To examine neutrophil EMR3 for early sepsis identification and longitudinal host-response dynamics in critically ill patients.
Approach:
Study Design: Single-center ICU study at Sir Run Run Shaw Hospital, including two independent cohorts: an early identification cohort and a longitudinal sepsis cohort.
Cohorts: The early identification cohort included 66 sepsis patients diagnosed within 24 hours of ICU admission, 292 non-septic ICU patients, and 81 healthy controls. The longitudinal cohort evaluated 293 sepsis patients over 7 days.
Measurement: Neutrophil EMR3 and CD64 were measured by flow cytometry, with nEMR3 calculated as median fluorescence intensity normalized to healthy controls.
Key Findings:
nEMR3 was significantly lower in sepsis patients compared to non-septic critical illness and healthy controls, with an AUC of 0.944.
nEMR3 showed better discrimination for sepsis than PCT, with an AUC of 0.936.
In the longitudinal cohort, nEMR3 was consistently lower in non-survivors from Day 3 onward.
Interval changes in nEMR3 provided strong discrimination for 28-day mortality, with ΔDay 7-Day 0 showing an AUC of 0.882.
Interpretation:
nEMR3 may reflect a unique aspect of the host response in sepsis, indicating early reduction and persistent suppression in patients with a fatal course.
Limitations:
Single-center study requiring external multicenter validation.
PCT comparisons were affected by clinically driven testing.
Later time-points may be subject to informative missingness and survivor bias.
Lack of direct comparisons with established immune-dysfunction markers.
Conclusion:
nEMR3 offers a different perspective on the sepsis host response and warrants further evaluation in multicenter ICU cohorts.
