Interleukin 6 (IL-6) is a cytokine with both pro- and anti-inflammatory characteristics.
- Serum levels rise quickly with the onset of SIRS and sepsis1
- Levels can provide information for risk stratification and prognosis with regard to severity2,3
- Rising levels correspond with increasing APACHE II scores (an in indicator of illness severity)4
- Fatal severe sepsis is associated with an early rise in IL-6 to 1000 ng/mL or more4
- High levels of IL-6 have shown to be predictive of later development of severe sepsis at the onset of hospital-acquired pneumonia and after surgery5,6
- Rising levels can predict development of kidney injury during severe sepsis7
IL-6 may be of particular value in neonatology and pediatrics:
- In healthy infants, adult levels are present at birth and remain stable
- In infants at risk for late-onset neonatal sepsis, IL-6 has been shown to rise up to 48 hours before bacterial sepsis becomes clinically apparent8
- Increased levels at hospital admission are predictive of septic shock in children9
- Increased levels at hospital admission are predictive of septic shock and death in pediatric burn patients10
Lipopolysaccharide-binding protein (LBP) recognizes the endotoxin component of the gram-negative bacterial membranes. It also recognizes similar lipid structures found in the membrane of gram-positive bacteria and the walls of pathogenic fungi.11
- LBP is present constitutively at low levels
- LBP rises within 24 hours of systemic bacterial or fungal infection11,12
- LBP can differentiate between bacterial and viral pathogenic sources of sepsis11,12
- LBP can help differentiate between bacterial pneumonia and nonbacterial acute bronchitis13
LBP is a valuable tool in pediatrics
- LBP rises in invasive bacterial infection in children14
- Elevated LBP indicate bacterial infection in neonates ≥ 28 weeks gestation15
- LBP may be the best differentiator between SIRS and early-onset sepsis in neonates <48 hrs old16
