NPPB and macrophage activation syndrome: There were also significantly higher median plasma concentrations of bilirubin, B-type natriuretic peptide (BNP) and N-terminal pro-B-type natriuretic peptide (NT-proBNP), troponin, and alanine and aspartate transaminases activities, and estimated glomerular filtration rate (eGFR) in MIS-C patients with MAS.