Increased pro-angiogenic factors, infiltrating neutrophils and CD163+ macrophages in bronchoalveolar lavage fluid from lung cancer patients

- CD163+ macrophages are the predominant subset of infiltrating macrophages in BALF from lung cancer patients.
- The levels of IL-8 and VEGF are elevated in the bronchoalveolar lavage fluids from lung cancer patients.
- Tumor cells contribute to VEGF production.
- Detection of CD163+ macrophages and angiogenic factors in BALF is helpful for diagnosis of cancerous inflammation in lungs.

Infiltration of inflammatory cells and production of pro-angiogenic factors are important in lung cancer immunity. The distributions of those cells and their contributions to the production of pro-angiogenic factors and the activation phenotype of macrophages in bronchoalveolar lavage fluid (BALF) from lung cancer patients remain unclear. We analyzed the presence of distinct inflammatory cells and the macrophage activation phenotype together with the levels of vascular endothelial growth factor (VEGF) and interleukin 8 (IL-8) within BALF from 54 smoking lung cancer patients including 36 squamous cell carcinoma (SCC), 9 adenocarcinoma (AC), and 9 small cell lung cancer (SCLC) in comparison with those from 13 non-smoking and 7 smoking patients with nonspecific chronic inflammation and 8 non-smoking normal controls. We found a significantly lower percentage of total macrophages and a much higher percentage of neutrophils among all inflammatory cells in BALF from lung cancer and non-specific chronic inflammation patients. BALF from AC patients had a significantly higher percentage of lymphocytes. CD163+) macrophages predominantly existed in BALF from SCLC patients. BALF of lung cancer patients had markedly higher levels of IL-8 and VEGF. Interestingly, IL-8 level was positively correlated to the numbers of neutrophils and lymphocytes. VEGF level was inversely correlated to the number of lymphocytes but positively to cancer cells in SCC cases, whereas no correlation existed between CD163+) macrophages and the levels of IL-8 and VEGF. Our results suggest that the detection of infiltrating inflammatory cells and pro-angiogenic factors in BALF will be helpful for diagnosis of cancerous inflammation in lungs.