Inflammatory Cytokine Levels Predict Patient Outcomes After Traumatic Injury

Measurement of the inflammatory cytokines interleukin-6 (IL-6) and interleukin-8 (IL-8) can be used to predict patient outcomes after traumatic injury.

Cytokines are peptides, which are important in cell signaling but cannot cross the lipid bilayer of cells to enter the cytoplasm. Cytokines have been shown to be involved in autocrine, paracrine, and endocrine signaling as immuno-modulating agents. They act through cell surface receptors and are especially important in the immune system where they modulate the balance between humoral and cell-based immune responses and regulate the maturation, growth, and responsiveness of particular cell populations.

Traumatic injury is the leading cause of mortality in patients under the age of 50. It is associated with a complex inflammatory response involving hormonal, immunologic, and metabolic mediators. The marked elevation of cytokines and inflammatory mediators subsequently correlates with the development of post-traumatic complications.

Investigators at the University of Kentucky (Lexington, USA) sought to determine whether elevated cytokine levels provided a predictive value for orthopedic trauma patients. For this study they measured IL-6, IL-8, IL-10, and migration inhibitory factor levels in samples obtained from 58 patients with an average age of 40 years who had experienced severe bone, joint, and muscle trauma. Six of the patients (10%) suffered pulmonary complications and five (9%) had acute kidney injury.

Results revealed that addition of IL-6 levels to baseline models significantly improved prediction of pulmonary complication and hospital length of stay. The addition of IL-8 significantly improved the prediction of acute kidney injury. The addition of post-injury IL-6 level to the baseline New Injury Severity Score (NISS) model was better able to predict the occurrence of pulmonary complications as well as prolonged ICU and hospital length of stay.

“This is the first time we have combined parameters of external anatomic injury (NISS) with parameters of the internal physiologic response to injury (cytokines) to determine trauma patient outcomes,” said first author Dr. Arun Aneja, assistant professor of orthopedics at the University of Kentucky.

The study was published in the November 2, 2021, online edition of the Journal of Orthopaedic Research.

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