Lipopolysaccharide Binding Protein and Bactericidal/Permeability-Increasing Protein as Biomarkers for Invasive Pulmonary Aspergillosis

Early diagnosis of invasive pulmonary aspergillosis (IPA) is crucial to prevent lethal disease in immunocompromized hosts. So far, lipopolysaccharide binding protein (LBP) and bactericidal/permeability-increasing protein (BPI) levels have not been evaluated as biomarkers for IPA. IL-8, previously introduced as a biomarker for IPA, was also included in this study. Bronchoalveolar lavage fluid (BALF) of IPA patients and control patients with non-infectious lung disease was collected according to clinical indications. Measurements in BALF displayed significantly higher levels of LBP (p < 0.0001), BPI (p = 0.0002) and IL-8 (p < 0.0001) in IPA compared to control patients. Receiver operating characteristic curve analysis revealed higher AUC for LBP (0.98, 95% CI 0.95-1.00) than BPI (0.84, 95% CI 0.70-0.97; p = 0.0301). Although not significantly different, AUC of IL-8 (0.93, 95% CI 0.85-1.00) also tended to be higher than AUC for BPI (p = 0.0624). When the subgroup of non-hematological patients was analyzed, test performance of LBP (AUC 0.99, 95% CI 0.97-1.00), BPI (AUC 0.97, 95% CI 0.91-1.00) and IL-8 (AUC 0.96, 95% CI: 0.90-1.00) converged. In conclusion, LBP and-to a lesser extend-BPI displayed high AUCs that were comparable to those of IL-8 for diagnosis of IPA in BALF. Further investigations are worthwhile, especially in non-hematological patients in whom sensitive biomarkers for IPA are lacking.