Single‐center study of autoimmune encephalitis‐related autoantibody testing in Hungary

Abstract

ObjectiveAutoantibody detection is crucial for the early diagnosis of autoimmune encephalitis (AIE) since prompt therapy can determine the disease outcome. Here, we report a single‐center 6‐year retrospective study of autoantibody testing in AIE in the Hungarian population.MethodsSerum and/or cerebrospinal fluid (CSF) autoantibody tests were performed using cell‐based indirect immunofluorescence assay for AIE diagnosis. Samples were provided by neurology clinics as part of a nationwide program. Test results were analyzed for samples received during the period from 2012 to 2018.ResultsWe tested 1,247 samples from 1,034 patients with suspected AIE. Autoantibodies were present in 60 patients (5.8% of total). The distribution of patients with different autoantibodies by age and sex was as follows: NMDAR (70%), mostly in young females, LGI1 (15%) in middle‐aged males, GABABR (12%) in elderly males, and Caspr2 (7%) in males. Long‐term follow‐up was conducted in 30 patients with repeated test requests, of which 17 remained positive, and 13 switched to negative.ConclusionWe report the most comprehensive clinical laboratory study of autoantibody testing in AIE in the Hungarian population. Our results show that the frequency of different autoantibody types in AIE corresponds to the data described in the literature.

Clinical Characteristics and Outcome of Neuronal Surface Antibody-Mediated Autoimmune Encephalitis Patients in a National Cohort

“…In our study, due to the low number of pediatric cases with age < 10 years (four cases), we could not confidently determine characteristics of pediatric patients. Although, the study has modest sample size, it summarizes detailed clinical data of 35 neuronal surface antibody positive patients from the 60 patients with positive autoantibody test results (N total = 1,034 patients with suspected AE) from 2012 through 2018 in Hungary published in our previous study (10). Our data confirms results of previous publications and further clarifies clinical data of AE patients with neuronal cell surface autoantibodies.…”

“…The study by Bien et al ( 21 ) reported 576 antibody-positive patients during testing of 10,919 patients for a broad panel of neural antibodies, including onconeural and neuronal cell surface autoantibodies. Our previous study ( 10 ) included results of 60 neuronal cell surface autoantibody positive patients (anti-NMDAR, anti-LGI1, anti-GABABR, anti-Caspr2, anti-AMPAR1, 2) and our recent study exclusively included both serologically (neuronal cell surface antibody positive, but not onconeural autoantibody positive) and clinically positive definite AE patients. The distinct results in autoantibody frequencies detected in the two laboratories, may be due to the exclusive inclusion of neuronal cell surface autoantibody positive AE patients in our study, making it impossible to compare accurately the data of autoantibody frequencies.…”

“…In our current study, we retrospectively identified 35 patients with positive neuronal cell surface autoantibody (NMDAR, LGI1, GABABR, Caspr2). Patients were selected based on our previous observational cohort study of patients who tested positive for at least one neuronal cell surface autoantibody in sera, CSF or both in sera and CSF at the Department of Immunology and Biotechnology, Clinical Center, University of Pécs Medical School, Pécs, Hungary, from January 2012 until December 2019 ( 10 ). Of the total 35 patients, 24 were tested in CSF-serum pairs (68.6%), 9 for serum only (25.7%) and 2 for CSF only (5.7%).…”

“…In AE, early introduction of proper therapy is associated with a more favorable outcome, emphasizing the importance of early diagnosis based on clinical symptoms and paraclinical tests at the time of presentation. In our previous single-center study of patients with suspected AE, we found positive autoantibody test results in 60 out of 1,034 patients from 2012 through 2018 as part of a Hungarian nationwide program (10). In that study, long-term (1-5 years) autoantibody testing was conducted in 30 patients with positive autoantibody results, of which 17 remained positive at different time points.…”

Search for Viral Infections in Cerebrospinal Fluid From Patients With Autoimmune Encephalitis

“…In the current study, antineuronal autoantibodies were detected in 8 (4%) out of 200 patients with a clinical diagnosis of encephalitis, which is similar to the proportion reported for the United States (4.2%; based on anti-NMDAR) [ 38 ] and only slightly lower than that reported for Hungary (5.8%; based on anti-NMDAR, anti-LGI1, anti-Caspr2, anti-GABABR, anti-AMPAR1, and anti-AMPAR2) [ 39 ] and the United Kingdom (7.9%; based on anti-VGKC and anti-NMDAR) [ 40 ]. In our study, the vast majority of detected autoantibodies were anti-NMDR (87.5%), which is compatible with other reports; for example, in the study by Saraya et al [ 41 ], anti-NMDAR antibodies were present in 81% of AE cases with detectable neuronal surface antibodies.…”