STAT3 and multiple sclerosis: In terms of other central nervous system (CNS) diseases, it is perhaps important that STAT3 plays a role in astrocyte differentiation and activity, and moreover astrocytes are immunocompetent cells and are capable of secreting inflammatory mediators that may be involved in CNS pathology such as Alzheimer’s disease, multiple sclerosis, Parkinson’s disease and brain injury [35, 36].