Additionally, concentrations of IL1B (hereafter referred to as IL-1β) and its receptor antagonist IL1RN (also known as IL-1RA) were significantly increased at ARDS 0 h (134-1527 pg ml−1, P=0.038 and 770-166,323 pg ml−1, P=0.024). Here, IL1RN is linked to acute respiratory distress syndrome.