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Updated: May 23, 2026
Laparoscopic Radical Gastrectomy for Remnant Gastric Cancer
Published on: October 31, 2025
Immunological milieu in the peritoneal cavity at laparotomy for gastric cancer
Akira Yoneda1, Shinichiro Ito, Seiya Susumu
1Department of Surgery, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
Insights
Gastric cancer patients show altered immune cell profiles in the peritoneal cavity. Surgical removal of tumors reversed these immune changes, suggesting potential for immune regulation in advanced gastric cancer.
Area of Science:
- Immunology
- Oncology
- Gastroenterology
Background:
- The peritoneal cavity hosts immune interactions crucial for cancer progression.
- The specific role of lymphocytes within the peritoneal cavity of gastric cancer patients remains incompletely understood.
- Understanding these interactions is vital for developing targeted immunotherapies.
Purpose of the Study:
- To comprehensively investigate the immunological repertoire within the peritoneal cavity of gastric cancer patients.
- To analyze the characteristics and cytokine production of lymphocytes in the peritoneal fluid and peripheral blood.
- To explore the potential for immune modulation in the context of gastric cancer treatment.
Main Methods:
- Analysis of lymphocytes from peripheral blood and peritoneal lavage in 64 gastric cancer patients and 11 controls.
- Flow cytometry was used to assess lymphocyte surface markers and cytokine production.
- Co-cultivation assays of CD4(+)CD25(high) T cells with intra-peritoneal lymphocytes to evaluate immune suppression.
Main Results:
- Gastric cancer patients exhibited increased frequencies of CD4(+)CD25(high) T cells in both peripheral blood and peritoneal cavity, particularly in advanced stages.
- Effector memory CD8(+) T cells (CCR7(-) CD45RA(-)) were identified in the peritoneal cavity during gastrectomy.
- Immune suppression observed in advanced gastric cancer was reversible upon co-cultivation with autologous CD4(+)CD25(high) T cells.
Conclusions:
- The peritoneal cavity in advanced gastric cancer patients displays a distinct immunological environment, characterized by a Th2-biased response.
- This immune dysregulation is potentially reversible, as indicated by the restoration of immune balance post-gastrectomy.
- Findings highlight the dynamic nature of the peritoneal immune response in gastric cancer and its susceptibility to surgical intervention.
Aim:
To investigate the immunological repertoire in the peritoneal cavity of gastric cancer patients.
Methods:
The peritoneal cavity is a compartment in which immunological host-tumor interactions can occur. However, the role of lymphocytes in the peritoneal cavity of gastric cancer patients is unclear. We observed 64 patients who underwent gastrectomy for gastric cancer and 11 patients who underwent laparoscopic cholecystectomy for gallstones and acted as controls. Lymphocytes isolated from both peripheral blood and peritoneal lavage were analyzed for surface markers of lymphocytes and their cytokine production by flow cytometry. CD4(+)CD25(high) T cells isolated from the patient's peripheral blood were co-cultivated for 4 d with the intra-peritoneal lymphocytes, and a cytokine assay was performed.
Results:
At gastrectomy, CCR7(-) CD45RA(-) CD8(+) effector memory T cells were observed in the peritoneal cavity. The frequency of CD4(+) CD25 (high) T cells in both the peripheral blood and peritoneal cavity was elevated in patients at advanced stage [control vs stage IV in the peripheral blood: 6.89 (3.39-10.4) vs 15.34 (11.37-19.31), P < 0.05, control vs stage IV in the peritoneal cavity: 8.65 (5.28-12.0) vs 19.56 (14.81-24.32), P < 0.05]. On the other hand, the suppression was restored with CD4(+) CD25(high) T cells from their own peripheral blood. This study is the first to analyze lymphocyte and cytokine production in the peritoneal cavity in patients with gastric cancer. Immune regulation at advanced stage is reversible at the point of gastrectomy.
Conclusion:
The immunological milieu in the peritoneal cavity of patients with advanced gastric cancer elicited a Th2 response even at gastrectomy, but this response was reversible.