[The composition of ascites lymphocytes in high-grade serous ovarian cancer and its correlation with clinical...

Objective: To explore the composition of ascites lymphocytes in high-grade serous ovarian carcinoma (HGSOC) and its correlation with clinical features. Methods: A total of 59 newly-diagnosed HGSOC patients, aged (58±11) years old, who were treated at the Department of Obstetrics and Gynecology of Peking University Third Hospital from July 2019 to December 2020 were included, collecting ascites and peritoneal irrigation fluid respectively. Detect the proportion of T, B, NK cell and its subpopulations by flow cytometry, and analyze its correlation with the clinical characteristics of patients. Results: Among 59 patients, 48 patients (81.4%) had ascites, and 11 patients (18.6%) had no ascites. Compared with the peritoneal irrigation fluid, the CD3⁺T (70.2%±15.6% vs 78.1%±6.7%, P=0.014), CD8⁺T (38.3%±11.2% vs 47.7%±10.1%, P=0.014) and CD16^-CD56^bright NK [2.0% (0.8%, 3.6%) vs 4.2% (1.5%, 7.1%), P=0.026] cells were significantly decreased in the ascites, while the CD16⁺CD56^dim NK cells was significantly increased [6.8% (2.8%, 15.7%) vs 2.6% (1.6%, 4.3%), P=0.008]. In patients with ascites volume ≥1 000 ml, CD16^-CD56^bright NK cells were significantly increased than those ascites volume<1 000 ml [3.1% (1.2%, 3.9%) vs 0.8% (0.4%, 2.3%), P=0.002]. Age was significantly positively correlated with the level of CD4⁺T cells (r=0.332, P=0.021) and the ratio of CD4⁺T/CD8⁺T (r=0.379, P=0.008) in ascites. In ascites from patients with poor response to treatment, the proportion of CD4⁺T cells was increased significantly than those with better response (64.7%±4.2% vs 48.3%±11.7%, P=0.002). Conclusion: The formation of ascites in newly diagnosed high-grade serous epithelial ovarian cancer patients would affect the lymphocyte composition in the abdominal cavity microenvironment, which is related to the patient's age, cancer progression and treatment response.