LSC Abstract – Correlation of IL-17A concentration with T regulatory cells in lung cancer microenvironment

There are many mechanisms that allow to escape tumour cells from the immune surveillance. It is known that T regulatory cells (Tregs) play a crucial role in the inhibition of immune response. Th17 cells are defined by production of IL17A and have pleiotropic function. The role of Th17 cells and Tregs and Th17 interaction in local environment of lung cancer remain unclear. The aim of this part of our study was a comparison of Tregs and Th17 in the BALF from lung affected by lung cancer (clBALF, as a local environment), healthy lung (hlBALF, as a control) and peripheral blood (PB, as a systemic environment) from the same patient. 17 patients with confirmed lung cancer were investigated. Flow cytometry method with a panel of monoclonal antibodies: anti: CD4/CD25/CD127/FoxP3 for Tregs evaluation and ELISA for IL-17A measurement were used. We observed significantly higher proportion of Tregs in clBALF than in hlBALF and PB (8.8 vs 5.0 vs.5.1%, respectively, p<0.05, ). The median proportion of IL-17A concentration was higher in clBALF than in hlBALF and serum (6.6 vs. 2.2 vs. 4.1 pg/ml, respectively, non-significant). We find positive correlation between IL-17 concentration and median proportion of Tregs in clBALF (r= 0.5, p<0.05), we didn9t observe this correlation in hlBALF and PB. The positive correlation between Tregs and IL-17A in clBALF indicates the role of these cells in regulation of local immune response in lung cancer. We confirmed the usefulness of BAL cells analysis which may be performed before immunotherapy and serve for monitoring immune status of patient.