IL17A and optic neuritis: In the experimental autoimmune encephalomyelitis (EAE) model, the transcription of Th1 and Th17-specific cytokine genes interferon gamma (Ifng) and interleukin 17A (Il17a) was upregulated in optic nerve, and decreasing Ifng expression had a protective effect on optic neuritis in EAE mice (29).