Daily Sepsis Research Analysis

OBJECTIVE: To integrate multi-cohort transcriptomic, single-cell, and experimental data to identify diagnostic signature genes for septic shock, establish a peripheral blood molecular diagnostic model, and elucidate the m6A regulatory mechanisms of key genes. METHODS: Candidate genes were identified from five GEO peripheral blood cohorts through batch effect-corrected differential expression analysis and WGCNA, followed by parallel GO/DO enrichment analysis. Feature genes were selected using PPI networks combined with LASSO, SVM-RFE, and random forest algorithms. A 5-gene artificial neural network (ANN) diagnostic model was constructed and validated using ROC and logistic regression in GSE95233, GSE131761, and clinical cohorts. Immune cell composition and expression of characteristic genes in neutrophils were analyzed using CIBERSORT and GSE167363 single-cell data. The METTL14/YTHDF1-S100A12 m6A axis was elucidated via qRT-PCR, Western blot, MeRIP-qPCR, RIP-qPCR, and Actinomycin D experiments. In CLP mice, siMETTL14 was administered for RESULTS: A total of 76 sepsis-shock-associated candidate genes were identified, enriched in the bacterial defense pathway. Five robust candidate genes (S100A12, MMP8, PGLYRP1, CEACAM8, MMP9) were selected by integrating PPI and three machine learning algorithms. The constructed ANN achieved high AUC across multiple cohorts, and all five genes showed significantly elevated mRNA and protein levels in peripheral blood from clinical sepsis patients. CIBERSORT and single-cell results indicated significant neutrophil expansion, with the five genes predominantly enriched in neutrophils and progressively elevated with worsening outcomes. m6A-related experiments demonstrated that METTL14 mediates m6A modification and stabilizes S100A12 mRNA through YTHDF1 recognition; knocking down either METTL14 or YTHDF1 accelerated its degradation. CONCLUSION: In this study, a diagnostic signature was established for septic shock comprising five neutrophil-associated genes and an ANN model, revealing the regulatory role of the METTL14/YTHDF1-mediated m6A-S100A12 axis in neutrophils. This suggests the METTL14/m6A pathway as a potential diagnostic and therapeutic target.

OBJECTIVES: Sepsis remains a major challenge in the ICU. Given the limitations of the one-size-fits-all strategy, precision medicine approaches are needed to identify distinct sepsis subtypes that may respond to different treatments. This study aimed to validate a temperature-trajectory model of sepsis developed in U.S. centers in a non-U.S. cohort from China, to characterize longitudinal immune and coagulation profiles, and to explore their potential value in guiding immunotherapy. DESIGN: This study validated a previously developed sepsis temperature-trajectory model, delineated longitudinal immune and coagulation dynamics across distinct subphenotypes, and, after propensity score matching, examined the heterogeneous effects of immunoglobulin treatment. SETTING: Retrospective data from a tertiary-care hospital ICU in China. PATIENTS: Adult ICU patients with suspected infection. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Clinical and microbiological characteristics were compared across subphenotypes, and the interaction between subphenotype and immunoglobulin therapy on 30-day mortality was assessed. In total, 2478 patients were included and classified into four subphenotypes: hyperthermic slow resolvers (567; 23%), hyperthermic fast resolvers (397; 16%), normothermic (780; 31%), and hypothermic (HT, 734; 30%). The HT subphenotype exhibited the highest mortality rate (25%), consistent with previous findings. In longitudinal immune and coagulation profiling, the HT subphenotype exhibited the lowest inflammatory response (low and rapidly declining C-reactive protein and rapidly declining interleukin-6), suppressed immunity (persistently low lymphocyte counts and monocyte human leukocyte antigen-DR), and coagulation abnormalities (persistently prolonged prothrombin time and activated partial thromboplastin time; the lowest platelet counts, fibrinogen, and hemoglobin; and the highest rate and dose of RBC transfusion). Immunoglobulin therapy showed heterogeneous effects across different subphenotypes, with patients in the HT subphenotype showing a consistent direction of benefit (primary subtyping: hazard ratio, 0.47; p = 0.03). CONCLUSIONS: The temperature-trajectory subphenotypes were validated in an international cohort. Patients in the HT subphenotype exhibited the highest mortality and showed persistent immune dysfunction and coagulopathy. Furthermore, different subphenotypes demonstrated distinct responses to immunoglobulin therapy.

BACKGROUND: In sepsis, personalized immunotherapy is being evaluated as a strategy to restore immune function in the most severely affected patients. Biomarkers are critical in this process, as clear clinical indicators of immune status are lacking. Functional testing is considered the gold standard for assessing immune function, but its clinical implementation faces analytical and standardization challenges. The objective of the present prospective, observational, single-center cohort study was to evaluate a fully automated protocol for assessing T cell functionality in septic shock patients. METHODS: In 66 patients with septic shock, we assessed T lymphocyte functionality using an interferon-γ release assay (IGRA) in response to mitogen. The assay was performed via a fully automated protocol during a one-year period. Patients were monitored three times during the first week after intensive care unit (ICU) admission. Phenotypic immunological parameters, including T cell subpopulation counts and monocyte HLA-DR expression (mHLA-DR), were also assessed. Patient outcomes were followed for 28 days, and a composite clinical deterioration score was defined by the occurrence of 28-day mortality and/or ICU-acquired infection. RESULTS: Compared with reference values, we observed a significant reduction in IFN-γ release capacity, which correlated with characteristic alterations in cellular immunological parameters. By the end of the first week, reduced IFN-γ release combined with low mHLA-DR identified a severe immunological phenotype associated with an increased risk of clinical deterioration. CONCLUSION: Given the observational nature of this study, further well-designed investigations in larger patient cohorts are required to validate these findings and assess their potential clinical relevance. If confirmed, this fully automated assay (performed on whole blood, requiring no technician intervention, and providing results within four hours) may offer a practical tool for monitoring immune functional alterations in routine clinical practice.