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

Autoimmune encephalitis in glial fibrillary acidic protein astrocytopathy

Autoimmune encephalitis due to glial fibrillar acidic protein (GFAP) astrocytopathy is a rare cause of subacute neuropsychiatric changes. In this case, a young patient presented with a viral prodrome and meningismus, followed by progressive encephalopathy and movement disorders over the span of 2 weeks. Due to his clinical trajectory, inflammatory cerebrospinal fluid (CSF) analysis, initial normal brain imaging and negative serum autoimmune encephalopathy panel, his initial diagnosis was presumed viral meningoencephalitis. The recurrence and progression of neuropsychiatric symptoms and myoclonus despite antiviral treatment prompted further investigation, inclusive of testing for CSF autoimmune encephalopathy autoantibodies, yielding a clinically meaningful, positive GFAP autoantibody. This case highlights the importance of appropriately testing both serum and CSF autoantibodies when an autoimmune encephalitic process is considered. Through this case, we review the clinical and radiographic manifestations of GFAP astrocytopathy, alongside notable pearls pertaining to this autoantibody syndrome and its management.

Performance of assessment tools in predicting neural autoantibody positivity in patients with seizures

BACKGROUND

The identification of patients with seizures of unknown etiology who would benefit from neural antibody testing necessitates effective assessment tools. The study aimed to compare the performance of the Antibody Prevalence in Epilepsy and Encephalopathy (APE2) score and the "Obvious" Indications for Neural Antibody Testing in Epilepsy or Seizures (ONES) checklist. We also intended to evaluate whether the performance of the tools varied by types of antibody.

METHODS

Patients diagnosed with epilepsy, seizures, or status epilepticus of unknown etiology at West China Hospital from January 2019 to December 2021 were included. Paired serum/cerebrospinal fluid samples were analyzed for antineuronal and antiglial antibodies. The APE2 score and ONES checklist were applied, and their outcomes were compared to laboratory antibody test results. Possible false positive neuronal antibody results were excluded in sensitivity/specificity analysis reasonably.

RESULTS

A total of 113 antibody-positive and 159 antibody-negative patients were enrolled in sensitivity/specificity analysis. The ONES checklist showed superior sensitivity than APE2 score (95.6 % vs.79.6 %, P < 0.001). Specificity was not statistically different (60.4 % vs. 57.9 %, P = 0.557). The negative predictive value (NPV) of ONES checklist was higher than that of APE2 score (94.8 % vs 80.7 %, P < 0.001). The positive predictive value of them was not statistically different (61.7 % vs 58.8 %, P = 0.557). APE2 score exhibited lower sensitivity for predicting LGI-Abs (52.9 % vs. 80.3 %, P = 0.022) compared to NMDAR-Abs. Similarly, ONES checklist showed lower sensitivity for LGI1-Abs than NMDAR-Abs (82.4 % vs. 100.0 %, P = 0.009).

CONCLUSIONS

The ONES checklist demonstrates superior sensitivity for neural antibody positivity than APE2 score. Specificity of the two assessment tools was similar. ONES checklist performed better NPV than the APE2 score. Both assessment tools performed less well in predicting the presence of LGI1- Abs when compared to NMDAR-Abs.

Validation of different predictive scoring scales in patients with new-onset epileptic seizures or epilepsy related to neuronal surface antibody-mediated autoimmune encephalitis

OBJECTIVE

To validate the different predictive scoring scales in the Chinese population with new-onset epileptic seizures or epilepsy of unknown etiology related to neuronal surface antibody (Ab)-mediated autoimmune encephalitis (AE).

METHODS

We retrospectively reviewed the charts of 174 consecutive patients from October 2018 to December 2022, whose serum and cerebrospinal fluid samples were tested for neuronal surface Abs. The antibody prevalence in epilepsy and encephalopathy (APE2), antibodies contributing to focal epilepsy signs and symptoms (ACES), "obvious" indications for neural antibody testing in epilepsy or seizures (ONES) checklist, and the combinations were used to validate the predictive models of neuronal surface Ab-mediated AE.

RESULTS

A total of 139 patients with new-onset epileptic seizures or epilepsy of unknown etiology were enrolled. Abs were detected in 37 patients (26.6%). The APE2/ONES reflex score had the highest sensitivity (89.2%) and lowest specificity (41.7%). The ACES score had the lowest sensitivity (67.5%) and highest specificity (64.7%). Variations in the performance were observed in the different types of AE. 100% of patients with anti-γ-aminobutyric acid B-B receptor encephalitis were predicted by ONES, APE2/ONES reflex, and ACES/ONES reflex scores. Only 75% of patients with anti-N-methyl-D-aspartate receptor encephalitis were predicted by the APE2/ONES and ACES/ONES reflex scores.

CONCLUSION

Our study was the first to validate various predictive scoring scales in the Chinese cohort of patients with new-onset epileptic seizures or epilepsy of unknown etiology related to neuronal surface Ab-mediated AE. Based upon clinical suspicion, more than one scoring scale should be performed to predict the chance of AE in those patients.

Anti-leucine-rich glioma-inactivated 1 encephalitis: two case reports and a review of the literature

Background

Anti-leucine-rich glioma-inactivated 1 encephalitis is a newly emerged entity characterized by frequent faciobrachial dystonic seizures and a wide spectrum of subacute clinical symptoms such as other seizure types, mood and behavioral changes, and memory loss. We should be aware of differentiating this diagnosis from psychogenic nonepileptic seizures. Mesial temporal, limbic structures, and basal ganglia are the most commonly involved regions.

Case presentation

Here we review the available data, and report on two young Iranian (White) females, 24 and 18 years old, who represent distinct aspects of the disease. The clinical presentation and degree of tissue involvement varies to some extent in the two reported cases. Case 1 had prominent neuropsychiatric symptoms and suffered from frequent faciobrachial dystonic seizures with more significant basal ganglia involvement, whereas case 2 suffered from severe memory decline and dialeptic seizures along with mesial temporal involvement. Symptoms were refractory to usual treatment and prompt immunotherapy was needed.

Conclusions

This disease has a rather favorable outcome provided that treatment is initiated early. However, resistance to first-line treatment, relapses, and long-term complications highlight the need to establish reliable biomarkers to distinguish different subtypes of this disorder to predict the clinical outcome and prognosis, and to refine management.

Factors predicting neuronal surface antibodies in the elderly with new-onset and unknown seizures

Objective

To investigate risk factors of neuronal surface antibodies (NSAbs) and develop a nomogram that could identify patients at the odds of NSAbs among the elderly (aged 60 years or older) with new‐onset seizures of unknown etiology.

Methods

Clinical data for aged ≥60 years diagnosed with new‐onset seizures of unknown etiology were retrospectively reviewed. A nomogram based on multivariable logistic regression was constructed. Model performance of nomogram was evaluated using area under the curve (AUC), calibration curve, decision curve analysis (DCA), and clinical impact curve (CIC). Meanwhile, it was internally validated by bootstrap validation in current cohort.

Results

Of 147 patients included in final analysis, 68 (46.3%) had NSAbs‐mediated encephalitis. Six factors were identified: duration of seizures less than 3 months (OR:14.259; 95% CI: 4.480–45.386), focal‐onset seizures (OR:12.457; 95% CI: 2.710–57.261), psychiatric deficits (OR:10.063; 95% CI: 3.231–31.343), sleep disorders (OR:3.091; 95% CI: 1.011–9.454), hyponatremia (OR:6.252; 95% CI: 1.445–27.043), and medial temporal lobe (MTL) lesions on MRI (OR:4.102; 95% CI: 1.382–12.169). The nomogram had a good discrimination with an AUC of 0.916 and with a corrected AUC of 0.881 after the bootstrapping validation, our model also exhibited a better predictive performance than scoring systems commonly used clinically. Additionally, the calibration curve showed that predicted NSAbs‐positive rates of nomogram were closely aligned with actual observed results. Moreover, the nomogram achieved well on clinical utility by using the DCA and CIC.

Interpretation

Our nomogram may provide a convenient and useful tool for identifying the elderly with new‐onset seizures of unknown etiology who are at risk of NSAbs‐mediated encephalitis, which would allow these patients receive earlier immunotherapy.

Antibody prevalence and immunotherapy response in Chinese patients with epilepsy and encephalopathy scores for patients with different neuronal surface antibodies

Background:

The scale assessment was helpful in predicting the presence of antibodies to autoimmune encephalitis. This study aimed to evaluate the application of antibody prevalence in Chinese patients with epilepsy and encephalopathy (APE2-CHN) and response to immunotherapy in Chinese patients with epilepsy and encephalopathy (RITE2-CHN) for patients with different neuronal surface antibodies.

Methods:

A total of 1365 patients with epileptic seizures as the prominent feature in Xuanwu Hospital, Capital Medical University, from June 2016 to June 2020 were enrolled in our study. Of these, 915 patients with epilepsy of unknown etiology whose serum and/or cerebrospinal fluid samples were examined for autoimmune antibodies were selected. All patients were scored with antibody prevalence in patients with epilepsy and encephalopathy (APE2), response to immunotherapy with epilepsy and encephalopathy (RITE2), APE2-CHN, and RITE2-CHN scores.

Results:

Of the 915 patients, 191 patients were positive for neural-surface specific antibodies (115 N-methyl-D-aspartate receptor (NMDAR) Ab, 47 leucine-rich glioma-inactivated protein 1 (LGI1) Ab, 8 contactin-associated protein 2 (CASPR2) Ab, 4 AMPA2R-Ab, and 11 GABAR-B-Ab; 3 CASPR2-Ab and LGI1-Ab, 2 NMDAR-Ab and CASPR2-Ab, and 1 NMDAR-Ab and myelin-oligodendrocyte glycoprotein [MOG] Ab). The sensitivity and specificity of APE2 ≥4 in predicting the presence of neural-surface specific antibodies in our study were 74.35% and 81.77%, respectively, and the sensitivity and specificity of APE2-CHN ≥4 were 75.92% and 84.53%, respectively. Eight cases had an APE2 score <4 and APE2-CHN score ≥5; all these patients had memory decline as the prominent manifestation. We divided the patients into six groups according to the different antibodies. APE2-CHN scores showed higher sensitivity for the prediction of NMDAR-Ab, but lower sensitivity for LGI1-Ab. A total of 187/191 (97.91%) patients received immunotherapy and 142/191 (74.35%) patients benefited from the treatments. The patients who were positive for LGI1-Ab with RITE2-CHN ≥8 responded well to immunotherapy.

Conclusions:

APE2-CHN had the highest value for predicting the positivity of NMDAR-Ab and RITE2-CHN evaluated the response of immunotherapy for anti-LGI1 encephalitis appropriately. However, RITE2 and RITE2-CHN do not appear to be good predictors of immunotherapy outcomes for patients with specific neuronal-surface antibodies and high APE2-CHN scores are often indicative of a poor response to immunotherapy.

Association between autoimmune encephalitis and epilepsy: Systematic review and meta-analysis

BACKGROUND

Diverse neuronal antibodies are related to autoimmune encephalitis (AE) and AE-related epilepsy. However, the epidemiological characteristics of AE, AE-associated antibodies, and AE-related seizures are still unclear.

AIMS

This research evaluated the relationship between AE, AE-related seizures, and neuronal antibodies, as well as the morbidity of AE with early incidence.

METHODS

The PubMed, Embase, Cochrane, and Web of Science databases were searched. Pooled estimates and 95% confidence intervals (CIs) were calculated using a random-effects model.

RESULTS

Of the 4,869 citations identified, 100 articles were reviewed in full, and 42 subgroups were analyzed. The overall incidence of AE patients with seizures was 42% (95% CI: 0.40-0.44), and among them, the incidence of epilepsy in anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis patients was 73% (95% CI: 0.70-0.77). Subsequently, we found that the prevalence of AE as the cause of epilepsy within the pooled period was 1% (95% CI: 0.01-0.02), while the overall positive rate of neuronal antibodies in epilepsy patients was 4% (95% CI: 0.03-0.05). Additionally, the detection rates of different antibodies among epilepsy patients were as follows: anti-NMDAR, 1%; anti-leucine-rich glioma inactivated 1 (LGI1), 1%; anti-contactin-associated protein-like 2 (CASPR2), 2%.

CONCLUSION

Based on our findings, neuronal antibodies may serve as a bridge to study AE and immune-related epilepsy. To further understand the differences in outcomes following different treatment measures, and to provide more information for public health policy and prevention, more research is needed to improve the accuracy of estimations.