Pro-Inflammatory Role of Neutrophils Populations in Trauma Patients: Monitoring Neutrophil Populations

Marcela Vlkova^1*Julie Stichova¹Karolina Sura¹Karolina Dvorakova¹Vojtech Kuncicky¹Ioanna Papatheodorou^2,3Gabriela Blazkova²Zuzana Tomasikova^2,4Kamila Bendíčková^2,5Ludmila Dohnalkova⁶Alexandra Mytnikova¹Jan Zak⁶Jan Kovarik⁷Milan Krticka⁷Tomas Tomas⁵Vladimir Sramek⁶Martin Helán^2,6Anna Kocurkova^1,8Jan Fric^2,5,9Marcela Hortova Kohoutkova^2,5

• ¹Institute of Clinical Immunology and Allergology, St. Anne’s University Hospital and Faculty of Medicine, Masaryk University, Brno, South Bohemia, Czechia
• ²International Clinical Research Center (FNUSA-ICRC), Brno, South Moravia, Czechia
• ³Department of Biology, Faculty of Medicine, Masaryk University, Brno, South Moravia, Czechia
• ⁴Department of Animal physiology, Faculty of Science, Masaryk University, Brno, South Moravia, Czechia
• ⁵International Clinical Research Center, Faculty of Medicine, Masaryk University, Brno, South Bohemia, Czechia
• ⁶First Department of Orthopaedic Surgery, St. Anne’s University Hospital and Faculty of Medicine, Masaryk University, Brno, South Bohemia, Czechia
• ⁷Department of Trauma Surgery, University Hospital Brno, Brno, South Bohemia, Czechia
• ⁸Department of Biophysics of Immune System, Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Olomouc, Czechia
• ⁹Institute of Haematology and Blood Transfusion (Czechia), Prague, Prague, Czechia

Background: Trauma is a leading global cause of mortality, and systemic inflammatory response syndrome (SIRS) remains a significant complication, contributing to adverse outcomes. Neutrophils, as first responders to tissue injury, undergo substantial phenotypic and functional changes following trauma. This study investigates neutrophil subpopulations defined by CD16 and CD62L expression in trauma patients, focusing on their correlation with clinical biomarkers, trauma severity, and functional properties.Methods: We included 50 non-infectious trauma patients, categorized into SIRS and Non-SIRS groups, and 43 elective surgery patients as controls. Neutrophil subsets were analyzed at two time points (TP1 and TP2) using flow cytometry. Functional assays evaluated phagocytosis, oxidative burst, mitochondrial function, and degranulation. Correlations between neutrophil subpopulations and clinical markers, including lactate, creatine kinase, Injury Severity Score, and Trauma and Injury Severity Score, were examined.Results: Patients with SIRS exhibited higher proportions of banded neutrophils and CD16 low CD62L low neutrophils at TP1, alongside reduced levels of mature neutrophils. Elevated lactate and creatine kinase levels positively correlated with banded neutrophils and CD16 low CD62L low neutrophils, while negatively correlating with mature neutrophils CD16 high CD62L high and hypersegmented neutrophils CD16 high CD62L low . Hypersegmented neutrophils were more prevalent in Non-SIRS patients at TP1 and in SIRS patients at TP2. Banded neutrophils showed a positive correlation with Injury Severity Score and an inverse correlation with Trauma and Injury Severity Score (TRISS), whereas hypersegmented neutrophils were negatively associated with ISS and positively correlated with TRISS. These correlations likely reflect the pro-inflammatory role of banded neutrophils and the inflammationresolving function of hypersegmented neutrophils. CD16 low CD62L low neutrophils displayed impaired phagocytosis, oxidative burst, and degranulation capacity, indicating functional deficiencies.Conclusion: This study highlights the dynamic changes in neutrophil subpopulations in trauma and their association with systemic inflammation and clinical severity. Increased banded neutrophils correlate with SIRS and metabolic stress, whereas hypersegmented neutrophils may contribute to resolving inflammation. CD16 low CD62L low neutrophils exhibit functional impairments, warranting further investigation. Monitoring neutrophil subpopulations could aid in identifying trauma patients at risk for non-infectious SIRS and guide therapeutic interventions.