Visualization of the inflammatory response to injury by neutrophil phenotype categories

Limited impact of traumatic brain injury on the post-traumatic inflammatory cellular response

PURPOSE

Trauma triggers a systemic inflammatory cellular response due to tissue damage, potentially leading to a secondary immune deficiency. Trauma severity is quantified by the Injury Severity Score (ISS). Severe Traumatic Brain Injury (TBI) is associated with high ISSs due to high lethality, despite limited tissue damage. Therefore, ISS might overestimate the post-traumatic inflammatory cellular response. This study investigated the effect of TBI on the occurrence of different systemic neutrophil phenotypes as alternative read-out for systemic inflammation.

METHODS

A single-center retrospective cohort study was conducted at a level-1 trauma center. Patients aged ≥ 18 years, admitted between 01-03-2021-01-11-2022 and providing a diagnostic blood sample were included. Four groups were created: isolated TBI, isolated non-TBI, multitrauma TBI and multitrauma non-TBI. Primary outcome was occurrence of different neutrophil phenotypes determined by automated flow cytometry. Secondary outcome was infectious complications.

RESULTS

In total, 404 patients were included. TBI and non-TBI patients demonstrated similar occurrences of different neutrophil phenotypes. However, isolated TBI patients had higher ISSs than their isolated non-TBI controls who suffered similar post-traumatic inflammatory cellular responses. Regardless of the type of injury, patients exhibiting higher systemic inflammation had a high infection risk.

CONCLUSION

When TBI is involved, ISS tends to be higher compared to similar patients in the absence of TBI. However, TBI patients did not demonstrate an increased inflammatory cellular response compared to non-TBI patients. Therefore, TBI does not add much to the inflammatory cellular response in trauma patients. The degree of the inflammatory response was related to the incidence of infectious complications.

Alterations in the immune landscape characterized by inflammatory activation and immune escape within 12 h after trauma

BACKGROUND

Trauma is statistically a significant cause of mortality among patients across countries. Nevertheless, the precise correlation between genetic diagnostic markers and the intricate mechanism of trauma remains indistinct.

METHODS

Our study exclusively centered on trauma patients and selected three trauma-related datasets from the Gene Expression Omnibus (GEO) database, all of which had blood samples collected within post-traumatic 12 h. Differential gene screening, the WGCNA and Cytoscape software were employed to analyze the two datasets, with a particular emphasis on the top 100 genes selected based on MCC algorithm scores. A logistic diagnostic model was constructed by analyzing the intersection genes in the third dataset, leading to the identification of diagnostic biomarkers with high efficiency. The global immune landscape of these patients was extensively investigated using a multidimensional approach. Meanwhile, the underlying pathological and physiological mechanisms associated with early trauma status are summarized by integrating existing literature.

RESULTS

Out of these two GEO datasets, 21 overlapping genes were identified and incorporated into in the logistic diagnostic model constructed in the GSE36809 dataset. A panel of 9 genes was uncovered as a diagnostic biomarker, and their expression and correlation were subsequently verified. Additionally, by virtue of various algorithms, the findings revealed an upregulation of neutrophil expression and a downregulation of CD8+ T cell expression, indicating characteristic early trauma-induced inflammation activation and immune suppression. The correlation observed between the feature genes and immune cells serves to validate the exceptional diagnostic capability of these 9 genes in identifying trauma status and their promising potential for patients who could benefit from targeted immune interventions. Drawing from these findings, the discussion section offers insights into the underlying pathological and physiological mechanisms at play.

CONCLUSION

Our research has discovered a novel diagnostic biomarker and unveiled its association with post-traumatic immune alterations. This breakthrough enables accurate and timely diagnosis of early trauma, facilitating the implementation of appropriate healthcare interventions.

Identification of neutrophil phenotype categories in geriatric hip fracture patients aids in personalized medicine

Objectives

The number of geriatric hip fracture patients is high and expected to rise in the coming years, and many are frail and at risk for adverse outcomes. Early identification of high-risk patients is crucial to balance treatment and optimize outcome, but remains challenging. Previous research in patients with multitrauma suggested that neutrophil phenotype analysis could aid in early identification of high-risk patients. This pilot study investigated the feasibility and clinical value of neutrophil phenotype analysis in geriatric patients with a hip fracture.

Methods

A prospective study was conducted in a regional teaching hospital in the Netherlands. At the emergency department, blood samples were collected from geriatric patients with a hip fracture and analyzed using automated flow cytometry. Flow cytometry data were processed using an automated clustering algorithm. Neutrophil activation data were compared with a healthy control cohort. Neutrophil phenotype categories were assessed based on two-dimensional visual assessment of CD16/CD62L expression.

Results

Blood samples from 45 geriatric patients with a hip fracture were included. Neutrophils showed an increased activation profile and decreased responsiveness to formyl peptides when compared to healthy controls. The neutrophil phenotype of all patients was categorized. The incidence of severe adverse outcome was significantly different between the different categories (P = 0.0331). Moreover, patients with neutrophil phenotype category 0 developed no severe adverse outcomes.

Conclusions

Using point-of-care fully automated flow cytometry to analyze the neutrophil compartment in geriatric hip fracture patients is feasible and holds clinical value in determining patients at risk for adverse outcome. This study is a first step toward immuno-based precision medicine for identifying geriatric hip fracture patients that are deemed fit for surgery.