Anti-Leucine-Rich Glioma-Inactivated 1 Encephalitis: A Single-Center Cohort Study in China

Objective To evaluate the clinical and paraclinical features of Chinese patients with anti- LGI1 encephalitis. Methods Patients with memory deficits, psychiatric symptoms, seizures or altered level of consciousness, suspicious of encephalitis, at presentation to Peking Union Medical College Hospital were recruited between July 2013 and January 2018, and tested for anti-LGI1 antibodies in their serum and/or cerebrospinal fluid(CSF) samples. Patients with anti-LGI1 antibodies were enrolled. The demographic characteristics, clinical manifestations, laboratory examination results, neuroimaging features, immunotherapy, follow-up practices and outcomes for included patients were registered and analyzed. Results The study enrolled 120 patients, of whom 66.7% were male. The median age was 61 years (interquartile range [IQR]: 49-66 years). Seizures(65.0%) were the most common initial symptoms. Most patients developed seizures (95.0%), including faciobrachial dystonic seizures (54.2%), memory deficits (92.5%), and psychiatric symptoms (69.1%). Brain MRI and 18F-FDG PET / CT showed that the lesions were mainly located in unilateral or bilateral medial temporal lobes, and (or) basal ganglia. Of the patients, 95.0% received intravenous immunoglobulin (IVIg) or corticosteroids, 47.5% received mycophenolate mofetil as long-term immunotherapy, and no one received second-line immunotherapy. The median follow-up was 34.2 months(IQR: 22.0-45.6 months). 91.2% had a good outcome (modified Rankin Scale score≤2 points). Residual mild memory deficits were present in 47.8% of the patients. Nine deaths were documented. Relapses occurred in 24.8% of the patients in the first year. In total, 24 (20%)cases were young patients(onset age ≤45 years).There were fewer males among the younger patients(37.5% vs. 74.0%, P < 0.01). Besides, there were fewer younger patients with psychiatric symptoms(50.0% vs. 74.0%, P=0.02), hyponatremia(33.3% vs. 68.8%, P < 0.01), and abnormalities on brain 18F-FDG PET/CT(20.8% vs. 47.9%, P=0.02). The relapse-free survival rate was significantly higher in the young patients. Conclusions Elderly males were predominant in patients with anti-LGI1 encephalitis. Most patients developed symptoms of limbic encephalitis and/or FDBS during the disease course. Several patients were young adults and lacked typical symptoms. Neuroimaging features were consistent with the involvement of limbic system or basal ganglia. Patients with anti-LGI1 encephalitis respond well to immunotherapy, irrespective of the age.