Intriguingly, IL-1 receptor antagonist (IL-1Ra, gene name: IL1RN), another member of the IL-1 family, can inhibit IL-1 signaling [13], and patients with PDA exhibit serum concentrations of IL-1Ra over 100-fold greater than those of IL-1 agonists [14, 15]. The gene discussed is IL1B; the disease is Patent ductus arteriosus.