Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 0 0 2026 08 15 1 18 Xiaoyan Huang Department of Oncology, 900th Hospital of PLA Joint Logistic Support Force, Fuzhou, Fujian, China Chunhong Xiao Department of General Surgery, 900th Hospital of PLA Joint Logistic Support Force, Fuzhou, Fujian, China Weixuan Hong Department of General Surgery, 900th Hospital of PLA Joint Logistic Support Force, Fuzhou, Fujian, China Xi Chen Department of General Surgery, 900th Hospital of PLA Joint Logistic Support Force, Fuzhou, Fujian, China Junwei Fang Department of Oncology, 900th Hospital of PLA Joint Logistic Support Force, Fuzhou, Fujian, China Zhirong Yang Department of Oncology, 900th Hospital of PLA Joint Logistic Support Force, Fuzhou, Fujian, China Lifen Cai Department of Oncology, 900th Hospital of PLA Joint Logistic Support Force, Fuzhou, Fujian, China Jiaqi Huang Department of Oncology, 900th Hospital of PLA Joint Logistic Support Force, Fuzhou, Fujian, China 2026 04 13 2026 05 17 Effective biomarkers are urgently needed to guide chemoimmunotherapy in advanced gastric cancer (AGC) and improve clinical outcomes. This study aimed to explore a blood-based immune score for predicting outcomes in patients with AGC receiving chemoimmunotherapy. In this retrospective analysis, patients with AGC receiving chemoimmunotherapy were included. Treatment response was assessed by Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1). Peripheral blood immune-inflammatory markers, including neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), systemic immune-inflammation index (SII), and C-reactive protein-to-albumin ratio (CAR), and immune cell subsets, including CD4+, CD8+, and natural killer (NK) cells, were measured pre- and post-treatment. Receiver operating characteristic (ROC) analysis determined optimal cutoffs. Logistic regression identified independent predictors of objective response rate (ORR), and a combined immune-inflammatory score was constructed. Progression-free survival (PFS) was estimated using the Kaplan–Meier method, with risk stratification based on the score. Bootstrap resampling was used for internal validation. Among 100 patients, the ORR was 46.0%. Multivariate analysis confirmed NLR ≤ 2.5 (adjusted odds ratio [aOR]=0.333), CD8+ T cells≥30% (aOR=3.439), and SII ≤ 600 (aOR=0.386) as independent predictors of ORR. The combined score (range 0–3) achieved an area under the curve (AUC) of 0.874 for ORR prediction. During a median follow-up of 15.3 months, patients with a score≥2 (favorable immune profile group) had significantly longer PFS than those with a score≤1 (unfavorable immune profile group) (median PFS: 15.6 vs 7.8 months). Bootstrap internal validation confirmed the stability of the score (concordance index [C-index]=0.814). The NLR/SII/CD8+ T-cell score was associated with treatment response and survival among patients with AGC receiving chemoimmunotherapy, suggesting that it is a hypothesis-generating tool requiring external validation and is not ready for clinical use. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/4799 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/4799/2388