In a recent multi-centre trajectory study of 382 PARDS episodes, Yehya et al. demonstrated that SP-D rose within 24 h of intubation and paralleled worsening dynamic compliance, whereas club cell secretory protein and KL-6 lagged by 48–72 h; although angiopoietin-2 retained the highest mortality AUC, its lack of lung specificity limited mechanistic insight [23]. This evidence concerns the gene SFTPD and pediatric acute respiratory distress syndrome.