Five organ dysfunction patterns emerged after severe trauma, not just two
Severe trauma does not funnel every patient into the same postinjury course. In this prospective, longitudinal cohort from a single Level 1 trauma center, investigators followed 69 severely injured patients at high risk for multiple organ dysfunction and tracked organ failure daily for up to 28 days, death, or discharge. Using a trauma-specific modified Sequential Organ Failure Assessment, or mSOFA, that excluded the neurologic subdomain, the analysis separated systemic organ dysfunction from traumatic brain injury and exposed five distinct trajectory phenotypes rather than the usual binary split between chronic critical illness and rapid recovery.
The separation matters because the usual labels flatten physiology into categories that can hide very different biologic courses. In this cohort, the five phenotypes differed in resuscitation requirements, shock severity, and 28-day mortality, yet they did not differ in baseline demographics, injury severity, or early physiologic parameters. In other words, the major divergence appeared after the initial injury window, when organ dysfunction either stabilized, worsened, or evolved along a more protracted path.
Trajectory modeling exposed heterogeneity that standard labels miss
Group-based trajectory modeling identified the five mSOFA phenotypes, labeled c1 through c5, from the daily organ dysfunction curves. The design gives a more dynamic view of critical illness than a single score at admission or a simple binary classification at the bedside. Instead of asking only whether a patient developed chronic critical illness, the model asked how the organ dysfunction curve behaved over time, and the curves did not collapse into a single pattern.
One of the clearest signals came from the most fulminant group, c5. This phenotype carried the most severe course and was distinguished immunologically by IL-17C, CXCL5, and CXCL6. Those mediators point toward epithelial-barrier stress and neutrophil trafficking, a combination that fits a rapidly escalating inflammatory state rather than a slow, linear decline. The phenotype with the highest incidence of chronic critical illness, c3, carried a different biologic identity, with rising CXCL9, ARTN, and TWEAK. That pattern points toward Th1 polarization and tissue-inflammation or repair signaling rather than the neutrophil-dominant profile seen in c5.
A third phenotype, c4, stood apart for a different reason: it was the clinically distinct older-age group and carried the largest differentiating protein signature, with 29 proteins spanning renal injury and repair, endothelial activation, and adaptive lymphocyte modulation. Age did not merely tag a demographic subgroup here; it aligned with a broader immune and organ-injury pattern.
Immune profiling tracked with the organ dysfunction curves
Plasma immune protein trajectories were compared across phenotypes with mixed-effects models that incorporated time interaction. Of the 92 measured immune markers, 40 showed phenotype-differentiated trajectories at an FDR threshold below 0.1. That is a substantial fraction of the assayed proteome and argues against a single inflammatory trajectory governing all severely injured patients.
The immune differences were not random scatter around a common inflammatory background. They tracked with the clinical course in a phenotype-specific way. The c5 pattern suggests early barrier injury and neutrophil recruitment. The c3 pattern suggests a more chronic inflammatory-repair state with signals linked to Th1 polarization. The c4 pattern spans endothelium, kidney, and adaptive immunity, which may help explain why older patients often deviate from younger patients after the initial resuscitation phase even when early bedside variables look similar.
These profiles also fit the broader problem in critical care: organ dysfunction after injury is not a single disease state. It is a family of related but separable biologic responses, and the trajectory method makes that separation visible.
Why the mSOFA approach changes the frame
The study used a trauma-specific modified SOFA score that excluded the neurologic component to isolate systemic organ dysfunction from traumatic brain injury. That choice is clinically important because neurologic injury can confound the interpretation of global organ failure in trauma. By focusing on non-neurologic organ dysfunction, the analysis sharpened the association between systemic trajectories and immune biology.
The data also show why early bedside measurements may not be enough to distinguish future courses. Baseline demographics and early physiologic parameters did not separate the phenotypes, but later organ dysfunction patterns and immune markers did. A patient can look similar to another patient on day 1 and still enter a very different biologic path over the following days.
For trauma teams, that has a direct practical implication: static classification may miss the window in which immune profiling or serial organ-dysfunction tracking could identify patients on a high-risk trajectory before the course becomes entrenched. The study does not establish a treatment strategy, but it does provide a map of the biology that might eventually support one.
Precision immunology now has a clearer target in severe trauma
The central message is straightforward. Multiple organ dysfunction after severe trauma is more biologically heterogeneous than conventional categories suggest, and distinct mSOFA trajectories correspond to distinct immune signatures. The findings support separable pathobiology rather than a single severity axis.
That distinction could matter for future interventional work. If c5 is driven by epithelial-barrier and neutrophil-trafficking biology, and c3 is driven by a different inflammatory-repair program, then a one-size-fits-all immunomodulatory approach would be unlikely to help every patient equally. The older-age c4 phenotype further suggests that host factors such as age may shape the immune response in ways that are not captured by injury severity alone.
The study remains observational and comes from a single center, so it cannot define causality or prove that these signatures should change management. It does, however, establish a framework for moving beyond coarse labels in trauma critical care. The immediate scientific task is to validate whether these phenotypes reproduce in other cohorts and whether the immune signatures can be used prospectively to guide treatment before the organ dysfunction trajectory hardens into irreversible critical illness.