CHI3L1 and encephalitis: Additionally, CSF CHI3L1 levels are associated with the mRS score both at admission and 6 months later (11, 12, 16) An [18F]-DPA714 PET/CT scan study revealed that one patient with recurrent anti-LGI1 encephalitis had activated microglia in the left medial temporal lobe indicating that microglia play a major role in the pathogenesis of anti-LGI1 encephalitis (30).