IL6R (interleukin 6 receptor) is a membrane-bound receptor that mediates interleukin-6 signaling through two distinct mechanisms. The soluble form of IL6R (sIL6R) acts as an agonist, complexing with IL-6 to enable 'trans-signaling' on cells lacking membrane-bound IL6R, thereby amplifying pro-inflammatory responses 1. The IL6:sIL6R complex binds IL6ST/gp130, inducing STAT-mediated signaling and VEGF production 2. IL6R signaling has broad immunological effects, displaying context-dependent pro- and anti-inflammatory properties 3. Genetically reduced IL6R activity associates with decreased circulating IL-6, C-reactive protein, and fibrinogen levels, with protective effects against coronary heart disease 4. Therapeutically, IL6R blockade via tocilizumab effectively reduces relapse rates in autoimmune neuroinflammatory diseases including neuromyelitis optica spectrum disorder and MOG-IgG-associated disease 56. IL6R polymorphisms influence chr1 obstructive pulmonary disease susceptibility 7. In cancer, elevated IL6R in colorectal cancer epithelium and elevated IL-6 in tumor stroma predict poor survival 8. IL6R thus represents both a key pathogenic mechanism in chr1 inflammation and an important clinical therapeutic target across multiple disease contexts.