Helicobacter pylori infection disturbs the tumor immune microenvironment and is associated with a discrepant prognosis in gastric de novo diffuse large B-cell lymphoma

BACKGROUND: Gastric diffuse large B-cell lymphoma (gDLBCL) related to Helicobacter pylori infection exhibits a wide spectrum of prognosis, and the tumor immune microenvironment (TIME) affects tumor progression. However, there are few studies on the correlation between prognosis and changes of TIME induced by H. pylori infection in de novo gDLBCL. METHODS: A retrospective study was performed to determine the prognostic value of TIME related to H. pylori infection in de novo gDLBCL. A total of 252 patients were included and have been treated with standard rituximab to cyclophosphamide, doxorubicin, vincristine, and prednisone chemotherapy or other similar regimens in addition to H. pylori eradication (HPE). All patients were stratified by H. pylori infection, HPE efficacy, and preliminary TIME evaluation using conventional criteria. Statistical analyses were conducted. To assess the mechanism, 30 subjects were assessed for H. pylori infection. The components and spatial distributions of TIME were analyzed. RESULTS: The median follow-up of the 252 patients was 66.6 months (range 0.7–119.2), and the 5-year overall survival (OS) was 78.0%. A total of 109 H. pylori-positive cases with pathological complete remission and high tumor-infiltrating T lymphocytes (cohort 1) had significantly higher 5-year progression-free survival (88.1% vs 70.5%, p<0.001) and OS (89.2% vs 76.6%, p<0.001) than the other 143 patients (cohort 2). Among 30 patients, 19 were cytotoxin-associated gene A-marked as the cohort 1 subset. Compared with cohort 2, cohort 1 exhibited increased inflammatory factors (tumor necrosis factor-α, interferon γ, etc) and decreased immunosuppressive components (PD-L1, PD-1, IL-10, etc). There was reduced NF-kB activation. Cancer-promoting immune cells (PD-1hiTim-3+ CTL, Tregs, M2-like macrophages, etc) occupied a minor spatial distribution, while the antitumor subtypes increased, corresponding to favorable survival. CONCLUSION: H. pylori-evoked inflammatory responses disturb the TIME, causing a differential prognosis in de novo gDLBCL, which can be used to identify patients who could benefit from HPE and immunochemotherapy.