LC patients, distinguishing dominant subpopulations, and showed the relocation from distant compartments of the circulation to the disease microenvironment, thus emphasizing their role.

Tolerogenic dendritic cells in radiation-induced lung injury

Radiation-induced lung injury is a common complication associated with radiotherapy. It is characterized by early-stage radiation pneumonia and subsequent radiation pulmonary fibrosis. However, there is currently a lack of effective therapeutic strategies for radiation-induced lung injury. Recent studies have shown that tolerogenic dendritic cells interact with regulatory T cells and/or regulatory B cells to stimulate the production of immunosuppressive molecules, control inflammation, and prevent overimmunity. This highlights a potential new therapeutic activity of tolerogenic dendritic cells in managing radiation-induced lung injury. In this review, we aim to provide a comprehensive overview of tolerogenic dendritic cells in the context of radiation-induced lung injury, which will be valuable for researchers in this field.

[Molecular mechanisms of impaired antigenic presentation as a cause of tumor escape from immune surveillance]

The review summarizes data on the features of antigen presentation in tumor cells. The molecular mechanisms of the antitumor immune response are considered with an emphasis on the ability of tumor cells to avoid the action of immune surveillance. The features of expression of MHC molecules depending on treatment regimens are provided. Ways to improve existing and create new treatment regimens aimed at elimination of tumor cells because of antitumor immune response are discussed.

Effector Memory T Cells and CD45RO+ Regulatory T Cells in Metastatic vs. Non-Metastatic Lymph Nodes in Lung Cancer Patients

Lymphocytes play a leading role in regulation of the immune system in lung cancer patients. The recognition of T cells profile may help in prediction of effectiveness of anticancer immunotherapy. The aim of the study was to determine the dominant subpopulation of CD4+ and CD8+ lymphocytes in metastatic and non-metastatic lymph nodes (LNs) of lung cancer patients. LNs aspirates were obtained during EBUS/TBNA procedure and cells were analyzed by flow cytometry. We showed a higher percentage of CD4+ and CD8+ effector memory T cells in the metastatic than in the non-metastatic LNs (28.6 vs. 15.3% and 28.6 vs. 14.0%, p< 0.05). The proportion of CD45RO+ T regulatory cells (CD45RO+ Tregs) was higher in the metastatic LNs than in the non-metastatic ones (65.6 vs. 31%, p< 0.05). We reported the significant differences in T cell subsets depending on the lung cancer metastatic process. We observed that the effector memory T cells were predominant subpopulations in metastatic LNs. Lymphocyte profile in LNs is easy to evaluate by flow cytometry of EBUS/TBNA samples and may reflect the immune status in lung cancer.