Initial plasma levels of lipopolysaccharide binding protein are associated with severe sepsis in patients with community-acquired pneumonia

Background

Many researchers are investigating the expression of inflammatory proteins as contributors to the variable onset and progression of infection, sepsis, and organ dysfunction. We explored the relationship between plasma lipopolysaccharide binding protein (LBP) levels and the development of severe sepsis in community-acquired pneumonia (CAP).

Hypothesis

Plasma LBP levels are higher in CAP patients who develop severe sepsis.

Methods

We are conducting a large multicenter inception cohort study of patients arriving in the Emergency Department (ED) with CAP. We conducted a planned interim analysis on the first 385 enrolled patients. Plasma LBP was assayed using a commercially available immunoassay system (Diagnostic Products Corp., Los Angeles, CA, USA). Severe sepsis was defined as a Sequential Organ Failure Assessment Score increase of 2 for any one nonrespiratory organ, or an increase of 1 for any two nonrespiratory organs, or an absolute score of 3 or 4 for the respiratory component.

Results

Plasma LBP levels were available for 379/385 (98.4%) patients. Of the 379 patients, 26.1% had severe sepsis at initial presentation; 29.8% were PSI class I or II, 27.2% class III, 33.0% class IV, and 10.0% class V; 29.6% had chronic lung disease; 50.9% were female; 12.9% were black and 85.0% white; average age was 65.5 ± 17.2 years. Day 1 serum LBP levels distinguished between ED presentation of CAP with severe sepsis (n = 87) and without (n = 236): 40.4 ± 31.9 μg/ml vs 27.9 ± 19.3 μg/ml, respectively; P = 0.0005 by Wilcoxon. Over the course of hospitalization, mean LBP levels for each patient correlated with worst diagnosis: 26.8 ± 17.2 μg/ml for CAP patients who at any time met criteria for severe sepsis (n = 158), compared with 20.8 ± 13.9 μg/ml for patients who did not (n = 221); P < 0.0001 by Wilcoxon. Mortality analysis was not possible in this preliminary interim analysis.

Conclusions

In our CAP cohort, patients who developed severe sepsis had significantly higher plasma LBP levels.