Antibody prevalence and validation of APE2 and ACES in epilepsy patients with suspected autoimmune origin: A retrospective study.

BACKGROUND

To investigate antibody prevalence and long-term seizure outcomes in epilepsy patients with suspected autoimmune etiology but without any signs of autoimmune encephalitis (AE), and to compare the performance of Antibody Prevalence in Epilepsy and Encephalopathy (APE2) score and Antibodies Contributing to Focal Epilepsy Signs and Symptoms (ACES) score.

METHODS

123 patients diagnosed with epilepsy with possible autoimmune etiology but without any signs of AE at the Second Xiangya Hospital from January 2016 to July 2023 were included, We compared clinical and paraclinical findings in included patients and analyzed the factors influencing long-term seizure outcomes. The APE2 and ACES scores were performed by external validation and sensitivity and specificity analysis.

RESULTS

The antibody positive rate was 16.2 %. In antibody-positive patients, new-onset epilepsy accounted for 60.0 % (n = 12), chronic refractory epilepsy for 15.0 % (n = 3), and status epilepticus (SE) for 25.0 % (n = 5). The ACES score showed better specificity than the APE2 score (87.4 % vs. 74.76 %, P = 0.02). The positive predictive value (PPV) of the ACES score was higher than the APE2 score (48.0 % vs 25.71 %, P = 0.038). Both areas under the curve (AUC) values>0.5 (both P < 0.05). An independent predictor of the favorable outcome of the AE was new-onset epilepsy (P = 0.01).

CONCLUSION

The APE2 and ACES scores are useful screening tools for identifying antibody-positive patients. The ACES score showed higher specificity and PPV for neural antibody positivity compared to the APE2 score. New-onset epilepsy may be associated with long-term epilepsy control outcomes.