Lipopolysaccharide binding protein: a poor parameter for the differentiation of SIRS and sepsis but useful as determinant of outcome in septic patients

Lipopolysaccharide binding protein (LBP) is an acute phase hepatic glycoprotein immediately involving in the process of immune response to endotoxin. Elevation of LBP appears to be an important marker associated with release of endotoxin and/or bacteriemia. In our study we investigated serum LBP levels as a prognostic marker for sepsis and Systemic Inflammatory Response Syndrome (SIRS). Also we assessed the correlation of LBP with procalcitonin (PCT), expression HLA-DR on monocytes and the production of TNF-α ex vivo by monocytes stimulated by lipopolysaccharide (markers of immunoparalysis).

Methods

The serum levels of lipopolysaccharide binding protein (LBP) and procalcitonin (PCT), the expression of HLA-DR on monocytes and the production of tumor necrotizing factor by monocytes stimulated ex vivo by lipopolysaccharide were measured in a group of 68 patients with Systemic Inflammatory Response Syndrome (SIRS), sepsis or septic shock (diagnosed according to ACCP consensus criteria).

Results

We have found that LBP levels:

• 1. Were elevated in 98% of patients over normal value of 7.3 ng/ml.

• 2. Were significantly higher in nonsurvivors than in survivors (mean 39.1 ng/ml and 26.1 ng/ml) – the difference being due to group of septic patients – their lethality was significantly increased when LBP levels exceeded 24.1 ng/ml.

• 3. Were significantly higher in patients with sepsis or septic shock than in patients with SIRS (mean (SD) – 40.5 (18.6) versus 29.8 (17.9) ng/ml).

• 4. The specificity and sensitivity of LBP levels to differentiate patients with SIRS versus patients with sepsis was low – 50% and 74.3%, respectively.

• 5. Did not differ between the groups of patients with and without immunoparalysis (37.1 ng/ml to 31.1 ng/ml).

• 6. Did not correlate with the serum levels of procalcitonin, expression of HLA-DR on monocytes or production of TNF after stimulation by lipopolysaccharide.

Conclusions

Lipopolysaccharide binding protein may be a useful marker for the prediction of outcome in patients with sepsis but its ability to discriminate patients with SIRS to patients with sepsis is low. Further studies are needed to elucidate its possible prognostic significance.