Application of the APE2-CHN and RITE2-CHN scores for autoimmune seizures and epilepsy in Chinese patients: A retrospective study

Abstract Purpose To assess the performance of the Antibody Prevalence in Chinese Patients with Epilepsy and Encephalopathy (APE2-CHN) and Response to Immunotherapy in Chinese Patients with Epilepsy and Encephalopathy (RITE2-CHN) scores in Chinese patients with epilepsy of unknown etiology. Methods We conducted a retrospective study of selected patients from Xiangya Hospital, Central South University (01/01/2017-02/28/2019) whose serum and/or cerebrospinal fluid (CSF) samples were examined for autoimmune encephalitis antibodies. Of these, patients with diagnostic code of seizure or epilepsy were selected in our study. An APE2-CHN score was assigned to each patient and a RITE2-CHN score was calculated for each patient who received immunotherapy. Receiver-operating characteristic (ROC) curve was used to assess each score. Results 191 patients were enrolled in our study. 36 were identified with specific etiologies. The remaining 155 patients had unknown etiology. Central nervous system-specific antibodies were detected in 76 (49.0 %) patients, after excluding patients with only anti-thyroid peroxidase or glutamic acid decarboxylase antibodies. N-methyl- d -aspartate receptor (NMDAR) antibody (48.7 %, 37/76) was the most common subtype of our sample, followed by γ-aminobutyric acid type B receptor (GABAR) (14.5 %, 11/76). Clinical features including new-onset epilepsy, neuropsychiatric changes, speech disorder, movement disorder and inflammatory CSF profile correlated with positive antibody results. The sensitivity and specificity of APE2-CHN ≥ 5 in predicting the presence of neural-specific autoantibodies in our study were 85.5 % and 58.9 % respectively. In the subset of patients who received immunotherapy (n = 112), sensitivity and specificity of a RITE2 -CHN ≥ 8 in predicting favorable seizure outcome were 98.6 % and 63.2 % respectively. The area under the curve (AUC) of RITE2-CHN was greater than that of RITE2 (Z = 3.196, p  Conclusion The APE2-CHN and RITE2-CHN scores may be useful screening tools in predicting positive antibody findings and prognosis of suspected autoimmune seizures or associated epilepsy in the Chinese population.