IL1RN and idiopathic pulmonary fibrosis: On the other hand, in fact, the importance of immune response in IPF has been shown by genetic studies, and the polymorphism of immune-related genes, such as genes encoding Toll-like receptor 3 (TLR3), Toll-interacting protein (TOLLIP), and interleukin-1 receptor antagonist (IL-1RA) proteins, are closely related to the risk or severity of IPF (Whyte et al., 2000; O’Dwyer et al., 2013).