AT THE ERS CONGRESS 2016
LONDON (FRONTLINE MEDICAL NEWS) – A cytokine known as tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) is showing potential as a biomarker for evaluating the severity of sepsis and septic shock, according to results of a prospective study presented at the annual congress of the European Respiratory Society.
In a prospective study undertaken in patients administered to an intensive care unit, “lower levels of plasma TRAIL correlated with both organ system dysfunction and mortality,” reported Thomas Nicholson, MD, of Cornell University, New York.
A series of studies associating low levels of TRAIL with increased sepsis severity have attracted attention to this potential biomarker, according to Dr. Nicholson. In a mouse model of sepsis, for example, exogenous administration of TRAIL was associated with improved survival. In a clinical study conducted in CHINA that was cited by Dr. Nicholson, low levels of TRAIL correlated with lower rates of survival.
In the data presented at the ERS Congress, plasma TRAIL was collected from 108 patients on the first day of ICU admission. Of these patients 59 (54%) had sepsis and 23 (21%) had septic shock. Those with a noninfectious critical illness served as controls.
All patients with sepsis or septic shock were required to meet diagnostic criteria from the recently published Third International Consensus Definitions for Sepsis and Septic Shock ( JAMA. 2016;315[8]:801-10 ). This is important because the newer criteria, relative to previous criteria, have “moved conceptually away from a condition defined by inflammatory biomarkers toward one that emphasizes signs of organ dysfunction,” Dr. Nicholson reported.
Although a dysregulated host response to infection is still a fundamental concept to the newer definition of sepsis, the importance of biomarkers of inflammation has been deemphasized, a change that would not be expected to favor an inflammatory cytokine as a biomarker.
Despite this, plasma TRAIL levels, which were measured with commercially available ELISA kits, were significantly lower for those with sepsis (P = .038) and for those with septic shock (P less than .001) relative to those with a noninfectious critical illness. There was a trend (P = .077) for lower plasma levels of TRAIL in patients with septic shock relative to sepsis.
In addition, there was a positive and significant correlation (r = –0.1983; P = .0397) between plasma TRAIL and degree of organ dysfunction as measured with the Sequential Organ Failure Assessment (SOFA) score. Higher plasma TRAIL levels also predicted survival at 28 days (P = .016). Although the overall mortality for patients with sepsis or septic shock in this series was 23%, there were no deaths among sepsis or septic shock patients with a TRAIL above the mean, which was 26.8 pg/mL.
“For every 10 mg/mL increase in TRAIL the odds ratio for survival increased by 1.9-fold,” Dr. Nicholson reported.
TRAIL is implicated in several processes that may explain these observations, according to Dr. Nicholson. For example, he reported that there is evidence that TRAIL induces apoptosis in neutrophils, a suspected mediator of sepsis-related injury.
“The observations in our study are consistent with a growing literature suggesting that TRAIL is an important mediator of inflammatory cells, such as neutrophils, tempering the degree of inflammation,” Dr. Nicholson explained.
More data are needed to verify that TRAIL is a clinically useful biomarker, but Dr. Nicholson emphasized that this is a promising area of research. He said the biomarker is being developed as a potential tool for evaluating sepsis severity.
Dr. Nicholson reported no relevant financial relationships.
