NPPB and hydrops fetalis: These analyses showed that for HF patients with reduced properdin levels (i.e., below 10.3 μg/mL) elevated levels of Nt-proBNP, a marker of myocardial wall stress, and C-reactive protein (CRP), an inflammatory response marker, were observed, as well as a reduced left ventricular ejection fraction (LVEF) (Fig. 3a–c).