| BackgroundLung cancer is the most common malignancy in China in terms of incidence and mortality.The advent of immune checkpoint inhibitors(ICI)has significantly improved the prognosis of some lung cancer patients,but the remission rate of single-agent immunotherapy is low and the efficacy of immunotherapy needs to be further improved.The response to immunotherapy is related to the immune infiltration status of the tumor immune microenvironment(TIME),and anti-angiogenic drugs not only participate in the remodeling of abnormal blood vessels in the microenvironment,but also modulate tumor immune cell infiltration and reverse the immunosuppressive state of the TIME.Bevacizumab,a recombinant humanised Vascular endothelial growth factor(VEGF)monoclonal antibody,has immunomodulatory effects in addition to its known anti-angiogenic effects,and is clinically effective not only in lung cancer,but also in patients with advanced lung cancer with pleural effusion,providing significant relief and prolonging survival.It can improve the quality of survival and prolong the survival period.As lung cancer tissue specimens cannot be repeatedly obtained to observe the dynamic changes in TIME,and because of the significant heterogeneity of tissue specimens for TIME testing,we selected lung adenocarcinoma patients with malignant pleural effusions,in which tumour cells directly contact and interact with host lymphocytes in the fluid phase in the patient’s pleural cavity.This experiment focused on the changes in lymphocyte subpopulations and PD-L1 expression in pleural effusions after bevacizumab treatment.MethodsA total of 45 patients with pleural effusion between April 2019 and March 2021 were collected from the Department of Respiratory Medicine,Qilu Hospital,Shandong University.For 35 cases of lung adenocarcinoma,peripheral blood and pleural effusion were collected at the time of admission,intravenous drip with bevacizumab 15 mg/Kg,and pleural effusion was collected after 3 days of treatment.All peripheral blood and 5ml of pleural fluid specimens before and after treatment were tested for CD3+T,CD4+T,CD8+T lymphocytes,B lymphocytes and NK cells by flow cytometry;200ml of pleural fluid sediment before and after treatment were made into pleural fluid wax blocks,which were tested for PD-L1 expression by immunohistochemistry and finally compared and analysed.The patients were selected for systemic treatment according to their driver genes and followed up.The correlation between various clinical data and lymphocyte subsets was analysed,and the efficacy of systemic and pleural effusions after 2 cycles of treatment was also followed up in this group.In 10 cases of tuberculous pleurisy,peripheral blood and pleural fluid were collected on admission and the pleural fluid was tested for CD3+T,CD4+T,CD8+T lymphocytes,B lymphocytes and NK cells by flow cytometry.Results1.The percentage of CD3+T,CD4+T lymphocytes and CD4+T/CD8+T ratio in the pleural effusion of patients with lung adenocarcinoma before bevacizumab treatment were significantly higher than those in peripheral blood;the percentage of NK cells was significantly lower than that in peripheral blood,and the difference was statistically significant(P<0.05).2.The percentage of CD3+T and CD4+T lymphocytes in the pleural effusion of patients with tuberculous pleurisy was significantly higher than that of peripheral blood;the percentage of NK cells was lower than that of peripheral blood,and the difference was statistically significant(P<0.05).3.The percentage of CD3+T lymphocytes in the pleural effusion of patients with tuberculous pleurisy was higher than that of lung adenocarcinoma;the percentage of B lymphocytes was lower than that of the lung adenocarcinoma group,and the difference was statistically significant(P<0.05).4.The percentage of CD3+T,CD4+T lymphocytes and CD4+T/CD8+T ratio in the pleural effusion in the lung adenocarcinoma group after treatment with bevacizumab were lower than before treatment,and the percentage of CD8+T lymphocytes was higher than before treatment,the difference was statistically significant(P<0.05).5.In the pleural effusion of lung adenocarcinoma,the percentage of NK cells was higher in female patients than in male patients,and the difference was statistically significant(P<0.05).6.In the peripheral blood of lung adenocarcinoma,the percentage of CD3+T lymphocytes was higher in patients with driver genes than in patients without driver genes;the percentage of B lymphocytes was higher in patients without smoking history than in patients with smoking history,and the difference was statistically significant(P<0.05).7.In patients with lung adenocarcinoma,PD-L1 expression was elevated in one patient after treatment with bevacizumab,and decreased in all four patients after treatment.8.35 patients with malignant pleural effusion were evaluated for clinical efficacy after 2 cycles of treatment.The results of systemic efficacy evaluation:Objective remission rate(ORR)was 53.13%and disease control rate(DCR)was 81.25%;the results of pleural efficacy evaluation.ORR was 71.88%and DCR was 84.38%.There were 29 cases treated with bevacizumab in combination or alone,and the results of the 2-cycle systemic efficacy evaluation were 53.6%ORR and 82.14%DCR,while the results of the pleural efficacy evaluation were 71.4%ORR and 85.71%DCR.Conclusions1.The percentage of CD8+T lymphocyte subpopulation in pleural fluid increased after 3 days of bevacizumab treatment for lung adenocarcinoma compared to the pre-treatment period.The increased level of CD8+T-infiltrating lymphocytes correlated with a better prognosis for immunotherapy,and it remains to be explored whether the increased percentage of CD8+T lymphocyte subpopulation in pleural fluid facilitates immunotherapy2.After bevacizumab treatment in the lung adenocarcinoma group,PD-L1 expression mostly showed a decreasing trend,and it needs to be further explored whether PD-L1 expression will increase again with time and whether this will be the best time for combination immunotherapy.3.Bevacizumab treatment in patients with advanced lung adenocarcinoma combined with pleural effusion has shown significant local efficacy in the treatment of pleural effusion.4.The percentages of CD3+T and CD4+T cells in the pleural effusions of both lung adenocarcinoma and tuberculous pleurisy groups were higher than those in peripheral blood,and the percentages of NK cells were lower than those in peripheral blood,indicating that regardless of benign and malignant pleural effusions,when lesions occur in the organism,the immune response is more pronounced locally than peripherally,and it is meaningful to use the dynamic changes of malignant pleural effusions to observe changes in the immune microenvironment;NK cells in pleural fluid were NK cells in the pleural fluid are significantly lower than in peripheral blood,indicating a defect in the aggregation of NK cells in the pleural fluid.5.In pleural effusions,the percentage of NK cells was significantly higher in women with lung adenocarcinoma than in men.In peripheral blood,the percentage of CD3+T lymphocyte subsets was higher in patients with lung adenocarcinoma combined with driver genes than in patients without driver genes;the percentage of B lymphocytes was higher in patients with lung adenocarcinoma without a history of smoking than in patients with a history of smoking. |
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