CTSL and acute respiratory distress syndrome: Using a methodology similar to ours but in a larger cohort of patients, Wang et al. were able to identify three proteins which were differentially expressed after cardiopulmonary bypass in patients who subsequently developed ARDS: thioredoxin domain containing 5 (TXNDC5), cathepsin L (CTSL), and NPC intracellular cholesterol transporter 2 (NPC2).