Adaptive NK cell expansion and activity in ovarian cancer patients with cytomegalovirus infection and inflammation (258)

Abstract

Objectives: Cytomegalovirus (CMV) infection has been shown to expand a subset of natural killer (NK) cells called adaptive NK cells (CD57+NKG2C+) that are long-lived, have enhanced cytotoxicity, and are thought to contribute to cancer control. CMV reactivation is associated with increased inflammation, which can impact patient outcomes. We sought to evaluate the impact of CMV exposure and inflammation, as measured by C-reactive protein (CRP), on adaptive NK cells in patients with high-grade serous ovarian cancer (HGSOC) using serum and ascites samples collected at the time of surgery. Methods: A total of 30 serum samples, collected at the time of cytoreductive surgery in women with HGSOC, were measured for CMV serostatus using an immunoassay and measured for CRP with an immunoturbidimetric method. The samples were categorized as reactive or non-reactive for CMV and low or high for CRP (≤10, >10 mg/L). Thirty serum and 23 ascites samples were evaluated by flow cytometry to quantify adaptive NK cells. A CyTOF panel of 42 antibodies was used to identify adaptive NK cells, differences in NK cell maturation and functional mediators, activation markers, a number of other immune subsets (CD8 T cells, T regulatory cells, B cells, monocytes), and proliferation signatures. Functional assays were performed to assess natural cytotoxicity and antibody-dependent cytokine cytotoxicity (ADCC) by CD1O7a degranulation and IFNy production. Data were analyzed using GraphPad Prism 8.2.0, and p-values ≤ 0.05 were considered statistically significant. Results: Patients with HGSOC with evidence of CMV exposure had increased percentages of CD57+NKG2C+ adaptive NK cells in the blood and ascites compared to those without CMV exposure (Figure 1, p=0.03). CRP blood levels were not significantly different (p=0.30). The increased percentages of adaptive NK cells, observed in the blood and ascites samples that were CMV IgG+, were not significantly altered by the presence (p=0.90) or absence (p=0.90) of CRP. Conclusions: CMV exposure influences the presence of an adaptive NK cell population in HGSOC patients. CMV expanded adaptive NK cells represent a unique NK cell population that, with their enhanced cytotoxicity and memory-like attributes, could be manipulated for future NK cell-based therapies in ovarian cancer. Objectives: Cytomegalovirus (CMV) infection has been shown to expand a subset of natural killer (NK) cells called adaptive NK cells (CD57+NKG2C+) that are long-lived, have enhanced cytotoxicity, and are thought to contribute to cancer control. CMV reactivation is associated with increased inflammation, which can impact patient outcomes. We sought to evaluate the impact of CMV exposure and inflammation, as measured by C-reactive protein (CRP), on adaptive NK cells in patients with high-grade serous ovarian cancer (HGSOC) using serum and ascites samples collected at the time of surgery. Methods: A total of 30 serum samples, collected at the time of cytoreductive surgery in women with HGSOC, were measured for CMV serostatus using an immunoassay and measured for CRP with an immunoturbidimetric method. The samples were categorized as reactive or non-reactive for CMV and low or high for CRP (≤10, >10 mg/L). Thirty serum and 23 ascites samples were evaluated by flow cytometry to quantify adaptive NK cells. A CyTOF panel of 42 antibodies was used to identify adaptive NK cells, differences in NK cell maturation and functional mediators, activation markers, a number of other immune subsets (CD8 T cells, T regulatory cells, B cells, monocytes), and proliferation signatures. Functional assays were performed to assess natural cytotoxicity and antibody-dependent cytokine cytotoxicity (ADCC) by CD1O7a degranulation and IFNy production. Data were analyzed using GraphPad Prism 8.2.0, and p-values ≤ 0.05 were considered statistically significant. Results: Patients with HGSOC with evidence of CMV exposure had increased percentages of CD57+NKG2C+ adaptive NK cells in the blood and ascites compared to those without CMV exposure (Figure 1, p=0.03). CRP blood levels were not significantly different (p=0.30). The increased percentages of adaptive NK cells, observed in the blood and ascites samples that were CMV IgG+, were not significantly altered by the presence (p=0.90) or absence (p=0.90) of CRP. Conclusions: CMV exposure influences the presence of an adaptive NK cell population in HGSOC patients. CMV expanded adaptive NK cells represent a unique NK cell population that, with their enhanced cytotoxicity and memory-like attributes, could be manipulated for future NK cell-based therapies in ovarian cancer.