Lipopolysaccharide-binding protein: a new biomarker for infectious endocarditis?

BACKGROUND Infectious endocarditis (IE) is a bacterial infection of the endocardium. Diagnosis is based on results obtained from echocardiography, blood cultures, and molecular genetic screening for bacteria and on data for inflammatory markers such as the leukocyte (WBC) count and the C-reactive protein (CRP) concentration. The aim of the present study was to evaluate lipopolysaccharide-binding protein (LBP) as a supportive biomarker for the diagnosis and therapeutic monitoring of IE. METHODS We measured LBP and CRP concentrations and WBC counts in 57 IE patients at hospital admission, 40 patients with noninfectious heart valve diseases (HVDs), and 55 healthy blood donors. The progression of these 3 markers and the influence of cardiac surgery on them were evaluated in 29 IE patients and 21 control patients. RESULTS Serum LBP concentrations were significantly higher in IE patients [mean (SD), 33.41 (32.10) mg/L] compared with HVD patients [6.67 (1.82) mg/L, P < 0.0001] and healthy control individuals [5.61 (1.20) mg/L]. The progression in the LBP concentration during therapy of IE patients correlated with the changes in the CRP concentration. The 2 markers were equally influenced by antibiotic treatment and surgical intervention. CONCLUSIONS Serial LBP measurement may provide an effective and useful tool for evaluating the response to therapy in IE patients. We found a strong correlation between LBP and CRP concentrations; LBP has a tendency to increase earlier in cases of reinfection.