IL-21 causes autoantibody production, which downregulates regulatory T cells leading to enhanced autoimmunity and increased CD8+ T cells and NK cells in AE [51], whereas IP10/CXCL10 is secreted in response to IFN-γ, which is produced as part of the Th1 in response to viral infection [52]. Here, CXCL10 is linked to viral infectious disease.