Background: In our previous single-center study of
autoimmune encephalitis (AE) related
autoantibody test results we found positivity in 60 patients out of 1,034 with suspected AE from 2012 through 2018 as part of a Hungarian nationwide program. In our current multicenter retrospective study, we analyzed the clinical characteristics and outcome of AE patients with positive neuronal cell surface
autoantibody test results. Methods: A standard online questionnaire was used to collect demographic and clinical characteristics, laboratory and imaging data,
therapy and prognosis of 30 definitive AE patients in four major clinical centers of the region. Results: In our study, 19 patients were positive for anti-NMDAR (63%), 6 patients (20%) for anti-LGI1, 3 patients for anti-GABABR (10%) and 3 patients for anti-Caspr2 (10%)
autoantibodies. Most common
prodromal symptoms were
fever or flu-like symptoms (10/30, 33%). Main clinical features included psychiatric symptoms (83%), epileptic
seizures (73%) and
memory loss (50%). 19 patients (63%) presented with signs of central nervous system (CNS)
inflammation, which occurred more frequently in elder individuals (p = 0.024), although no significant differences were observed in sex,
tumor association, time to diagnosis, prognosis and
immunotherapy compared to AE patients without CNS inflammatory markers.
Anti-NMDAR encephalitis patients were in more severe condition at the disease onset (p = 0.028), although no significant correlation between mRS score, age, sex and
immunotherapy was found. 27% of patients (n = 8) with associated
tumors had worse outcome (p = 0.045) than patients without
tumor. In most cases,
immunotherapy led to clinical improvement of AE patients (80%) who achieved a good outcome (mRS ≤ 2; median follow-up 33 months). Conclusion: Our study confirms previous publications describing characteristics of AE patients, however, differences were observed in
anti-NMDAR encephalitis that showed no association with
ovarian teratoma and occurred more frequently among young males. One-third of AE patients lacked signs of
inflammation in both CSF and brain MRI, which emphasizes the importance of clinical symptoms and
autoantibody testing in diagnostic workflow for early introduction of
immunotherapy, which can lead to favorable outcome in AE patients.