Antibody Regression In Patients With Anti-NMDAR,anti-LGI1 And Anti-GABABR Encephalitis In Remission And Its Clinical Significance

Objective:To observe the proportion of antibody-negative and-positive patients with anti-N-methyl-D-aspartate receptor(NMDAR),anti-leucine-rich glioma inactivated protein 1(LGI1)and anti-gamma-aminobutyric acid type B receptor(GABA_BR)encephalitis at the time of clinical remission after a 6-month course of immunotherapy.The clinical significance for those patients who do not convert to antibody negative in terms of relapse and prognosis and the factors that may influence antibody non-negative conversion were investigated.Methods:Patients continuously diagnosed with anti-NMDAR,anti-LGI1 and anti-GABA_BR encephalitis in the Department of Neurology,First Hospital of Shanxi Medical University from October 2020 to June 2022 were prospectively included.The proportion of antibody-negative and-positive patients at 6 months of immunotherapy was observed.These patients were divided into antibody-positive and antibody-negative groups.The demographic data of these patients,and the clinical symptoms,laboratory tests,auxiliary examinations,treatment and follow-up in the acute phase of the initial onset and 6 months later were summarized.Comparisons were made between the antibody-negative and antibody-positive groups.Results:A total of 21 patients were enrolled,including 11 patients with anti-NMDAR encephalitis,8 patients with anti-LGI1 encephalitis and 2 patients with anti-GABA_BR encephalitis.At 6 months of immunotherapy,10(47.6%)patients were negative for antibodies and 11(52.4%)were positive,and there was no significant difference in clinical manifestations,laboratory tests,auxiliary examinations and treatment between the two groups(P>0.05).At a mean follow-up of 23 months(range:9 to 35 months),antibody-positive patients were more likely to have relapse(54.5%vs 0.0%,P=0.035),and all but one patient with GABABR encephalitis with small cell lung cancer had a good prognosis(m RS≤2),and there was no significant difference between the two groups.Compared with the antibody-negative patients,antibody-positive patients were more likely to have seizures(100.0%vs 50.0%,P=0.012)in the acute phase of the initial onset,and there was no significant difference in other aspects such as prodromal symptoms,laboratory tests,auxiliary examinations,and treatment between the two groups(P>0.05).Conclusion:Some patients with anti-NMDAR,anti-LGI1,and anti-GABA_BR encephalitis remained antibody positive after 6-month immunotherapy.Antibody-positive patients have a higher risk of relapse than antibody-negative patients.And antibody non-negative conversion at 6months of immunotherapy may be associated with seizures in the acute phase of the initial onset.