NPPB and hemophagocytic syndrome: Abbreviations: ALT, alanine transaminase; AST, aspartate transaminase; pro-BNP, pro-B-type natriuretic peptide; BUN, blood urea nitrogen; CRP, C-reactive protein; CT, computed tomography; ESR, erythrocyte sedimentation rate; GI, gastrointestinal; HLH, hemophagocytic lymphohistiocytosis; IL, interleukin; MIS-C, multisystem inflammatory syndrome in children; NK, natural killer; NP, nasopharyngeal; PT, prothrombin time; PTT, partial thromboplastin time; RT-PCR, reverse transcriptase polymerase chain reaction; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.