Itolizumab is a monoclonal antibody used in the treatment of autoimmune diseases, particularly in the context of severe plaque psoriasis and other immune-mediated conditions. Itolizumab targets and binds to the CD6 receptor, a protein present on the surface of T cells, which are key players in the immune response. By binding to CD6, itolizumab modulates T cell activation and function, thereby reducing the inflammatory response seen in autoimmune diseases. It is primarily used for the treatment of moderate to severe plaque psoriasis in adults who have not responded well to other systemic therapies. It has also shown efficacy in other autoimmune conditions, such as rheumatoid arthritis and psoriatic arthritis.