Depletion of proBNP1-108 in Patients with Heart Failure Prevents Cross-Reactivity with Natriuretic Peptides

Background After synthesis by cardiomyocytes, precursor proBNP1-108 is cleaved into NT-proBNP and BNP. Recently, cross-reactivity between these assays was discussed. The aim of this study was to characterize the cross-reactivities, through a new biochemical innovative approach consisting in the total depletion of the circulating proBNP1-108 in patients with heart failure (HF). Methods This prospective study included 180 patients with chronic HF. BNP and NT-proBNP were dosed with commercial kits. ProBNP1-108 was determined using an ELISA research assay specific to the precursor. ProBNP1-108 depletion was performed by immunocapture with a specific antibody targeting exclusively the ProBNP1-108 hinge region. ProBNP1-108, BNP and NT-proBNP levels were determined before and after depletion using this process in HF patients. Results Mean age was 74.34 +/-12.5 y, and 69% of patients were males. NYHA classes II and III were the most frequent (32% and 45% respectively). Before depletion, ProBNP1-108, NT-proBNP and BNP levels were 316.8+/-265.9 pg/ml; 6,054.0+/-11,539 pg/ml and 684.3+/-82.1 pg/ml respectively, and were closely correlated with NHYA classes. After immuno-depletion, proBNP1-108 was decreased in mean by 96% (p