Towards near-patient innate immune system monitoring

Automated flow cytometry (AFC) with immediate analysis may offers solutions to improve immune monitoring. In addition, routine implementation of AFC in the clinic has the potential to rapidly identify infections in the emergency department and to optimize the treatment of trauma patients. These were the main findings in the PhD research of Bernard Jukema (UMC Utrecht) who defended his PhD thesis on April 14, 2025 at Utrecht University.

The innate immune system forms the first line of defense against pathogens. A balanced immune response is crucial since both a hyperactive and hypoactive response leads to an inadequate immune response with an increased risk of complications. By studying the innate immune system, better insight is gained into whether it is balanced. This can then be applied clinically to identify, monitor and manage high-risk patients.

The PhD thesis of Bernard Jukema, MD (Department of Experimental Pulmonology and Center for Translational Immunology, UMC Utrecht) examined how automated flow cytometry (AFC) can assist in measuring the status of the innate immune system. Flow cytometry is a technique for counting, examining, and sorting immune cells suspended in a fluid stream. It allows for simultaneous multiparametric analysis of the physical and/or chemical characteristics of single cells flowing through an optical and/or electronic detection system. This new technique has advantages over traditional flow cytometry as it is easier to use, quicker and more accurate.

 Watch here a video featuring Bernard Jukema on the use of automated flow cytometry with help of a mobile laboratory

Practical uses of automated flow cytometry

AFC was applied in research with healthy volunteers to better understand the innate immune response under various conditions. The research focused on the ex vivo activation of innate immune effector cells, which poses challenges of measuring innate immune response. The rapid activation of these cells post-venipuncture presents obstacles for accurate and reliable analysis. Jukema investigated the feasibility of a mobile, automated, point-of-care AFC laboratory to mitigate ex vivo activation bias. This approach offers potential solutions for improved immune monitoring, both inside and outside hospital walls, with minimal burden for the patient.

1. Infections
AFC was also applied in patients in a point-of-care setting to rapidly identify infections in the emergency department. It appeared that AFC was able to differentiate bacterial from viral infections already within 30 minutes (instead of 2 hours), which may have a significant impact on patient outcome and it may prevent the misuse of antibiotics.

2. Trauma care
In a study in trauma patients, distinct immunophenotype categories were defined, that consisted of different neutrophil populations. Injury severity scores and risk of infectious complications increased with ascending immunophenotype category. Identification of trauma patients at risk for infectious complications by monitoring the immunophenotype category with AFC results in more rapid and personalized point-of-care decision making in trauma care.

3. Post-COVID
AFC also revealed specific mature neutrophil and eosinophil activation patterns in primary care patients with COVID-19 disease, during and 3-6 months after active disease. Results suggested that the neutrophil and eosinophil compartments are long-term affected by COVID-19, which indicates that these compartments may be involved in the pathogenesis of Post-COVID.

Bernard Jukema concluded: “My thesis highlights the potential of innate immune system monitoring to enhance our understanding of innate immune responses and to support clinical decision-making. Our examples represent just the initial exploration of the numerous potential applications where innate immune system monitoring could enhance patient care. One of the primary functions of the innate immune system is to provide a quick first line of defense against pathogens. Consequently, it is not surprising that our findings consistently demonstrate that innate immune system monitoring offers significant prognostic and diagnostic value for infections and clinical outcome.”