Abstract General Information

Title

Neurological syndromes and potential triggers associated with antibodies to neuronal surface antigens

Abstract

Introduction: Autoantibodies against surface neuronal antigens have been associated with specific neurological presentations including autoimmune encephalitis (AE), with variable association with neoplasia and infections.
Objectives: We describe patients with antibodies to cell-surface antigens evaluated in a tertiary center in the South of Brazil.
Results: We identified 16 patients, 15 had subacute and one a progressive disease course. Among patients with subacute onset, 11 (73%) were N-Methyl-D-Aspartate receptor (NMDAr-IgG)+, 3 (20%) were Leucine-rich Glioma-Inactivated-1 (LGI1-IgG)+, and 1 (6%) was positive for Glycine receptor-IgG. The patient with progressive disease course had antibodies against IgLON5. Most patients had disease onset on spring and summer suggesting environmental factors for the development of AE. Also, we observed a different pattern of brain lesions when NMDAr-IgG encephalitis followed herpes encephalitis and a previously not described association with Rosai-Dorfman-Destombe disease.
All patients with encephalopathy met criteria for possible AE and all proven NMDAr-IgG+ met criteria for NMDAr-IgG encephalitis. However, only one LGI1-IgG+ patient fulfilled clinical criteria for limbic encephalitis. All but one received high dose intravenous methylprednisolone, 11 also had intravenous human immunoglobulin and 4 plasma exchange. Furthermore, all patients received second-line immunotherapy. Importantly, most patients improved with immunotherapy, even when initiated later in disease course.
Conclusion: Seasonality, post herpetic autoimmune encephalitis with brain lesions in less typical locations and the association with histiocytosis suggest possible environmental triggers for neurological conditions associated with neuronal surface antigens. Moreover, immunotherapy improved the clinical outcome even when administered later in the disease course.