SFTPD and acute respiratory distress syndrome: The NHLBI ARDS Network study, demonstrated that the combination of clinical risk factors and eight biological plasma markers (VWFAg, SP-D, TNFR1, IL-6, IL-8, ICAM-1, protein C, PAI-1) resulted in a prognostic index for mortality in patients with ALI/ARDS superior to clinical or biological risk factors alone [7].