RT Journal Article SR Electronic T1 Immunosuppressive properties of human PD-1+ PDL-1+ dendritic cell from Lymph Nodes Aspirates of NSCLC patients JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 1656 DO 10.1183/13993003.congress-2020.1656 VO 56 IS suppl 64 A1 Iwona Kwiecień A1 Elżbieta Rutkowska A1 Rafał Sokołowski A1 Joanna Bednarek A1 Agata Raniszewska A1 Karina Jahnz-Różyk A1 Piotr Rzeepecki A1 Joanna Domagała-Kulawik YR 2020 UL http://erj.ersjournals.com/content/56/suppl_64/1656.abstract AB Dendritic cells DCs play a pivotal role in homeostasis of the immune system. The tumor microenviroment impairs the proper function of DCs. Despite the progress in anticancer immunotherapy, there are still many unresolved issues. Among them the immunomodulatory propeties of DCs in lung cancer are of interes.We investigated the differences of DCs subsets and with expression of immunomodulating and costimulatory molecules: PD-1, PD-L1 and CD80 in metastatic, non-metastatic LNs aspirates and peripheral blood PB.LNs aspirates were obtained during EBUS/TBNA procedure of 14 patients with primary NSCLC. The cells were analysed by flow cytometry.We reported the higher percentage of DCs in metastatic than in non-metastatic LNs and PB (0.324% vs 0.042% vs 0.036% p<0.05). The myeloid DCs was higher in metastatic LNs than in non- metastatic (49.2 vs 23.2 p<0.05). The proportions of PD-1 and PD-L1 DCs were higher in metastatic LNs than in non-metastatic (45.5% vs 13.3% and 52.7% vs 24.1% p<0.05). The proportion of DCs with CD80+ was higher in metastatic LNs than non-meatstatic (46.4% vs 11.0% p<0.05). Patients with metastatic disease have higher proportion of regulatory DCRegs (PD-1+ PDL-1+ CD80low) than patients with non-metastatic (respectively 6.7% vs 3.7%). Significantly lower expression of both PD-1+, PD-L2+ and CD80+ DCs was found in PB (2.2%, 2.2% and 3.2%).We report for the first time that DCs cells show increased expression of PD-1 and PD-L1 molecules that can interact with T lymphocytes in tumor suppressory microenvironment. It can be assumed that mature DCs infiltrating metastatic LNs can develop into DCRegs, which are involved in suppression of anti-tumor response.FootnotesCite this article as: European Respiratory Journal 2020; 56: Suppl. 64, 1656.This abstract was presented at the 2020 ERS International Congress, in session “Respiratory viruses in the "pre COVID-19" era”.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).