IL6 and autoimmune encephalitis: IL-6 is a critical cytokine in the Th17 pathway of T cell development in addition to B cell differentiation or antibody production.[12] Previous reports have suggested that IL-6 is involved in the autoimmune encephalitis, because these patients have elevated levels of IL-6 in the CSF.[13] In contrast to these reports, IL-6 is presumed to be purely injurious to the nervous system.[14] The expressions of the autoantigens, such as collagens, initiate inflammatory responses of RP.