The bone marrow of a heart attack patient starts releasing cells it normally holds in reserve – cells so immature they shouldn’t be in the bloodstream at all. That biological emergency signal has been visible to researchers for nearly a century. What doctors could never do was read it.
A 2026 study from the University of Münster has changed that. By analyzing what happens inside a routine blood test drawn at hospital admission, the research team found that these primitive immune cells don’t just reflect how sick a patient is – they can predict, with greater accuracy than existing tools, whether that patient will be alive 30 days later. A research team led by the University of Münster demonstrated that the maturity level of neutrophils can be used to determine the short-term risk of death, assessable through a simple blood test, with findings published in the journal Nature Cardiovascular Research.
The implications reach beyond cardiology. Cardiologists, emergency physicians, and intensivists have long sought a reliable way to separate high-risk from lower-risk patients in the chaotic first hours after a cardiac event. Troponin tells you the heart was damaged. What this new marker tells you is how the body is coping with that damage – and whether it’s losing the fight.
The Scale of the Problem: Why Heart Attack Survival Prediction Matters
Cardiovascular diseases are the leading cause of death globally, responsible for an estimated 19.8 million deaths in 2022 – approximately 32% of all global deaths – with 85% of those deaths attributed to heart attack and stroke, according to the World Health Organization. In the United States alone, heart disease killed 371,506 people in 2022 and remains the leading cause of death in the country, according to the CDC.
Despite recent improvements in critical care medicine, patients with ST-segment elevation myocardial infarction – identified on an electrocardiogram at hospital arrival – remain at elevated risk of mortality and serious harm even if they survive the initial ischemic event, according to a 2018 study in Scientific Reports. The problem is triage. Not every patient who arrives in the emergency department after a heart attack faces the same risk of dying in the next month. Yet until now, the tools available to make that distinction quickly have been imprecise or required specialized testing that most hospitals can’t perform at admission.
Neutrophil mobilization during an acute heart attack has been known for almost a hundred years, but how to reliably identify high-risk patients immediately upon hospital admission has remained unresolved. The new study, led by Professor Oliver Soehnlein – Professor of Regulatory Mechanisms of Inflammation and Director of the Institute of Experimental Pathology at the Center for Molecular Biology of Inflammation at the University of Münster – offers an answer drawn from biology that hospitals already have access to.
The Biology Behind the Biomarker
What Neutrophils Are – and Why Their Maturity Level Matters
During a heart attack, the immune system reacts alongside the heart itself. Large numbers of neutrophils – the most abundant type of white blood cell in the body – are released from the bone marrow into the bloodstream, even though under normal circumstances only mature cells circulate there.
Neutrophils serve as the immune system’s first-responder units. They rush to sites of tissue injury, attacking pathogens and clearing cellular debris. In a healthy adult at rest, the bone marrow sends only fully developed neutrophils into circulation. Immature forms – earlier stages of the same cell that haven’t yet completed their development – are held back in the marrow until they’re ready. When the body is under severe stress, such as during a heart attack, the bone marrow also releases more immature precursors of these cells into the bloodstream.
The more severe the condition, the greater the number of immature neutrophil precursor cells present in the blood, and the presence of the most immature of these precursor cells significantly increases the short-term risk of death. The bone marrow, in effect, is broadcasting distress – pulling its most unfinished product off the shelf because it has nothing else left to send.
The Role of Preneutrophils in Predicting Outcomes
The University of Münster researchers profiled distinct neutrophil maturation stages in patients with ST-elevation myocardial infarction (STEMI), heart failure, and stroke. Patients with STEMI showed the most pronounced engagement of this response, including the appearance of CD16-low CD10-negative preneutrophils – the final mitotic neutrophil progenitor – which was associated with disease outcome.
CD16 and CD10 are surface proteins that scientists use to identify how mature a neutrophil is. Research has consistently linked high immature granulocyte counts with severe, rapidly evolving conditions, including sepsis – but their significance in cardiac events has been far less studied. Plasma cytokine profiling in the Münster study identified a coordinated inflammatory signature associated with preneutrophil mobilization, consistent with emergency granulopoiesis (the bone marrow producing blood cells in an accelerated, emergency state). These preneutrophils were identifiable as immature granulocytes in routine blood count analysis, where they predicted 30-day mortality better than established biomarkers in two clinical cohorts, according to the published findings in Nature Cardiovascular Research.
STEMI: The Deadliest Form of Heart Attack
The study specifically examined patients following ST-elevation myocardial infarction, showing that routine blood test assessment of neutrophil progenitor mobilization can predict 30-day mortality and enable rapid risk stratification. STEMI is the most severe category of heart attack. ST-elevation myocardial infarction is caused by total blockage of a coronary artery, meaning blood flow to a section of heart muscle is completely cut off. Time to treatment is critical – but so is knowing which patients require the most aggressive management after that treatment is delivered.
What remained clearly unresolved before this research was how to identify patients at higher risk upon hospital admission. The team, led from the Center for Molecular Biology of Inflammation (ZMBE) at the University of Münster, compared patients with heart attack, heart failure, and stroke to build their findings. The study’s first author is Mathis Richter, a PhD student at the Institute of Experimental Pathology, who focused the paper’s clinical dimension on translating laboratory-grade immunological profiling into a signal detectable by routine blood analyzers, according to the University of Münster’s press release.
The Research: What Was Done and What Was Found
Study Design and Patient Population
For the study, the researchers analyzed blood samples from over 200 patients who had experienced a heart attack, stroke, or heart failure, alongside samples from healthy individuals. Using high-resolution spectral flow cytometry – a technique that can identify and count cells based on their surface proteins with exceptional precision – they identified the different stages of neutrophil maturation.
This level of detail in cell identification allowed the team to do something previous studies couldn’t: distinguish not just between “mature” and “immature” neutrophils in bulk, but to pinpoint exactly which stage of immaturity a cell had reached. That granularity turned out to be the key to the predictive power.
The Immature Granulocyte Count as a Clinical Tool
The immature granulocyte (IG) count, measurable in a routine differential blood test, independently predicts 30-day mortality and outperforms established biomarkers, enabling early risk stratification after heart attack, stroke, or heart failure, as Medical Xpress reported covering the University of Münster release.
A differential blood test – sometimes called a CBC with differential, or complete blood count with differential – is one of the most commonly ordered tests in any emergency department. It counts all the different types of cells in the blood and breaks them down by category. The IG count is already a field on that test. Most hospitals run it automatically. What this research establishes is that a number hospitals have been generating for years holds diagnostic information they haven’t been using.
Prior research had pointed in this direction. A 2018 study published in Scientific Reports examined the delta neutrophil index – a measure that reflects the proportion of circulating immature granulocytes – and found it to be an independent predictor of 30-day mortality and poor clinical outcomes in STEMI patients following primary percutaneous coronary intervention (the procedure used to reopen blocked coronary arteries). In that earlier study, delta neutrophil index values above 2.5% at the time of the procedure were associated with increased risk of 30-day mortality. The Münster study builds substantially on that foundation, using more precise cell-identification technology and a broader patient population to validate the finding across multiple acute cardiovascular conditions.
The Münster team’s findings indicate that a fatal outcome after STEMI is accompanied by broad inflammatory activation, and that the ensuing mobilization of the deepest neutrophil progenitor compartments provides an applicable readout of mortality risk.
Outperforming Established Biomarkers
The phrase “outperforms established biomarkers” carries significant weight in clinical cardiology. Current risk-stratification tools after STEMI rely heavily on troponin – a protein released by damaged heart muscle cells – as well as imaging data and clinical scoring systems. These are valuable but imperfect. Troponin confirms injury; it doesn’t directly measure the immune system’s emergency response to that injury.
According to the University of Münster, the immature granulocyte signal is associated with the severity of the condition and can predict the risk of death within the first 30 days. The severity gradient matters enormously. A patient with a small STEMI and a low IG count represents a very different risk profile from a patient with a large STEMI and a high IG count – even if their troponin levels or ejection fractions look similar. Clinicians managing post-STEMI patients need tools that separate those two groups quickly, and the IG count delivers that at the moment of the first blood draw.
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The Immune System’s Role in Heart Attack Severity
Understanding why this biomarker works requires a brief look at how the immune system responds to a cardiac event. When heart muscle tissue dies – starved of oxygen because a coronary artery is blocked – the body doesn’t just lose muscle. It triggers an inflammatory cascade that can either help clear damaged tissue and promote repair, or spiral into a systemic response that causes further organ damage.
Following acute myocardial infarction, neutrophils rush to the damaged heart tissue. Their presence is critical, and how they die influences whether the heart heals or suffers further injury – a process determined by specific cell death pathways including NETosis, apoptosis, and autophagy. NETosis can be harmful when neutrophils release sticky, web-like structures filled with toxic enzymes during early thromboinflammatory amplification. These structures trap platelets and trigger clotting, which blocks blood vessels and worsens heart damage, according to a 2026 review in Frontiers in Immunology.
The deployment of the most immature neutrophil precursors reflects the most extreme version of this process. The bone marrow is, in effect, sending reserves into a battle it’s not winning. When the body is under severe stress during a heart attack, the bone marrow also releases more immature precursors of these cells into the bloodstream, indicating that the bone marrow is operating in an emergency state and drawing on its earliest reserves. The depth of that mobilization – how far back into the developmental pipeline the bone marrow has to reach – is what correlates with 30-day survival.
Clinical and Practical Significance
What This Means for Emergency Cardiology
Heart attack survival prediction has long been impeded by a timing problem. The most accurate prognostic data – imaging results showing how much heart muscle was damaged, assessments of pump function, response to initial treatment – takes hours or days to accumulate. Meanwhile, the critical window for decisions about intensive monitoring, additional interventions, or transfer to specialized units is narrow.
The IG count sidesteps that timing problem entirely. It’s available from the first blood draw, drawn routinely at admission in virtually every hospital system. No additional test, no additional equipment, no specialist consultation is required to generate the number. The mobilization of neutrophil progenitors assessed from routine blood tests can predict 30-day mortality in patients following ST-elevation myocardial infarction and enable rapid risk stratification, as confirmed in the Nature Cardiovascular Research study.
Applicability Across Acute Cardiovascular Events
The study’s patient population extended beyond STEMI. Patients with stroke and heart failure were also included, and immature granulocyte mobilization was observed across all three groups. The most pronounced response was seen in STEMI patients – consistent with STEMI being the most hemodynamically severe of the three conditions – but the predictive signal was present across the cardiovascular spectrum.
Cardiovascular diseases are the leading cause of death worldwide, and according to the World Health Organization, caused 19.8 million deaths in 2022, with 85% of those deaths due to heart attacks and strokes. A biomarker that applies across multiple cardiovascular emergencies would have an outsized impact on how emergency departments and cardiac care units stratify and manage their most vulnerable patients.
The Professor Behind the Research
The research was led by Professor Oliver Soehnlein, Director of the Institute of Experimental Pathology at the Center for Molecular Biology of Inflammation at the University of Münster. First author Mathis Richter, a PhD student at the same institute, oriented the paper’s clinical focus toward making laboratory-grade immunological profiling detectable by any routine blood analyzer – the key step that moves this finding from a research curiosity to a potential bedside tool.
Limitations and the Path Forward
The Münster study is a significant advance, but it is not yet a clinical protocol. The research was conducted in a defined patient population, and while results were validated across two clinical cohorts, broader prospective trials will be needed before the IG count is formally embedded in post-STEMI care pathways. Clinicians will also need guidance on the specific threshold values that should trigger elevated concern – prior work with the delta neutrophil index suggested that values above 2.5% at the time of primary intervention were associated with significantly increased risks of 30-day mortality, but the Münster team’s use of more granular cell-staging data may require new threshold definitions.
There is also a question of what clinicians should do differently once a high IG count is identified. The marker stratifies risk; it doesn’t prescribe treatment. Earlier and more aggressive monitoring of high-IG patients, closer post-discharge follow-up, or more intensive medical therapy all represent logical responses to an elevated reading – even before formal guidelines are updated.
The immune system’s role in post-heart attack outcomes is also an active area of therapeutic development. Researchers are investigating whether modulating the neutrophil response – either dampening harmful aspects of it or supporting beneficial ones – can improve cardiac repair. A validated, widely available biomarker that tracks the depth of neutrophil mobilization in real time would be a valuable tool for any clinical trial examining those therapies.
What This Means for You
For most people, the words “blood test at hospital admission” don’t conjure any sense of urgency or significance – it’s a routine step in a long chain of procedures that follows a cardiac emergency. The Münster findings reframe that moment. The complete blood count with differential drawn in the first minutes after a STEMI contains a number – the immature granulocyte count – that can now be understood as a direct read on how hard your body’s bone marrow is working to keep you alive. The deeper it has to dig into its developmental reserves, the more serious the prognosis.
For patients and families navigating a cardiac emergency, the practical takeaway is this: ask your care team whether the IG count from your admission blood work has been reviewed alongside other markers. The number is already there. The research now tells clinicians how to use it. For physicians, the immediate action is to familiarize themselves with the study’s two validated cohorts and the specific granulocyte staging methodology, ahead of what may become a formal addition to post-STEMI risk protocols. Neutrophil mobilization as a biological signal has been recognized for almost a century – what the University of Münster has now provided is the clinical key to reading that signal accurately from a test every hospital already runs.
Disclaimer: This information is not intended to be a substitute for professional medical advice, diagnosis, or treatment and is for information only. Always seek the advice of your physician or another qualified health provider with any questions about your medical condition and/or current medication. Do not disregard professional medical advice or delay seeking advice or treatment because of something you have read here.
AI Disclaimer: This article was created with the assistance of AI tools and reviewed by a human editor.
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