BALF immune profile - towards clinical usefulness in lung cancer

Abstract

The results of immunotherapy in lung cancer are highly individual and seem to be better in ‘hot’ tumors than in ‘cold’ ones. We previously showed usefulness of bronchoalveolar lavage fluid (BALF) examination in lung cancer. Here we aimed to assess if BALF profile might show the signs of active ‘hot’ immune response in tumor site and if the BALF from the lung free of tumor may serve for the characterization of local immune status. BALF of 68 patients was taken from the lung affected by cancer and opposite site: lung without tumor. BALF cells and blood cells were analyzed by flow cytometry for lymphocyte phenotyping (antibodies anti: CD3, CD19, CD4, CD8, CD45RA, CD69, CD25, Foxp3, CD127, CTLA4, PD-1) and by immunofluorescence for macrophage subtypes (CCR7 and CD163), the concentration of panel of 27 cytokines was analyzed using Bio-Plex Assay. We selected the markers to two groups: the effectory and regulatory/ suppressory ones. The profile of immune cells differed significantly between BALF and blood. The indications of active immune response were found in 53% of samples, in the majority of adenocarcinoma or NOS, without relation to mutational addiction. The proportions of Tregs, CTLA4+Tregs, activated and memory PD-1+ lymphocytes, CCR7lowCD163high macrophages, involved in regulatory pathways were significantly higher in cancerous than in ‘healthy’ lung. The proportion of effectory cells and cytokines did not differ between both lungs, indicating that they form an integrated immune system. BALF analysis may help in recognition of ‘hot’ immune response before immunotherapy. BALF from the ‘healthy’ lung, which is easier to obtain, may serve for the evaluation of individual natural profile of the anti-cancer response.